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Masticatory performance in patients with myasthenia gravis
F G Weijnen1, A van der Bilt, J B M Kuks
1Department of Oral-Maxillofacial Surgery, Prosthodontics and Special Dental Care, University Medical Center, P.O. Box 85060, 3508 AB Utrecht, The Netherlands.
Archives of Oral Biology
|May 17, 2002
Summary
Patients with bulbar myasthenia gravis exhibit reduced chewing performance and electromyograms (EMGs). This study found no subclinical weakness in remission or ocular myasthenia gravis patients, highlighting jaw support needs in bulbar cases.
Area of Science:
- Neurology
- Biomedical Engineering
- Clinical Research
Background:
- Myasthenia gravis (MG) is a neuromuscular disorder affecting voluntary muscles.
- Bulbar MG specifically impacts muscles controlling swallowing, speech, and chewing.
- Quantifying masticatory muscle function in MG subtypes is crucial for understanding disease impact.
Purpose of the Study:
- To quantitatively assess masticatory muscle electromyograms (EMGs) and performance in patients with bulbar MG.
- To compare these measures against patients with ocular MG, those in remission, and healthy controls.
- To investigate compensatory mechanisms and identify characteristic signs of bulbar MG.
Main Methods:
- Electromyograms (EMGs) of masticatory muscles were recorded during artificial food chewing.
- Masticatory performance was measured in patients with bulbar MG, ocular MG, remitted bulbar MG, and healthy individuals.
- EMG activity and chewing efficiency were analyzed and compared across groups.
Main Results:
- Patients with bulbar MG showed significantly reduced masticatory performance and lower EMG activity compared to controls.
- No evidence of subclinical masticatory muscle weakness was found in ocular MG or remitted bulbar MG patients.
- Bulbar MG patients demonstrated minimal compensation for muscle weakness, indicated by a higher percentage of maximal EMG during chewing.
Conclusions:
- Reduced EMG activity and chewing performance are characteristic of active bulbar myasthenia gravis.
- Jaw support may be necessary for bulbar MG patients experiencing significant masticatory muscle weakness.
- Ocular MG and remitted bulbar MG patients do not exhibit detectable masticatory muscle deficits.