v. clinical picture and course

V. Clinical Picture and Course

Already Strumpell (1888) and Friedmann (1892) considered it possible to discern a characteristic symptom picture, i.e. a syndrome, among the symptoms that often arise after cerebral concussion. This view has now become common. As the principal symptoms of the PCS are usually regarded those described in Chapter 11. Lately, however, the adequacy of considering the post-concussional symptom picture as a syndrome has been questioned by some authors (e.g. Caveness 1966, and Gerstenbrand 1969).

The prevailing opinion regarding the semiology of the post-concussional symptoms has been based mainly on clinical observations of a somewhat unsystematic kind. The incidence of various symptoms differs considerably from one series to another. Information on the joint occurrence of the symptoms is very sparse.

MellergArd (1967) appears to be the only worker who has tried to analyse the symptom picture in a more systematic way. Although his investigation is of the retrospective type, and carried out at an average of nine years after the injury, his work is interesting since it is the first elaborate attempt to study the symptom picture. Using a correlation technique, MellergArd identified post-concussional symptom groups composed of symptoms that tended to appear jointly more often than in combination with other symptoms. One such symptom group consisted of headache and dizziness, another of fatigue, subjective memory impairment, irritability and anxiety, and a third of visual, auditory, olfactory and gustatory symptoms. He noticed that the course differed in the separate symptom groups. Headache and dizziness were common symptoms soon after the injury and then tended to decrease successively in frequency. The symptoms of the second symptom group were rare during the acute stage but tended to increase in frequency over a Iong period of time. The third symptom group showed a more ir- regular course.

The relatively late onset of post-traumatic ‘mental symptoms’ was also observed by e. g. Adler (1945).

Since we have systematically interviewed our patients at regular intervals during the first three months after injury we find it justified to present an analysis of the clinical picture and course, especially since clues to etiology may be one result of semiological analysis.

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INCIDENCE OF SINGLE SYMPTOMS

PCS-sym ptoms

Of the 83 patients in the present series 64 (77 %) reported one or more PCS-symptoms on at least one occasion during the observation period. As shown in Figure V:l, the percentage of patients reporting at least one com- plaint of this kind steadily declined from initially 73 per cent to 24 per cent at the end of the observation period. The decrease was particularly pronounced during the first week after the injury, at the end of which approximately every second patient declared himself to be free from symptoms.

The percentage of patients reporting a given symptom at any examination during the observation period is shown in Table V:l. Headache and dizziness were the PCS-symptoms most often reported, while irritability and hypersensitivity to sound and light were reported relatively seldom.

In Table V:2 it will be seen that no patient ever reported all the nine tabulated symptoms on any one occasion. Moreover, very few patients reported more than five symptoms simultaneously. Using the simultaneous occurrence of five or more symptoms as an arbitrary criterion for ‘a fully developed PCS’ only ten patients (12 % of the total number) ever fulfilled this criterion. The number of patients reporting one or few symptoms tended to decline from one occasion to the next while patients reporting many

2 6 14 30 90 Number of days after the trauma

FIGURE V: 1. Percentage of patients reporting one or more PCS-symptoms on various occasions during the observation period.

TABLE V:l. Number of patients reporting a given PCS-symptom at some time during the observation period

The symptoms are ranked according to frequency of occurrence

PCS-symptom n %

Headache Dizziness Fatigue Difficulty in concentration Anxiety Memory impairment Irritability Hypersensitivity to light Hypersensitivity to sound

48 39 31 25 19 13 11 11 6

58 47 37 30 23 16 13 13 7

TABLE V:2. Number of patients reporting a given number of PCS-symptorns on various occusions during the observation period

No. of PCS- 2 6 14 30 90

symptoms n 70 n % n 70 n 70 n %

No. of days after the trauma

0 1 2 3 4 5 6 7

9 n

22 26 14 11 6 2 1 1 0 0

27 31 17 13 7 2 1 1 0 0

43 22 12 3 2 1 0 0 0 0

52 49 59 54 65 63 76 27 17 20 14 17 5 6 14 8 10 6 7 6 7 4 2 2 3 4 4 5 2 1 1 1 1 2 2 1 3 4 4 5 2 2

1 1 0 2 2 0 0 0 0 0 0 0 0 0 0 1 1 1 1 0 0

0 0 0 0 0 0 0

symptoms (five or more) did not clearly decrease in number. Thus, among the patients with PCS-symptoms more cases of ‘a fully developed PCS’ were found at the end of the period than at the beginning.

