An examinee completes the WAIS-IV. Their performance on the Processing Speed Index (PSI) is significantly lower than their scores on the Verbal Comprehension Index (VCI) and Perceptual Reasoning Index (PRI). During the administration of the Coding subtest, the examiner notes the individual has considerable difficulty with graphomotor control, and their pencil grip appears awkward and inefficient. Which statement is the most accurate interpretation?
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A
The low PSI score is likely a valid measure of slow cognitive processing, independent of motor skills.
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B
The examinee likely has a co-occurring learning disability in reading, which is often linked to low PSI scores.
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C
The observed fine-motor difficulties may have suppressed the PSI score, suggesting it may not be a pure measure of cognitive speed for this individual.
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D
The discrepancy between the PSI and other indices suggests a lack of effort or motivation on the timed tasks.