Thesis (M.Sc.) - Cairo University - Faculty of Medicine - Department of Neuro Physiology

Summary:Assessment of the small peripheral fibers is not feasible by the conventional nerve conduction studies (NCS). The use of the cutaneous silent period (CSP) could serve as an objective functional measure of the thin nerve fibers using NCS machines. Objectives: To evaluate normal values of CSP including normal onset latency, end latency, duration, and latency difference (LD) of CSP, as well assess the effect of age, gender, upper limb length,and body height on CSP values, and detect inter-side differences. Material and methods: 71 healthy volunteers with an age range of 20-60 yearswere included.Several CSP parameters were measured includingCSP latencies, duration, and LD of the upper and the lower limbs for the bilateral median, unilateral ulnar,and bilateral sural nerves. Results:We obtainedmean CSP parameters for thementioned upper and lower limb nerves across the different decades. Age had a significant impact on the latencies of the CSPand was positively correlated to LD. Males showed delayed latencies than females. No significant inter-side CSP differencewas noted the median nerves,as well as no effect of hand dominance. While there was a significant latency onset difference between sural nerves.Upper limb length correlated positively to CSP onset latencies of the upper limb nerves, similarly, the height correlatedpositively to CSP onset latencies of all nerves, in addition to end latencies of sural nerves.Conclusion: The CSP is a simple, non-invasive, and well-toleratedtechnique that can objectively assess the function of the small peripheral fibers and could serve as a valuable adjunct to the routine electrophysiological examination.Obtaining normal values serve as an important reference for future tests

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