[Preoperative Examination:Neuro-Otological Examination and Its Significance].

Neuro-otologic examinations are essential to identify lesion sites in patients with hearing and balance disorders. These tests assess the functions from the peripheral sensory organs to the central auditory and vestibular pathways. They are valuable for evaluating inner ear function and detecting central nervous system involvement. Auditory tests, such as pure-tone audiometry and auditory brainstem response, help localize lesions along the auditory neural pathway. Vestibular function can be assessed using the caloric test, video head impulse test, and vestibular evoked myogenic potentials, which individually evaluate the semicircular canals and otolith organs. Additionally, eye movement recordings using the ENG or VOG during visual stimulation aid in the detection of central vestibular dysfunction. Cerebellopontine angle (CPA) tumors vary in size and extent, from small lesions within the internal auditory canal to large masses compressing the brainstem and cerebellum. Preoperative neuro-otologic assessment provides insight into the extent of the tumor and affected functional areas. This is valuable for understanding the pathophysiology of CPA tumors and contributes to surgical planning and prognosis.