Background Motor disturbances in Huntington's disease can be subdivided into a predominantly choreatic or hypokinetic-rigid subtype. The relation between these motor subtypes and cognitive and general functioning is poorly understood, but can be of importance in the care for Huntington's disease patients.
Aims Investigating the possible clinical differences between predominantly choreatic and predominantly hypokinetic-rigid Huntington's disease.
Methods/technique Cross-sectional data from the European Huntington's Disease Network Registry study up until 2011 were analysed. Data of the first visit of all subjects with an expanded CAG ≥36 and a total motor score ≥5 and complete cognitive, function and motor assessments were retrieved. A total of 1882 subjects were classified as predominantly choreatic (N=528) or predominantly hypokinetic-rigid (N=432), according to their score on those items of the total motor score a priori labelled as either choreatic or hypokinetic-rigid items; the other 922 patients were of a mixed motor type. The relationship between motor type and cognitive (total cognitive score) and general functioning (total functional capacity) was investigated using a linear regression model.
Results/outcome Motor subtype was a significant predictor of both cognitive and general functioning (p<0.001). In both analyses the patients with the choreatic type had significantly better scores than those with the hypokinetic-rigid type. The total amount of variance explained by the cognitive model is 58% and by the general functioning model 56% (p<0.001). In both models motor subtype was the second most influential predictor (p<0.05).
Conclusions We conclude that Huntington's disease patients with a predominant choreatic motor phenotype exhibit better global and cognitive functioning than patients with a predominant hypokinetic-rigid motor phenotype.