Facial dyskinesia induced by auditory stimulation: a report of four cases.
BACKGROUND
The Vibroacoustic Disease (VAD) is an occupational pathology induced by long-term (>10 yr) exposure to large pressure amplitude (> or = 90 dB SPL) and low frequency (< or = 500 Hz) noise. During studies contributing to the characterization of VAD, abnormal facial movements induced by repetitive auditory stimuli were observed in one individual employed as an aeronautical mechanic. The goal of this study was to investigate the existence of movement disorders triggered by auditory stimuli in a group of VAD-diagnosed patients.


METHODS
Sixty VAD patients received auditory and median nerve stimulation. Simultaneously, EEG monitoring was performed.


RESULTS
Abnormal myoclonus movements were triggered by auditory stimuli in four patients. EEG recordings were normal in all 60 patients. Stimulation of the median nerves did not trigger any abnormal movements.


CONCLUSIONS
These data suggest that this facial dyskinesia has a subcortical origin.
Martinho Pimenta
A J
AJ
Santo António dos Capuchos Hospital, Lisbon, Portugal.
Castelo Branco
N A
NA
D000161:Acoustic Stimulation; D000328:Adult; D000401:Aircraft; D002680:Chin; D005152:Facial Muscles / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009069:Movement Disorders / Q000175:diagnosis / Q000209:etiology* / Q000503:physiopathology*; D009207:Myoclonus / Q000175:diagnosis / Q000209:etiology* / Q000503:physiopathology*; D009623:Noise, Occupational / Q000009:adverse effects*; D009784:Occupational Diseases / Q000175:diagnosis / Q000209:etiology* / Q000503:physiopathology*; D014732:Vibration / Q000009:adverse effects*; D014743:Videotape Recording