The team at the Tampere Reference Centre for Neuromuscular Diseases (Finland) examined the results of functional electrophysiological tests in 27 patients with canalopathy, myotonic dystrophy type 1 (DM1) or type 2 (DM2) :
- the most frequent symptoms were muscle weakness, myalgias, cramps and muscle stiffness,
- the median age at the time of functional electrophysiological testing was 43.2 years,
- 59.3% had functional tests (short effort, long effort, cold test and short effort) compatible with Fournier’s scheme,
- 33.3% had only one abnormal functional test,
- 18.5% had no electrophysiological abnormality (2 had DM2 and 3 had heterozygous SCN4A abnormalities).
The authors conclude that more precise and sensitive neurophysiological tests are needed to detect muscle channelopathies.
