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Marked Intraindividual Cognitive Variability in a Sample of Healthy Graduate Students

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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 lowest z-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.

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The research was solely funded through a University of Toronto Fellowship.

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Authors and Affiliations

  1. Department of Psychology, University of Toronto Scarborough, 1265 Military Trail, Toronto, M1C 1A4, Ontario, Canada

    Eliyas Jeffay & Konstantine K. Zakzanis

  2. Graduate Department of Psychological Clinical Science, University of Toronto Scarborough, 1265 Military Trail, Toronto, M1C 1A4, Ontario, Canada

    Konstantine K. Zakzanis

  3. Independent Practice, Beaverton, OR, USA

    Laurence M. Binder

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Jeffay, E., Binder, L.M. & Zakzanis, K.K. Marked Intraindividual Cognitive Variability in a Sample of Healthy Graduate Students. Psychol. Inj. and Law 14, 171–183 (2021). https://doi.org/10.1007/s12207-021-09417-x

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