Sex-differences in adverse symptoms reported as side-effects by Parkinson´s disease patients receiving Deep brain stimulation (DBS) in the subthalamic nucleus

Parkinson’s disease (PD) is a neurodegenerative disorder affecting motor and non-motor function. In advanced-stage PD, Deep Brain Stimulation (DBS) is applied to relieve motor symptoms. The subthalamic nucleus (STN) is a common target area. While STN-DBS efficiently relieves PD motor symptoms, there have been reports of adverse side-effects. This study collated reports on adverse symptoms reported as side-effects upon STN-DBS and examined their sex distribution; biological male vs biological female. Overall, most studies had a disproportion of males to females, or did not report sex at all. 17 original articles providing information of reporting patients´ sex, were identified and analysed. Articles included single case reports and larger clinical cohorts to cover the range STN-DBS related symptoms. Adverse side-effects were separated into three main categories (physiological, affective, cognitive). Sex-difference was detected in the all categories. Findings support recent publications of gender-differeces. Depression was the main affective side-effect reported by females. Males, but not females, reported aggressive behavior and sexual dysfunction. This review of published clinical reports revealed sex-differences in adverse side-effects of STN-DBS described by PD patients and also detected sex-differences in the descriptive details of reported side-effects. These findings advocate for sex-inclusion and streamlining of data to equalize information from both sexes when reporting beneficial and adverse effects of this treatment. With lack of equal level of description across sexes, progress in treatment is hampered. Further knowledge of sex-differences will support tailor-designed treatments for improved efficacy in PD patients of both sexes.