Sensory group Ia proximal conduction velocity.
The fastest median and ulnar velocities derived by recording motor and mixed nerve action potentials, F waves, H-reflexes, and somatosensory evoked potentials (SEPs) were compared. H-reflex recording was facilitated by employing selective group Ia excitation during voluntary muscular contraction. Mixed nerve, SEP, and H velocities, considered to predominantly reflect group Ia conduction, measured 63.2 +/- 3.2 m/sec, 63.4 +/- 4.5 m/sec, and 67.2 +/- 4.3 m/sec, respectively, between the wrist and elbow. Conventional motor conduction velocity was significantly slower (58.3 +/- 5.1 msec), but F velocity, which although nonuniform is also a measure of motor conduction, was 68.4 m/sec. Mean F latency was considered more reliable and representative than minimum F latency. F and H velocities accelerated proximally by 4.5 m/sec. They complement each other when evaluating motor and sensory group Ia conduction. The H-reflex and SEP use identical stimulus characteristics and when simultaneously recorded allow direct comparison of the fastest conducting peripheral and central sensory pathways.
D000293:Adolescent; D000328:Adult; D004550:Elbow / Q000294:innervation; D004558:Electric Stimulation; D005073:Evoked Potentials, Somatosensory; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009046:Motor Neurons / Q000502:physiology*; D009431:Neural Conduction; D009475:Neurons, Afferent / Q000502:physiology*; D011930:Reaction Time; D014953:Wrist / Q000294:innervation