CHAPTER 7 From: Rosemary Lubinski (Ed.) Dementia and Communication Philadelphia: B.C. Decker, Inc. 1991 and San Diego, California: Singular Publishing Group. 1995

Language Changes in Dementia oE the Alzheimer Type DANIEL KEMPlER, Ph.D.

In 1907 Alzheimer described a demroted woman wbo "frequendy used petplexing phrases ... some paraphrastic expressions" (milk-pollrer instead of cup) and suffered from a significantlanguage com­prchen.<ion deficit.' Language disorders continue to be one of the most obvious and well-studied symptoms of dementia and are particularly pronounced in dementia of the A1zbeimer type (OAT). The incidence oflanguage impainnent in dementia is estimated to be between 88 and 95 percent, and is cI05e to 100 percent in OAT."·1l' This chapter will (1) describe the language disorder associated with various scages of OAT; (2) review several prominent rcseatch questions about the ori­gin and intetpretation of these language disorden; (3) discuss clinical implications of this research for diagnosis and treatment of language disorders in OAT; and (4) sketch out imponant areas of fu­ture research.

Overview of Language in OAT

The many descriptions of language in demen­tia that have appeared over the past decade con­flOIl aod expaod Alzheimer'. original observation of word.finding deficits, paraphasias. and compre­hension impainnent:3.9·~·64,9 1.106 , 10l It should be noted that Alzheimer patients havc litde or no petiphecal weakness or incoordination, and have no obvious motor .peech deficits: control of pho­nation. articulation. and resonance remains intact until the latest stages. In addition, the ability to anange words into grommatical sentences appears ro be relarivcly spared throughout the course of the disease. The communication problems of this

98

population are largely confmed to the two ";p~Cts oflanguage: lexicon (word knowledge) and prag­matics, the use of contexrually appropriate lan­guage. As might be expeaed with a degenerative process, the deficits change over time, and each phase of the disease is charactetized by a distina profile of language deficits.·

EARLY ·STAGE DEFICITS

The earliest language deficit observed in OAT is anomia. OAT patients have difficulty coming up with words in StrUctured tasks such as word­list generation (e.g., name as many animals as you can) as well as in elicited narratives aod .pontaoe. OU! conversation.72,II04 ,101 Semantically empty words (e.g. , thing, stuff, do) are scattered through. out the DAT patient's utterances in place of can· tent words, thereby maintaining fluency and sacrificing informational content. Language com­prehension fur simple. StIIlCtIllCd, concrete mareri· al appears intaa during these early stage •. However, comptebension of abstraa language that docs not rely on maning of .ingle words in syn. taaic srruaurcs, but rather requires inference (e.g., Rome wasn't built in a day; She took a sudden tum fur the worse), is poor even in the earliest stages ofDAT." ·" Also, early on, parients have a difficult time generating spontaoeous laoguage via writing, although the mechanics of writing and

"ThroughOUt this chapter. the rums "earlylinild:' "moder­.~." and .. .....wlaa: .. will be wed to dcscribc: the DOD­

dis=tt saga associated with th., to I' yar 00""" ofDA1; which begins with mild cogo.iri:~ symptoms and eDds in a. pcamDt vegetativt state.

.;.

reading remair patientS can co: cial situations, fullow comple digress or repc patient is ofre· language defi, by the end of

A sample Kempler) of 1

Boston ~iogo< illustrates sam Iy the repetitic es), empty WOI

(single pencil: pronouns (M) awareness of t here .. . ). Des able to descril in the picture

I want you ju piaurc.

Momm.a.'sw; jam or jelly litde fella's , Momma's w:

Good. Any,

Well, the o·

FiJl1UC7.1 ( H, !Capl'" . ordm. Phil.

LANGUAGE CHANGES IN DEMENTIA OF TIlE AIZHEIMER TYPE 99

reading remoin intact.30·"J13 At this point, DAT patients can communicate sufficiendy lOr most s0-

cial situations, although they may not be able to mllow complex C01lVl:mttions and may tend to digress or repeat themselves. Although the DAT patient is often initially aware of his or her own language deficits, this awareness appc"" to wane by the end of the early phase.

A sample of a narrative description (from Kempler) of the cookie theft piccurc from The Boston Diagnostic Aphasia m.min.tion (Fig. 7.1) illustrates some of these points." Note particular· Iy the repctition of ideas (Momma's washing dish· es), empry words (somebody's doing), paraphasias (single pencil), difficulry with appropriate usc of pronouns (My teacher ... they ... ), and a hint of awareness of the difficulry (My teacher should be here,,· .. ). Despite these difficulties, this patient is able to describe the major events and participants in the pictUre.

Examiner

I want you just to tell me what's going on in this picture.

Alzheimer patient

Momma's washing dishes and childtcn are taking jam or jelly or something from the jar, and the lilde fella's about ready to fallon the floor. And Momma's washing dishes.

Examiner

Good. Anything else?

Alzheimer patient

Well, the overflow of the water.

Figure 7.1 Cookie theft picrure. Reprinted from Goodglass H, Kaplan E. The assessment of a.plwia and related dis­o[d~. Philadelphia: Lea & Fcbigcr. 1972.

Examiner

That's tight. What about that?

Alzheimer patient

That's the overrun of, I said, of the dish ..... ter on the floor.

Examiner

Why do you think that's happening?

Alzheimer patient

You can sec her mouth is open and she is 'talking, and not paying any attention. That's about all I can think of. Or somebody's going, one of the chil­dtcn arc about to climb, or something lila: these one, these ones. My teacher should be here and they'd throw me out the door.

Examiner

Oh, you're doing a good job. What about here (point to girl taking cookie)?

AI.beirner patient

The lime one? She's asking her mother lOr a cookie. It's ""ry easy. They're very, uh, well done, you know, by a single, uh, jar, no, I mean single pencil, whatever they're using.

Examiner

Great.

MODERATE-STAGE DEFICITS

By the moderate scages of DAT, patients be· gin to have more difficulty with both production and comprehension of language. In producrion, anomia WOt5Cns and wom.finding deficits arc made more obvious by copious substitutions of empty words aod circumlocutions lOr infOrmation· bearing nouns and verbs. The utterances of moderate DAT patients arc often difficult to mllow because of pragmatic deficits, including poor topic main· tenance and poor use of pronouns. 12,".1D<l,l1.f,128 It is somewhat surprising that in the context of these pronounced discourse: deficits, certain other dis­course skills. such as tum-taking in conversation, remoin undiscorbed. Comprehension lOr complex material (e.g., sequential instructions) is often im· paired by this stage.' Although the mechanics of reading aloud and wtiring remain uniropaired, deficits in producing well·mrmed coherent writ· ing and reading lOr comprehension parallel problems observed in auditory-spoken Ian. goage.,.,..l1 In the moderate scagcs, DAT patients'

100 LANGUAGE CHANGES AND DBMENTIA

con>elS2tions become difficult to fullow, and the patients may withdraw slightly from social situa­tions in which communication demands may occur, They often appear unaware of their com­municative deficits at this point. ,

The more severe language deficits associated .,ith this srag<: are illustrated by another narrative d=ription of the coolcie theft pictl.=6. At thi.' point, the empty words and paraphasias render the narrative l2rgely un.intetpret2ble. The patient's use of desctiptive phtases that hav<: no direct relation­,hip to the pictUte (canned goods, politicolly well known) elicit several requests fur clarification from the aaminer. However, the patient appears unable [0 clarify the narrative. Notice the preservation of sentence structure, including some syntactic com~ plaities (e.g., "apparently because he has a ten­

. dency to be hlliog").

EDminer

I jUst W2Ilt you to describe what's going on in this pictUte. Tell me what's going on here.

