Is deep brain stimulation effective in Huntington's disease? - a systematic literature review

Introduction. Huntington's disease (HD) is an autosomal dominant neurodegenerative disorder. Substantial for a diagnosis of the disease are motor disorders, with chorea as a hallmark symptom. Other disease manifestations include cognitive dys-function and psychiatric disorders. Currently, pharmacological treatment plays the most important role in the therapy of HD patients. However, deep brain stimulation (DBS) is considered a potential therapeutic option.Aim of the study. Systematic review of current literature on DBS efficacy and safety in the management of motor, behavioural and cognitive functions in patients with HD.Material and methods. A systematic review was conducted with the use of the Scopus database and the following search criteria: TITLE (huntington*) AND TITLE-ABS-KEY ('deep brain stimulation' OR 'neuromodulation'). Our search criteria included original studies with at least five patients, reporting any motor, cognitive and/or behavioural, and functional assessment data with at least a 6-month follow-up. Finally, four selected publications were analysed.Results. In all analysed publications, we found a statistically significant improvement of Unified Huntington's disease Rating Scale (UHDRS) chorea subscore by an average of 40, to over 60% after DBS implantation. Heterogeneous results were obtained for UHDRS total motor score. DBS did not improve functional capacity of HD patients in the analysed studies. We found no systematic assessment concerning the effect of DBS in HD on behaviour, cognition or speech.Conclusions. DBS implantation could be considered as a therapeutic option for patients with severe, drug-resistant chorea. However, the evidence for this is limited. To date, no high-quality data based on randomised controlled trials supports the long-term safety and efficacy of DBS in HD. This treatment option should therefore currently be considered as investigational.