Objective assessment of gait and posture in premanifest and manifest Huntington disease - A multi-center study.

BACKGROUND: Deficits in posture and gait are known to contribute to the complex motor phenotype of Huntington disease (HD). Objective and quantitative measures of posture and gait provided by posturography and GAITRite® assessments may supplement categorical rating scales such as the UHDRS-TMS and increase power and sensitivity of clinical trials. OBJECTIVES: To investigate whether posturography and GAITRite® measures reveal (1) changes in manifest or premanifest HD mutation-carriers, (2) a correlation to the UHDRS-TMS and functional measures in manifest HD, and (3) a correlation to the disease-burden-score (based on CAG-repeat-length and age). METHODS: Posturography and GAITRite® were applied in premanifest (n = 26) and manifest HD gene-mutation-carriers (n = 40) in different paradigms compared to age-matched controls (n = 30) in a cross-sectional multi-site study conducted in three centers. Subjects were assessed clinically with the UHDRS Total-Motor-Score, Total-Functional-Capacity and Functional-Assessment-Scale. RESULTS: Several posturography measures were able to discriminate between controls, premanifest, and manifest mutation-carriers in both conditions assessed. Only one GAITRite® measure separated controls and premanifest participants, while discrimination between controls and manifest same as between premanifest and manifest participants was possible in several measures. Correlation with all clinical measures was seen in only one measure per device while correlations to the disease-burden-score seen in posturography only. CONCLUSION: Overall the results suggests that posturography detects alterations in premanifest and manifest mutation-carriers more reliably than GAITRite® measures. Correlations with clinical assessment scores are limited; correlation with disease-burden-score is seen in posturography only. Data acquisition and analysis was easier with posturography than GAITRite® assessments in out-patient settings.

Huntington's disease: objective assessment of posture--a link between motor and functional deficits.

BACKGROUND: Postural deficits in Huntington's disease are linked to functional impairment. We investigated whether assessment of center-of-mass variability using posturography provides objective and quantitative measures that correlate to the severity of motor phenotype, functional measures, and genotype as assessed by a disease burden score (based on repeat length and age). In addition, we investigated whether withdrawing visual feedback facilitates the detection of postural deficits. METHODS: Using a force plate, the ability of symptomatic Huntington's disease patients (n = 34) and controls (n = 20) to stand as stably as possible was assessed in eyes-open and eyes-closed conditions. RESULTS: All posturographic measures (DISTANCE, VELOCITY, and SURFACE of centre-of-mass mobility) were increased in patients and correlated to (1) the UHDRS Total Motor Score, (2) the UHDRS Total Functional Capacity, (3) the UHDRS Functional Assessment Score, and (4) the disease burden score. Correlations to motor and functional measures were stronger when visual feedback was provided. CONCLUSIONS: Posturography may provide useful objective and quantitative measures of postural motor dysfunction in Huntington's disease.