A quantitative electrophysiological study of motor neurone disease.

Abstract

Barwick, 1974;Lenman and Ritchie, 1976), the increase in motor unit muscle fibre densities (Stalberg et al., 1975) and anatomical territories (Erminio et al., 1959) are the electrophysiological signs of a relentlessly progressive denervation of the somatic musculature. Active reinnervation from surviving motor units is evident but inadequate to prevent the clinical and electrophysiological deterioration of the patient.The electrophysiological literature provides copious qualitative but little quantitative information on the electrophysiological changes in motor neurone disease. The purpose of the present paper is to present the results of the application of our computer assisted electrophysiological techniques Address for correspondence: Dr J. P. Ballantyne, Department of Neurology, Institute of Neurological Sciences, Southern General Hospital, Glasgow G51 4TF. Accepted 9 May 1978 for the quantitation of the number of motor units in the extensor digitorum brevis (EDB) muscle (Ballantyne and Hansen, 1974a) along with the measurements of the parameters of the surviving and electrically evoked motor unit potentials (MUPs) in the same muscle by a computer subtraction method (Ballantyne and Hansen, 1974b MethodsThe composition and placement of the surface recording electrodes over the EDB muscle, the properties of the stimulating electrodes over the anterior tibial nerve at the ankle, and the details of the rate and strength of stimulation used to evoke motor unit potentials have been described (Ballantyne and Hansen, 1974a

Motor unit number estimate as a predictor of motor dysfunction in an animal model of type 1 diabetes

“…In particular, MUNE has been applied in human diabetic neuropathy. Hansen and Ballantyne (18,19) found MUNE to be reduced in both uremic and diabetic neuropathies, with diabetic patients showing more evidence of compensatory reinnervation on the basis of individual motor unit size. These electrodiagnostic findings are supported by pathological studies suggesting more reinnervation in diabetic than uremic nerves (39).…”

Assessment of Motor Units in Neuromuscular Disease

“…Collateral reinnervation after denervation is an ongoing process and accounts for the finding on muscle biopsies of fiber-type grouping with loss of the normal checkerboard pattern, and for an increased size of the motor unit action potentials on electromyography (EMG). It occurs with progressive incomplete denervation [26,27], in nonprogressive diseases exemplified by poliomyelitis which has very large motor units, and to a lesser extent with normal aging. Collateral reinnervation can compensate for the loss of at least 50 % of the motor neuron pool [25], and probably occurs to some degree until only 5 % of the motor unit pool remains [27,28].…”

“…It occurs with progressive incomplete denervation [26,27], in nonprogressive diseases exemplified by poliomyelitis which has very large motor units, and to a lesser extent with normal aging. Collateral reinnervation can compensate for the loss of at least 50 % of the motor neuron pool [25], and probably occurs to some degree until only 5 % of the motor unit pool remains [27,28]. From collateral reinnervation, synaptic sprouts occur such that immature reinnervating end plates form unstable connections with muscle, creating motor unit instability [29].…”

Biceps vs extensor carpi radialis recovery in Frankel grades A and B in spinal cord injury patients

“…3 Hansen & Ballantyne reported that reinnervation in motor neuron disease was sufficient to compensate com pletely for the loss of up to 50% of the motor neuron pool supplying the muscle. 38 Gordon and her coworkers found that single motor units enlarged up to five times their original size in the hand muscles of quadri plegic subjects, resulting in the ability to compensate for up to 80% of motor neuron loss.36 Most of the subjects in the present study did not recover completely. There fore, these subjects presumably had greater than 50-80% denervation at the time of SCI.…”