Tehran University of Medical Sciences Auditory and Vestibular Research 2423-480X 35 4 2026 02 23 349 356 Mohammad Akbar Fayaz Department of Audiology, School of Rehabilitation, Tehran University of Medical Sciences, Tehran, Iran Mansoureh Adel Ghahraman Department of Audiology, School of Rehabilitation, Tehran University of Medical Sciences, Tehran, Iran Elham Tavanai Department of Audiology, School of Rehabilitation, Tehran University of Medical Sciences, Tehran, Iran Kazem Malmir Department of Physiotherapy, School of Rehabilitation, Tehran University of Medical Sciences, Tehran, Iran Nasrin Yazdani Otorhinolaryngology Research Center, Tehran University of Medical Sciences, Tehran, Iran Akram Farahani Department of Audiology, School of Rehabilitation, Tehran University of Medical Sciences, Tehran, Iran 2 Mohammad Amin Safari Audiology Unit, Amir A’lam Hospital, Tehran University of Medical Sciences, Tehran, Iran 2025 12 31 2026 02 18 Background and Aim: Inflammatory processes play a key role in vestibular neuritis (VN) pathogenesis, and recent research has associated vitamin D deficiency with various audio-vestibular conditions, including reduced serum 25-hydroxyvitamin D (25(OH) D) concentrations in individuals with acute VN. Given its notable immunomodulatory and anti-inflammatory actions, vitamin D may serve as an adjunct to enhance Vestibular Rehabilitation Therapy (VRT) outcomes. The present study examined the impact of combining 25(OH)D supplementation with VRT on vestibular function among patients with VN. Methods: In this randomized controlled trial, 41 patients with VN were allocated into two groups. The VRT group (n=20) received individualized vestibular rehabilitation for 30 minutes, three times daily for 12 weeks. The VRT+VitD group (n=21) received the same VRT protocol plus a weekly oral dose of 50,000 IU of 25(OH)D for 12 weeks. Outcomes were assessed pre- and post-intervention using the Dizziness Handicap Inventory (DHI), Vertigo Symptom Scale-short form, and affected canal Vestibulo-Ocular Reflex (VOR) gains with video head impulse test, within- and between-groups. Results: Both groups improved significantly across all measurements. The VRT+VitD group showed a normal serum level of vitamin D post-intervention (39.36±3.06; p<0.001) and greater improvements in subjective symptom reduction (DHI; p=0.023; partial η²=0.126), and VOR gains (p<0.001 with partial η²=0.459, 0.576, and 0.197 for lateral, anterior, and posterior canals, respectively) compared to the VRT group. Conclusion: Correcting vitamin D deficiency supports and potentially enhances the effects of vestibular rehabilitation in patients with vestibular neuritis, although these outcomes should be interpreted with caution due to the study’s limitations. Trial Registration Number: The trial was registered with the Iranian Registry of Clinical Trials (IRCT20240512061714N1). https://avr.tums.ac.ir/index.php/avr/article/view/1533