UC San Diego

Objective: To assess the clinical utility of a standardized, non-invasive electrodiagnostic testing protocol in refining the diagnosis and management of patients referred for tremor evaluation. Methods: In this prospective observational study, patients with tremulous limb movements with indeterminate clinical diagnoses involving tremor as a cardinal symptom were referred by movement disorders neurologists. Participants underwent standardized phenotyping and electrodiagnostic studies for tremor analysis including four-channel surface electromyography polygraphy and two-channel accelerometry. Results: Clinical and electrophysiological data from 31 consecutive individuals were analyzed. Electrodiagnostic testing refined the differential diagnosis in 25/31 (80.6 %) participants and changed therapy in 14/29 (48.3 %). Changes included adjusting pharmacotherapy (n = 10), undergoing deep brain stimulation surgery (n = 2), or avoiding invasive procedures (n = 2). Conclusions: We propose that electrodiagnostic testing is a clinically valuable tool that can narrow the differential diagnosis and impact treatment of tremor. Significance: Clinical evaluation alone may be insensitive in diagnosing the tremor type when findings are subtle or when multiple movement disorders coexist. This may lead to inaccurate diagnosis and management, increasing cost and patient burden, and prolonging or preventing a successful journey towards adequate treatment. Clinical neurophysiology is a useful diagnostic procedure that can detect and quantify movements that may be otherwise indistinguishable by visual observation.