Turkish Journal of Medical Sciences
Abstract
Background/aim: Bell’s palsy (BP) has traditionally been considered an isolated peripheral facial nerve mononeuropathy; however, subclinical trigeminal involvement has been suggested. We evaluated whether cranial somatosensory evoked potentials (cSEP) demonstrate electrophysiological alterations in the trigeminal system in patients with BP.
Materials and methods: The records of 32 patients with BP who underwent cSEP between March 2010 and April 2023 were retrospectively reviewed. For the six patients without explicit chart documentation, the affected side was determined using acute-phase facial electromyography records. During routine clinical assessment, cSEP recordings were obtained using inferior alveolar nerve stimulation according to a standardized protocol. Latencies (N1, P1, N2, P2) and amplitudes (N1–P1, P1–N2, N2–P2) were compared between the affected and unaffected sides using paired t tests and Wilcoxon signed-rank tests, with the significance level adjusted using the Bonferroni correction. An exploratory subgroup analysis was restricted to the 26 patients with primary chart documentation.
Results: In the primary analysis (n = 32), N1 latency was prolonged on the affected side before Bonferroni adjustment (p = 0.03) but did not remain statistically significant after Bonferroni adjustment (p = 0.12). In the secondary subgroup analysis (n = 26), prolonged N1 (p = 0.04) and P2 (p = 0.02) latencies observed before multiple-comparison adjustment were no longer statistically significant after adjustment (p > 0.05). These exploratory latency shifts may reflect subclinical electrophysiological variations; however, their interpretation remains highly dependent on cohort composition and the limited sample size.
Conclusion: The findings of cSEP recordings may suggest subclinical electrophysiological alterations within the trigeminal pathway in patients with BP, indicating that the underlying pathophysiology may not be confined to an isolated facial nerve lesion. Trigeminal electrophysiological assessment may provide an exploratory approach for detecting subclinical pathway involvement; however, larger multicenter prospective studies are needed to establish its clinical utility.
Author ORCID Identifier
AHMET HAKANHAKAN EKMEKCİ: 0000-0002-5595-7251
BURCU ÇAĞAR: 0009-0005-1996-3821
NADİRE ÜNVER DOĞAN: 0000-0001-5696-5547
DOI
10.55730/1300-0144.6396
Keywords
Bell's palsy, facial nerve, somatosensory evoked potentials, trigeminal nerve
First Page
1504
Last Page
1513
Publisher
The Scientific and Technological Research Council of Türkiye (TÜBİTAK)
Creative Commons License

This work is licensed under a Creative Commons Attribution 4.0 International License.
Recommended Citation
EKMEKCİ, A, ÇAĞAR, B. S, & ÜNVER DOĞAN, N (2026). Subclinical trigeminal involvement in Bell’s palsy: insights from cranial somatosensory evoked potentials . Turkish Journal of Medical Sciences 56 (5): 1504-1513. https://doi.org/10.55730/1300-0144.6396