[Spinal increase of the Hoffmann reflex by stimulation of the sural nerve at a low intensity: study of the paraplegic].

The effects on the H reflex of stimulating the sural nerve at a low intensity were investigated in 9 paraplegic patients with complete spinal sections. Six delays between the cutaneous and the reflexogenic stimuli were tested: 20, 50, 70, 80, 100 and 120 msec. The results show a very significant increase of the H reflex at delays between 50 and 120 msec. We conclude that the increase of the H reflex observed in normal subjects at the same delays after a sural nerve stimulation is indeed a spinal phenomenon.