Transcript The Auditory Nervous System

The Auditory Nervous System
SPA 4302
Summer 2007
The Neuron
Generally:
• Dendrites receive stim.
• Creates ______________
– Transmitted along axon
– Causes ____________
____________
– Stimulates new neuron
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
• ________________ Neurons
• ______________ Neurons
• Innervation of Middle Ear _____________
Olivo-Cochlear Efferent Neurons
Descending Pathways from Auditory Cortex
Efferent
Innervation of
Tensor Tympani
& Stapedius
Muscles
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
–
–
–
–
___________!
___________ SNHL, Initially high frequency
Possibly poor Word Recognition
___________ Nerve Symptoms
• Disorders of the Auditory Nerve
–
–
–
–
Vestibular Schwannoma
_____________
Multiple Sclerosis
Auditory Neuropathy: a new dx category
• Normal ________, Abnormal _______
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 __________ deficits
– Extra-axial: ____________ deficits
• Higher level lesions
– CVA/Stroke/Aneurysm
– produce _____________ deficits
Tests for Auditory Processing Disorder
• ______________
• Filtered Speech
• Speech with Competition
–
–
–
–
_____________
Competing Sentence Tests
Dichotic Digits Test
Staggered _________ Word Test
• Masking Level Difference Test
Therapeutic Management
• _____________ Modifications
– Improve Signal To Noise Ratios
– Pre-Teaching
• ______________ Activities
– Listening “Games”
– Computer Based Auditory Training
• ______________ Strategies
– Homework Buddy