Different PCS-symptoms have different courses. This is seen in Figure V:2, which shows the percentage of patients reporting a given symptom on various occasions after the trauma. Some symptoms, such as headache and dizziness, tended to be gradually less frequently reported, while other symptoms, such as anxiety and irritability, did not display this relatively ‘benign’ course. The incidence of some symptoms (e.g. fatigue, difficulty in mental concentration, anxiety, irritability) tended to increase during the week after discharge from hospital, i.e. from the 6th to the 14th day after the injury.

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FIGURES V:2 a-i. Percentuge of patients reporting n given PCS-symptorn on various occasions during the obserwtion period.

% 50

25

0%

50

25

1 , I

2 6 I4 30 90 Number of days after the trauma

FIGURE V:2 a.

DIZZINESS

1 , I


FIGURE V:2 b.

21 HYPERSENSITIVITY TO SOUND

I

25-

- - 0


FIGURE V:2 c.

31

25-

[,I 30 90

2 6 14 Number of days after the trauma

FIGURE V:2 d.

FATIGUE


FIGURE V:2 e .

DIFFICULTY IN MENTAL CONCENTRATION

FIGURE V:2 f .

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Yo 50

25

SUBJECTIVE MEMORY IMPAIRMENT

1 , I *


FIGURE V:2 g.

ANXIETY


FIGURE V:2 h.

IRRITABILITY


FIGURE V:2 i .

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TABLE V:3. Number of patients reporting a given PCSL-symptom on various occasions during the observation period

No. of days after trauma

n % n % n % n % n % PCSL-sy mptom 2 6 14 30 90

Headache

Dizziness

Hypersensitivity to sound

Hypersensitivity to light

Fatigue

Difficulty in concentration

Memory impairment

Anxiety

Irritability

2 2 3 4 2 2 1 1 1 1

2 2 5 6 3 4 1 1 3 4

1 1 1 1 1 1 1 1 1 1

2 2 3 4 4 5 3 4 3 4

6 7 4 5 8 10 7 8 8 10

2 2 2 2 4 5 3 4 3 4

1 1 2 2 5 6 5 6 5 6

9 11 9 11 11 13 10 12 10 12

4 5 4 5 4 5 4 5 4 5

Immediately after the injury the symptom picture was dominated by headache and dizziness. These symptoms were reported considerably more often than the other PCS-symptoms. Then the symptom picture became more polymorphous, and at the end of the observation period several of the symptoms occurred about equally often.

Hitherto we have only given an account of the series as a whole. How- ever, when the PCS-group is examined separately it will be seen that after discharge from hospital no less than two out of three patients in this group reported an increased number of PCS-symptoms. (See case histories in the appendix.)

PCSL-symptoms

PCSL-symptoms were reported nearly half as often as PCS-symptoms. Twenty-nine patients (35 % of the total number) reported such symptoms. The various PCSL-symptoms were reported with approximately unchanged frequency at each examination (Table V:3). As shown in Table V:4, anxiety was the most common of these symptoms, followed by fatigue. Headache, which was the most frequent PCS-symptom, was relatively uncommon as PCSL-symptom.

Acta neurol. scand. (Suppl.) 3

34

TAB LEV:^. Number of patients reporting a given PCSL-symptom at some rime during the observation period

The symptoms are ranked according to frequency of occurrence

PCSL-symptom n %

Anxiety 13 16 Fatigue 10 12 Dizziness 7 8 Memory impairment 6 7 Hypersensitivity to light 5 6 Headache 4 5 Difficulty in concentration 4 5 Irritability 4 5 Hypersensitivity to sound 2 2

PCSL-symptoms were reported by sixteen of the patients in the PCS- group and by thirteen of those in the C-group.

COVARIATION OF PCS-SYMPTOMS

Definition and statistics

One may accept a provisional definition of a ‘syndrome’ as a group of symptoms which tend to appear jointly. This definition gives an entirely descriptive meaning to the concept. As a measure of the covariation between two symptoms can be used the proportion of patients reporting these symptoms simultaneously. This measure is simple and it has a concrete meaning with a close relation to the syndrome concept as defined above.

However, if the aim is to use symptom grouping as a basis for etiological hypotheses, it is necessary to have a measure of covariation between symptoms which is corrected for chance and thus makes it possible to discern a correlation between infrequent symptoms. The usual measure of covariation between dichotomous variables, the phi coefficient, is corrected in this way. However, the phi coefficient is unsuitable for use when the correlated variables are very skewly distributed. Since the distribution of symptoms at the majority of the examinations showed a pronounced skewness we de- cided to limit the analyses based on phi coefficients to those symptoms which on a single occasion were reported by at least 10 per cent of the patients. In this way the most extreme degrees of skewness were avoided and consequently also those spurious coefficients that would too heavily have stressed the covariation between very infrequent symptoms.

