Utility of a contemporary digital cognitive-motor biomarker in Huntington's and Parkinson's diseases

Background Cognitive impairment significantly impacts the quality of life in patients with neurodegenerative disorders, including Huntington's disease (HD), Parkinson's disease (PD), and Alzheimer's disease (AD). Objective This study aims to assess the utility of MemTrax, a contemporary digital continuous recognition task platform originally developed for AD, as an effective tool for revealing cognitive and clinical motor impairments in HD and PD populations as aligned with respective disease staging. Methods A total of 135 healthy controls, 131 HD, and 212 PD participants were included in the study. MemTrax metrics, recognition accuracy (MTx-%C), response time (MTx-RT), and a composite score (MTx-Cp) were correlated with clinical motor and cognition scales and disease staging. Results MemTrax metrics showed stage-dependent declines in both HD and PD. In HD, both MTx-%C and MTx-Cp decreased significantly from pre-HD stage to stage 2 ( p < 0.001), showing negative correlations with motor impairment and cognitive scales. In PD, MTx-Cp declined across Hoehn and Yahr stages (1–4, p < 0.001), with strong negative correlations to Unified Parkinson's Disease Rating Scale Part III (UPDRS III) and positive links to Montreal Cognitive Assessment/Mini-Mental State Examination. Additionally, MTx-RT increased with disease progression and correlated positively with UPDRS III, indicating it could assess psychomotor slowing in PD ( p < 0.01). Conclusions MemTrax effectively captures cognitive-motor decline in HD and PD. The responsivity of MemTrax to the severity of these disorders extends its utility beyond AD, positioning MemTrax performance as a cross-disease digital biomarker for early detection in neurodegenerative diseases.