[Peripheral and central somatosensory pathways and evoked cerebral potentials during aging (author's transl)]

This study used electrical stimulation of the fingers and hands and evoked potentials to determine the functional state of the peripheral and central somatosensitive pathway in octogenarian subjects after very strict selection to exclude associated disease. The nerve fibers of the digital nerves were studied by recording the antidromic potential. Despite a marked reduction in the amplitude of this potential and an increase in latent period and duration, absolute and functional refractory periods were not increased with aging. Slowing in the rate of orthodromic conduction was demonstrated by the recording of nerve potentials and the spinal evoked potential. The amplitude of this evoked activity in the neck is significantly reduced in octogenarians. By contrast, the central transit of the somatosensory afferent impulses from the spinal cord to the cortex is remarkably well preserved. In addition, the amplitude of the parietal components of S.E.P. are significantly increased in the octogenarian.