Alzheimer patient

Ibis picture incorporates a certain amount of com­ing and going, and cheating, and doing the things in the world ... [pause J ... planning some fur uh money on the floor, not -worrying a.bout it. Fall~ ing over onto the ground.

EDm.i.net

Speak a little louder.

Alzheimer patient

Oh that he has the abilicy to-she has the ability [0 change the timing aod then and thea the wind is blowing in the wind_ blowing in the floor. Wind is blowing on the canned goods.

Examiner

The wind is blowing 00 the canned goods?

Alzheimer patient

Yeah, splattering.

Examiner

What's she doing (point to woman at sink)?

Alzheimer patient

5he is not only losing, doings, washing her pay­plare there, but also being careful of the child, • pparently because he has a tendeocy to be fall­ing this, slipping. And chen chere's a child slip­ping again, or more normally.

More normally?

Alzheimer patient

Yeah, politically well lcnown.

Enmiaer

Politically welllcnown. What's going on over here (point to Stool)?

Alzheimer patient

Well, it seems to be that they're crying to, filling up and ideal of it inside there ... (pause) . .. chings that we eat ... play with and maybe get hurt. Candy Ot something.

LATE·STAGE DEFICITS

By the latet stages of the disease, verbal produetion becomes unintetprerable because of paraphasias (word and sound substitutions) and lack of coherence. Ute in the CO""" of the disease, dysarthria may impair speech intelligibility. EV<:D­tually, the patients manifest echolalia (repetition of others), palilalia (repetition of selt), and mute­ness. At this point. comprehension is impaired in all modalities, even fur single words, and the pa­tients are no longet successfully participatiog in s0-

cial interaction through language or any other communicative modalities.

INTERPRETING LANGUAGE DEFICITS IN OAT

A fi:w important obsetv.ltions about language in DAT must be mentioned befure proceeding. First, there are language impairments that do not occur in OAT. fur instance, there arc: no repons o( agrammatism of the type associated with Broca's aphasia in DAT. There are also no reportS of dis­proportionate difficulty with repetition: in fact, unbidden repetition in the furm of echolalia and palilalia is one of the charactetistics of late-Stage DAT. And finally, there ate no d=riptions of phonologic disturbance; that is, D.AT patients ap­parendy do not violate the phonoraetic constraints. of their nati.., language (using nonnative sounds or sound tombinations) or make etrors in prosodic aspects of language.",..·127 We emerge with 'a pic­ture of language breakdown in DAT that is quite specific S<:mantic and pragmatic deficits ate matla:d; motphosynraetic deficits are rare, and phonologic deficits are rarer still .

Second, many author.; have attempted to d=ribe the language disturbance of DAT by com-

parison, sian, fu, Wemido avoided DAT as a1thougl any lan, with SY' mary. OJ

rom.Tl Althou~ typical ' paraph, languag ed but impairr "aphasi apply i dctcCOJ order ~ concon: the [eo tifying Sla ma)

that th that th becaus genera cd wit. changi The Ia similaI ways, (see ,,; must (ansie ttt'OlttT.

F j

F functi impai defici·

estar As", origi. mue.:.

was : <:vide

LANGUAGE CHANGES IN DEMENTIA OF THE Al2HEIMER TYPE 101

puison wi<h fuaI aphasia, arriving at <he conclu­sion, fur example, that uanscorucal sensory 2lld Wemicke's aphasias ate frequent in OAT.3'" I ha.., avoided classifying <he l2llguage disturbance of DAT as 211 "aphasia" fur two reasons. Fint, although the term aphasia can be used to describe any l2llguage disorder, it has become associated with syndromes where l2llguage disorder is pri­mary, or signific211dy worse <han any other symp­tom. This is not true fur <he DAT population. AI<hough <he l2llguage nfOAT does manif<sr some typical aphasic symptoms (anomia, semantic paraphasias, and comprehension deficits), <he l2llguage disorder ofDAT is not primary or isolat­ed but ra<her penists among other intellectUal impairments. I concur with Holland et al <hat "aphasia ... is a difficult, if not glib, diagnosis to apply in such cases. In the context of general deterioration nf intellectUal function, language dis­order typically becomes intertwined with so many concomitant nc:urobe:havioral changes as to [cnder the term aphasia almost uselc:ss."" Second, iden­tifying the language disotder of DAT as 211 apha­sia may imply (by association with fucal aphasias) that <here is a static qualiry to <he disorder 2lld that there is the possibiliry of recovery. Howe..:r, because OAT is unrelentingly progressive and de­generative, so are the language: disorders associat­ed with it. The l211guage deficits ate continually changing and recovery has ne..:r been observed. The language patterns of fucal aphasias may be similar to the language disorder of OAT in some _ys, but also differ in many important respects

. (see also Ulatowska et al fur discussion).!28 This must be remembered when planning research, considering diagnoses. or contemplating treatment.

Research: Dissociations and Associations

Ibur areas of cuttent reseuch on 1211guage functions in OAT will be reviewed here: semantic impairment, syntactic preservation. pragmatic deficits, and brain-bebavior relationships.

SEMANTIC IMPAIRMENT IN OAT

Anomia (word-finding difficulty) is the eatli­est and most common l2llguage symptom ofDAT. As such, accurate description of <he symptoms and origins of anomia in DAT has been the subjeer of much research.

The earliest explanation fur anomia in DAT was a visual perceptual deficit. S...,ra1 pieces of evidentt support this claim: natning by OAT

patient> is impro..:d if the patients are allowed additional sensory cues (e.g., touching the ob­jeer)! OAT patients often use the natOe of an object that is visually similar to the stimulus in tasks of confrontation naming (e.g., calling an anchor a "hatorner" );11> these patients are better able to name objects that ate very f2miIiar and thus require less visual recognition (e.g., body parts) than less &miliat objects. n Kirshner, Webb, and Kelly systematically investigared the effect of visual perception on naming by comparing object QatD­

ing of actual objects, photographs, line drawings, and visually degraded drawings.79 Their results in­dicated that perceptual difficulty did playa sig­nificant role in anomia ofDAT patient>. Howe..:r, problems with this <heoty ate obvious: Fint, it does nOt explain why DAT patients ate anomic in spon­taneous conversation where no visual perceprual skills come intO play," and, second, the theory is not consistent with the finding that most verbal paraphasias in DAT ate substitutions of semanti­cally (not visually) related objm names. 1UO·70 fur­ther evidence against the visual perceptual argument comes from recent studies that demon .. strate that OAT patients with significant anomia perfurm relatively well on independent measures of visual form discrimination,lO.61

The search fur clues into the origin of anomia in DAT has continued beyond the visual percep­roal theory and has fucused on specifically semantic deficits, that is, problems in (1) impaired lexical access and (2) detetioration of lexical representa­tions. There is some evidence that underlying lexi­cal representations are intact and that naming difficulties arise from a problem in lexical access or retrieval fur verbal production. Evidence sup­potting this view includes the findings that:

1. In tasks of confrontation naming, OAT patients can often give a related name or circumlocution, suggesting that they know much about the meaning of the word but cannot fmd <he exact natae (e.g., "rutter" fur saw; " this is fur your eyes" fur.­glasses).!L"

2. Comprehension of words is generally superior to ptoduction of the same words. indicating that the underlying represen­tation can often be accessed in a passive co~prehc:nsion task when the: name can .. not be generated or retrieved on demand."

