Paired associative stimulation improves hand function after nontraumatic spinal cord injury: a case series

Abstract Objectives Long-term paired associative stimulation (PAS) is a non-invasive combination of transcranial magnetic stimulation and peripheral nerve stimulation and leads to improved hand motor function in individuals with incomplete traumatic tetraplegia. Spinal cord injuries (SCIs) can also be induced by neurological diseases. We tested a similar long-term PAS approach in patients with nontraumatic neurological SCI. Methods In this case series five patients with nontraumatic tetraplegia received PAS to the weaker upper limb 3 to 5 times per week for 6 weeks. Patients were evaluated with manual muscle testing (MMT) before and immediately after therapy and at the 1- and 6-month follow ups. Patients were also evaluated for spasticity, hand mechanical and digital dynamometry, pinch, and Box and Blocks tests. Results All patients had improved MMT values at all post-PAS evaluations. The mean±standard error MMT increase was 1.44±0.37 points (p=0.043) immediately after PAS, 1.57±0.4 points (p=0.043) at the 1-month follow-up, and 1.71±0.47 points (p=0.043) at the 6-month follow up. The pinch, digital dynamometry values, and Box and Blocks test results also improved in all patients. Conclusions Long-term PAS may be a safe and effective treatment for improving hand function in patients with nontraumatic tetraplegia. Significance This is the first report demonstrating the therapeutic potential of PAS for neurological SCI.