Suprascapular Nerve Conduction Study: Comparative Analysis between Surface and Needle Recording Methods in Normal Subjects

ABSTRACT

OBJECTIVE: An electromyographic examination is often utilized to confirm the diagnosis of suprascapular neuropathy in patients with shoulder pain and dysfunction. The purpose of this study was to compare two recording methods (surface and monopolar needle electrode recordings) for the evaluation of suprascapular nerve. METHOD: Twenty-two healthy subjects were tested with each method. Differences between the recording methods were compared for compound muscle action potential (CMAP) latencies and amplitudes. And the parameters obtained from two recording methods were correlated. RESULTS: The mean age was 43.6+/-12.4 years (range from 23 to 72 years old). The surface recordings appeared to give a more reproducible latency and amplitude of CMAP of the infraspinatus. The surface recorded CMAP latency and amplitude were 2.58+/-0.46 ms, and 12.6+/-2.7 mV, respectively. Those of the needle electrode recording were 2.49+/-0.41 ms and 27.6+/-6.55 mV, respectively. The two recordings were significantly correlated in latency (r=0.876, p<0.05) and amplitude(r=0.484, p<0.05). CONCLUSION: Considering the invasiveness of study and compliance of the patient, the surface electrode recording may be prudent for the convenient assessment and follow up studies in suprascapular nerve conduction study.