3. OAT patients can utilize phonemic rues to belp tdri..., words, indicating again that <he infurmation is there but cannot be e2Sily rcuicved.1l·101

4. There have been se..:raI reporu ofDAT pa­tients using gesture to indicate the func­rion of an objeer that they could not name, suggesting that the deficit is limited to

102 LANGUAGE CHANGES AND DEMENTIA

laical retrieval and may not affi:ce basic symbolic representations presumed to underlie both gestun! and language productions.32.10,119

Another source of suppon ror this view comes from semantic priming data that indicate that sub­conscious semantic associations may be intact in OAT. ".100.101 The findings of semantic priming in OAT are perhaps the most curlow of all and re­quire some explication. Seven! reseanhers have demonstrated that, lila: normal subjects, OAT patienrs react &ster in laical decision roernats (i.e., is it a word?) if the target word (e.g., nurse) is preceded by a related word (e.g., doceor) than if it is preceded by an unrelated word (e.g., shoe).1111

- Initiilly, this was taken to indicate that underlying semantic associations were intact and that the ano­mia was not the result of permanent underlying semantic problems but must be an effect of im­paired laical access. Howew:r, findings from other studies have not always confinncd intact semantic priming in OAI For instance, Smith er al round that OAT patients did not exhibit any effect of priming,12' and Alben and Milberg round seman­tic priming only in a subset of OAT patients. 2

Seven! other srudies have round char DAT patients . actUally show greater priming effects than control subjects.2O·" In addition, Chenkow et al found that hyperprirning in OAT was associated specifi­cally with words that were shown to be semanti­cally degraded on a variery of other tasks (e.g., responses to probe questions)."

In summary, the positive results of the early priming studies suggested intact semmtic representations in DAT, but rollow-up srudies have demonstrated abnormal responses to semantic priming including (1) lack of priming effectS; (2) subgroup di.ffi:rences; and (3) hyperpriming. Pethaps most interesting, the finding of hyper­priming appears co coincide with tkgrrzded seman­tic representations ror particular words and has been used to suppon the theory that DAT patients suffer from disrupted semantic teprescntacioas.]O It is to this possibiliry that "" now turn.

Perhaps the first convincing evidence fur rhe proposal that anomill in DAT is a refleenon of impaired semantic representations W2S presenred in a case stUdy. n, Through a variety of memodol­ogies to =mine laical knowledge (e.g., narning, ..,rbal, and nonverbal match to sample), Schwanz et aI were able to attribute the naming errors (e.g., calJing a dog a "cat") to an erosion of rcfi:rential boundaries. This finding has been supponed by observ:ations that many OAT naming enors are witbin-caregory errors (e.g., "truck" fur car),. find­ing consistent with a deficit in the underlying conceprual and semantic representations.'· Addi­tional evidence that representations within seman­tic categoties may be degraded in DAT comes from

studies that have demonstrated coltespondence be­tween narning and word comprehension errors and consistency of response across several testing ses· sions.20.)4,71.89 These findings are consonant with the notion of central degeneration of laical representation. which would be expected to per­manenrly affect both comprehension and produc­tion of specific items. Although there is a growing consensus that DAT patients do exhibit evidence of impaired laical representations. there are only genen! proposab about the rype of disruption that occurs within the laical representation. For in­stance, Schwaru et aI discwsed the problem as a "brealcdown in the structUre of the underlying categories:'n, while Chcnkow et al referred to the "degraded" semantic represcDtarions,20 and Grober et aI proposed that the representations are disorganized." SpeciHc models of the = na­ture of the representational deficit will undoubt­edly be the subject of future research.

In summary, word-finding problems are among the earliest and most obvious symptoms of DAT, but the underlying cause(s) of anomill remain disputed. 9•11•30 Although most researchers concur that the origins are primarily cognitive, there is still considerable disagreement about whether the deficit is best characterized as a processing limita­tion that interferes with laical access or as a deficit in the underlying lexical representations. Funher, because OAT patients have significant problems in attention and memory. correlations between per­formance on tests of attention and tests of nam­ing have led other researchers to attribute anomill in DAT to problems in attention and concentra· tion. 101.120 This review of recent research. suggests that the anomi>. of OAT is heterogeneow and that no single explanation can account for the naming perfurmance of any group of DAT patients. Visual perception, attention, lexical access, and deterio­ration of laical representations all playa role in anomia of DAT. It is likely that individual patients may be more or less affocted by one particular deficit and that groups of OAT patients fall inro distinct subgroups demonstrating anomia ror different reasons. '1

SYNTACTIC ABILITIES IN OAT

Although most descriptions of language in DAT have obsetved that syntactic abiliry appears intact, fi:w c:xperimenn! investigations have ad­dressed this question. The earliest detailed inves­tigation of this phenomenon W25 Whitaker's description of a severely demented patienr who spontaneously corrected agrammatic but not semantically anomalous sentences in repetition (e.g., "Thet< are cwo bOok on the table" was repeated as "There are few books on the table"

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s

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LANGUAGE CHANGES IN DEMENTIA OF lHE AlZHEIMER TYPI! 103

while ''1he book is "'ty happy" 'ftS n:pcated ",r­batim). U1 This finding 'ftS taken to indicate that gwnmatical compctcD<C was selccthdy pn:setV<:d and, therc:fun:, must be somehow autonomous from the n:st of cognition. Schwanz, Marin. and Saffian also =mined a single subject in detail and mund that their patient. despite seV<:n:ly dcrcrio­rated semantic ability. was able to manipulate syn­tactic = (e.g .• tum an actiV<: in a p2SSive), again supporting the notion that the syntactic processor may in f2ct be special and neutopsycho­logically insulated from cognitive and cortical de­generation seen in OAT.1l9 Sub.equcnt attempts to address this issue have mund OAT patients to produce syntactically complex and _ll-mrmed sentences in spont2.Dcous speech as well. ".71

Kempler et al ew.!uated the spontaneous speech of 10 OAT patients and 10 nonna! controls. and demonstrated that che spontaneous speech of OAT patients con rained fi:w syntactic errots and many lexical semantic errors.1l More important, the range and frequency of sentence types (e.g .• relam., ch.uscs. questions. and adverbial clauses) were almost identical to che nonna! controls (rank otdercoadation. p = .9833; p < .0000), and chere was no diffi:rence be.-en che OAT patients and the conuol population on a measure of struCtural complexity. A second stUdy reported by Kempler et al furcher confirmed che relative preservation of syntactic competence through iil dictation task adapted from Schwanz et al. )1,119 Twenty OAT pa­tients and 20 normal controls were asked to write shoit phrases containing a homophone, a word chat has one pronunciation (si) but two spellings (sealsee) and two meanings (body of water/visual perception). In each case, che words can be disam­biguated by semaotic cues (a word with a similar meaning such as "lake·sca," u'OOR4SeC") or a syn­tacic cue (a word with little semantic content but definite syntactic restrictions on what can follow such as "Ihe sea. "I see"). The OAT patients made significantly more errors chan did che concrol sub­jects with both types of cues. and significantly more errors with the semantic cues than with the syn· tactic cues, suggesting that the disease does seem to spare the ability to usc syntactic (more chan semantic) knowledge in a wtiting task of this sort.

Comprehension of syntax has not proven to be 25 consistendy intact as production of syntax. Sch,,'artZ. Marin. aod Saffran ll9 demonstrated intact comprehension of four syntactic forms (acti·...,. passive. preposition, and comparative ad­jectives) by a single demented patient. However. Eme:y. using che Test of Syntactic Complexity" aod the Chomsky '!est of SyntaX, 21 has document­ed sym:actic comprehension deficits in a larger sample of 20 OAT subjects." These tests ew.!uate che patient's comprehension of syntax by eliciting verbal responses to grammatically complex stimuli

(e.g .• "The dog_ birrcn by the ear; which anima1 bit the ocher and which was bitten?") or gestucal responses to similarly complex auditoty stimuli (e.g .• "Mickey tells Donald to hop up and down; make him hop.") In contrast to Schwanz et ai's fmdings of preserved compn:hension of grammat­ically complex strUctUres. Emery mund significant impairment in OAT patientS' ability to process syn­tactically complex. grammatical constrUctions.

