The Auditory Nervous System SPA 4302 Spring 2007
The Ascending Auditory Pathway Primary Auditory Cortex Medial Geniculate Body Inferior Colliculus Lateral Lemniscus Superior Olivary Complex Cochlear Nucleus VIIIth Nerve
The Descending Auditory Pathways Olivo-cochlear Neurons Cortical Neurons Innervation of Middle Ear Musculature
Olivo-Cochlear Efferent Neurons Map of Auditory Efferents
Descending Pathways from Auditory Cortex Descending neurons from Auditory Cortex, MGB, and IC
Efferent Innervation of Tensor Tympani & Stapedius Muscles Innervation of middle ear musculature.
Development: VIIIth N. and Central Auditory Nervous System VIIIth nerve initially: days 25 to 45 Spiral Ganglion, Vestibular Ganglia identifiable by day 35 Little else known about dev. of CANS
Hearing Loss and the CANS VIIIth N: some SNHL, some normal Tinnitus! Unilateral SNHL, Initially high frequency Possibly poor Word Recognition Facial Nerve Symptoms Disorders of the Auditory Nerve Vestibular Schwannoma Neuritis Multiple Sclerosis Auditory Neuropathy: a new dx category Normal OAEs, Abnormal ABR
Disorders of the Cochlear Nuclei Kernicterus: Result of Rh incompatibility Hyperbilirubinemia Cerebrovascular Accident: A brainstem stroke Congenital trauma, malformation Pressure (trauma, increased CSF pressure) Syphilis Aging
Disorders of the Higher Auditory Pathways Brainstem Tumors: Intra-axial: contralateral or bilateral deficits Extra-axial: ipsilateral deficits Higher level lesions CVA/Stroke/Aneurysm produce contralateral deficits
Tests for Auditory Processing Disorder PI-PB Filtered Speech Speech with Competition SSI Competing Sentence Tests Dichotic Digits Test Staggered Spondaic Word Test Masking Level Difference Test
Therapeutic Management Classroom Modifications Improve Signal To Noise Ratios Pre-Teaching Remediation Activities Listening “Games” Computer Based Auditory Training Compensatory Strategies Homework Buddy