Sonographic changes in denervated facial muscles trough long-term home-based surface electrostimulation

Introduction If denervation occurs in facial nerve palsy, muscle atrophy and irreversible loss of function sets in. For the leg muscles of paraplegics, surface electrostimulation has been shown to stop and reverse these processes. Whether this is also applicable to the mimic muscles, is going to be explored in this study.

Methods Five patients, with confirmed facial paralysis through Electromyography (EMG), underwent surface electrostimulation for at least 5 months twice a day for 15 minutes as home training. In this feasability study the training was conducted with the Stimulette r2x (Dr. Schuhfried GmbH, Vienna). Exponential currents with phase lengths of initally 250ms-500ms (3-10mA, 1.3Hz) were applied according to the schedule and then optimized individually every four weeks. MRI and ultrasound examinations were performed using a linear ultrasound probe (3-13Hz) at MyLab7 (Esaote, Genoa, Italy) in compliance with a standardized protocol.

Results Over the duration of the home training the stimulation frequency within the 15 minute intervals could be increased. Patients reported an increase in the tonus of their cheek muscle. The changes in the sonographic cross-sectional areas over time corresponded to the volume increases on the MRI. Increases in the cross-sectional area of ​​10% within 4 weeks are indications of the effectiveness of the training.

Conclusions The training of aforementioned muscles led to a subjective gain in quality of life and objective improvements in sonographic imaging. The denervation atrophy appears to be countered and thus, e.g. the time window for a successful reinnervation can be significantly extended. To quantify the training effect more reliably, a control group and a larger patient sample size are necessary.

Publication History

Article published online:
24 May 2022