It is not simple to ew.!uate the intactness of grammatical knowledge with conflicting data: intact production ",rsus impaired comprehension. Uneven profiles rL grammatical abilities across tasks have been obse""d in other mrms of brain damage, and explanations mr chese dissociations fall into two broad categories:" those that postu­late modality specific blockage (e.g .• a motor out­put problem in the case of preserved comprehension and impaired production in Broca', aphasia) and chose that postulate selectively im­paired independent processors mt diff<rent gram­matical tasks.I3" The dissociation between intaCt syntactic production and impaired comprehension in OAT may have anocher explaoation: Overall memoty and processing demands may have a£Iect­ed perfurmance on comprehension casks more chan production casks. Emety argued against this expla­nation. citing the finding that DAT patients were able to repeal all of the stimuli accutately even chough they could not comprehend chem. suggest­ing that the problem is not necessarily one of memory but more likely the n:suIt of deterioration of complex syntactic processing." A recent stUdy by Smich investigated che relative contribution of syntactic knowledge and general processing de­mands to performance on testS of syntactic com· prehension.12l Smich presented a gtOUp of 22 OAT patientS with a picture-pointing task to as­sess comprehension of reciproals and reflexives, systematically varying elements that contribute to processing difficulty aod syntactic complexiry (e.g .. two- versus four-choice response 2.tf'ays and differ· eot position of the reflexive in the sentence). The resulrs demonstrated that bach OAT patientS and controls showed perfonnance decrements as task difficulty increased, and boch groups showed a similar pattern of errors. These results were inter­preted to indicate that comprehension deficits in OAT may be attributed to general processing limi­tations aod not to a specifically synractic deficit.

We are left wich che fmding chat despite severe lexical semaotic deficits. OAT patients retain grammatical abiliry in (1) spontaneous utterance production; (2) tasks of sentence comprehension; and (3) writing to dictation. This dissociation be­tween syntaetic and semantic abilities has been ex­plained by recourse to the notion of automati­city.66.1l.Ul Syntactic strUCWtr has the characteris­tics of a domain that could be run by an automat-

--

104 LANGUAGE CHANGES AND DEMENTIA

ic processor: The number of syn=ric 5UUcru",s is limited, ond each instance is frequenL Syntactic ability appear.; to fit the characteristics of automa­ticity insofar 2S syntactic processes "operate in­dependendy of the subje",:'s control. .. do not requite attention ... and they do not use up sbort­term capacity.".l1 Lexical selection, on the other hand, CaD be characterized as a system opera",d by a controlled pr.ocessor: There is a large range of alternatives fur each occurrence, and each wotd is relatively iofrequent when compared with each syntactic smicturc. On the basis of this dichotomy. it has been suggested that automatic functions may be p",scrved in DAT," and that grammatical abil-

_ ity may be JUSt one instance of 2Il automatic cog­hitive open.tion being preserved in the context of general cognitive decline."

The ~ch on syn=ric abilities in DAT has more general implications fut theoties of mental functions. Dissociations between mental functions reveal the cognitive and neurologic independence of these abilities and have led scientists to many of the impottant discoveties of hemisphetic specialization 2.lld loalizwon of function. 16,44J30

Age-old arguments about the relative interdepen­dence: of cognitive functions continue:: today under the terms modularity",)9 and connectiorusm. l17

Although the research in these areas increasingly relies on mathematic modds and computational solutions. data from abnormal populations still provide supporting evidence fur the ",Iative inter­dependence of variow cognitive abilities. As such, syntactic sparing in DAT demonstrates that syn­tactic ability C21l function in the adult without sup­port from semantic and other cognitive or conceptual operations.

PRAGMATICS: UNEXPLAINED DEFICITS

Pragmatics, the study of language use in COD­

teXt, includes a large variety of language skills from rum-taking to approptiate topic introduction and overall discourse structure. all generally considered within the context of interpersonal interaction. In its broadest sense. pragmatics covers everything relevant to communication beyond sentence suuc­ture and linguistic semantics, often including ex­tralinguistic fi:arures of facial exptession and body language. In comparison with other longuage func­tions, we know least about pragmatic disturbance in OAT. Because very little research has been report­ed on the pragmatic abilities of DAT patients. much of what can be said about this area is anec­dotal and in need of confirmation (see Chapter 8 fur more derail on discourse and dementia).

Some aspects of discotme are clearly preserved in DAT through the mild and moderate stages: DAT patients tala: conw:rsational turns when ap­propriate and often produce socially ritualized parts of the conversations (e.g .• greetings and leave takings) with apptopriate timing. affect. and lin­guistic structure. These observations indicate that DAT patients are able to adhere to basic 5UUctures and obey pragmatic rules of some verbal intet­actions. Howevet, there are also subtle pragmatic problems early on. such as a tendency to repeat things unnecessarily and to lose the topic of the conversation. At this stage the deficits are often attributed to failing artention and memory.

By the moderate stages of the disease, the dis­coutse of DAT patients often becomes irrelevant. laclting in topical cohesion, and gtossly insensitive to the needs of the listencr. I2.5),IOuI4.ua Hutchin­son aod Jensen analyzed conversations of 10 de­mentia patients (aod 5 healthy controls) ond mund sevetal pragmatic abnormalities'including: (1) pa­tienrs produced fewer utterances and more rums, ",suiting in fewet urterances per tum; (2) patients produced more directives (utterances aimed at getting the listener to do something. such as explain or clarify); (3) patients ptoduced more utterances for which DO intent could be deter­mined; aod (4) patients initiated more new topics. often inappropriately." Further investigations of discourse in DAT have confrrmed and expanded Hutchinson and Jensen's original findings.""'" Particular attention has fucused on the production of decreased infurmation content and lack of co­herence. Ripich and Terrell suggested that the per­ception of conversational incoherence on the pm of DAT patients might be attributed to "absent pieces of discourse that sbould ptovide relation­ships between preceding texts and that which ful­lows."'" Ulatowska et al fuund that decreased infotmativeness could be traced back. at least in part. to problems in reference such as the overuse of demonstratives (e.g., here, there) and exophor­iC reference (e.g.. this without a clear an­tecedent).128

Still unaddressed are the underlying causes of the discourse problems in DAT. These deficits could be secondary to existing and documented problems such as aoomia, decreased artention, and poor memoty. On the other hand. they may tesult from more genetal pragmatic deficits that impair the ability of the OAT patient to take the per­spective of the listenet and to judge what infur­mation is impomnt in the p'UticuIar discoursc. Funher, DAT may selectively affect ,pecific dis­course knowledge. fur instance, cenain discourses are structuted largely on the basis of internalized sctipts-rules about what type of infurmation is

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LANGUAGE CHANGEs IN DEMENTIA OF lHE AlZHEIMER TYPE 105

Dlentioned lim, second, and so on. This knowl­edge of aarmive SUpelSl1Ucture, much lit..: inter­nal represenlation of lexical items, could dcrctiorate and cause discounc bteakdown. Any of rhese deficilS could creale incoherent conver­satiOJl5.

