PMID- 17890147
OWN - NLM
STAT- MEDLINE
DCOM- 20080212
LR  - 20211203
IS  - 1388-2457 (Print)
IS  - 1388-2457 (Linking)
VI  - 118
IP  - 11
DP  - 2007 Nov
TI  - Neuromuscular excitability properties in myotonic dystrophy type 1.
PG  - 2375-82
AB  - OBJECTIVE: To study neuromuscular excitability in patients with dystrophia 
      myotonica type 1 (DM1). METHODS: The neuromuscular recovery cycle following motor 
      nerve stimulation was assessed in 16 DM1 patients who had no sign of peripheral 
      neuropathy or diabetes. Compound muscle action potentials were recorded from the 
      adductor digiti minimi muscle to ulnar nerve stimulation at the wrist. Paired 
      pulses were delivered, consisting of a conditioning stimulus of supramaximal 
      intensity, followed by a submaximal test stimulus. Interstimuli intervals (ISIs) 
      ranged between 1 and 8ms. Durations of the absolute and relative refractory 
      periods (ARP, RRP) and percentages of refractoriness and supernormality at ISIs 
      of 2.6 and 7ms, respectively, were computed using a subtraction method. The 
      results obtained in the series of DM1 patients were compared to those obtained in 
      six patients with other forms of myotonia and to normative values established in 
      a series of age-matched healthy subjects. Correlations were made between 
      excitability parameters, the number of cytosine-thymine-guanine (CTG) repeats, 
      and the severity of myotonia, scored clinically. RESULTS: Compared to controls, 
      DM1 patients presented prolonged durations of ARP and RRP, increased 
      refractoriness and reduced supernormality. The decrease in refractoriness 
      correlated with both the number of CTG repeats and the severity of myotonia. 
      CONCLUSIONS: Changes in the recovery cycle following supramaximal motor nerve 
      stimulation revealed the existence of subtle alterations of neuromuscular 
      excitability in DM1 patients. SIGNIFICANCE: Increase in refractoriness together 
      with a reduced supernormality was consistent with a process of membrane 
      depolarization. Such a depolarization may be related to the loss of chloride 
      channels or to alterations in sodium conductance in the motor axon or the muscle 
      fiber.
FAU - Boerio, Delphine
AU  - Boerio D
AD  - Service de Physiologie--Explorations Fonctionnelles, Hopital Henri Mondor, 
      Assistance Publique--Hopitaux de Paris, Creteil, France.
FAU - Hogrel, Jean-Yves
AU  - Hogrel JY
FAU - Bassez, Guillaume
AU  - Bassez G
FAU - Lefaucheur, Jean-Pascal
AU  - Lefaucheur JP
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
DEP - 20070924
PL  - Netherlands
TA  - Clin Neurophysiol
JT  - Clinical neurophysiology : official journal of the International Federation of 
      Clinical Neurophysiology
JID - 100883319
RN  - 0 (DMPK protein, human)
RN  - EC 2.7.11.1 (Myotonin-Protein Kinase)
RN  - EC 2.7.11.1 (Protein Serine-Threonine Kinases)
SB  - IM
MH  - Action Potentials/*physiology/radiation effects
MH  - Adult
MH  - Aged
MH  - Electric Stimulation/methods
MH  - Electromyography/methods
MH  - Female
MH  - Humans
MH  - Male
MH  - Middle Aged
MH  - Muscle, Skeletal/*physiopathology
MH  - Myotonic Dystrophy/genetics/*physiopathology
MH  - Myotonin-Protein Kinase
MH  - Protein Serine-Threonine Kinases/genetics
MH  - Reaction Time
MH  - Time Factors
MH  - Ulnar Nerve/*physiopathology/radiation effects
EDAT- 2007/09/25 09:00
MHDA- 2008/02/13 09:00
CRDT- 2007/09/25 09:00
PHST- 2007/05/14 00:00 [received]
PHST- 2007/07/05 00:00 [revised]
PHST- 2007/07/28 00:00 [accepted]
PHST- 2007/09/25 09:00 [pubmed]
PHST- 2008/02/13 09:00 [medline]
PHST- 2007/09/25 09:00 [entrez]
AID - S1388-2457(07)00399-9 [pii]
AID - 10.1016/j.clinph.2007.07.018 [doi]
PST - ppublish
SO  - Clin Neurophysiol. 2007 Nov;118(11):2375-82. doi: 10.1016/j.clinph.2007.07.018. 
      Epub 2007 Sep 24.