[Electrophysiologic study of Achilles areflexia of aged subjects].

The elderly often presents loss of Achilles tendon reflex. In this electrophysiological study the authors examined 19 patients with loss of the ankle jerk and with no known etiology of peripheral neuropathy. They compared them with 24 subjects who had no areflexia. The study included measurement of the H reflex, of the tendon reflex, of the conduction velocity of Ia fibers and of motor conduction velocity of the tibial nerve. Amplitude of H and tendon response and H/M ratio are diminished in the areflexic group. In 4 cases the H reflex is preserved while the tendon reflex is abolished. The meaning of these impairments is discussed.