Measures of general intelligence and specific neuropsychological domains will be made for each participant in the study in a separate visit. These measures will be used to characterize the cognitive function of the subject sample as well as to examine associations between functional MRI activation patterns and behavior. The particular measures selected have several characteristics, including demonstrated acceptable reliability and validity; the availability of appropriate normative data; suitability for longitudinal follow-up studies; and the potential to demonstrate a wide range of functioning in a population with a normal rather than a dichotomous distribution. Every attempt was made to ensure uniformity of the test battery across the age range, although there are some unavoidable differences between the tests proposed for the younger versus older subjects.
Wechsler Preschool & Primary Scale of Intelligence, Third Edition (WPPSI-III) (ages 2 ½ to 5). Wechsler Intelligence Scale for Children, Fourth Edition (WISC-IV) (ages 6 to 16). Wechsler Adult Intelligence Scale, Fourth Edition (WAIS-IV) (age 17 and 18). The Wechsler Scales are the most psychometrically sound and widely used measures of general intellectual capacity. They are a mainstay of most clinical neuropsychological batteries. They have excellent reliability and validity. The tests consist of a series of individual subtests tapping various intellectual dimensions including verbal comprehension, perceptual organization, and processing speed. Each test yields Verbal, Performance, and Full Scale IQs. The WISC-III rather than the WISC-IV will be used in order to allow direct comparisons with the normal population data from our previous study.
Bayley Scales of Infant and Toddler Development, Third Edition
Bayley Scales of Infant and Toddler Development, Third Edition (Bayley –III) Screening Test, distributed by Pearson Education, Inc. is designed to test a child’s capacity in three domains of development, cognitive, language, and motor. Bayley–III will be administered by a trained neuropsychologist on an individual basis to infants and toddlers ages 1 to 42 months. This widely used assessment of development in very young children lasts 30-45 minutes and allows the examiner to gauge development using child-friendly activities.
Verbal fluency The Word Generation subtest from the Developmental Neuropsychological Assessment-2 (NEPSY-2) will be used for children between the ages of 5 and 16. The NEPSY-2 has been standardized on a representative sample of the US population of children between the ages of 3 through 16, with 100 children in each age group for a total sample size of 1,000 cases. Subjects age 17 and 18 will be administered the Controlled Oral Word Association Test that has appropriate age-specific norms.
Vocabulary The Peabody Picture Vocabulary Test-4 (PPVT-4) will be used to measure lexical and receptive vocabulary skills. The PPVT-4 is a well-established measure of receptive vocabulary. It involves the presentation of four pictures on each trial, following which the subject chooses the one that goes with what the examiner says. The Expressive Vocabulary Test-2 (EVT-2) will be used to measure naming and expressive skills. It involves the presentation of a series of pictures, each presented with an oral question; the child responds with one word that provides a name, answers a question about the picture, or provides a synonym for a word that fits the picture. Both tests have large normative samples ranging from 2 ½ years through late adulthood as well as alternate forms.
Verbal memory will be assessed using the Verbal Learning subtest of the Wide Range Assessment of Memory and Learning, 2nd Edition. This test provides normative data for individuals from age 5 to age 90 and has reliability coefficients ranging from .86 to .93. The Verbal Learning subtest involves the presentation of a list of 13 or 16 words, depending on age, over four learning trials and one delayed recall trial. There is also a recognition trial.
Visual-constructional ability will be assessed using the Developmental Test of Visuomotor Integration (VMI), a copying task that involves line drawings of increasing complexity. The VMI is normed for ages 3 through 18. It provides standardized scores.
Motor function will be assessed using the Purdue Pegboard, a peg placement task that indexes fine motor coordination. There are normative data for preschool children from the ages of 2 ½ years through 5 years and for school-aged children from the ages of 5 through 16 years.
Executive function will be assessed via parent report on the Behavior Rating Inventory of Executive Function. It is an 86-item questionnaire designed to be completed by parents or caregivers of children between 5 and 18 years of age. It yields a number of clinical scales indexing aspects of executive function such as initiation, planning, organization, and so on, as well as two summary scales reflecting behavioral regulation and metacognitive skills based on normative data obtained on more than 1400 children.
Behavior will also be assessed via parent report. The Child Behavior Checklist has forms for children from 18 months to 18 years of age. It has been normed on a very large group of healthy children and yields narrow-band indices of behavioral and emotional problems as well as broad-band Internalizing and Externalizing problem scores. It has been used in numerous studies of both normal child development as well as chronic illness.
For children ages 0-3 that return for longitudinal follow-up visits, age-appropriate testing will be given. For example, a 24-month old that completed a Bayley at the first visit would complete the WPPSI at the 36-month follow-up visit.
For children age 7-9 that that return for longitudinal follow-up visits, no repeat testing will be given. However, at their one-year follow-up visit, children will complete two additional measures:
Woodcock-Johnson III: Word Attack, Letter-word, Calculation, and Passage Comprehension subtests to assess reading and academic achievment skills
Conners’ Continuous Performance Test II Version 5 will assess sustained and selective attention.
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