What the exam asks
- Section I (Multiple Choice): You will apply auditory and somatic principles to everyday scenarios (e.g., diagnosing why a concertgoer has ringing ears, explaining why food tastes bland during a cold, or distinguishing balance from joint awareness in an athlete).
- Section II (Free Response): An AAQ or EBQ may present experimental data on pain management, taste sensitivity, or auditory decline. In an EBQ, concepts like gate control theory, supertasters, or sensory interaction can earn the 2nd point in Parts B(ii) and C(ii) when you apply them correctly to explain the evidence.
Core ideas
Hearing (Audition)
Sound waves have two key physical properties:
- Wavelength (frequency): Determines pitch (measured in hertz, ). Short wavelengths = high frequency = high pitch.
- Amplitude (height): Determines loudness (measured in decibels, ). Tall waves = high amplitude = loud sound.
Sound waves vibrate the eardrum and middle ear bones (ossicles: hammer, anvil, stirrup), which amplify vibrations and push against the oval window of the cochlea in the inner ear. Fluid movement ripples the basilar membrane, bending hair cells (the auditory receptors) to trigger action potentials along the auditory nerve to the thalamus and auditory cortex (temporal lobe).
| Pitch Theory | Mechanism | Pitch Range Explained |
|---|---|---|
| Place theory | Sound waves trigger activity at different locations along the cochlea’s basilar membrane. | High pitches |
| Frequency theory | The basilar membrane vibrates at the same rate as the sound wave (e.g., ). | Low pitches |
| Volley principle | Groups of neurons alternate firing in staggered succession to achieve combined frequencies above . | Middle pitches (above about , where one neuron cannot fire fast enough) |
Sound localization relies on the placement of our two ears: a sound coming from the right reaches the right ear microseconds earlier and is slightly louder (more intense) than in the left ear.
Hearing loss falls into two categories:
- Conduction deafness: Mechanical damage to the eardrum or middle ear bones prevents vibrations from reaching the cochlea. (Often helped by conventional hearing aids that amplify vibrations.)
- Sensorineural (nerve) deafness: Damage to the cochlea’s hair cells or the auditory nerve, caused by biological aging, disease, or prolonged exposure to loud noise. (Hearing aids can help milder loss; severe hair-cell damage may need a cochlear implant, a device that turns sound into electrical signals for the auditory nerve.)