Wechsler Adult Intelligence Scale

IV- Verbal and Performance

IQ

Verbal Intelligence Quotient• Verbal intelligence quotient (IQ) measures an individual’s ability to

use language to analyze and solve problems. • It includes the ability to listen to, analyze, remember, and

understand information in either verbal or written form.• Skills such as reasoning and the grasp of both abstract and

concrete ideas, and includes their overall understanding of concepts, comparisons, and other similar characteristics of language, too are measured.

• Verbal skills may also be measured on an academic level. The tests can be administered individually or in a group setting.

• Included are 7 tests and provided 2 sub indexes- verbal comprehension and working memory.

Verbal Comprehension

Index (VCI)

VCI intends to measure the verbal concept formation

As well as, assesses the ability to question, infer from learned information, reason to create responses and express thoughts verbally.

It involves 4 subtests- 1) Similarities2) Vocabulary3) Comprehension4) Information

Working Memory Index (WMI)

Blackboard of the mind. Measure ability to

memorize new information, concentrate, manipulate that information to produce some result.

Important in higher order thinking, learning and achievement.

The subtests involved are-

1) Arithmetic2) Digit Span3) Letter number

sequencing

Performan

ce Intelligence Quotient

• PIQ consists of 6 subtests which provide 2 sub indexes – perceptual reasoning index (PRI) and processing speed index (PSI).

• The Performance IQ is a measure of fluid reasoning, spatial processing, attentiveness to details, and visual-motor integration.

Perceptual Organization Index

(PRI)

Measures the non-verbal (perceptual) and fluid reasoning, spatial processing, visual-motor integration, and the ability to learn new information

Indicates a preference for visual information or kinesthetic learning.

Includes tests like- 1) Block design2) Matrix reasoning3) Picture completion4) Figure Weights5) Visual puzzles

Processing Speed Index (PSI)

Assesses skills on focus, attention, scanning, discrimination, and sequentially ordering visual information

Measures working under time pressure and motor coordination

Related to memory skills, mathematics, reading.

Sub tests part of PSI are- 1) Digit-symbol coding2) Symbol search

VIQ > PIQ by 15 points!

Guertin, Ladd, Frank, Rabin, and Hiester (1966) reviewed a number of studies suggesting that lower PIQ stores are indicative of right hemisphere pathology

It could also result of misinterpretation.

Also indicative of traumatic brain Injury.

Findings are inconclusive.

PIQ outruns VIQ by 15 Runs…err, Points!

lower VIQ scores are indicative of damage to the left hemisphere, Reitan (1955) and of Klove and Reitan (1958).

The results indicate that Visual Puzzles is not a pure measure of visuo-perceptual reasoning, because memory, mental flexibility, processing speed, and language abilities also contribute to successful performance of the task.

Symbol search was associated with greater activity in bilateral medial occipital, occipito-parietal, occipito-temporal, parietal, and dorso-lateral prefrontal cortices (DLPFC). Across both tasks, slower processing speed was also related to greater activity in these areas, except right DLPFC.

Discrepancy

Between Verbal IQ

and Performa

nce IQ

• The discrepancy has been associated specifically with a variety of verbal, motor, peri-natal, and neurological problems in reports by Holroyd (1968).

• Although Wechsler (1974) stated that a VIQ-PIQ score difference of 15 points is important and although Cronbach (1961) agreed that the VIQ-PIQ score has an estimated reliability (.74 at the 99% level of confidence), he pointed out that one quarter of the WISC-R standardization sample had VIQ-PIQ discrepancy scores of 15 or more and cautioned the clinician to use a "statistical abnormality" criterion for diagnostic or educational purposes

• Lezak -a pattern of clear-cut differences between subtests involving primarily verbal functions on the one hand and those involving primarily visuo-spatial functions on the other is likely, but not necessarily, a product of lateralized brain injury.

• Although Wechsler's intelligence scales were not originally designed as neuropsychological tests, the verbal and performance IQ scores measures of functions that are primarily lateralized in the two cerebral hemispheres (Kolb & Whishaw, 1985).

THANK YOU!