Objective: To evaluate the potential use of digital biomarkers in the treatment assessment of hemifacial spasm (HFS) using botulinum toxin, also assessed with conventional methods including standard clinical scales (Sunnybrook Facial Grading System, SFGS) and subjective quality of life assessment (HFS-8).

Background: Hemifacial spasm is a peripheral nerve disorder characterised by involuntary, unilateral contractions of the facial muscles innervated by the facial nerve. It most commonly results from neurovascular compression at the root entry zone of the nerve and presents with progressive, often socially disabling facial twitching.  Traditional outcome assessment relies on clinical rating scales such as the SFGS and patient-reported measures such as the HFS-8; however, these methods are subject to inter-rater variability and recall bias. Digital biomarkers derived from facial movement analysis represent an emerging approach that may enable more objective, reproducible, and potentially remote monitoring of treatment response in HFS.

Method: Ten patients were enrolled (1 male, average age 56 years), of whom nine participated in the follow up session (one month after BoNT). Six digital biomarkers were assessed using the FaceRehab software: neutral face, brow furrow, brow raise, gentle eye closure, lip pucker, and smile. Results were collected together with SFGS and subjective HFS-8 questionnaire scores.

Results: Digital biomarkers detected change (clinical improvement) in two digital biomarkers — neutral face and gentle eye closure  (p = 0.040 for both). No improvement was observed in the remaining four biomarkers. Objective assessment showed a clinical improvement in the Voluntary Movement Score (part of SFGS) from 19.09 to 22.5 points (p = 0.009) and a reduction in pathological synkinesis in 88.9% of patients. Subjective HFS-8 scores decreased from 22.09 ± 5.12 to 17.67 ± 6.56 points (p = 0.018), with 87.5% of patients reporting improved quality of life.

Conclusion: Digital biomarkers can detect changes in facial movement, supporting the clinical validity of this approach. These data can be used for the objective assessment of treatment outcomes (BoNT, physiotherapy, surgery). Study limitations included a small sample size. Further research in larger, standardised cohorts with a control group is needed to validate the role of digital biomarkers in the management of HFS.

« Back to 2026 International Congress

MDS Abstracts - https://www.mdsabstracts.org/abstract/digital-facial-movement-analysis-in-hemifacial-spasm-potential-and-limitations-as-a-clinical-biomarker/