Nerve conduction study findings and their predictors in clinically diagnosed patients with carpal tunnel syndrome in a Saudi population.

Background: Despite the reports of carpal tunnel syndrome (CTS) being commonplace in Saudi Arabia, there is scarcity of cross-sectional or prospective studies detailing the profile of nerve conduction study (NCS) findings in patients with CTS.

Objective: The study aimed to evaluate the neurophysiologic profile of CTS with the view to finding the determinant of abnormal findings in clinically diagnosed cases of CTS in a population of Saudis.

Methods: Nerve conduction study was performed on consecutive patients with clinically diagnosed CTS. Median sensory, ulnar sensory, radial sensory median motor and ulnar motor nerves were assessed. The nerve conduction parameters measured were median and ulnar sensory peak latency, amplitude and velocity. Median conduction velocity, distal latency, and amplitude were also measured. Comparative median-ulnar and median-ulnar-digit 4 studies were done and the severity of CTS was determined. Data was analyzed using STATA software version 12.

Results: A total of 152 patients, comprising 59 males and 93 females (mean age of 42.7 years) with clinically diagnosed CTS were seen during the study period. About 72.4% patients had numbness and paresthesia in the affected fingers, 66.5% had pain in the hands, and 10.5% had weakness in the affected hands. Majority of the patients (62%) had bilateral clinical features. Carpal tunnel syndrome was confirmed with NCS in 84 (55.26%) patients. Presence of weakness in the affected hand, positive Phalen' sign, and positive Tinel's sign in patients appear to predict [6.1 (1.2-30.7), 3.9 (1.2-30.2), and 4.9 (1.4-17.0) respectively] abnormal NCS findings after adjustment for age, gender and the presence of DM.

Conclusion: The study revealed that over half of the patients with CTS had NCS/ Electromyography (EMG) abnormalities. Presence of hand muscles weakness, positive Phalen and Tinel's signs predict abnormal findings on NCS/EMG in patients with CTS.