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The short exercise test is normal in proximal myotonic myopathy.

Authors :
Sander HW
Scelsa SN
Conigliari MF
Chokroverty S
Source :
Clinical neurophysiology : official journal of the International Federation of Clinical Neurophysiology [Clin Neurophysiol] 2000 Feb; Vol. 111 (2), pp. 362-6.
Publication Year :
2000

Abstract

Objectives: Proximal myotonic myopathy (PROMM) is a multisystem disorder that may mimic myotonic dystrophy (MD). Previously we demonstrated that the 60 s exercise test was normal in two siblings with PROMM. The test enabled distinction of PROMM from MD, as there is a well documented immediate post-exercise compound muscle action potential (CMAP) amplitude decline in MD.<br />Methods: We now performed exercise testing using several exercise durations in 8 PROMM patients from 6 kinships, and one MD patient, extending our previous observations. Repetitive stimulation and needle electromyography findings were also recorded.<br />Results: The 10 (n = 8), 30 (n = 5), and 60 (n = 5) s, and the 5 min (n = 1) exercise tests were normal in all PROMM patients. Specifically, the maximum post-exercise CMAP amplitude decline was 8%. In contrast, the MD patient had CMAP amplitude declines of 48% (10 s exercise test) and 26% (30 s exercise test). The distribution of repetitive stimulation and motor unit duration abnormalities were variable and less diagnostically useful.<br />Conclusions: The 10, 30, and 60 s exercise tests help distinguish PROMM from MD. As the 10 s exercise test is rapid and easily tolerated, we recommend this test for clinical testing.

Details

Language :
English
ISSN :
1388-2457
Volume :
111
Issue :
2
Database :
MEDLINE
Journal :
Clinical neurophysiology : official journal of the International Federation of Clinical Neurophysiology
Publication Type :
Academic Journal
Accession number :
10680573
Full Text :
https://doi.org/10.1016/s1388-2457(99)00231-x