Abstract
Background and aim : Use of F-wave studies is a recent development in electrophysiology. Abnormalities in F-wave latency may be the sole abnormality in certain types of peripheral neuropathy when other conduction studies have been normal. Our work aimed to determine mean values for the principle components of the ulnar nerve F-wave, namely: latency, amplitude, duration in normal Sudanese adults, to compare between right and left, distal and proximal mean values of the F-wave latency, amplitude and duration, and to find out sex and age related changes in the principle components of the F-wave as well as to find a relationship between the different F-wave parameters.

Subject and Methods : Observational nerve conduction study was performed on one hundred normal Sudanese adults (male=55, female=45), on voluntary basis, using an inclusion criteria of being normal Sudanese adult with no history of neurological disease. Recording took place in the faculty of medicine, university of Khartoum, using an electromyography machine.

Results : Values obtained in this study showed a mean of 27.6±0.23 (SE) msec for F-wave distal latency, a mean of 433.75±17.46 (SE) mV for F-wave distal amplitude and a mean of 6.27±0.22 (SE) msec for F-wave distal duration. No significant difference observed between right and left upper extremities in the different F-wave parameters and between distal and proximal values of the F-wave amplitude and duration. There was sex related changes in F-wave distal latency and duration with shorter latency in females and shorter duration in males, but no age related changes was observed concerning latency, amplitude and duration. A significant correlation between distal and proximal values of the F-wave components as well as between F-latency & duration and between F-amplitude and duration had been suggested.

Conclusion : Mean values of ulnar nerve F-wave components among healthy Sudanese adults seems to similar to universal figures. Right and left and distal and proximal values were similar and no age related changes observed in the different F-wave parameters. F-wave latency revealed a significant relationship with sex, F-wave duration was more related to F-latency than to sex, with shorter latency in female and shorter duration in males. A strong positive correlation between distal and proximal values and between distal amplitude and duration was also suggested, while a negative correlation was found between distal latency and duration.

Key words: F-wave, F-latency, Ulnar nerve, electromyography