A-waves in patients with Bell’s palsy
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Дата
2008-12
Автори
Alexandrov, A.
Muradyan, N.
Christova, L.
Kosarov, D.
Daskalov, M.
Ishpekova, B.
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ISSN на списанието
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Издател
Централна медицинска библиотека, МУ София / Central Medical Library - MU Sofia
Резюме
The aim of this study is recording and investigation of multiple A-waves from frontalis and orbicularis oris muscles in patients with Bell’s palsy. Twenty-one males and 34 females with Bell’s palsy participated in electrophysiological studies. The control group consisted of 28 subjects (16 women and 12 men). A-waves were obtained during conventional F-wave investigation with 16 supramaximal stimuli with a frequency below 1Hz. Electrical stimulation with square wave pulses 0.2 ms in duration was applied via a bipolar surface electrode fixed over the nerve just below the ear and anterior to the mastoid process. The evoked compound muscle action potential (CMAPs) of frontalis and orbicularis oris muscles was recorded with concentric needle electrode (diameter of 0.45 mm) at an amplification of 200 V/div. On the basis of the electromyographic manifestations (parameters of recorded CMAP of m. orbicularis oris and m. frontalis and conduction time (CT) of n. facialis), the patients were separated in three groups – with mild, moderate and severe facial paresis. A-waves were observed between CMAP and F-wave. They were with lower amplitude, approximately constant shape and latency. In 2 patients, A-waves were not found in both investigated muscles. Single A–wave recorded from frontalis muscle were observed in 8 (14.5%), multiple A-waves – in 35 (63.6%), and in 12 (21.8%) of patients, A-waves were not found. Multiple and single A-waves were observed in orbicularis muscle in 33 (60%) and 8 (14.5%) of patients respectively and in 14 (25.5%) of them, A-waves were not recorded. The multiple A-waves are common signs in the early stage of Bell’s palsy in cases of mild and moderate degree of paresis.
Описание
Address for correspondence:
Alexander S. Alexandrov, Ph.D.
Institute of Biophysics
Bulgarian Academy of Science
Acad. G. Bonchev Str., Bldg. 21
1113 Sofia Bulgaria
e-mail: asalexandrov@abv.bg or alex@bio.bas.bg
Ключови думи
A-waves, Bell’s palsy, EMG, m. frontalis, m. orbicularis oris, multiple A-waves
Цитирания
Alexandrov, A., N. Muradyan, L. Christova, D. Kosarov, M. Daskalov and B. Ishpekova. A-waves in patients with Bell’s palsy Acta Medica Bulgarica, 35, 2008, № 2, 23-30.