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Abnormal cortical responses in patients with writer's cramp
1Department of Neurology and Neurological Surgery (Neurology), Washington University School of Medicine, St. Louis, MO 63110.
Neurology
|November 1, 1993
Summary
Patients with writer's cramp show reduced brain responses in sensorimotor areas. This suggests bilateral brain dysfunction, even in unilateral cases, indicating abnormal central sensorimotor processing.
Area of Science:
- Neuroscience
- Motor Control
- Medical Imaging
Background:
- Writer's cramp is a focal dystonia affecting fine motor skills.
- The underlying neurophysiological mechanisms remain incompletely understood.
- Previous studies suggest central nervous system involvement.
Purpose of the Study:
- To investigate sensorimotor processing in patients with writer's cramp.
- To determine if brain dysfunction is localized or bilateral.
- To provide objective evidence of central abnormalities.
Main Methods:
- Positron Emission Tomography (PET) with H2(15)O blood flow scans.
- Comparison of six right-handed patients with unilateral writer's cramp and eight right-handed controls.
- Assessment of brain activity at rest and during tactile vibration of the hand.
Main Results:
- Vibration consistently activated the primary sensorimotor area (PSA) and supplementary motor area (SMA).
- Both PSA and SMA responses were significantly reduced (approx. 25%) in writer's cramp patients compared to controls.
- This reduction occurred regardless of whether the affected or unaffected hand was vibrated.
Conclusions:
- Patients with writer's cramp exhibit bilateral brain dysfunction.
- Abnormal central sensorimotor processing is evident in writer's cramp.
- These findings offer objective neuroimaging evidence for central nervous system involvement in writer's cramp.