Information effect on the perception of pain during electromyography.

Pain during the performance of electromyography (EMG) is an important clinical problem because pain distresses the patient and can interfere with diagnostic accuracy. We hypothesized that anxiety and pain perception associated with EMG would decrease if patients received written material describing the EMG before examination. Forty-two subjects received written material and 30 did not. Information before the test significantly decreased pain perception for women during the nerve conduction studies (p = .008), but not during the needle examination. A similar effect was not identified for the men. Other results indicate that women perceive the test as more painful than do men, older subjects perceive more pain and experience greater anxiety than do younger subjects, and all subjects perceive greater pain during the performance of (concentric, bipolar) needle electromyography than during the nerve conduction studies.