Implantable Subcutaneous Peripheral Nerve Stimulation Improves Degenerative Ataxia

Degenerative cerebellar ataxias have no pharmacological or rehabilitation evidence-based treatment so far. Patients remain highly symptomatic and disabled despite receiving the best medical treatment available. This study investigates the clinical and neurophysiologic outcomes of the use of subcutaneous cortex stimulation (in keeping with the established protocol of peripheral nerve stimulation applied in chronic intractable pain) in degenerative ataxia. We report a case of a 37-year-old right-handed man who developed moderate degenerative cerebellar ataxia at the age of 18 years. His symptoms progressively worsened and impaired his daily activities. We observed clinical improvement for at least one month following an initial two-week trial of parietal transcranial direct current stimulation. Although preoperative non-invasive transcranial neuromodulation application does not predict invasive cortex stimulation outcome, we pursued a long-lasting effect by implanting parietal and occipital subcutaneous electrodes. At 12 months following permanent implantation, the patient exhibited amelioration of his symptoms and a change in neurophysiologic parameters. Central neuromodulation based on peripheral stimulation is considered part of neurosurgical clinical practice for the treatment of a variety of neurological disorders. The underpinning neurophysiological mechanism that explains the effectiveness of the method has not been fully elucidated. We believe that further studies are warranted to investigate these promising results in such devastating conditions.