Unfortunately, this restriction resulted in the analyses based on phi coefficients being performed on only a small number of symptom registra-

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TABLE V:5. PCS-symptoms reported by 10 % or more of the patients on various occasions during the observation period The symptoms are marked with an X

No. of days after the trauma 2 6 14 30 90 PCS-symptom

Headache X X X X X Dizziness X X X X Hypersens. to sound Hypersens. to light X Fatigue X X X X X Diffic. concentration X X X Memory impairment Anxiety i< A.

Irritability r: \ I

tions. As shown in Table V:5, there remains of the original 5 x 9 = 45 registrations only 21 after the introduction of the 10 per cent limit. More- over, only two symptoms are represented at all five examinations.

Using the two measures of covariation just mentioned the symptoms reported at each examination were brought into groups (or sub-syndromes) by means of cluster analysis. The method used here is of the hierarchical type and is devised by Johnson (1967). This method is to be recommended because it uses only the ordinal properties of the covariation measures.

Clustering of symptoms based on proportion values

The clustering of symptoms, reported at different examinations, is illus- trated in Figure V:3. In order to facilitate the interpretation of the cluster analyses, the discussion is limited to those combinations of symptoms reported by at least 5 per cent of the patients. The choice of this value is, of course, arbitrary, but it is intended to restrict the interpretation to a covariation pregnant enough to be of practical interest.

Two days after the injury two groups, or clusters, of symptoms satisfied this requirement. The largest cluster consisted of headache, dizziness, fatigue, and difficulty in mental concentration. The other cluster consisted of only two symptoms: hypersensitivity to light and subjective memory impairment. Six days after injury three small over-lapping clusters appeared. The most common symptom group on this occasion was headache and dizziness. The other two combinations satisfying the five per cent criterion were the pairs headache and fatigue, and dizziness and fatigue, respectively. Two weeks after the trauma there emerged two clusters, one composed of

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difficulty in

FIGURES V:3 a-e. Clustering of PCS-symptoms reported on various occasions during the observation period.

The figures in the diagrams show the criterion for clustering (in per cent) at the level indicated. This criterion equals the minimum percentage of joint occurrences of two symptoms in the cluster formed at the level. Symptoms jointly reported by 5 % or

more of the patients are given the same one-figure index. a. 2 days, b. 6 days, c. 14 days, d. 30 days, e. 90 days after the trauma.

0-

irritability

hypersensitivity to sound

Zsubjective memory impairment

hypersensitivity to light

mental concentration

subjective memory impairment

hypersensitivity 0- anxiety

0-

l2 to sound

1 difficulty mental concentra- in 3, 1 fatigue

tion

dizziness

headache FIGURE V:3 a.


irritability


1 -

hypersensitivity to light 1 1

- 23 fatigue


4-

2 anxiety

difficulty in mental concentration

dizziness I

to light

1 fatigue

9-

headache FIGURE V:3 c.



difficulty in mental concentra - tion

4 -

1 -

1 -

irritability

dizziness

1 anxiety

1 fatigue

1'-

headache

FIGURE V:3 d.

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subjective memory impairment 1 difficulty in mental concentration

dizziness

O t hypersensitivity to light 1 hypersensitivity to sound

irritability

34 fatigue

l3 anxiety

14 headache FIGURE V:3 e.

headache, fatigue and dizziness, the other of difficulty in concentration and anxiety. One month after injury only one cluster was found. This consisted of anxiety, fatigue and headache. At examination three months after injury four small clusters appeared, of which three over-lapped. The most frequent symptom group at this time was headache and anxiety. The remaining three clusters appeared equally often. These consisted of dizziness and difficulty in mental concentration, fatigue and anxiety, and fatigue and headache.

To summarize, we found that covariation between symptoms was most prominent at the examinations 2, 14 and 90 days after injury. During the first week headache and dizziness were the two symptoms most often reported to occur jointly. At the end of the second week headache and fatigue, and later headache and anxiety, were the symptoms most often jointly reported.

Clustering of symptoms based on phi coeficients

The results of cluster analyses of symptoms reported by at least ten per cent of the patients on various occasions after injury are shown in Figure V:4.

As an arbitrary cut-off limit in the clustering process we chose the level at which the minimum correlation between two symptoms in a cluster is significant at the 5 % level (r,,l,i 0.21).

When applying this criterion there emerged two clusters at the examina-

FIGURES V:4 a-e. Clustering of PCS-symptoms reported on various occasions during the observation period.

