RESUMO
OBJECTIVE: To establish normal ranges of F-wave measures in China as compared to published data in Brazil and Japan. METHOD: We studied F waves in 127 healthy Chinese subjects, aged 21-78 years old, stimulating the median, ulnar, tibial and peroneal nerves distally and proximaly. RESULT: The F-wave latencies had a linear correlation to the subject height in all nerves tested, showing a steeper (P < 0.05) regression line in Brazil compared to China and Japan for the tibial nerve. The Chinese population also had a higher distally elicited F-wave persistence and faster F wave conduction velocities than previously reported for both ulnar and tibial nerves. These values showed significant difference (P < 0.05) compared to Brazil but not to Japan. CONCLUSION: F-wave latencies show a linear correlation to subject height, although the slope of regression lines varies among countries, reflecting the difference in F-wave persistence and F-wave conduction velocity. SIGNIFICANCE: Our study provides a rational for the use of a latency-height nomogram in clinical studies and underscores the importance of developing country specific normative data.