One investigation specifically looked fur as­sociations between discOUISC impainnenu and o!her language ddicirs fur a clue to !he underlying cause of the discOUISC problems. Nicholas er aI compared DAT parienlS' perfurmance on rhe Boston Naming Test (BN1,)" with c1emenrs of CDlpry spco:h in nanarive descriptions of!he cookie rheft picture," in an allempt to cvaluate rhe claim rhat discOUISC incoherence could be ataibuI­cd to anomia .... The aurhors repolled a signifi­cant negative conclation between rhe score ofDAT pati<!l1S on rhe Boston Naming Test and rhe use of indefinite te:nns (e.g" "thing" and "stuff") and a significant positive colIClation bc:twecn the BNT and rhe production of "conlent elements" (i.e., references to characte.rs and activities, in cookie rheft stoties), They concluded that rhe naming deficil did not underlie rhe emptiness of discOUISC, presumably because many orher measures of dis­course emptiness (e.g., paraphasias, pronouns wirh antttedena, and deiet:ic terms) did not correlale wirh rhe BNT scores. The data, however, also sug­gest that at 1 ... 1 some of the referential problems that malee discourse difficult to fullow might be a result of anomia. That is, to the degree to which patients ue anomie and subStitute or omit con­tent elements, rheir discourse will be difficult to ;nte:rpret. Nicholas et al are undoubtedly COlICet in their general conclusion that the anomia da~J not ,,,,derli. the discOUISC deficilS, but it is un­arguable rhat rhe anomia does contrihute to rhe observed discourse deficilS.

Funher description of the discourse problems in DAT can be used to delineate which aspeclS of pragmatics are related to which aspects of linguistic and nonlioguistic cognition. fur instance, it can be hypothesized that some aspects of discourse (e,g., topic maintenance) depend on recent mem­ory but may be independent of lexical and mor­phosynr:accic function. Thercfure, we could predict rhat these fi:atures would cOlICla,te wirh decreased memory and be deficient early on in the disease. Conversely, some aspeas of discourse arc mote structural (e.g., the use of definite and indefinire articles to signal new versus old topics) and may be retained with morphosyntactic abilities. Other aspects of pragmatics may be unrelated to either memory or morphosynrax (e.g" politeness and usc of speech registers) and thercfure should not COIIC­late wirh either. At this rime, these arc only con­j= to be investigared in the future. In

snmmary, although little research has been repolI­cd to date:, OAT is a lik.:ly plate to start identify­ing the cognitive bases of pragmatic knowledge.

BRAIN-BEHAVIOR RELATIONSHIPS

Any neurogenic language disorder provides the opportuniry to learn more ahout the language, the brain, and the relationship between the two. By correlating language disturbance with various types and locations of brain lesions, we have learned a great deal about the newal representa­tion (iateralization and localization) of lan­guage."',. A1rhough the language and neuro­parhologic change. associated with OAT arc not as fuca! and specific as in cases of cerebral vascular accident (CVA), neither are they global or diffuse. fur instance, we have seen that language changes affect semantics and pragmatics prcft:rcntially but leave grammatical and phonologic abilities rela' ti..,ly spared. Likewise, the neurologic picture is multifucal: Excessive numbers of neurofibrillary tangles, plaques. neuronal loss, gliosis, and amyloid angiopathy arc fuund in association cor­tex and in rhe limbic system, but the primary mo­tor and sensory areas arc characteristically spared. 2),29

There arc both direct and indirect methods of investigating the neurologic bases of language dcficilS in OAT. Direct observation of ncuroparhol­ogy is possible only through brain biopsy or au­topsy. Because of the time course of rhe disease, direct histologically dcri..,d clinicopathologic corre­lations arc difficult to specify in OAT; the distri­bution of plaques and tangles at posrmollem can tell you little about rhe relationship between the brain and language performance at the point of interest some years earlier. Noncrheless, grossly spared versus grossly parhologic areas of the brain correlate with what is known about behavior in OAT and contribute to our theories of brun func­tion. Chui reviewed clinicopathologic correlations in OAT and associated the fluent speech produc- -:: cion ofDAT with sparing of the primary moror and sensory COrtex. while the impaired semantics -was associated wirh deteriorated temporal-parietal association cOrtoe:.23 Clinicopathologic correla­tions, rhen, suggest rhat exptessive fluency and syn­",die ability may be subscrv<:d by primary motor and sensory 2Iea.s in the anterior portions of the cerebtal hemispheres, while semanric abilities de­pend on temporal and parietal association cona:. By inference, this strong association between fun­damentallinguistic and basic sensorimotor abili­ties lends SUpPOII to theories of brain function that

106 LANGUAGE CHANGES AND DEMEN11A

ha.., st=d the functional and even evolution­ary connections between neural cQauol of motor and sequencing skills and the specialized linguis­tic capacity of man's left hemisphere, 71

Noninvasive, indirea measurements ofb;ain structure and function ha"" \he distinCt advantage of allowing comparison ofbtain stni= and func­tion at or near the time of language cwIuation. In vivo measures can be divided intO t'W!> general cate«ories: those showing brain ,rNeWrc­computed tomography (CT) and magnetic resonance imaging (MRI}-and those showing brain function-decuoencephalogeam (EEG), positron emission tomography (PET), and single photon scanning (SPEC!'). Studies of structural ab-

- normality in OAT have been relatively unreveal­. ing. OAT patients tend to hav.: enlarged ventricles and widened cortical sulci on CT and MRI, and these changes generally do not condare with the presence or """rity of dementia. G.'", Although this is essentially a negative resuit, it highlights the interesting fact that structural abnormality on CT and MRl ~ans is in no 'Way prerequisite to seriow, pennanent language disturbance.

Studies of brain function in OAT have shown that the srruaural daa>a«e that m1y be minimal or invisible on CT or MlU has sipUficant COD­

sequences fOr brain function as measured by blood flow or glucose utilization. Decrease in cerebral blood flow is a consistent fmding in O.Al; '" it ap­pe2.tS to correlate with severity and to be most pronounced in the parietal regions.6' The partic­ular partems of brain dysfunction in comparison with language deficits are of interest here. Recent researth has demonsrrared that there arc subgroups of OAT patients that present with ptimarily lan­guage or constructional deficits, and these sub­groups display different patterns of cortical hypometabolism in the apected directions: Pa­tients with marked anomia demonsttated lower metabolic rates in the left temporal regions; patients with focal visuo-ronsuucnYe impairment showed rel~tivdy more hypofunction in the right temporal and patieral regions. 19 ...... These stUdies extend our notions of brain-behavior relations to include measures of gluIJose utilization. To date. most stUdies ~ppear to coincide with the familiar division of function hetween the hemispheres and becween the lobes that we have come to accept from years of clinicopathologic cOrR:lations.

The next step toward deciphering the neuro­functional code is to perfOrm detailed case stUdies in which we can correlate specifiC language and cognitive deficits with specific patterns of brain dys­function. One case stUdy with setial PET scans of a OAT patient has attempted to do this." In this case, although the patient showed significant memory deficits early on, the initial PET scan showed no abnonnality. In addition, although no

additional neuropsycbologic deficits appeared dut­ing the course of the stUdy, the patient showed decreased parieral metabolism in the two later scans. This case highlights the lack of correla­tion between observed behavior and measutable brain function when OAT patients ate ClWIlined individually.

In summary, the investigations intO brain­behaviot relationships with OAT tend to uphold traditional models of cerebral function of language, but force us to apand those models in certain ways. It is clear that gross left-hemisphere struc­tUral change is not prerequisite for a lasring lan­guage disorder and that measures of brain func­tion (e.g., blood flow) arc not yet sensitive enough to correlate with language dysfunction on an individual case basis. It is also cleat that the type of structural and functional damage seen in OAT Spates primary motor and sensoty regions as well as areas thoughr to subserve synt2ctic function . Fur­ther research intO brain function in OAT will un­doubtedly add to our knowledge of the neural representation and neuropathology of language.

Clinical Issues

Any clinical consideration of dementia or DAT must include a discussion of evaluation, differential diagnosis. and potential ueannent. Each of these issues will be taken up in rum. fur further discussion of diagnostic and treatment issues, see Chapte" 13 and 15 .

