Comparison between the C5 or C6-Cz electrode assembly and C3 or C4-Cz assembly for transcranial electric motor activation of muscular response of the contralateral facial nerve.
OBJECTIVE
We used an assembly of electrodes C3 and C4-Cz in order to activate the motor cortical area of the corticobulbar tract to elucidate the motor-evoked potential of the contralateral mentalis muscle.


METHODS
We compared this setup to that of an assembly with electrodes C5 or C6-Cz using a train of electrical pulses and a single electrical pulse. This analysis was made in 23 consecutive patients who underwent several varied surgeries and were prospectively operated on at Santa Paula Hospital between January and June 2011.


RESULTS
The results showed that the assembly with C5 or C6-Cz produced a multisynaptic motor-evoked potential in the contralateral mentalis muscle in 86.9 % of the patients, whereas 82.6 % of patients stimulated at points C3 or C4-Cz presented the same response. However, both assemblies showed similar behavior with the use of a single electrical pulse for peripheral contralateral nerve stimulation.


CONCLUSIONS
We concluded that the C5 or C6-Cz assembly was similar to C3 or C4-Cz in obtaining a multisynaptic response in the contralateral mentalis muscle, although it required less intensive stimulation than the C3 or C4- Cz assembly.
Post-Graduation Department, São Paulo Medical School, University of Sao Paulo, Brazil. silviaverst@terra.com.br
Silvia Mazzali
SM
Verst
Tae Mo
TM
Chung
Andrea Caivano
AC
Sucena
Marcos Vinicius Calfat
MV
Maldaun
Paulo Henrique Pires
PH
Aguiar
D000328:Adult; D000368:Aged; D004558:Electric Stimulation / Q000295:instrumentation / Q000379:methods*; D004566:Electrodes; D019054:Evoked Potentials, Motor / Q000502:physiology*; D005152:Facial Muscles / Q000294:innervation / Q000503:physiopathology*; D005154:Facial Nerve / Q000033:anatomy & histology / Q000503:physiopathology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D016343:Monitoring, Intraoperative / Q000295:instrumentation / Q000379:methods*; D011712:Pyramidal Tracts / Q000503:physiopathology*; D055815:Young Adult