Hypokinesia in Huntington's disease co-occurs with cognitive and global dysfunctioning.

Besides chorea, hypokinesia is an important motor disturbance in Huntington's disease (HD) but its clinical, neuropsychiatric, and cognitive functioning correlates are largely unknown. This cross-sectional study investigates correlates of hypokinesia in HD and its effect on global functioning. Among 150 HD gene carriers, 96 patients were clinically motor manifest. Hypokinesia was assessed using the motor section of the Unified Huntington's Disease Rating Scale and global functioning was measured using the Total Functioning Capacity (TFC) scale. Neuropsychiatric measures included the Apathy Scale and the Composite International Diagnostic Interview for diagnosis of depression. The Mini Mental State Examination (MMSE) and a composite executive cognitive measure were used to assess global and executive cognitive functioning, respectively. Compared with 45 patients with no or mild hypokinesia, 51 patients with moderate to severe hypokinesia showed a significant difference in most clinical and neuropsychiatric variables and had worse cognitive functioning scores. However, using forward logistic regression analysis, poor executive cognitive functioning was the only independent correlate of hypokinesia (OR 7.33; 95% CI: 2.82-19.0; P < 0.001). Hypokinesia score was inversely associated with the TFC score (P < 0.001), also after adjusting for chorea, use of antipsychotics, apathy, and global and executive cognitive functioning. In conclusion, the presence of moderate to severe hypokinesia in HD patients co-occurs with executive cognitive dysfunction and adversely affects global functioning.