Deep brain stimulation for chorea-acanthocytosis: a systematic review

Deep brain stimulation (DBS) is a reversible treatment for chorea-acanthocytosis (ChAc). Its safety and efficacy remain elusive due to the low prevalence of ChAc. We aimed to investigate the safety and efficacy of DBS for ChAc by systematically reviewing literature through PubMed and EMBASE. Inclusion criteria were reports on the efficacy or safety of DBS for ChAc and English language articles, and exclusion criteria were other movement disorders, non-human subjects, and studies without original data. Most studies were published as case reports, and we therefore pooled these cases in one cohort. Twenty studies with 34 patients were included. The mean age of symptom onset was 29.3 years (range, 17-48). The median follow-up was 12 months (range, 2-84). Twenty-nine patients underwent GPi-DBS, two received STN-DBS, and one underwent Vop-DBS. Electrodes were implanted into the ventralis oralis complex of the thalamus and the pallidal in two patients. Symptoms seemed to be easier relieved in chorea (88.5%) and dystonia (76.9%) but dysarthria of most patients (85.7%) was no response after DBS. The Unified Huntington's Disease Rating Scale-Motor Score was used to assess the efficacy of DBS in 25 patients; the mean score decreased from 43.2 to 22.3 and the median improvement rate was 46.7%. Of 24 patients with data on adverse events, complications occurred in 9 patients (37.5%; mostly transient and mild events). DBS is a promising treatment for ChAc with satisfactory efficacy and safety based on the review. Pallidal and thalamic DBS have been applied in ChAc; GPi-DBS seems to be more widely used.