Clinical measurement of mobility and balance impairments in Huntington's disease: Validity and responsiveness

BackgroundMobility and balance in Huntington's disease (HD) are currently assessed in the clinic with three items from the unified Huntington's disease rating scale (UHDRS): walk, tandem and pull tests. These tests may not be optimal because they are scored on an ordinal scale and do not test anticipatory balance. We tested the validity and responsiveness of three clinical tests of mobility and balance.MethodsThree clinical tests (FRT, timed up and go (TUG), Berg balance scale (BBS)) were validated with seven quantitative gait measures and two indicators of functional limitation (HD-ADL and total functional capacity) in 30 subjects with HD. These tests were also assessed for responsiveness to disease severity.ResultsFRT and BBS were correlated with five quantitative gait measures, and TUG with eight (all p < 0.05). All tests were correlated with indicators of functional limitation (p < 0.05) and were responsive to disease severity.ConclusionsFRT, TUG and BBS are valid, responsive and easy to administer clinical tests that should be routinely included with the UHDRS in therapeutic trials for subjects with HD.