Tehran University of Medical Sciences Auditory and Vestibular Research 2423-480X 0 0 2025 10 12 1490 1490 Noor Abdulazeez Abdulhameed Alrawi Mustansiriyah University/ M.B.Ch.B Haider AlSarhan Ibn Sina University for Medical and Pharmaceutical Sciences/M.B.Ch. B, F.I.B.M.S, Consultant Otolaryngologist Mohamed Al Tamimi College of Medicine / Mustansiriyah University/ M.B.Ch. B, F.I.C.M.S in Neurosurgery 2025 08 25 2025 10 12 Background and Aim: Posterior fossa lesions often present with slowly progressive hearing loss, making diagnosis challenging. Pure-tone audiometry (PTA) and the Auditory Brainstem Response (ABR) are essential tools for assessing retro-cochlear involvement and establishing hearing thresholds. This study aimed to assess the audiometric profiles of patients with posterior fossa lesions and ascertain whether they could distinguish between different types of lesions. Methods: A cross-sectional study was conducted on 36 patients aged 10-65 years. Each participant underwent otoscopic examination, tympanometry, PTA, and ABR testing.  The data were analyzed using the chi-square and Kruskal-Wallis tests in SPSS version 25, with Cohen's f and Cramer's V for effect size. A p-value of less than 0.05 was considered significant. Results: Lesion types showed a strong correlation with clinical presentation. Vascular loops were associated with tinnitus, vestibular schwannomas with facial numbness and hearing loss, and meningiomas with vertigo and headache. Schwannoma cases exhibited significantly higher ipsilateral hearing thresholds, especially at high frequencies (p < 0.05). ABR results varied by lesion type: vascular loops mostly caused delayed wave III, meningiomas produced prolonged wave V and I–V intervals, while schwannomas showed the most severe abnormalities, including missing or delayed waves and interpeak intervals. Contralaterally, only schwannomas displayed ABR delays in wave V and I–V interval. Conclusion: Lesion differentiation was aided by the clinical and audiological characteristics of posterior fossa lesions. ABR offers objective data on retro-cochlear involvement, while PTA identifies changes in hearing threshold. When used together, they improved diagnostic precision and patient care. https://avr.tums.ac.ir/index.php/avr/article/view/1490