Effects of apomorphine, spinal rTMS, and BoNT on camptocormia: an exploratory wearable sensor-based analysis in a patient with MSA

Multiple System Atrophy (MSA) is a progressive neurodegenerative disorder characterized by autonomic dysfunction, parkinsonism, and cerebellar signs. Among its motor manifestations, camptocormia-defined as an abnormal forward flexion of the trunk-often emerges early in the disease course and significantly compromises patients' quality of life. Aside from physical therapy, the treatment of camptocormia remains particularly challenging, especially in MSA, where surgical approaches such as deep brain stimulation and spinal cord stimulation are generally contraindicated. This underscores the urgent need for effective, non-invasive therapeutic strategies. We report a case of MSA presenting with early-onset and severe camptocormia, who underwent sequential treatment with three non-invasive interventions: subcutaneous apomorphine injection, repetitive trans-spinal magnetic stimulation (rTMS), and botulinum neurotoxin (BoNT) injections targeting the abdominal muscles. We aimed to evaluate and compare the efficacy of each intervention using standardized clinical rating scales, instrumented gait analysis, and static posturography. All three interventions resulted in partial improvements, though with varying degrees of efficacy. Subcutaneous apomorphine injection improved walking velocity and step length but was limited by adverse effects (nausea and hypotension), which precluded the use of continuous subcutaneous infusion as a long-term therapeutic option. Spinal rTMS enhanced performance on the Timed Up and Go (TUG) test, particularly during the return phase, but had no significant effect on posture-related measures. BoNT treatment yielded the most substantial improvements in both walking velocity and step length. Moreover, it was the only intervention to improve the posture item of the Unified Multiple System Atrophy Rating Scale (UMSARS) part II. This case underscores the importance of an integrated therapeutic approach in managing camptocormia, emphasizing the role of neurophysiological and biomechanical assessments in identifying biomarkers of therapeutic response and evaluating the efficacy of treatments such as BoNT and neuromodulation.