A useful cognitive motor dual task paradigm in prodromal and manifest Huntington’s disease

Introduction

Individuals with Huntington's disease (HD) experience increased difficulty with balance throughout disease progression. Adding a simultaneous cognitive task to a balance assessment, referred to as a dual task (DT) paradigm, may have a deleterious effect on balance, which can be expressed in terms of a Dual Task Cost (DTC), relative to a single task (ST) condition. The aim of this study is to explore whether a cognitive-motor DT paradigm uncovers balance deficits in prodromal (Pro-HD) and manifest HD, compared to healthy adults (HA).

Methods

Balance under ST and DT conditions was examined using the BTracks Balance Plate and Balance software in 30 individuals with HD, 17 individuals with Pro-HD, and 20 HA. During the DT condition, participants were simultaneously administered a version of the Paced Auditory Serial Addition Test (PASAT). DTC is calculated as the relative ratio of ST to DT, controlling for ST performance: DTC= (ST − DT)/ST x100.

Results

The HA group performed significantly better than the HD group on both the ST and DT conditions (p < 0.01), while balance scores between the HA and the Pro-HD groups were not significantly different. The DTC scores, however, were significantly better in the HA compared to both the HD (p < 0.001) and Pro-HD (p < 0.05) groups.

Conclusion

Our findings indicate that the addition of a cognitive task interferes with participant's balance, reflecting real-life performance, and may have additional value for estimating transition to manifest disease, appraising fall risk, or serving as a valid outcome measure in observational and interventional trials in HD.