Background Objective assessment of balance control in dynamic posturography (DP) may be helpful to assess motor phenotype in premanifest (pHD) and symptomatic (sHD) Huntington's disease (HD). HD patients are known to develop a decline of balance that results in a high risk of falls.

Aim To investigate whether DP using a mobile platform (one degree of freedom, anterior-posterior) is able to detect a motor phenotype in pHD and sHD and to assess whether these measures correlate to the severity of disease as assessed by the UHDRS-TMS, DBS (Disease Burden Score), CS (Cognitive Score), FAS (Functional Assessment Score) and TFC (Total Functional Capacity).

Methods 32 HD patients (pHD=11, sHD=21) and 20 age-and-sex-matched controls stood on a mobile platform on a force plate for 25 s, (outcome measures were surface (S), velocity (V) and distance (D) of the center of mass movement). Patients were assessed by the UHDRS-TMS, DBS, CS, FAS and TFC. Non-parametric statistics were performed to compare patients and controls (Mann-Whitney-Test) and to assess dependent variables (Wilcoxon-Test) using SAS 9.2. Correlation analysis was performed using non-parametric Spearman correlations.

Results DP measures were significantly increased in pHD subjects compared to controls (S: p<0.025, V: p<0.009 and D: p<0.006) in contrast to no significant increase observed in static posturography (S: p<0.226, V: p<0.334 and D: p<0.349). In sHD, measures were significantly increased (p<0.0001). Across all HD subjects DP measures S(r=0.647***), V(r=0.577***) and D(r=0.542***) were correlated to the severity of the disease as assessed in the UHDRS-TMS, DBS (r≥0.475**), CS (r≥−0.376*), FAS (r≥−0.456**) and TFC (r≥−0.416**).

Conclusion Assessment of balance in DP is more sensitive in pHD than static measures and provides objective and quantitative readouts. The DP measures correlated to the severity of the motor phenotype assessed in the UHDRS-TMS, DBS, CS, FAS and TFC.