Myotonic Dystrophy 1
Conditions
Brief summary
The study design is a prospective cohort study. It aims to evaluate the neuromuscular junction in dystrophic myotonia 1 (DM 1) using low-frequency repetitive nerve stimulation (RNS) on several nerve-muscle pairs of the one side including proximal and distal muscles of upper and lower extremities. First, it will be investigated whether a decrement with 3 Hz stimulation, as described in literature, is reproducible in our patient population. If this is the case, it will be examined whether it is the consequence of a dysfunction of the neuromuscular junction or rather linked to a hypo-excitability of some muscle fibers due to myotonia. For this purpose, additional tests including short exercise test (to observe any decrement resulting from an inexcitability in myotonic muscle fibers) and needle EMG (for mapping myotonic discharges in the muscles tested with repetitive nerve stimulation) will be performed. Single fiber-EMG will not be provided in this study as an abnormal result does not necessarily indicate a dysfunction of the neuromuscular junction but could just as well be due to the muscular dystrophy in the context of DM1. Finally, it will be investigated if there is a correlation between the decrement with 3 Hz stimulation and clinical signs as fixed muscle weakness (via Medical Research Counsil (MRC) scale, DM-activ scale \[30\]) and fatigue (via MG-ADL scale).
Interventions
DIAGNOSTIC_TESTLow frequency repetitive stimulation
Neuromuscular transmission was tested by using short-lasting low frequency RNS (10 stimuli at 3 Hz). The test was applied on the abductor digiti minimi (ADM), anterior tibial, orbiculis oculi, trapezius, anconeus and EDB muscles of one side, in this particular order, by supramaximal stimulation of the corresponding nerve.
Sponsors
Vrije Universiteit Brussel
Study design
Allocation
RANDOMIZED
Intervention model
SINGLE_GROUP
Primary purpose
BASIC_SCIENCE
Masking
NONE
Eligibility
Sex/Gender
ALL
Healthy volunteers
No
Inclusion criteria
\* genetically confirmed DM1
Exclusion criteria
* minor age * auto-immune diseases * medical conditions involving the neuromuscular junction: (myasthenia gravis, Lambert-Eaton myasthenic syndrome, congenital myasthenia syndromes).
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Reproducibility of rapid decrement at low frequency stimulation. | 1 year | Low stimulation frequency was tested in 6 muscles, to verify the presence of an anomalie of the neuromuscular transmission. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Correlation of decrement with grade of EMG-myotonia | 1 year | Search of correlation between decrement, obtained bij low frequency stimulation, and EMG-myotonia (via needle EMG), to differentiate muscle fiber hypoexcitability in the context of myotonia, from neuromuscular junction block resulting in decrement of the CMA |
| Is there any clinical expression (muscle fatigability) of a possible neuromuscular junction dysfunction | 1 year | Search of correlation between muscle fatique (questionnaires and grip strength via dynamometer) and decrement of CMAP (compound muscle action potential). |
Countries
Belgium
Outcome results
None listed