Three montages for Transcranial electric stimulation in predicting the early post-surgery outcome of the facial nerve functioning

• Published in: Clinical neurophysiology 2024-11, Vol.167, p.282-293
• Main Authors: Izzo, Mikael Gian Andrea, Rossi Sebastiano, Davide, Catanzaro, Valentina, Melillo, Ylenia, Togni, Ramona, Visani, Elisa, Falco, Jacopo, Casali, Cecilia, Gemma, Marco, Ferroli, Paolo, Gallone, Annamaria, Cazzato, Daniele, Devigili, Grazia, Alverà, Sara, Lanteri, Paola
• Format: Article
• Language: English
• Subjects: Acoustic neurinoma; Adult; Aged; Corticobulbar-motor evoked potentials; Evoked Potentials, Motor - physiology; Facial nerve; Facial Nerve - physiology; Facial Nerve - physiopathology; Facial Nerve - surgery; Female; Humans; Intraoperative neuromonitoring; Intraoperative Neurophysiological Monitoring - methods; Male; Middle Aged; Skull-base surgery; Transcranial Direct Current Stimulation - methods; Treatment Outcome; Young Adult
• ISSN: 1388-2457; 1872-8952; 1872-8952
• DOI: 10.1016/j.clinph.2024.07.008

•At low voltage, FCC5h/FCC6h-Mz stimulation evoked larger Cb-MEPs than C3/C4-Cz.•At low voltage, FCC5h/FCC6h-Mz stimulation induced less peripheral responses by direct activation of facial nerve than C5/C6-Cz.•FCC5h/FCC6h-Mz stimulation is safe and increases the accuracy and the specificity of Cb-MEPs with respect to facial nerve outcome. We assessed the Transcranial Electrical Stimulation (TES)-induced Corticobulbar-Motor Evoked Potentials (Cb-MEPs) evoked from Orbicularis Oculi (Oc) and Orbicularis Oris (Or) muscles with FCC5h/FCC6h-Mz, C3/C4-Cz and C5/C6/-Cz stimulation, during IntraOperative NeuroMonitoring (IONM) in 30 patients who underwent skull-base surgery. before (T0) and after (T1) the surgery, we compared the peak-to-peak amplitudes of Cb-MEPs obtained from TES with C3/C4-Cz, C5/C6-Cz and FCC5h/FCC6h-Mz. Then, we compared the response category (present, absent and peripheral) related to different montages. Finally, we classified the Cb-MEPs data from each patient for concordance with clinical outcome and we assessed the diagnostic measures for Cb-MEPs data obtained from FCC5h/FCC6h-Mz, C3/C4-Cz and C5/C6-Cz TES stimulation. Both at T0 and T1, FCC5h/FCC6h-Mz stimulation evoked larger Cb-MEPs than C3/C4-Cz, less peripheral responses from direct activation of facial nerve than C5/C6-Cz. FCC5h/FCC6h-Mz stimulation showed the best accuracy and specificity of Cb-MEPs for clinical outcomes. FCC5h/FCC6h-Mz stimulation showed the best performances for monitoring the facial nerve functioning, maintaining excellent diagnostic measures even at low stimulus voltages. We demonstrated that FCC5h/FCC6h-Mz TES montage for Cb-MEPs in IONM has good accuracy in predicting the post-surgery outcome of facial nerve functioning.