EVALUATION

The goal of the language evaluation is to reach or confirm a diagnosis and, ultimately, to develop a treatment plan. Language cwIuation of demen­tia patientS combines two elementS not usually relevant to other populations: age and multiple cognitive deficits. The special considerations that need to be addressed because of the relan~y old age of these patientS are well described in a recent chapter by Groher, and include admopishments fOr the clinician to: (1) allow ample time fOr all aspects of the cwIuation to compensate fOr the inevitable slowing th~t accompanies age; and (2) compensate to the degree possible fOr peripheral disturbance (e.g., decreased vision and hearing) within the test environment to prevent these fac .. tors from contaminating the C'V2.luation of central language abilitles."

The second imponant point to remember in cwIuation of a demented patient is the likelihood of multiple cognitive deficits in addition to lan­guage distUrbance. It is essential to establish the relative severity of nonl.anguage deficits in memoty,

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LANGUAGE CHANGES IN DEMENTIA OF THE AlZHEIME!l TYPE 107

attention, non""rbal problem solving, daily living skills, and spuial oricn!Uion. Th ... hero .. will be imporrant fur reaching a diagnosis as well as fur implementing a treatment program. fur instance, severely impaired epoodic memory (memory fur pelSOnai experiences) will preclude direct tcaching of any compcnsarory tecbniqu .. (e.g., sdf-<:ueing); the seIf-care 1...,1 will tell you what the patient's daily interactions are liltt and wbat type of lan­guage production and comprehension skills the patient needs in his particular social environment.

Both furmal and infunnal tesrs should be used. Standardized aphasia batteti .. arc valuable fur their inclusion of many aspeers of language functioning (naming, comprehension, reading, writing. spontaneous speech. repetition),47.n.lu and the Communication Abilities in Daily Living (CADL) provide, additional infurmation about functional skills." H""""",. with the =eption of The Arizona Battery fur Communication OOOrd ... of Dementia, standardized tests have little or no normative data fur the demented Population. 10

Other specific tcsrs (e.g., Thkcn '!est, !lading Com­prehension Battery mr Aphasia, and Boston Nam­ing Test) arc valuable mr in-depth analysis of partitular aspccrs of language. Analysis oflanguagc samples ra.ken from conversation is also important because they provide a gauge of an individual', communicative abilities in a relatively unstructured situation.

DIFFERENTIAL DIAGNOSIS

Differential diagnosis refe", to the characteris­dcs that distinguish one disease from another. It is an important step in reaching a probable diag­nosis and crucial in arriving at a. useful treatment plan. With most dementi .. and with OAT in par­ticular, defInite diagnosis can only be made on the basis of histopathology and is theremre limited to pacienrs who agree to a brain biopsy or have: come to postmortem. Therefore, there is a grat need to improve our abiliry to diagnose OAT on the basis of clinical evaluation. The issue of the differential clinical diagnosis of OAT has been taken up by ,a special composite panel ofNINCOS-AORDA per­sonnel that produced published guidelines mr diagnosis of probable OAT.90 The criteria include documented dementia with deficits in twO or more areas of cognition (including language), progres­sive vt'oncning of cognitive deficits, no disrurbance of consciousness, and the absence of other disorde", or clliC2.SCS that could 2CCOun[ for the: progressive defIcit in memory and cognition. Some =arche", have proposed somewhat moce stringent criteria for the clinical diagnosis of OAT, requiring defIcits in three: areas of cognition and even suggesting that language disturbance be required mr the diag-

nosis." From the ~ of the speech­~ pathologist, it ~ hoped that an adequate descnptJon of language 10 OAT will help to dis­tinguish this from other mrms of dementia, includ­ing multi-infarct dementia, normal ptessure hydrocephalus, and dementia associated with cru:apyramidal disord .... An adequate history of lan~ !fIllptoms and a thorough language evaluatJon should go a long way toward differen­tiating OAT from other mrm. of dementia. lan­guage featur .. that help to distinguish OAT from other demcnw.. syndromc!5 include:: presence: or absence of specific language symptoms, ODSCt and COU!llC of language disorder. and order of appear­ance of language ~rder vis·a-vis other problems such as motor disturbance. The remainder of ~is section 'O'i.11 hig~lig~t the use of language dISOrder.; mr d.isc=tmg between various de­mentia syndromes.

Reversible Dementlas

There are many causes of potentially tcVC",ible dementia, including intracranial conditions (e.g., cumo", and hydrocephalus). vitamin-defIciency states. endocrine disorders. drug intoxication. exposure to toxins or infections. and dementia resulting from affective disorders. 29 Some srurucs estimate that up to 30 percenc of the demented population may be suffi:ring from a potentially revcaible dementia. A thorough history and med­ical work-up are the best ways to dilttrentially diag­nose reversible dementias. A few of the more common reversible dementias. however, do distin~ guish themselves from OAT on the basis of lan­guage symptoms, or more specifIcally, their lack of language symptoms. For inmnce, the demen­tia associated with normal pressure hydrocephalus, resulting from impairment in the circulation of cerebrospinal fluid through the ventricles. is perhaps the most common potentially treatable cause of dementia. 87 Hydrocephalic 'demenrias generally present with a triad of dementia, araxia of gait, and urinary inconrinence. Although Jan. guage defIcits arc generally not presenr, these pa­tients may appear to have :l sentence-formulation problem or anomia caused by the substantial psy_ chomotor retardadon (ment.' slowing) tho{ cypi­cally accompanies the syndrome. Unlike those with OAT, hydrocephalic patients con eventually gener. ate the appropnate vrord or sentence without cues and have no language comprehension defIcitS. The absence of trUe language disturbance and the presence of a motodc (gait) disturbance early on in the co= of the disease should alett the clini­cian to a clinical presentation inconsistent with OAT.

Another porentially reversible furm of demen­'cia is the "pseudodementia" associated with affec-

108 LANGUAGE CHANGES AND DEMENTIA

t1'Ve disorders such as depression. The dementia syndrome accompanying depression typiully presents with psychomotor slowing, furgetfulness, disorientation, impaired attention, and disturbed ability to abstract and grasp the meaning of situa· nom.29 Signs of conical impairment such as lan­guage disturbance: are no~ present. This dementia, if recognized and treared appropriately, has the same: cure rate: as any depressi~ illness.

Subcortical Dementia

Dementia is a common and debilitating symptom associated with enrapyramido..l disorders such as Huntington's disease, Parkinson's disease, and progressive supranuclear palsy.".l' Althougb motor disturbance is generally the: c:2.Cliest and most pe!V25ive symptom in subcomcal diseases. cogni­tive deficits occur in a large percentage of these pa· cients. The standard symptoms of subeortico..l demrotias include disorders of motivation, mood. attention, memory. personality, slowness of thought processes, and impaired ability to manipu· late acquired knowledge (see Chapter 2).,·21.29 These: patients generally do not present with ag­nosia or apraxia. It has also been assumed that, although communication is severely impaired by dysarthria and cogniti .... deficits, patients with sub· corucal dementia are not aphasic. However, recent research calls into question the status of preserved language in subcortical dementia: Demented pa­tients with Huntington's disease are anomie and demonstrate a range of other language: deficits in­cluding reduced syntactic complexity; 17.48 dement­ed patients with progressive: supranuclear palsy (PSP) have been noted to haY<: deficits in word selection; 107 and demented PArkinson's patientS have been sbown to have severdy impaired syn· tactic comprehension. B2 The data demon.suating impaired comprehension in Parkinson's disease are particularly imPOrtant because they demonstrate a language deficit beyond language production, one that cannot be easily attributed to moraric or memory impairment. These studies that have round evidence of language deficits in subcortico..l dementia are consistent with data suggesting the presence of aphasia in patients with subcortical Strokes and with an integrated view' of brain sys­(ems in which damage to certain subcortical regions strongly influences the functioning of corrico..l areas traditionally tied [0 language ability. 93.97

