How is Cognition Assessed?

Cognition is often assessed with an individual intelligence (IQ) test. School or clinical psychologists usually administer these measures. Various tests may be used, and scores may vary depending upon the measure chosen.

The Bayley Scales are often used for infants and toddlers from two months to two and one half years in age. The parent usually stays in the room with the child, who plays with objects and carries out various tasks (e.g. putting pegs in holes, stacking blocks) while the examiner observes and scores the responses.  Testing infants and very young children can be difficult, and early scores do not always predict later performance very well. Still, infant tests can give valuable information about the developmental levels of very young children.

The Stanford-Binet Intelligence Scale-4^th edition is often given after age two and a half. The Stanford-Binet relies heavily on verbal items, with questions to the child regarding vocabulary, same-different judgments, reasoning, and sentence completion. The Stanford-Binet also measures nonlanguage reasoning with tasks such as drawing, memory for sequences of beads and numbers, and puzzles.

The most commonly used tests after age four and a half are the Wechsler Scales. The Wechsler Preschool and Primary Scale of Intelligence-Revised (WPPSI-R) is designed for children ages 4 ½-6 years old. The Wechsler Intelligence Scale for Children-III (WISC-III) is for children ages 6-16. The Wechsler Adult Intelligence Scale-Revised-III (WAIS-III) is for adolescents and adults. Two scores are given, one for Verbal reasoning (based on items such as word definitions, memory for information, comprehension of questions, and arithmetic word problems) and one for Performance (using subtests in visual-spatial and visual-motor reasoning with pictures, puzzles, and block designs).

A test that has been recommended as very appropriate and helpful for children with fragile X syndrome is the Kaufman Assessment Battery for Children (Kaufman-ABC), which is designed for children ages two and a half to twelve and a half. The Kaufman measures two types of information processing: simultaneous processing (which is often a strength for children with fragile X) and sequential processing (often a weakness ). Simultaneous processing items involve whole pictures with parts missing, recognition of faces, and certain spatial memory tasks. Sequential processing involves placing information in a step-by step order, such as words in sentences, number series, or sequences of hand movements. Girls with fragile X syndrome have the same patterns as boys on this measure (that is, higher simultaneous processing scores than sequential), but their overall scores are generally higher.

The Kaufman also offers an achievement test (Kaufman Achievement Test), which measures learning of vocabulary, reading, and arithmetic. Boys with fragile X syndrome have been found to perform better on such achievement tests than would be expected from their overall IQ scores, and particularly from their sequential processing scores. The Kaufman Achievement Test measures more crystallized abilities (accumulation of past knowledge), with more familiar, concrete, and contextual information, all of which are helpful for children with fragile X. Scores in vocabulary and reading are often higher than arithmetic scores.

Other measures that have been used with children who have fragile X syndrome are non-verbal IQ tests, originally designed for persons with hearing impairments, such as the Leiter or the Ravens Progressive Matrices.

There are a number of issues that must be considered when planning or evaluating IQ testing of individuals with fragile X. Anxiety and attention deficits may interfere with test performance. Being tested by a stranger in a strange locale may cause anxiety, which interferes with performance. Direct questioning may be difficult, due to poor impulse control. Calming activities and visual cues (e.g. a list of what is to be done, with a sticker for each one accomplished) may help the child through a lengthy testing session.

Attention deficits, language disorders, fine motor problems, and sensory motor integration problems may all cause depressed scores. Such scores may not be valid indicators of intelligence, but more representative of the multiple processing problems that many individuals with fragile X have.

Adaptations of formal tests, informal tests, and indirect questioning may provide more accurate results and helpful information. Authentic assessment measures, which use classroom materials, and portfolios of work may do a better job of showcasing at what level many individuals are functioning.

Gail Harris-Schmidt, Ph.D., CCC-SLP
Saint Xavier University
Chicago, Illinois

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