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H‐reflex and M‐wave recordings: effect of pressure application to the stimulation electrode on the assessment of evoked potentials and subject's discomfort
Author(s) -
Cattagni Thomas,
Merlet Angèle N.,
Cornu Christophe,
Jubeau Marc
Publication year - 2018
Publication title -
clinical physiology and functional imaging
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.608
H-Index - 67
eISSN - 1475-097X
pISSN - 1475-0961
DOI - 10.1111/cpf.12431
Subject(s) - stimulation , medicine , anesthesia , intensity (physics) , h reflex , soleus muscle , reflex , electrode , blood pressure , biomedical engineering , chemistry , skeletal muscle , physics , quantum mechanics
Summary This study aimed to compare the effect of different types of pressure applied to the stimulation electrode on assessing the efficiency of Ia‐α‐motoneuron transmission of the soleus muscle and the associated discomfort using electrical nerve stimulation. Twelve healthy young adults participated in three experimental sessions (one for each knee angle). The amplitudes of the maximal Hoffmann reflex ( H max ) and motor potential ( M max ) were recorded from the soleus muscle at 0°, 30° and 90° knee angles (0° full extension) through three pressure applications to the stimulation electrode: no pressure, pressure with manual application and pressure using adhesive tape. The soleus H max / M max were calculated to assess the efficiency of Ia‐α‐motoneuron transmission during varied knee angles and pressure application to the stimulation electrode. At the stimulation intensity evoking soleus H max and M max , subjects were asked to orally provide a value between ‘no discomfort’ (0) and ‘worst possible discomfort’ (10). The application of pressure on the stimulation electrode, particularly using adhesive tape, decreased both the stimulation intensity needed to evoke an electrophysiological response and the associated self‐reported discomfort ( P <0·05), while the H max / M max remained constant. At the stimulation intensity evoking M max , the electrical stimulation appeared to be more painful at 0° knee angle compared with 30° and 90° angles ( P <0·01). To conclude, this study showed that a knee flexion and a pressure application to the stimulation electrode, especially using tape pressure, are recommended in the objective to reduce the patient/subjects’ discomfort when eliciting evoked potentials on soleus muscle.