Hearing and listening Flashcards
How are sounds produced?
By objects that vibrate, causing air molecules to condense and rarefy
What do the grouped and spaced sections on a diagram represent?
Grouped = peaks, spaced = troughs
What is our audible range
20uPA to 100,000,000uPA
Define wavelength
Distance between 2 peaks
Define frequency
Rate at which pressure cycles between compression and rarefraction
What determines timbre?
Different frequencies determine timbre
What is the outer ear called?
Pinna
What do funnels into the ear canal assist with?
Helps with sound localisation
What are the middle ear bones known as?
Ossicles
State the purpose of ossicles
Connects tympanic membrane to cochlea.
What does the middle ear act as?
An impendence transformer
What is the cochlea?
Fluid filled spinal canal, divided by flexible membrane
What does peak location depend on?
Depends on stimulus frequency
Describe the function of the basilar membrane?
Filters sound according to frequency
State the 3 sections of the cochlea
Scala vestibuli, tectorial & basilar membrane, scala tympani
Describe the structure of the organ of corti
Sits on top of basilar membrane, inner and outer hair cells are mounted on it
How is depolarisation caused by hair cells?
Hair cells are pushed right
What happens when the hair cells are pushed left?
Hyperpolarisation
What causes the outer hair cells to move?
Move in response to electrical and chemical stimulation
What are the 3 consequences?
Dancing hair cells, amplifies movement of basilar membrane, vibrations transmitted as sound
The 2 causes of hearing loss are what?
Age related changes to the inner ear, noise induced hearing loss
Older age changes are in what…
Temporal processing and auditory cognition
State the 2 types of hearing impairment
Conductive and sensorineural
Define conductive hearing impairment
Abnormality before cochlea, problem with sound conduction
Define sensorineural hearing impairment
Arising in cochlea/auditory nerve, sound not getting to brain properly
Describe optoacoustic emissions
Motor of outer hair cells generated vibrations on basilar membrane, vibrations transmitted out of ear as sound
What is the supratemporal plane?
Low-level speech cues
Describe the superior temporal sulcus
Intelligible speech
The superior temporal gyrus is what?
Pre-lexical processing of phonetic cues
The SSQ represents what?
Speech, spatial and qualities of hearing questionnaire
The 5 things associated with hearing impairment are…
Poorer speech identification, more social identification, social isolation, lower quality of life, depression, accelerated cognitive decline
Why is there a low uptake of hearing aids?
Reluctance to feel/look old, amplifying sounds is harder, modern ones convert sound into electrical signals, amplify signal and convert back into sound energy
How do cochlear implants work?
Electrode array inserted into cochlea - microphone picks up sound outside head, transmitted to electrode array in cochlea, stimulates auditory nerve.
State the 2 ways signals are degraded
Spectrally and temporally
How are signals degraded spectrally?
Implant users receive fewer channels of information
Describe how signals are degraded temporally
Cochlear implants limited to show fluctuations in amplitude over time
