Various aspects of F-wave values in a healthy population (original) (raw)

2004, Clinical Neurophysiology

Objective: To characterize various aspects of F-wave in a healthy population and establish normative data for future clinical use. Methods: A total of 100 healthy volunteers underwent sensory and motor nerve conduction studies of the ulnar and tibial nerves, including F waves elicited by 32 stimuli. Results: The F-wave measurements (mean^SD for ulnar vs tibial nerve) consisted of persistence (83^19 vs 97^5%), minimum, mean and maximum latencies (26.5^2.1, 28.1^2.2, and 30.4^2.3 vs 47.0^4.1, 49.6^4.4, and 52.5^4.4 ms), minimum, mean and maximum F-wave conduction velocities (FWCV) (55.0^2.7, 60.0^2.3, and 64.0^3.0 vs 49.0^2.9, 52.2^3.1, and 55.5^3.4 m/s), chronodispersion (3.9^0.9 vs 5.5^1.4 ms), mean amplitude (347^152 vs 384^148 mV) and mean duration (8.6^2.9 vs 13.0^4.5 ms). Additional measures, registered by electronic averaging, included latency (27.4^2.3 vs 48.6^4.7 ms), duration (9.6^2.2 vs 16.4^4.2 ms), and amplitude (299^156 vs 208^116 mV). Conclusions: The use of a height nomogram serves well as an acceptable means to adjust F latencies for the limb length. In addition to the commonly used minimal latency, maximal FWCV, and persistence, clinically relevant measures with a narrow variability includes mean and maximal latencies, chronodispersion, and mean duration. In particular, mean latency obtained with 10 stimuli gave accurate results either for group or individual analysis. Significance: The data help establish an adequate manner of recording F-wave latencies in clinical evaluation.