Ahmet Hakan EKMEKCİ, Burcu Sümeyye ÇAĞAR, Nadire ÜNVER DOĞAN
Turkish Journal of Medical Sciences - 2026;56(5):1504-1513
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.
