Objective: Focal neuropathies are the most frequently encountered disorders in the electroneuromyography (ENMG) practice. In this study, in order to obtain useful data on the epidemiology and classification of nontraumatic focal neuropathies, we retrospectively evaluated the etiology of the nontraumatic focal neuropathies as well as their distribution according to the nerves involved in patients who presented to our electrophysiology laboratory.

Materials and Methods: The patient records were retrospectively analyzed to perform the study. A total of 4759 patients [3843 (80.8%) females and 916 (19.2%) males], who presented with the referral diagnosis of focal neuropathy between 1996 and 2009, were included.

Results: The ENMG study was normal in 2136 (44.9%) patients. The referral diagnosis was concordant with the final diagnosis in 2502 (52.6%) patients, and focal neuropathy was evident. Polyneuropathy was diagnosed in 63 (1.3%) patients while 58 (1.2%) had other diagnoses (radiculopathy, motor neuron disease). Two thousand and seven (80.2%) patients with focal neuropathy were females and 495 (19.8%) were males. The mean age of the subjects was 48.33±13.32 years. The median nerve was the most frequently affected nerve and carpal tunnel syndrome (CTS) (74.6%) was the most frequently encountered focal neuropathy. Facial nerve (16.8%) and ulnar nerve (4.7%) neuropathies followed them.

Conclusion: The proportion of the normal cases was high in our study and the concordance between referral and final diagnosis was not satisfactory. This result indicates that ENMG must be performed after a detailed history and physical examination. In contrast to traumatic focal neuropathies, females predominated among the patients with nontraumatic focal neuropathies and the mean age was higher than that of men. Unlike traumatic focal neuropathies (ulnar and sciatic nerves), the median nerve was the most frequently affected nerve and CTS was the most frequently encountered focal neuropathy, as mentioned in the literature.