Background Whereas behavioural disorders, including impulsivity, are frequent and early in Huntington’s disease (HD), their physiopathology remains still poorly understood, especially by lack of validate instrument for their evaluation.

Aim The aim objective of this study was to objective that impulsivity is increased in HD by a quantitative evaluation using a delay discouting paradigm, an experimental task specific of impulsive choice.

Methods 19 patients with symptomatic MH and 19 healthy and matched controls from the general population were included. Patients underwent a neurological and standardised neuropsychological examination, with an additional assessment exploring behavioural disorders including the delay discounting task (DDT), performed on a computer, and scales of self-report questionnaires to measure impulsivity (Barratt Impulsiveness Scale-11) and apathy (Starkstein scale), and an hetero-report questionnaire, the Behavioural Dysexecutive Syndrome Inventory (BDSI).

Results 52.3% of HD patients performances at the DDT were incoherent and could not be interpreted according to the experimental model. Evaluation by BDSI showed significantly impulsivity in HD patients (p = 0.001), as well as irritability and apathy. Statistical analysis did not reveal cognitive factor or factor related to the evolution of HD correlated with the scores at the DDT, BDSI or behavioural scales. Apparent fluctuations between impulsivity and apathy in HD patients could involve inhibitory control disturbances.

Conclusion Quantitative evaluation of impulsivity by a delay discounting paradigm seems to be inappropriate in HD. The BDSI is a validate instrument relevant for the qualitative assessment of behavioural disorders in HD, and should be widely used in this pathology.