*2.1. Procedure*

Forty-five patients diagnosed with PD and treated at the Geneva University Hospitals were included between 31 January 2013 and 8 June 2017 in a global study investigating the possible determinants of quality of life after DBS. The study procedure consisted in filling out a series of self-reported questionnaires 2 weeks before DBS surgery (T0), as well as 6 (T1), 12 (T2) and 18 (T3) months after. Inclusion criteria were a DBS medical indication for idiopathic PD collaboratively established by senior neurologist, neurosurgeon, neuropsychologist and consultation-liaison psychiatrist; a su fficient French level to read and understand a series of self-administered questionnaires; and agreemen<sup>t</sup> to sign a consent form. Participation was proposed to all patients clinically accepted for DBS, which includes capacity of discernment, and all participants agreed with the study procedure.

The present study received approval from the Canton of Geneva ethics committee under the registration number 14-182.
