Vibration sense in the upper limb in patients with repetitive strain injury and a group of at-risk office workers.
OBJECTIVE
To investigate in patients with repetitive strain injury (RSI) and in office workers using computer keyboard equipment (a) whether the vibration threshold in the hand was altered, (b) the immediate effects of keyboard use on vibration thresholds and (c) whether the tolerance of suprathreshold vibration was normal.


METHODS
A vibrametre (Somedic Ab, Stockholm Sweden) was used to obtain threshold vibration measurements, by the method of limits, for all peripheral-nerve cutaneous distributions in the hand. Tolerance of suprathreshold stimulation was obtained by stimulation of the soft tissues of the forearm by increasing the amplitude of vibration.


RESULTS
Thresholds for vibration were significantly raised for the median nerve in both the patient and office-worker groups. The patient group additionally had raised thresholds for the ulnar nerve. Following use of the keyboard, thresholds for the median nerve were further elevated in the patient group, but not in the other groups, demonstrating a work-related exacerbation. At suprathreshold stimulation. 14 members (82%) of the patient group experienced an allodynic response to vibration, indicating, possible changes in the central processing of non-noxious sensory information. This changed sensory response was not seen in either the office-worker or control groups.


CONCLUSIONS
Patients may have a minor polyneuropathy, whereas the office workers demonstrate early signs of the condition. Quantitative measurement of vibration perception may prove useful in patient assessment and for detection of the early onset of RSI in the work environment.
Greening
J
J
Physiology Department, University College London, England. j.greening@ucl.ac.uk
Lynn
B
B
D000328:Adult; D001132:Arm / Q000294:innervation / Q000503:physiopathology; D016288:Computer Terminals; D012090:Cumulative Trauma Disorders / Q000175:diagnosis / Q000453:epidemiology / Q000209:etiology* / Q000503:physiopathology; D004576:Electromyography; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008475:Median Nerve / Q000503:physiopathology*; D008875:Middle Aged; D009784:Occupational Diseases / Q000175:diagnosis / Q000453:epidemiology / Q000209:etiology*; D010523:Peripheral Nervous System Diseases / Q000175:diagnosis / Q000453:epidemiology / Q000209:etiology* / Q000503:physiopathology; D012016:Reference Values; D012307:Risk Factors; D012678:Sensation Disorders / Q000175:diagnosis / Q000453:epidemiology / Q000209:etiology* / Q000503:physiopathology; D014459:Ulnar Nerve / Q000503:physiopathology*; D014732:Vibration / Q000009:adverse effects*; D017132:Workplace