Evaluation of the Cutaneous Silent Period in a Healthy Brazilian Population

PURPOSE: To establish cutaneous silent period (CSP) normative values and investigate the variables that may influence them. METHODS: We tested 41 healthy subjects. All subjects underwent nerve conduction studies, and we evaluated the CSP in both arms. RESULTS: Four subjects did not have CSP and were excluded. The analyses were performed in the healthy group composed of 23 women and 14 men, with a mean age of 35 (range, 19-64) years. The CSP median duration was 23.2 milliseconds (ms), with 2 to 98th percentile at 11.3 and 48.7 ms. The median onset latency was 87.9 (range, 72.9-109) ms, and the median end latency was 112 (range, 93.8-138) ms. The CSP onset latency positively correlated with height, whereas CSP end latency and duration were weakly but significantly associated with age. Some measurements of ulnar nerve conduction study also correlated with CSP measures. The interrater coefficients for the primary measures of onset and end latency demonstrates the reproducibility of the method. CONCLUSIONS: The CSP with the fifth digit stimulation and recording from the abductor digiti minimi muscle is a valid diagnostic tool that can be used in clinical practice.