The Use of Electrophysiology for Movement Disorders: Experience from a Single Academic Center’s Clinical Practice
Yasoda Satpathy1, Dietrich Haubenberger1, Katherine Longardner1
1University of California San Diego, Dept. of Neurosciences, La Jolla, CA
Objective:
We aimed to assess the clinical utility of a standardized non-invasive electrophysiology protocol in altering the diagnosis and management of patients referred for evaluation of jerky movement disorders.
Background:
Movement disorders are typically diagnosed based on clinical history and observation during the physical exam. However, it can be difficult for even expert clinicians to differentiate between movement disorders based on these measures alone when findings are subtle, unusual, or there are overlapping phenotypes. Electrophysiology testing can be a helpful objective measure to aid in the diagnosis of movement disorders such as tremor and myoclonus.
Design/Methods:
In this prospective observational study, we recruited participants who were consecutively referred for characterization of jerky movements (clinically diagnosed tremor or myoclonus) under our research protocol (UCSD IRB # 191526). Participants underwent electrophysiological testing of upper and/or lower extremities, depending on the affected limbs, using two tri-axial accelerometers (Kistler, sensitivity 20mV/g) and 4-channel surface electromyography at rest and with action, and during tasks. Demographics, results from the electrophysiological testing, and changes in the clinical diagnosis and treatment regimen after the electrophysiology tests were analyzed.
Results:
We have recruited 22 participants (59.1% female, age range 13-82 years, mean age 59.8 years). Diagnoses included orthostatic tremor (n=6), enhanced physiological tremor (n=6), myoclonus (n=3), Parkinsonian tremor (n=2), task-specific tremor (n=2), posture-specific tremor (n=2), Holmes tremor (n=1), dystonic tremor (n=2), and functional tremor (n=2); some participants had more than one type of movement disorder. Electrophysiology changed the diagnosis of 12/22 patients (54.5%, data unavailable for 2 patients) and altered the clinical management of 11/22 patients (50%, data unavailable for 2 patients).
Conclusions:
Our findings support that electrophysiology is a useful tool in clinical practice to improve the diagnosis and guide treatment in patients with jerky movement disorders.