Marked Intraindividual Cognitive Variability in a Sample of Healthy Graduate Students

Abstract In this pilot study, intraindividual variability in neurocognitive test performance was examined in 24 healthy individuals with high levels of education and average full-scale IQ of 121.9 on a short neuropsychological battery across multiple cognitive domains. Marked variability was found across all domains. Intraindividual differences between the highest and lowestz-scores ranged from 2.05 to 6.92 (M = 3.89,SD = 1.25). Based on the definitions of abnormality proposed by Lezak, Wechsler and Heaton, 46% of our sample participants had at least one score that was more than 2 standard deviations below the population mean; 50% had at least one score that was less than the 5th percentile (z <   −1.68); 66% had at least one score below the 10th percentile (z <   −1.28); and 92% had at least one score lower than one standard deviation below the mean (z <   −1.00). Construction, orientation and attention, and verbal memory domains showed the highest average standard deviation values (>1.0 SD) across our sample. Our findings suggest the need for caution when inferring the presence of cerebral dysfunction in high academic achievers, particularly in a medical legal setting where false-positive diagnoses may be of particular consequence.
Source: Psychological Injury and Law - Category: Medical Law Source Type: research