Factors influencing aversion to specific electrodiagnostic studies

Objective To compare the degree of discomfort caused by nerve conduction studies (NCS) versus needle electromyography (EMG), and to determine what factors predict aversion to one test or the other. Methods Two hundred patients underwent both EMG and NCS, and were asked to indicate which test was more uncomfortable. Responses were then correlated with demographic information, testing characteristics, and medical histories to identify any notable associations. Results Of the 200 patients, 58.5% (117) of the patients found the NCS more uncomfortable than EMG. Sixty-one percent (11/18) of the younger patients (18–29 years old) found EMG more uncomfortable (P = 0.08), whereas 68% (40/59) of the older patients (age greater than 60 years old) found NCS more uncomfortable (P = 0.05). Sixty-seven percent (14/21) of the patients whose BMI was less than 22 kg/m2 rated EMG as more uncomfortable (P = 0.01). Sixty-nine percent (27/39) of the patients whose BMI was greater than or equal to 38 found the NCS more uncomfortable (P = 0.02). A positive correlation existed between NCS discomfort and number of nerves tested. 67% (35/52) of the patients with polyneuropathy found NCS more uncomfortable. Conclusion Nerve conduction studies are more uncomfortable than needle EMG in the majority of patients, and predictions regarding which test will be more uncomfortable for a given patient are possible.