Objectives: Electrical stimulation (ES) of the paralyzed eyelid, triggered by the corresponding function on the contralateral healthy side, has been proposed to treat eyelid closure impairment in unilateral facial paralysis. However, results in terms of functional and cosmetically acceptable eyelid closure have been poorly documented. We propose a new method to quantify the effective restoration of the blink provided by a prototypal device developed for a contralaterally elicited eyelid ES. Methods: On a healthy subject surface EMG electrodes were used to detect the natural eyeblink (N-blink) on one side and to trigger an electrical stimulation leading to an artificial blink (A-blink) of the orbicularis oculi muscle on the controlateral side. Trains of 10 pulses (4mA amplitude, 2ms duration) were delivered at various frequencies: 50, 100, 150, 250Hz. Assuming that during the eyeblink the eyelid rotates around the axis passing through eye canthi, a miniature gyroscopic sensor was used to estimate maximum eyelid motion from open eye to complete closure (CC) and eye-blink duration (D). Both the N-blink and A-blinks evoked by the different patterns of stimuli were measured and compared. Results: The N-blink was characterized by a CC of 3.5mm and D of 380ms. Stimulation at 50 and 100Hz showed distinct differences from the N-blink: 50Hz train caused ineffective eyelid closure (CC= -41%) and an excessive eyeblink duration (D=+215%), while 100Hz train showed a more complete eyelid closure (CC=+6%) but longer eyeblink duration (D=+67%). Conversely, 150Hz train and 250Hz train provided a quite natural-like A-blinks (CC=+10%,+11%; D=+14%,-15%, respectively). Conclusions: The new gyroscopic-based method showed to be a valuable tool to quantify the effective and natural-like eyeblink restoration provided by the EMG–triggered ES device. Further studies will be necessary to evaluate the method in facial paralysis patients and to also provide quantification of potential alterations of facial mimicry associated with ES.
E. Marcelli, L. Cercenelli, R. Fanti, P. Cavallari, A. Frigerio, S. Brenna, et al. (2011). A new method to quantify eyeblink restoration in facial paralysis.
A new method to quantify eyeblink restoration in facial paralysis
MARCELLI, EMANUELA;CERCENELLI, LAURA;
2011
Abstract
Objectives: Electrical stimulation (ES) of the paralyzed eyelid, triggered by the corresponding function on the contralateral healthy side, has been proposed to treat eyelid closure impairment in unilateral facial paralysis. However, results in terms of functional and cosmetically acceptable eyelid closure have been poorly documented. We propose a new method to quantify the effective restoration of the blink provided by a prototypal device developed for a contralaterally elicited eyelid ES. Methods: On a healthy subject surface EMG electrodes were used to detect the natural eyeblink (N-blink) on one side and to trigger an electrical stimulation leading to an artificial blink (A-blink) of the orbicularis oculi muscle on the controlateral side. Trains of 10 pulses (4mA amplitude, 2ms duration) were delivered at various frequencies: 50, 100, 150, 250Hz. Assuming that during the eyeblink the eyelid rotates around the axis passing through eye canthi, a miniature gyroscopic sensor was used to estimate maximum eyelid motion from open eye to complete closure (CC) and eye-blink duration (D). Both the N-blink and A-blinks evoked by the different patterns of stimuli were measured and compared. Results: The N-blink was characterized by a CC of 3.5mm and D of 380ms. Stimulation at 50 and 100Hz showed distinct differences from the N-blink: 50Hz train caused ineffective eyelid closure (CC= -41%) and an excessive eyeblink duration (D=+215%), while 100Hz train showed a more complete eyelid closure (CC=+6%) but longer eyeblink duration (D=+67%). Conversely, 150Hz train and 250Hz train provided a quite natural-like A-blinks (CC=+10%,+11%; D=+14%,-15%, respectively). Conclusions: The new gyroscopic-based method showed to be a valuable tool to quantify the effective and natural-like eyeblink restoration provided by the EMG–triggered ES device. Further studies will be necessary to evaluate the method in facial paralysis patients and to also provide quantification of potential alterations of facial mimicry associated with ES.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