The figures in the diagrams show the criterion for clustering at the level indicated. This criterion equals the minimum correlation between two symptoms in the cluster

formed at that level (decimal points omitted). a. 2 days, b. 6 days, c. 14 days, d. 30 days, e. 90 days after the trauma.

fatigue

difficulty in mental concentra - tion

dizziness


headache FIGURE V:4 a.

dizziness

anxiety


fatigue

headache

FIGURE V:4 c.

fatigue

dizziness

headache

FIGURE V:4 b.


anxiety

fatigue

dizziness

headache

FIGURE V:4 d.

1 fatigue

3 anxiety

headache -1 FIGURE V:4 e.

tion two days after injury. One consisted of dizziness and difficulty in concentration, the other of headache and hypersensitivity to light.

Six days after injury only headache and dizziness correlated highly enough to qualify as a cluster.

As pointed out earlier, the degree of covariation between symptoms rises again at the examination two weeks after injury. With the criterion for clustering used here all five symptoms accepted for analysis at 14 days

39

after injury were joined to one large cluster. The nucleus of this cluster consisted of anxiety and difFiculty in concentration.

One month after injury headache disappeared from the cluster observed on the previous occasion. The most prominent symptoms on this occasion were fatigue and anxiety.

Three months after injury only three symptoms met the criterion of an incidence of at least ten per cent. However, all three symptoms, headache, anxiety and fatigue, were included in the same cluster.*

So far, none of the analyses has demonstrated the existence of a general PCS. The sub-syndromes found in the cluster analyses turned out to be quite unstable, varying both in extent and character with time.

GROUPING OF PATIENTS ACCORDING TO SIMILARITY OF SYMPTOM PICTURE

In order to investigate whether any subgroups, more homogeneous with respect to symptom picture, could be distinguished among the patients, latent class analyses (LCA) were performed on the symptom pictures reported on single occasions as well as on ‘the total symptom picture’ dis- played over all five occasions of examination. A statistical classification of the series, performed in this way, might function as an alternative to the classification in PCS- and C-groups based solely on clinical judgement (see Chapter 111).

In all analyses, solutions with three observed profiles were considered to give the most adequate description of the material. Any further splitting-up of the material resulted in a number of very small groups in addition to the large group of patients with few or no symptoms.

At each examination there could be distinguished a large group of patients (56 to 75 persons) who reported few or no symptoms. Moreover, at each examination except at the one six days after injury, there emerged a small group of patients (3 to 9 persons) with many symptoms. The third group of patients was also small (3 to 20 cases) and was characterized by a specific combination of a few symptoms on each occasion.

A LCA, performed on the symptom picture reported over all occasions, disclosed the symptom profiles shown in Figure V:5.

* Principal components analyses of correlations between symptoms reported on single occasions by ten per cent or more of the patients with Varimax rotation of components with eigenvalues 2 1.0, resulted in symptom groupings almost identical with those that appeared in the cluster analyses based on phi coefficients (only component loadings 2 0.50 were taken into consideration at the interpretation).

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Profile 1 (9 patients) contains the most severe cases of PCS. These patients reported several symptoms on each occasion, and most of them reported a gradually increasing number of symptoms during the observation period.

SYMPTOM _I 1 headache

NUMBER OF DAYS AFTER THE TRAUMA

LCA3 L C A 2 LCAl

jirziness hypersensitivity to light

fatigue difficulty in mental

dizziness

fatigue

1 headache

dizziness

fatigue difficulty in mental concentration

anxiety

headache

dizziness

fatigue

difficulty in mental concentration

anxiety

headache

dizziness

anxiety

I I J

0 50 100 0%

FICUREV:~. Percentage of patients in the three profile groups reporting a given syniptom on various occasions during the observation period.

Only symptoms with an incidence of 10 % or more were accepted for the analysis.

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Profile 2 (10 patients) is characterized by frequent reports of headache and dizziness two days after injury, followed by reiterated complaints of fatigue throughout the observation period.

Profile 3 (64 patients) consists of patients who, in addition to headache and dizziness during the first week after injury, reported few or no symptoms during the remaining period of observation.

COMMENTS

From a statistical point of view, the PCS-symptoms do not constitute one syndrome, a syndrome being defined as a certain frequent combination of symptoms.

An early and a late phase of the post-traumatic course is clearly dis- cerned. Headache and dizziness dominated among the symptoms during the first week after injury. Anxiety did not tend to appear until a few weeks after injury and from then on constituted the nucleus of the polymorphous late symptom picture.

Our study will be limited to the late PCS-symptoms and their causes.

v. clinical picture and course

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