Related Experiment Video
Updated: Apr 3, 2026
Pupillary Response as Assessment of Effective Seizure Induction by Electroconvulsive Therapy
Published on: April 11, 2019
Electrical Stimulation of Eye Blink in Individuals with Acute Facial Palsy: Progress toward a Bionic Blink
Alice Frigerio1, James T Heaton, Paolo Cavallari
1Milan, Italy; and Boston, Mass. From the Human Physiology Section, Department of Pathophysiology and Transplantation, Università degli Studi di Milano; the Facial Nerve Center, Carolyn and Peter Lynch Center for Laser and Reconstructive Surgery, Division of Facial Plastic and Reconstructive Surgery, Department of Otology and Laryngology, Massachusetts Eye and Ear Infirmary, Harvard Medical School; and the Department of Surgery, Massachusetts General Hospital, Harvard Medical School.
Background:
Elicitation of eye closure and other movements via electrical stimulation may provide effective treatment for facial paralysis. The authors performed a human feasibility study to determine whether transcutaneous neural stimulation can elicit a blink in individuals with acute facial palsy and to obtain feedback from participants regarding the tolerability of surface electrical stimulation for daily blink restoration.
Methods:
Forty individuals with acute unilateral facial paralysis, HB grades 4 through 6, were prospectively studied between 6 and 60 days of onset. Unilateral stimulation of zygomatic facial nerve branches to elicit eye blink was achieved with brief bipolar, charge-balanced pulse trains, delivered transcutaneously by adhesive electrode placement; results were recorded on a high-speed video camera. The relationship between stimulation parameters and cutaneous sensation was analyzed using the Wong-Baker Faces Pain Rating Scale.
Results:
Complete eye closure was achieved in 55 percent of participants using stimulation parameters reported as tolerable. In those individuals, initial eye twitch was observed at an average current of 4.6 mA (±1.7; average pulse width of 0.7 ms, 100 to 150 Hz), with complete closure requiring a mean of 7.2 mA (±2.6).
Conclusions:
Transcutaneous facial nerve stimulation may artificially elicit eye blink in a majority of patients with acute facial paralysis. Although individuals varied widely in their reported degrees of discomfort from blink-eliciting stimulation, most of them indicated that such stimulation would be tolerable if it could restore eye closure. These patients would therefore benefit from a biomimetic device to facilitate eye closure until the recovery process is complete.
Clinical Question/Level Of Evidence:
Therapeutic, IV.
