Question

1. describe the common causes for hearing loss.
2. how does a cochlear implant help to restore hearing for someone?
3. how do we detect/perceive loudness?
4. identify and explain the theories used for perceiving pitch.
5. how do we locate sounds?

Explanation:

1. Common causes of hearing loss include genetic factors, aging (presbycusis), exposure to loud noise over time, certain medications (ototoxic drugs), ear - infections, head injuries, and diseases like meningitis.
2. A cochlear implant bypasses damaged parts of the inner ear and directly stimulates the auditory nerve. It has an external processor that picks up sound, converts it into electrical signals, and an implanted electrode array that sends these signals to the auditory nerve, which the brain then interprets as sound.
3. Loudness is detected by the number of hair cells that are activated in the cochlea and the rate at which they fire. The more hair cells that are stimulated and the higher their firing rate, the louder the perceived sound.
4. The main theories for pitch perception are the place theory (pitch is determined by the location of the most active hair cells on the basilar membrane in the cochlea), the frequency theory (pitch is related to the frequency of the sound wave and the rate of neural firing), and the volley theory (for intermediate - frequency sounds, groups of neurons fire in volleys to match the sound frequency).
5. Sound location is determined by differences in the time it takes for a sound to reach each ear (inter - aural time difference), differences in the intensity of the sound reaching each ear (inter - aural intensity difference), and the shape of the outer ear (pinna), which helps to filter and localize sound based on its direction.

Answer:

1. Genetic factors, aging, loud - noise exposure, ototoxic drugs, ear - infections, head injuries, diseases like meningitis.
2. Bypasses damaged inner ear, stimulates auditory nerve with electrical signals.
3. Detected by number of activated hair cells and their firing rate.
4. Place theory (location of active hair cells), frequency theory (neural firing rate), volley theory (group neural firing for intermediate frequencies).
5. Inter - aural time difference, inter - aural intensity difference, shape of pinna.