# Intra-individual variability in cognitive performance predicts falls in older adults with chronic stroke

## TL;DR

This study finds that variability in cognitive performance can predict falls in older adults who have had a chronic stroke.

## Contribution

The study introduces intra-individual variability in cognitive performance as a novel predictor of falls in post-stroke older adults.

## Key findings

- Intra-individual variability in cognitive performance predicted falls in older adults with chronic stroke.
- A one-unit increase in rISD was associated with a 20.5% increase in fall rate.
- Traditional reaction time measures did not show the same predictive power as IIV.

## Abstract

Common consequences of a stroke include impaired motor and cognitive function, with both being linked to increased falls and frailty. Intra-individual variability (IIV) of cognitive performance, which refers to the within-person trial-to-trial variation in reaction time during cognitive tasks, may be a useful predictor for falls in older adults with chronic stroke.

To examine whether IIV or “traditional” reaction time (RT) measures of cognitive performance predict falls in older adults with chronic stroke.

This study is a secondary analysis of a proof-of-concept randomized controlled trial (RCT) among community-dwelling adults with a history of stroke, aged 55 years and older, able to walk 6 m, and without dementia. Residualised intraindividual standard deviation (rISD) was the measure of IIV and mean RT was the “traditional” measure of performance on a computerised Stroop Task. Falls were tracked and adjudicated over six months.

120 participants with a mean (SD) age of 70 (8) years, and 46 (38%) female participants, experienced a mean of 0.61 (SD = 1.15) falls over 6 months. rISD for the congruent Stroop Task condition predicted falls, such that a one-unit increase was associated with 20.5% increase in fall rate.

The findings suggest that IIV metrics may have the potential in fall risk screening post-stroke. Further research is required to evaluate whether IIV in cognitive performance can be improved via interventions such as cognitive training and physical activity.