Sex-related differences in the short and long-term outcome of internal pallidus stimulation for dystonia

Objectives: The importance of sex as a determinant of Globus pallidus internus deep brain stimulation (GPi-DBS) outcome in adults with dystonia remains uncertain. We investigated whether sex is a determinant of the efficacy and safety of GPi-DBS in dystonia. Methods: In this double-center, retrospective cohort study, we followed patients with idiopathic, inherited, or secondary dystonia for at least 12 months after surgery. Dystonia was assessed using the Burke-Fahn-Marsden Dystonia Rating Scale (BFMDRS). Adverse events were recorded. Results: Fifty-six consecutive patients (22 M/34F) were studied. GPi-DBS led to comparable improvements in both sexes. Male patients showed a motor improvement of 62.6 ± 42.4% at 1 year and 53.9 ± 20.9% at the last follow-up (8.6 ± 3.3 years), while female patients showed a motor improvement of 60.5%±29.0% at 1 year and 48.6 ± 28.3% at the last follow-up (at 7.1 ± 4.2 years). Improvement in disability and adverse events were comparable between the two groups. At the first reglage, females showed lower electrical energy delivery, which increased significantly during follow-up. The position of the optimal stimulation center did not differ significantly between the two groups. Conclusion: Our study suggests that the overall motor outcomes and safety profiles were similar across sexes, indicating that factors such as age at implant, precision of lead positioning, and severity of dystonia may be more critical determinants of efficacy than sex itself.