Sensitivities of Sensory Nerve Conduction Study Parameters in Carpal Tunnel Syndrome

Abstract

It is generally accepted that median sensory nerve conduction studies are more sensitive than motor nerve conduction studies in the electrodiagnostic evidence of carpal tunnel syndrome (CTS). This study was conducted to compare the sensitivities of various parameters of sensory nerve conduction studies in the diagnosis of CTS. This prospective study included 88 consecutive patients (151 hands) with CTS and 106 control subjects. CTS was diagnosed clinically by two neurologists. Median sensory nerve responses with wrist stimulation were determined. The onset and peak latencies, peak-to-peak amplitudes, negative peak duration, and area were measured. The differences between the peak and onset latencies were also calculated as a measure of waveform temporal dispersion. Among each measured parameter, values between the 2.5th and the 97.5th percentile range of the control subjects served as the normal limits. Among the 151 hands with suspected CTS, five (3.3%) had normal electrodiagnostic studies and 146 (96.7%) had at least one abnormal electrodiagnostic study. Among the 146 hands with an abnormality, 138 had abnormal onset latency, 143 had abnormal peak latency, and 88 had abnormal difference between peak and onset latency. In addition, 87 had abnormal amplitude, 70 had abnormal duration, and 59 had abnormal area. The sensitivity was 91.4% for onset latency, 94.7% for peak latency, 58.3% for difference between peak and onset latency, 57.6% for amplitude, 46.4% for duration, and 39.1% for area. Our study shows that in patients with CTS, the most sensitive sensory nerve conduction parameter is the peak latency. Studying various additional sensory nerve conduction parameters did not significantly increase the diagnostic yield.

Suprascapular neuropathy: what does the literature show?

“…10,66,78,86 Abnormal findings in these studies can localize the area of compression or nerve injury, or both; however, a negative result on a nerve conduction study does not necessarily preclude a diagnosis of suprascapular neuropathy. A selective injection of local anesthetic can also aid in the diagnosis and localization of nerve injury.…”

Work-Related Carpal Tunnel Syndrome

“…Less than 10% of patients with clinical CTS have normal NCV results. [26][27][28][29][30] In these cases, the treating physician should be sure that the most sensitive and specific NCV tests are done. If not, a request for these tests should be made.…”

Karpal Tünel Sendromu Tanısında Provokasyon Manevraları Duyusal Sinir İletim Çalışmalarının Duyarlılığını Arttırmakta mıdır?

“…A standard orthotic device was used to maintain the wrist either in extension or in flexion. In hands with clinically diagnosed CTS, we confirmed the diagnosis by assessing NCV over the palm-wrist segment (5,6).…”

“…The diagnosis is usually made on the basis of patient history, clinical examination, and electrophysiological test results. The most sensitive diagnostic test for CTS is the sensory nerve conduction study (NCS) (1)(2)(3)(4)(5)(6). Several electrodiagnostic techniques with comparable sensitivity and specificity have been recommended to confirm the clinical diagnosis of CTS (4,5).…”