Motor demands of cognitive testing may artificially reduce executive function scores in individuals with spinal cord injury

Abstract

Objective: To determine whether the motor demands of cognitive tests contribute to differences in cognitive function scores in participants with and without spinal cord injury (SCI).

Design: Cohort study.

Setting: Rehabilitation research laboratory.

Participants: 68 individuals without SCI (“NON”) and 22 individuals with motor complete SCI (“SCI”).

Interventions: None.

Outcome Measures: NIH Toolbox cognitive assessments, including two with motor demands and reaction-time based scoring (Dimensional Change Card Sort (DCCS), Flanker Inhibitory Control and Attention (Flanker) and two without timed scoring (List Sorting Working Memory (List Sorting), Picture Sequence Memory Test (Picture Sequence). Tests were administered with and without the assistance of a proctor on two randomly-determined days (>24 hr interval). For DCCS and Flanker, the motor-task score offset was estimated as the difference between the proctored and non-proctored scores.

Results: For demographically-corrected data, proctoring reduced DCCS and Flanker scores (P < 0.001) but mitigated apparent differences between SCI and NON (all P > 0.403). SCI and NON did not differ for List Sorting (P > 0.072) but did differ significantly for Picture Sequence (P < 0.001). Significant practice effects existed for memory-based tests (List Sorting and Picture Sequence); all P < 0.015, effect size>0.645.

Conclusions: DCCS and Flanker scores for individuals with SCI may be artificially reduced consequent to secondary motor demands of the tests. Proctoring and computation of a motor-response score offset enables comparisons to be made between individuals with SCI and a Non-SCI control cohort; however, further work is needed to determine whether offset-adjusted scores can be compared to standardized normative values.

Keywords:

• Spinal cord injuries
• Cognition
• Executive function
• Memory

Disclaimer statements

Contributors None.

Funding This work was supported by National Center for Medical Rehabilitation Research [grant number R01 HD082109]; National Center for Medical Rehabilitation Research [grant number R01 HD084645]; National Center for Advancing Translational Sciences Research [grant number UL1TR002537].

Conflicts of interest Authors have no conflict of interests to declare.