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Intellectual Disabilities

Psychological Tests and Intellectual Disabilities Continued

Tammy Reynolds, B.A., C.E. Zupanick, Psy.D. & Mark Dombeck, Ph.D.

Some of the more commonly used IQ tests are described below:

Wechsler Intelligence Scale for Children (WISC): This is an IQ test for children ages 6 to 16. The test has several subtests. The subtests provide insight into two distinct areas of intelligence. These are verbal skills and spatial (performance) skills. The verbal tests include: vocabulary, similarities, comprehension, math, and informational knowledge. The performance tests include: picture completion and arrangement; block design; object assembly; and coding.

Wechsler Preschool and Primary Scale of Intelligence: This is an IQ test for children 3 to 7 years old. This test is organized like the WISC (see above). It measures two key aspects of intelligence: verbal skills and spatial (performance) skills. It has multiple subtests measuring different aspects of each major area. This test is not appropriate for individuals with severe intellectual disability.

Wechsler Adult Intelligence Scale (WAIS): This is an IQ test for people over sixteen years of age. This test is similar to the WISC (see above). However, the questions are more difficult since it tests adults. Like the WISC, it is comprised of multiple subtests. These subtests measure different aspects of the two major areas of intelligence.

Stanford-Binet Intelligence Scale: This is an IQ test for people between 2 to 23 years of age. There are fifteen subtests for older groups. Six subtests are administered to all age groups. These are vocabulary, comprehension, pattern analysis, quantitative, bead memory, and memory for sentences.

McCarthy Scales of Children's Abilities: This test measures the cognitive and motor abilities of children between the ages of 2.5 to 8.5 years old. There are six sections to this test. These are: Verbal Scale; Perceptual-Performance Scale; Quantitative Scale; Memory Scale; Motor Scale; and General Cognitive Scale. The results do not provide an IQ score. Instead, the test yields a General Cognitive Index (GCI). This is similar but broader than a simple IQ. The McCarthy Scales also provide individual ability scores. These are: verbal; non verbal reasoning; number aptitude; short-term memory; and coordination. These scores help diagnosticians evaluate learning problems in younger children.

Bayley Scales of Infant Development: These tests are used to assess the development of infants and toddlers ages 1-42 months. This test is also used with older children who are unable to take age-appropriate tests. There are three sections. The first is mental abilities. This includes tests of recognition memory; object permanence; shape discrimination; attention; nonverbal communication and vocalization; receptive and expressive language. The second is motor abilities. This includes tests of gross and fine motor skills. The third is behavioral abilities. This includes tests of social and emotional behavior.