Motor exam in Huntington's disease: is one leg stand a useful test for clinical and quantitative motor assessment?

Background: Motor phenotype in Huntington's Disease (HD) is usually assessed using the “Unified Huntington's Disease Rating Scale Total Motor Score“ (UHDRS-TMS) (Huntington Study Group 1996). One of the sub-items of the UHDRS-TMS examines postural stability. We observed in clinics that testing balance in one leg stand maybe an additional sensitive parameter to assess deficits in motor coordination early on in HD. We previously observed that postural instability in two leg stand in HD can be assessed objectively using a force plate and found a correlation of deficits to the UHDRS-TMS (Rumpf et al. 2007). Objectiv…