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Two different pathogenetic mechanisms in psychogenic tremor
J Raethjen1, F Kopper, R B Govindan
1Department of Neurology, University of Kiel, Germany.
Neurology
|September 15, 2004
Summary
Psychogenic tremor may stem from two distinct mechanisms. Some cases show coherent oscillations, suggesting voluntary action, while others exhibit independent movements, indicating nonvoluntary processes.
Area of Science:
- Neurology
- Movement Disorders
Background:
- The underlying pathophysiology of psychogenic tremor remains unclear.
- While voluntary tremor can be entrained, some patients exhibit continuous tremor, suggesting nonvoluntary mechanisms.
Purpose of the Study:
- To investigate the potential pathogenetic mechanisms of psychogenic tremor.
- To differentiate between voluntary and nonvoluntary oscillatory mechanisms in psychogenic tremor.
Main Methods:
- Fifteen patients diagnosed with psychogenic tremor were studied.
- Accelerometry and electromyography (EMG) recorded postural tremor in both hands.
- Coherency analysis of EMG signals between hands was performed.
Main Results:
- Seven patients displayed significant coherence between hand tremors, suggesting voluntary production.
- Eight patients showed independent oscillations, indicating a nonvoluntary mechanism.
- No significant differences in tremor frequency or amplitude were observed between groups.
Conclusions:
- Psychogenic tremor may arise from distinct pathogenetic pathways.
- Coherent tremor suggests voluntary movement, while absent coherence points to nonvoluntary mechanisms like clonus or enhanced physiologic tremor.