Cortical thickness, stance control, and arithmetic skill: An exploratory study in premanifest Huntington disease.

•Neurodegeneration in Huntington disease may be traced before symptom manifestation.•A multimodal protocol for phenotypic study of premanifest carriers is proposed.•Striatal atrophy and occipital thinning is confirmed in close-to-onset carriers.•Posturography shows stance control deficits in close-to-onset carriers.•Calculation subtraction test shows defective combinatorial rule application.