Dual-task gait and white matter hyperintensities in Lewy body diseases: An exploratory analysis

Abstract

Background: Parkinson’s disease (PD) and dementia with Lewy bodies (DLB) are part of a spectrum of Lewy body disorders, who exhibit a range of cognitive and gait impairments. Cognitive-motor interactions can be examined by performing a cognitive task while walking and quantified by a dual task cost (DTC). White matter hyperintensities (WMH) on magnetic resonance imaging have also been associated with both gait and cognition. Our goal was to examine the relationship between DTC and WMH in the Lewy body spectrum, hypothesizing DTC would be associated with increased WMH volume.

Methods: Seventy-eight participants with PD, PD with mild cognitive impairment (PD-MCI), PD with dementia or DLB (PDD/DLB), and 20 cognitively unimpaired participants were examined in a multi-site study. Gait was measured on an electronic walkway during usual gait, counting backward, animal fluency, and subtracting sevens. WMH were quantified from magnetic resonance imaging using an automated pipeline and visual rating. A median split based on DTC was performed. Models included age as well as measures of global cognition and cardiovascular risk.

Results: Compared to cognitively unimpaired participants, usual gait speed was lower and DTC was higher in PD-MCI and PDD/DLB. Low DTC participants had higher usual gait speed. WMH burden was greater in high counting DTC participants. Frontal WMH burden remained significant after adjusting for age, cardiovascular risk and global cognition.

Conclusion: Increased DTC was associated with higher frontal WMH burden in Lewy body disorders after adjusting for age, cardiovascular risk, and global cognition. Higher DTC was associated with age.

Plain Language Summary

There is an accepted way to test how the brain is responsible for walking. It involves participants doing an additional task while walking. While this has been studied a lot with older people with and without cognitive problems, this study compares the performance of people living with various Lewy body disorders, a common cause of cognitive problems in older people. In addition, we examine how lesions in brain white matter are associated with performing a task while walking. White matter lesions are potentially treatable and preventable brain changes. The results show slowing your walking speed while counting backwards is related to white matter lesions, especially in the front part of the brain. Slowing while walking can increase the risk of falls and thinking problems. Prevention of white matter changes might help prevent falls and thinking problems in people with Lewy body disorders.