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The auditory startle response in relation to outcome in functional movement disorders
Y E M Dreissen1, J H T M Koelman1, M A J Tijssen2
1Department of Neurology and Clinical Neurophysiology, Amsterdam University Medical Center, University of Amsterdam, the Netherlands.
Parkinsonism & Related Disorders
|July 18, 2021
Summary
Functional movement disorder patients showed reduced auditory startle reflex (ASR) after treatment, indicating normalized hyperarousal. However, the late ASR component persisted, suggesting ongoing altered behavioral processing despite symptom improvement.
Area of Science:
- Neuroscience
- Clinical Neurology
- Psychophysiology
Background:
- Functional movement disorders (FMD) are characterized by an enlarged auditory startle reflex (ASR).
- Understanding the ASR's role in FMD symptomology and treatment response is crucial.
Purpose of the Study:
- To investigate the relationship between ASR changes and symptom reduction in FMD patients undergoing a placebo-controlled Botulinum Neurotoxin (BoNT) trial.
- To assess if ASR normalization correlates with clinical improvement in FMD.
Main Methods:
- 14 FMD patients and 11 controls underwent electromyography (EMG) to measure ASR and sympathetic skin response (SSR) before and after one year of treatment.
- Treatment response was evaluated using the Clinical Global Impression - Improvement scale (CGI-I).
Main Results:
- 71.4% of FMD patients reported symptom improvement, largely attributed to placebo effects.
- The early ASR component normalized post-treatment, while the late ASR component remained elevated.
- The SSR normalized after treatment, unlike the persistent late ASR component.
Conclusions:
- Clinical improvement in FMD patients was associated with normalization of the early ASR, likely reflecting reduced anxiety and hyperarousal.
- The persistent enlargement of the late ASR component suggests enduring alterations in behavioral processing in FMD patients, even with motor symptom improvement.
