Low‐rate nerve stimulation during regional ischemia in the diagnosis of muscle glycogenosis

Five patients with muscle glycogenoses (Gly), 30 normal subjects (NS), and 52 disease controls received 3 Hz repetitive stimulation of the ulnar nerve for 4 min (P‐LRNS) during regional ischemia and during normal circulation. During regional ischemia, the compound muscle action potential (CMAP) of NS showed 8.5% (SE: 1.0) facilitation after 1 min of P‐LRNS and 4.8 ± 1.5% facilitation after 4 min. Gly showed 8.1 ± 1.0% facilitation after 1 min of P‐LRNS but −58.6 ± 6.9% depression after 4 min of P‐LRNS. During normal circulation, in 18 NS and 4 Gly tested, the facilitation detected after 1 min of P‐LRNS was unchanged until the end of stimulation. Compared with the mean ± 2 SD of NS, individual values of CMAP depression were abnormal in all Gly patients already by the 3rd min of ischemic P‐LRNS. of disease controls, myasthenia gravis patients only showed a CMAP depression during ischemic P‐LRNS which was distinguishable from that detected in Gly, being mainly induced by neuromuscular transmission block. © 1996 John Wiley & Sons, Inc.