Central and peripheral respiratory electrophysiological studies in myotonic dystrophy
Acute and chronic respiratory failure is a common and potentially life-threatening feature in patients with myotonic dystrophy (MD). The causes may be varied, and can involve both the central and peripheral nervous system. To evaluate the incidence of respiratory muscle involvement and the function...
Saved in:
Published in | Brain (London, England : 1878) Vol. 119; no. 6; pp. 1911 - 1922 |
---|---|
Main Authors | , , , , , |
Format | Journal Article |
Language | English |
Published |
Oxford
Oxford University Press
01.12.1996
Oxford Publishing Limited (England) |
Subjects | |
Online Access | Get full text |
Cover
Loading…
Summary: | Acute and chronic respiratory failure is a common and potentially life-threatening feature in patients with myotonic dystrophy (MD). The causes may be varied, and can involve both the central and peripheral nervous system. To evaluate the incidence of respiratory muscle involvement and the function of the central motor inspiratory pathway to phrenic motor neurons we performed magnetic stimulation of the cortex and cervical spinal cord, phrenic nerve conduction studies and needle EMG of diaphragm and intercostal muscles in 25 patients with MD. The results were compared with those from 35 healthy subjects. In addition, pulmonary function tests, blood gas analyses and static mouth pressures were evaluated. Abnormalities in response to magnetic stimulation, including a reduced compound muscle action potential (CMAP) from the diaphram and increased excitability threshold, indicated impaired central inspiratory drive in 20% of cases. Phrenic nerve conduction showed a reduced diaphragmatic CMAP amplitude in 20%, and a delayed negative peak onset latency in 4% of cases. Abnormalities in diaphragm and intercostal muscle needle EMG were found in 76% of cases, these were mainly myotonic discharges (68%) and a decrease in the number of active motor units (36%). Patients with abnormal respiratory electrophysiological parameters had a significantly lower functional vital capacity (FVC; P = 0.005). The duration of the disease correlated negatively with diaphragmatic CMAP amplitude to phrenic nerve, but not magnetic, stimulation. Our results demonstrate that the involvement of the central inspiratory pathway is common in MD patients. Central and peripheral electrophysiological studies of the diaphragm should be considered in the diagnosis and management of patients with MD and dyspnoea. |
---|---|
Bibliography: | ark:/67375/HXZ-R0D0MCGC-J Correspondence to: Dr C. F. Bolton, Department of Clinical Neurological Sciences, University of Western Ontario, Victoria Hospital 375 South Street, London, Ontario, Canada N4A 6G5 ArticleID:119.6.1911 istex:D1EAF17ED5C2FA763C34BD9EEB8110CF3E0D6975 ObjectType-Article-2 SourceType-Scholarly Journals-1 ObjectType-Feature-1 content type line 23 ObjectType-Article-1 ObjectType-Feature-2 |
ISSN: | 0006-8950 1460-2156 |
DOI: | 10.1093/brain/119.6.1911 |