Audiovestibular function in adults with Hashimoto thyroiditis: a prospective case–control study

Background Hashimoto’s thyroiditis (HT) is a common autoimmune disorder, and autoimmune mechanisms have been implicated in cochlear and vestibular dysfunction. The aim of this work is to assess the audio-vestibular involvement in adults with HT compared with healthy controls. Methods This prospective cross-sectional case–control study was performed on 25 Hashimoto’s thyroiditis patients (study group) and 25 heathy subjects (control group) underwent clinical ENT and vestibular examination, laboratory thyroid profiling, basic audiological evaluation, and vestibular evaluation using videonystagmography (VNG) including caloric testing. Results Groups were comparable in age and sex. Family history of thyroid disease was more common in HT ( P < 0.001). All HT patients were positive for anti-Tg and anti-TPO (100% vs. 0%; P < 0.001). No substantial difference was recorded concerning subjective symptoms between the two groups, vertigo was reported in 12% of study group ( P < 0.074), imbalance in 8% vs. 0% ( P = 0.203) and tinnitus in 8% ( P = 0.203). Audiometric thresholds were similar across frequencies (e.g., 250 Hz: 21.4 ± 6.2 vs. 20.0 ± 4.1 dB HL; P = 0.351; 8000 Hz: 22.6 ± 8.3 vs. 22.8 ± 2.5 dB HL; P = 0.909); all participants had Type A tympanograms, preserved reflexes, and excellent speech discrimination (100%). VNG results show no abnormalities except one patient who had vertical nystagmus and bilateral caloric weakness not suppressed by fixation (4%; P = 0.312). Conclusions In this small euthyroid-treated HT cohort, conventional audiometry and VNG/caloric testing did not demonstrate significant group-level audiovestibular impairment compared with controls. One patient showed central vestibular abnormalities, and a minority reported vestibular or auditory symptoms. Larger longitudinal studies using extended high-frequency audiometry, OAEs, vHIT, and VEMP are needed to determine whether HT is associated with subclinical cochlear or vestibular dysfunction particularly in symptomatic patients.