Nerve conduction studies (NCS) formed a part of broad cross sectional study done to assess the musculoskeletal discomforts (MSD) related to long hours of computer use. With ever increasing use of computer in various establishments, its role in causing injury to the nerves of upper limbs has generated much debate and discussion.
To find out the prevalence of Carpal Tunnel Syndrome (CTS) in computer operators.
To detect any abnormality with nerve conduction following varied period of computer use and correlate it with clinical symptoms.
It is a community based cross sectional study of nerve conduction done on sub-sample of 61 subjects randomly selected from a sample of 419 subjects who work on computer for varying period of time, using standard procedures. Bilateral median and ulnar nerves were studied for both motor and sensory components. F-wave study was also performed.
Majority(82.0%) of the subjects showed a higher than 0.2ms difference between sensory latency of their median and ulnar nerves, including 20(32.8%) subjects who reported clinical symptoms suggestive of CTS. The mean ipsilateral difference between median and ulnar latency of sensory component in these 20 subjects was 0.615ms ± 0.688 on right side and 0.857ms ± 1.339 on left side, higher than the mean difference of all 61 subjects. Five(25%) out of these 20 subjects showed reduction in Sensory Nerve Action Potential(SNAP) amplitude ranging from 21.8 to 34.1 mV. In only two subjects, both clinical as well as electrodiagnostic criteria of CTS were satisfied, making the prevalence of CTS as 3.3%. Six (9.8%) subjects showed the difference between motor latency of median and ulnar nerves greater than 1.1ms on both sides. While 11(18.0%) subjects had F-wave minimum latency of median nerve greater than ulnar nerve on both sides.
In our study, prevalence of CTS was 3.3% in computer operators, which is probably the same as that seen in the general population. However, the symptomatic subjects reported a higher ipsilateral difference between sensory latency of median and ulnar nerves than that in asymptomatic subjects along with SNAP amplitude reduction. These subjects may be followed up prospectively and appropriate prevention plan should be implemented.
Computer operators, nerve conduction, Carpal Tunnel Syndrome