Cortical Dementias

Alzheimer's and Pick's diseases are the cwo most common conical de.mentias, but DAT is by f.u the mOSt common, accounting fOr approxi.matc­ly 50 percent of dementia<, and being 10 to 15 rimes more common than Pick's disease.19 They

differ pathologiully in that Pick's disease affc:Cts primarily the anterior temporal and frontal areas of the brain, while the pathology of DAT is con. cenuated more posteriody, including parietal and tempo!allobcs and the hippocampi. NeuropS}dlo. logically, the cwo dementi .. are similar in presetved motoc functions, impaired language, and altered personoJity through the early and moderate stages, They differ primarily in the areas of memory and visuo-spatialabilities dut are spared in Pick's un· til later stages and impaired in DAT from the be· ginning. Descriptions of the language impairments in these two syndromes look grossly similar: ano· mia in the early stages, progressing to more marked language disturbance with comprehension deficits in the moderate stages. progressing ultimately to echolalia and terminal muteness. A case study by Holland et ai, in one of the few detailed descrip· tions of language dissolution in Pick'" disease, documented a pattero unch:uacteriscic of language deficits in DAT" This patient presented with spoken language marked by lite!al paraphasia< and some omissions of grammatical words, and even­tually progressed to muteness. Auditory compre­hension deficits were also observed. However, other language skills, including reading and writing, were relatively preserved and few other signs of dementia appeared through much of the 12 Y, -year course. 'This case description is unlike: DAT in sever­al respects: The Pick's p2.tient had preservation of memory and the "creative" aspects of language (semantics), while DAT patients typico..lly present with significant memory deficitS and semantic Un# pairment. In addition, the Pick's patient appeared mute before the severe stages of the disease, but muteness is a late-appearing symptom in DAT.

Occasionally, DAT, Pick's, or Creutzfddt· Jakob patients present with an isolated and progttssive language disorder and only subsequent· ly go on to develop other symptoms and an iden· tifiable dementia syndrome. a6.IU. LZ9 Another group of patients also present with progressive lan­guage deficits but do nOt develop a dementia syn. drome.73.91.91.96 There has been lively discussion about whether or not tht;se patients, if followed and tested carefully, will develop a range of neuro· psychologico..l deficits consistent with DAT or other dementia syndromes.78.91.96. I02.1I0.tlI So far, there has been little agreement about the appropriate diag. nosis for these patients, and it has become clear that distinguishing the slowly progressive aphasia from dementia is not o..lways easy, Serio..l cvaluations documenting isolated and progressive language impairments can lead to a provisional diagnosis of slowly progressive aphasia However, fullow.up test·

ing and thorough neuropsychological cvaluarions are essenrial in order to discinguish this syndrome from more widely recognized forrru of dementia such as DAT and Pick's disease.

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LANGUAGE CHANGES IN DEMENnA OF TIm A1ZHEIMEIl'TYPE 109

Mixed Dementlas

The second most common cause of demen­tia is V2SCUlar or multi-infarct dementia (MID), which results from multiple cerebral infarctions and often presents with a com\>ination of cortical and subcortical signs and symptoms. The symp­toms are varied and are therefure sometimes difficult to distinguish from the symptoms ofDAI A thorough history can document abrupt onset, stepwise deterioration, and a fluctUating course that contrasts with the insidious onset and gradual course rypical of OAT. "' Moreover, interim recov­ery of lost function is often observed in MID but not in DAT. A history of hypertension or mokes, with fOcal neurologic signs, also suggests vasrular dementia. .

One rotular dementia, the angular gyrus syn­drome (AGS), resulting from posterior middle cerebral-artery lesions, has been particularly easy to confuse with DAT." The lesions in AGS are often roo smaIl to be visible on cr scans, and meal motor-seosocy signs may be absent, leaving diag­nosis largely dependent on neuropsychological findings, which appear similar to OAT, particularly in the area of language. AGS presents with fluent aphasi2. alc:xio. with agraphia, acaltuli2. left-right disorientation, fiQger agnosia. and constructional disrurbances. The differences between AGS and OAT lie rruUnly in the preserved nonverbal memory and preserved awareness of language disorders in AGS.

Two important caveats must be made regard­ing the differential diagnosis of OAT. First, although up to 84 percent of dementia patienrs are clinically diagnosed with a primary degenera­tive dementia consistent with DAT, the diagnosis is complicated by factors of accuracy and specific. ity: 20 percent or more of cases with the clinical diagnosis of Alzheimer's disease are mund at autopsy to ha~ other conditions and not Alzheim­er's disease, and dementia patients, like most older patients. 'tcnd to have multiple disease processes at work.90 fur instance, in the case of OAT, 1 j to 20 percent of the patients have been shown ro have pathologic fi:atures consistent with both OAT and multi.infarct demc:nm.. 29 These facts force us to temper any generalizations we make about the be·

, havior of clinirally diagnosed DAT patients without histologic confumation.

The second problem lOr differential diagnosis is variabiliry oflanguage symptoms within the DAT population. Alzheimer patients differ from one another. Some of the differences may be because of premorbid dispositions. 'and some may be because of stage of the disease. However, there remains a good likelihood that differences observed in language functions will be traced to subgroups of OAT parients with different etiologies." The

most fn,quently mentioned subgroup of patienrs are those with genetic or familiaI OAI" The as­sociation between familiaI DAT and language dis­order> has been difficult to ascerrain because researchers have mund correlations between lan­guage defIcits and positive f.amily history of DAT," negative family histories," as well as no relationship between Ianguagc disturbance and family history." Other subgroups based on lan­guage diffCrcnces haw: ba:n proposed, citing corre­lations between language disorders and age at onset36J7 and rate: of progression.8O,Ul but these too have not ba:n replicated.I.'-"' ... .u<> Therefure, it is clear that some DAT patients show more or less language disturbance than others, but the ex­tent of these differences and the source of the var­iation are yet to be determined.

Treatment Implications

Once a diagnosis has been reached, a creat­ment mategy is designed. Although there is cur­rently no cure lOr DAT, it is possible to compensate lOr some of the language problems described in this chapter. Candidacy lOr creatment will depend on the stage of the disease, the patient's social environment. the patient'S awareness of his or her defIcits, the nature and degree of other (e.g., cognitive) impairments, and. flnally, the clini­cal judgment of whether "eatment can help (see Chapter 15 lOr perspectives on "eatment alternatives).41.84

iladitional disect language therapy, as used to treat focal aphasias. 19 may not be appropriate with DAT patients lOr several reasons. It is impor­tant to remember that DAT patients have a lan­guage disorder that differs in crucial ways from typical aphasias. fur instance, unlike patients with lOcal aphasia, OAT patienrs present with intact grammatical and phonologic abilities, and the bulk of treatment must focw on semantic and pragmatic deficirs. Because there has been a substantial body of research in the area of lexical semantics in OAT, there is now informacion that can be used to strUc­ture treatment. Unlike meal aphasia. where the anomia can be largely attributed to impaired lori­cal access," the anomia in DAT is probably poly­genic (having multiple causes).14.71.1)2 Therefure, treatment and compensation will have to be multi­dimensional and tailored to individual patienrs. To the extent that visual perceptual impairment and lexical access defIcirs underlie the anomia, environmental supporr (e.g., good lighting) and lexical probing (Is it an' X?) may alleviate the problem. However, because at least some of the anomia appears to stem from degraded lexical repre5CncaUoDs. probes~ cues, and environmcnt2l support are less likely to be of any help. In these

110 LANGUAGE CliANGES AND DEMEIffiA

instances, bCC4Luse research has demonstrated that superordinate category information remains rela­ti.dy inaa in DAI, communication might b<ndit from us<: of superordinate category names (e.g., furniture and tools) rather than basic 1cvc:1 names (e.g., footstool and socket wrencb)."

