Brain Stem and Audio-Vestibular Regulation

AbstractThe central pathologies present with perverted auditory perception and compromised postural control. Considering the existing controversy this study involves assessments of 100 cases of post fossa tumefactions in which a detailed clinical and neuro-otological (pure tone audiometry, electronystagmography, brainstem evoked response audiometry) profile is compared with their imaging patterns. The CP angle schwannomas (N  = 26) presented with abnormal speech tests (N = 18), abnormal auditory adaptation (N = 7) and ABR with pathologically increased latency of wave V (N = 32), poor formation of wave I (N = 31) along with abnormal inter-wave interval (N = 32). In lesions (N = 32) compressing deeper nuclei, vermis and axial parts of brain stem, a gross truncal ataxia, incoordination, nystagmus, speech defects, subtotal deafness and bilateral ABR abnormalities were observed. The abnormal optomotor activities were seen as saccadic (N = 44) and deformed slow pursuit eye movements (N  = 20). Inability to sustain holding function resulted in gaze nystagmus (N = 71), and poor timing manifested as fixation overshoots (N = 42). The midline cerebellar and upper brain stem lesions revealed bilateral OKN abnormalities whereas paramedian pathology showed only ipsilateral distor tion. Caloric tests revealed culmination frequency as the most sensitive parameter for assessment of the hypo-reflexia in diffuse cerebellopathies while slow phase veloc...
Source: Indian Journal of Otolaryngology and Head and Neck Surgery - Category: ENT & OMF Source Type: research