Defining the spectrum of spasticity-associated involuntary movements

Background: Spasticity can be associated with several hyperkinetic involuntary movements generally referred to as spasms despite different phenomenology and clinical characteristics. Objective: To better characterize the phenomenology and clinical characteristics of spasticity-associated involuntary movements. Methods: We performed a cross-sectional study of a consecutive patient sample from the spasticity clinic. Each patient was interviewed by a movement-disorder neurologist who conducted a standardized movement-disorder survey and a focused exam. Patients with involuntary movements were video-recorded and videos were independently rated by a separate blinded movement-disorder neurologist. Results: Sixty-one patients were included (54% female, mean age 49.7 +/- 13.9 years). Of the entire cohort, 11.5% had spinal, 44.3% had cerebral, and 44.3% had mixed-origin spasticity. Fifty-eight patients (95%) reported one or more involuntary movements: 75% tonic spasms (63% extensor, 58% isometric, 41% flexor/adductor), 52% spontaneous clonus, 34% myoclonus, 33% focal dystonia, and 28% action tremor. One third of the involuntary movements were painful. Only 53% of patients reported that their involuntary movements were much or very-much improved with their current anti-spasticity management. Patients treated with intrathecal baclofen therapy were more likely to report much or very-much improvement compared to patients receiving oral and/or botulinum therapy (P = 0.0061 and 0.0069 respectively). Conclusion: Most spastic patients experience spasticity-associated involuntary movements of variable phenomenology and impact. However, only half of these patients experience significant improvement with the current management strategies. More research is needed to explore better treatment options for spasticity-associated involuntary movements with focus on phenomenology-specific approaches.