It is also crucial to beat in mind that the lan­guage disorders of DAI "" embedded in a demen­tia syndrome and therefore occur atOong other, often mott severe, cognitive deficits. These ocher aspects of the dementia preclude the usc of tradi· tional therapeutic techniques that rely largely on self· monitoring and on the acquisition of strate­gies to ' aid performance. Therefore, therapeutic intervention mUSt emphasize compensation for loSt function with little empbasis on learning. This in­cludes indirect therapy sucb as counseling for the patient'S caregivers and investigation of methods to enhance the patient's communicative abilities. A . few compensation strategies that might prove useful with DAI patients arc discussed below. Remember, how=:r, that there is still very lictle research demonstr2.ting positive effects of these ap­proaches on communicatoD.

GeStural communication has been used" to compensate for language ddicits in aphasia and might be considered as an augmentative strategy with DAT patients. H.ll<l In fact, the literature on naming impairment in DAT includes severn ob­servations that DAT patients spontaneously panto­mime the use of objects that they are unable to narne."·u, Although this indicates that DAI pa­tients might be able to use gesture to compensa.te for anomia. several studies ha.ve: also documented a decline in DAT patients' abiliry to produce and understand pantomime, which parallels ddicits in spoken language and indicates that compensation through gesture may be difficult for this group."" It should be noted, howevcr, that the research has not found a one-to-one correspon­dence between word loss and gesture loss. There­fore, even if the pa.tient cannot produce or understand a specific ""rd, he may still be able to make use of a re~ated gesture and vice versa. No research has systematically explored the efficacy of gestural compensation in the treatment of DAT patients.

Because DAI impairs multiple aspects of cog­nition, and many of these nonlanguage ddicits will impair communication, languag~ therapy need not be limited to treating only the language ddicits. fur instance, deficits in memory and orientacon may result in language comprehension problems and pragmatic deficits of poor topic maintenance and discourse incoherence. Improving these non­linguistic cognitive abilities would likely have benc:ficial c:ffects on communication. Perhaps the oldest and most common cognitive intervention for dementia is "reality orientation therapy." This

consists of providing orienting informacion to the patient with the goal of improving all aspects of functioning that rdy on orientation (including daily communication and participation in thera­

. pies). Studies on the effectiveness of rcaliry otien­tation therapy suggest that although this rype of therapy may have a positive overall effect, the benefits arc difficult to document objectiw:ly.'

Other cognitive intervention stI2.tegies for DAT patients arc drawn from the lirerature on · methods to improve: and compensate for memory ddicits in normal aging."" One technique for improving recall involycs suucturing the inPUt to aid memory. Iflanguage addressed to DAI patients could be strucrurcd SO that it is encoded morc com­pletely and remembered more thoroughly, lan­guage comprehension and discourse abilities that depend on memory might improve. In one series of experiments, DAI patients were asked to remember a series of objects that were presented in different conditions (e.g., objects, objects with an instruction to tell the function of each one, and objects with a motoric instruction) and asked to recall the list of items in various conditions.6 One impoClllDt finding is that the input condition ap­pears to hayc different effects at different stages of the disease. For example, for mild DAI patients, the conditions with multiple input modalities (e.g .. object and action) did not appear to affect perfor­mance significantly, suggesting that multiple mo­daliry inPUt docs not enhance memoty at this stage of the disease. However. for moderate and severe DAI patients, verbal input alone was the optimal condition for free recall, sparking speculation that a "pure verbd presentation enables these patienrs to use verbd repetition to a greater C'Xtent than in the other condicions."6 These initial findings sug· gest that multimodaliry inPUt may be of little help to memory in the initial stages and ma.y be a hin­drance later on. Other memory-enhancing strate­gies sucb as "subject performed tasks" during encoding (e.g., lift the cup, put on the glove) ap­pear to enbance memory at all stages 'of DAI,67 indicating that some interventions, partIcularly those that 'rdy on motor acts, may be more effec­tive for the population as a whole. Although many investigations have demonstrated cffi:cts of encod­ing manipulations on memory performance, the effects of such manipulations on language perfor­mance are unclear.

One research project has rested the effect of altered input directly on language comprehension. Young and Kennedy presented two patients with scvcre DAT 'with pragmatic or linguistic orienting cues prior to a simple picrure-pointing comprehen­sion task. IJ6 The pragmatic cue consisted of an "alerting strategy," in which the =miner called the subject's natOe, made eye contact, and then gave the instruction (e.g., "Point to snow plow").

i J

i

LANGUAGE CHANGES IN DEMENI1A OF TIiE AlZHEIMER TYPE 111

The linguistic cue consisted of a semantic context as in "Show me something that clears the road in winter. Point to soow plow." One subject profited from both cue conditions, but more so from the simple pragmatic alertiog cue. The other subject's perfOrmance did not improve with either cue. This stUdy highligbts both the potential effectiveness fur improving language comprehension by a simple alertiog cue prior to stimuli presentation and the importance of considering individual differences in any treatment program: What works fur one OAT patient may not work fur another.

There are many other reehniques that may be effective in enhancing communication with OAT patients, althougb there is very little research to prove their efficacy. For instance, a reduced rate of speech has been shown to improve auditory com­prehension in normal elderly, and may be effec­tive with OAT patients as well. 133 Ostuni and Santo-Pietro'09 and Bayles and KaszniaklD recom­mend many simple and potentially hdpful alter­ations in caregiver's speech that might enhance communication with DAT patients. These include: using short sentences; paraphrasing a sentence when repeating it; avoiding open-ended questions; being redundant; avoiding analogies; establishing eye-contact before addressing the patient; using pictures. objects, and gestures to enhance the mes­sage; and allowing time fur processing.

Finally, it must be emphasized that, because there is no cure for DAT. and direct treatment is of unproven value with this population, caregivers are crucial participants in any treatment for DAT patients. The caregivers must be educated about the disease itself (etiology, course, and complica­tions) and counseled about the patient's impair­ments and abilities. There are now many good. comprehensive books that can help to educate caregivers.33,43.49.109 Thorough language evaluations will help the caregivers understand the com­municative strengths and limitations of the patient, and :epeat evaluations can be a valuable method of monitoting the progress of the disease. It is the caregivers who will be primarily in charge of im­plementing the therapeutic strategy on a daily basis. and it is they who will ultimately benefit most from improved communication. a4

Future Research

There are many places where our research needs to be expanded, and I will make only a few suggestions here. There is ample evidence that there are individual differences in language abili­ties and deficirs within the DAT population and that -:hese differences are not random. It is crucial that variability of language impairments be documented, and if reliable subgroups exist, they

must be adequarely desctibed. Much of the incon­sistency in current research findings will ultimately be attributed to variability within the population rather than variabiliry in experimental paradigms. Considering the extent of behaviotal variability within the OAT population, it is essential that future treatment fur this population be empirically derived and tailored to individual patients.

Over the past decade, there has been an almost blind devotion to stUdying the lexical deficits in OAT to the exclusion of other aspects of language. This makes sense in that anomia is one of earliest and most apparent deficits in the disease. However, we have produced little basic research on pragmatic and discotme deficits that are also early and apparent in OAT, and we have produced even less clinical research to document how and when intervention is most effective. Both of these areas deserve: more attention in the next decade.

Collaboration across disciplines must also be increased. This may come in the furm of collabo­ration with psychophannacologists who are test­ing new drugs and need behavioral measures to test the c:£fect of their medicines on cognitive deficits. It may come in the furm of collaboration with epidemiologists attempting to sort out the behaviotal markers of familial versus sporadic sub­types of DAT. It should certainly come in col­laboration with caregivers and other clinical specialists (e.g .• primary care physicians. nurses, and occupational therapists) who communicate daily with OAT patients.

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