Trigeminal nerve electrophysiological findings in hemifacial atrophy: A systematic literature review and retrospective chart review

Objective: Hemifacial atrophy (HFA) is a rare disorder characterized by progressive unilateral wasting facial soft tissue, muscle, and/or bone. Trigeminal nerve abnormalities may contribute to or result from disease pathophysiology. We aimed to gain further insights into the role of trigeminal pathophysiology along the HFA severity spectrum. Methods: A systematic literature review was performed according to PRISMA standards. Retrospective cases of HFA from the literature and Mayo Clinic EMG database were pooled for descriptive and semi-quantitative analysis. Results: Overall, 13 total HFA patients were identified through literature and database reviews. Trigeminal nerve testing was abnormal in 9/13 (69%), exclusively in moderate-severe cases. Abnormalities suggested a peripheral (7/9, 78%) or mixed central/peripheral (2/9, 22%) localization. Trigeminal nerve abnormalities were not identified in any of the 4 cases with mild disease severity. Conclusion: Moderate to severe cases of HFA were associated with electrophysiological trigeminal abnormalities. No abnormalities were seen in mild cases of HFA. Significance: Trigeminal nerve electrophysiology may serve as a biomarker of moderate-severe disease progression, likely reflecting the consequences of progressive soft tissue atrophy.