Long-term outcome of deep brain stimulation in fragile X-associated tremor/ataxia syndrome

Introduction: Fragile X-associated tremor/ataxia syndrome (FXTAS) presents as complex movement disorder including tremor and cerebellar ataxia. The efficacy and safety of deep brain stimulation of the nucleus ventralis intermedius of the thalamus in atypical tremor syndromes like FXTAS remains to be determined. Methods: Here, we report the long-term outcome of three male genetically confirmed FXTAS patients treated with bilateral neurostimulation of the nucleus ventralis intermedius for up to four years. Results: All patients demonstrated sustained improvement of both tremor and ataxia - the latter included improvement of intention tremor and axial tremor. Kinematic gait analyses further demonstrated a regularization of the gait cycle. Initial improvements of hand functional disability were not sustained and reached the preoperative level of impairment within one to two years from surgery. Conclusion: Our data on patients with a genetic cause of tremor show favorable outcome and may contribute to improved patient stratification for neurostimulation therapy in the future.