Cochlear Damage and Loss of Peripheral Auditory Input
Hair cell damage reduces the signal reaching the auditory nerve.
- Variable: Hair cell loss (placeholder metric)
- High-freq: Frequencies affected (placeholder metric)
- Gradual/acute: Onset type (placeholder metric)
- Noise, age: Common causes (placeholder metric)
Cochlear hair cell damage
Placeholder: outer hair cells damaged reduce cochlear output signal.
Reduced Afferent Signal Reaching the Auditory Brainstem
Weaker cochlear output lowers activity in brainstem nuclei.
- Reduced: Cochlear nucleus input (placeholder metric)
- Lower: Signal-to-noise (placeholder metric)
- Altered: Relay latency (placeholder metric)
- Partial: Deafferentation (placeholder metric)
Brainstem relay deafferentation
Placeholder: cochlear nucleus receives diminished afferent drive.
Compensatory Hyperactivity Along the Central Auditory Pathway
Deprived central neurons raise spontaneous firing rates.
- Elevated: Spontaneous firing (placeholder metric)
- Increased: Neural synchrony (placeholder metric)
- Reduced: Inhibition (placeholder metric)
- Multiple: Affected nuclei (placeholder metric)
Gain increase and disinhibition
Placeholder: central gain rises to compensate reduced input.
Auditory Cortex Map Reorganization Over Time
Cortical tonotopic maps shift with prolonged deprivation.
- Present: Tonotopic shift (placeholder metric)
- Time-dependent: Map plasticity (placeholder metric)
- Increased: Cross-modal input (placeholder metric)
- Cumulative: Duration effect (placeholder metric)
Cortical map plasticity
Placeholder: cortex reorganizes frequency representation zones.
Subjective Tinnitus as Phantom Auditory Perception
Brain perceives sound despite absent external stimulus.
- Phantom: Perceived sound (placeholder metric)
- ~10-15%: Prevalence (placeholder metric)
- Often persistent: Chronicity (placeholder metric)
- Variable: Distress link (placeholder metric)
Phantom percept generation
Placeholder: hyperactive cortical networks generate conscious phantom sound.
Placeholder: tinnitus reflects maladaptive central plasticity, not ear damage alone.