Differential WAIS/WAIS-R IQ discrepancies among institutionalized mentally retarded persons

Area of Science:

• Psychometrics
• Intellectual Disability Assessment
• Neuropsychology

Background:

• The Wechsler Adult Intelligence Scale-Revised (WAIS-R) is a widely used measure of cognitive ability.
• Previous research suggests WAIS-R scores may differ from its predecessor, the Wechsler Adult Intelligence Scale (WAIS), particularly in nonretarded and retarded populations.
• Understanding these differences is crucial for accurate diagnosis and treatment planning.

Purpose of the Study:

• To replicate previous findings on WAIS-R IQ score differences compared to the WAIS.
• To investigate potential differential effects of the WAIS-R across various levels of intellectual disability.
• To examine the implications of these score differences for the classification of intellectual disability.

Main Methods:

• Study conducted with subjects in a residential treatment center.
• Comparison of IQ scores obtained from the WAIS-R and potentially the WAIS (implied).
• Statistical analysis to identify significant differences in Full Scale IQ scores within subgroups.

Main Results:

• Replication of general findings: lower WAIS-R IQs for nonretarded subjects and unchanged for retarded subjects.
• Significant increase in WAIS-R Full Scale IQ (mean of 6 points) observed in the moderately intellectually disabled subgroup.
• Potential for reclassification as mildly intellectually disabled for 64% of the moderately intellectually disabled subgroup.

Conclusions:

• The WAIS-R demonstrates level-specific effects on IQ scores in individuals with intellectual disability.
• A significant increase in WAIS-R IQ scores for the moderately intellectually disabled subgroup may impact diagnostic classification.
• Careful interpretation of WAIS-R IQs, considering adaptive functioning, is essential for individuals with intellectual disability.