Central Auditory Processing Disorders

Sound perception and interpretation are responsibilities of the central auditory nerve system (CANS), which includes central auditory processing. A wide range of abilities are involved in auditory processing, including sound localization and lateralization, pattern recognition, temporal aspects of hearing, performance, and the ability to gradually decrease performance with competing and degraded acoustic signals The CANS is the primary target of central auditory processing disorder (CAPD). While the external, middle, and inner ear structure and function of patients with CAPD are typically standard, the abnormalities in the brain processing of auditory inputs that are not caused by cognitive or higher-order linguistic dysfunction. The CANS stretches from the brainstem’s cochlear nucleus to the auditory cortex. The auditory nerve carries signals from the periphery of the auditory system to the cochlear nucleus. Several nuclei, including the cochlear, superior olivary, lateral meniscus, inferior colliculus, and medial geniculate nuclei, relay information to the cortex so that hearing can occur. Various auditory processing functions are supported by ipsilateral and contralateral signals, which are sent across multiple levels of brainstem crossing fibers. A series of descending neural circuits within the auditory system makes different levels of modulation of auditory processing possible.