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Loss of Consciousness is Associated with Elevated Cognitive Intra-Individual Variability Following Sports-Related Concussion

Published online by Cambridge University Press:  10 August 2020

Victoria C. Merritt Open the ORCID record for Victoria C. Merritt [Opens in a new window] ,
Liora S. Greenberg ,
Jessica E. Meyer  and
Peter A. Arnett Open the ORCID record for Peter A. Arnett [Opens in a new window]
Victoria C. Merritt*
Affiliation:
VA San Diego Healthcare System, San Diego, CA, USA
Liora S. Greenberg
Affiliation:
The Pennsylvania State University, University Park, PA, USA
Jessica E. Meyer
Affiliation:
University Hospitals Cleveland Medical Center, Cleveland, OH, USA
Peter A. Arnett
Affiliation:
The Pennsylvania State University, University Park, PA, USA
*
*Correspondence and reprint requests to: Victoria C. Merritt, Ph.D., VA San Diego Healthcare System (151B), 3350 La Jolla Village Drive, San Diego, CA92161, USA. Tel: +1 858-558-8585x2670; Fax: +1 858-642-6340. E-mail: victoria.merritt@va.gov
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Abstract

Objective:

The purpose of this study was to evaluate whether loss of consciousness (LOC), retrograde amnesia (RA), and anterograde amnesia (AA) independently influence a particular aspect of post-concussion cognitive functioning—across-test intra-individual variability (IIV), or cognitive dispersion.

Method:

Concussed athletes (N = 111) were evaluated, on average, 6.04 days post-injury (SD = 5.90; Mdn = 4 days; Range = 1–26 days) via clinical interview and neuropsychological assessment. Primary outcomes of interest included two measures of IIV—an intra-individual standard deviation (ISD) score and a maximum discrepancy (MD) score—computed from 18 norm-referenced variables.

Results:

Analyses of covariance (ANCOVAs) adjusting for time since injury and sex revealed a significant effect of LOC on the ISD (p = .018, ηp2 = .051) and MD (p = .034, ηp2 = .041) scores, such that athletes with LOC displayed significantly greater IIV than athletes without LOC. In contrast, measures of IIV did not significantly differ between athletes who did and did not experience RA or AA (all p > .05).

Conclusions:

LOC, but not RA or AA, was associated with greater variability, or inconsistencies, in cognitive performance acutely following concussion. Though future studies are needed to verify the clinical significance of these findings, our results suggest that LOC may contribute to post-concussion cognitive dysfunction and may be a risk factor for less efficient cognitive functioning.

Keywords

Injury severity characteristicsCognitionDispersionIIVSports concussionCollege athletes
Type
Brief Communication
Information
Journal of the International Neuropsychological Society , Volume 27 , Issue 2 , February 2021 , pp. 197 - 203
Copyright
Copyright © INS. Published by Cambridge University Press, 2020

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