An 18-month follow-up study on vibrotactile sense, muscle strength and symptoms in computer users with and without symptoms

Abstract

The aim was to explore whether symptoms, sensory perception and muscle strength among computer users with and without symptoms in forearm or hand had changed after 18 months. Twenty-six out of 30 females, experienced computer users, from a baseline study participated in the follow-up. In addition, five control subjects participated. The subjects completed a questionnaire regarding exposure to computer work, prevalence and severity of symptoms, health status and physical activity. Perceived thresholds for vibration were measured twice with 3 h in between on the right hand on four different sites innervated by the radial, median or ulnar nerve. Furthermore, sensory perception was measured on the left hand on two sites innervated by the median and ulnar nerve, respectively. Skin temperature was measured at each site prior to sensory perception measurements. Maximal handgrip strength and maximal pinch-grip strength were measured for both hands. Eighty-three percent of the subjects who had symptoms at baseline still had symptoms and 21% of the subjects who did not have symptoms at baseline experienced symptoms at follow-up. The first and the second sensory perception measurement were highly correlated. Vibrotactile sensory threshold representing the radial nerve was increased since baseline among the subjects who originally had symptoms. At follow-up, the vibrotactile sense for the computer users who reported symptoms in forearm or hand at baseline was deteriorated for the sites representing the median, ulnar and radial nerves compared to the control group. Among the original symptom free subjects with intensive computer work increases in vibrotactile perception thresholds were found for the sites representing the median and ulnar nerves. Handgrip muscle strength remained unchanged for all groups. The study indicates that sensory dysfunctions as well as symptoms in forearm and hand among computer users to a high degree are persistent. Muscle strength seems to be well maintained.