Triggered by Trimming: Haircut-Induced Hemifacial Spasm After Responsive Neurostimulation Implant
Abstract number :
3.223
Submission category :
3. Neurophysiology / 3E. Brain Stimulation
Year :
2025
Submission ID :
119
Source :
www.aesnet.org
Presentation date :
12/8/2025 12:00:00 AM
Published date :
Authors :
Presenting Author: Ramesh Shrestha, MD – University of Mississippi Medical Center
Laveena Singla, MD – University of Mississippi Medical Center
Shade Smith, BS – University of Mississippi Medical Center
Ananya Vasudhar, MD – University of Mississippi Medical Center
Sukriye Kara, MD – University of Mississippi Medical Center
Rationale: Responsive Neurostimulation (RNS) is an advanced therapeutic option for refractory epilepsy that delivers targeted electrical stimulation to disrupt seizure activity. While generally well tolerated, its implantation may inadvertently affect nearby structures. We report a novel RNS-related complication in a patient with refractory epilepsy who developed right-sided hemifacial spasm following adjustment of stimulation settings. The spasms were triggered by hair trimming and use of the RNS wand and are hypothesized to result from inadvertent stimulation of the facial nerve by an electrode positioned near the internal acoustic meatus—a phenomenon not previously documented in the literature.
Methods: N/A
Results: A 34-year-old male with medically refractory temporal lobe epilepsy remained seizure free for two years following partial left temporal lobectomy in 2015, however then developed focal impaired consciousness seizures with the following evolution: adjustment to the stimulation, at right cortical lead (current at 6 mA with charge density (CD) 3 µC/ cm²), he developed transient right hemifacial spasms, triggered during haircuts when the hair clipper (Andis clipper devices) went over the RNS site, and also separately with use of edance of all electrodes was normal. To investigate, baseline stimulation was turned off, and the right lead was stimulated independently after disabling the left lead. This reproduced the hemifacial spasms when the right lead was stimulated at or over 6 mA and a CD of 3 µC/cm². No abnormal discharges were observed on live electrocorticography during these spasms (fig. 1). The hemifacial spasms resolved when stimulation on electrode 1 (closest to the tip) on the right cortical lead was disabled. Therapy settings were then adjusted for the remaining contacts with 5.2 mA and CD of 3.5 µC/ cm².
Conclusions: This case highlights a previously unreported RNS-related complication, in which unintended facial nerve stimulation—due to electrode proximity to the internal acoustic meatus—led to hemifacial spasm. (fig. 2). The patient also reported spasms triggered by hair trimming over the RNS site, suggesting possible electromagnetic interaction with the hair clipper—an association not previously described. Further research is needed to clarify this mechanism.
Funding: N/A
Neurophysiology