How do we hear?
What is the threshold for deafness and disabling hearing impairment?
81 dB or greater hearing threshold (“4FAHL”: avg at 0.5, 1, 2, 4 kHz)
146.000 deaf-born children per year*
35 dB or greater hearing threshold (avg at 0.5, 1, 2, 4 kHz) in better ear
250 million people in the world affected: projected 700 Mio in 2050
Half of deafness and hearing impairment is avoidable
Unaddressed hearing loss’ global annual costs US$ 980 billion
Adult-onset hearing loss is the 2nd leading cause for Years Lived with a Disability (YLD).
Effects and burden of hearing impairment
Impaired development of speech, language, cognitive skills in children
Slow progress in school
Difficulties in obtaining, performing and keeping an occupation
Social isolation and stigmatization in all ages and both sexes
Profound social and economic effects in communities and countries.
What gadget can be use for electrical stimulation of the auditory nerves?
At first: only one wire (single channel), not possible to understand speech, but ok with lip reading
Waveform strategies: Continuous Interleaved Sampling
sound signal is amplified -> filtered -> envelope=fluctuation -> compression -> electrode transmits
one electrode at a time
What are vocoder?
Vocoder: Simulate information reduction in CIs
Shows information that is transmitted by a cochlear
What are the defferent ways of stimulation to calibrate a cochlear?
Put up an electric field -> cell membrane gets charged (channels open for ions)
pulse usually is followed by an action potential
3: not beeing used, too quiet
Electrical stimulation of the auditory system
Pulse = Stimulus
The leaky integrate-and-fire model: A simple model for the electrically stimulated auditory nerve
bucket gets filled and bucket has holes
What is the reaktion of nerves on pulses?
action potential
with rate adaptation (if there are too many pulses, AP can not keep up - nerve would eventually stop firing)
What happens if you change the pulses per second?
Numbers=elektrodes are ranked by pitch by patient
rankings are off because nerver fibers have died, so multiple electrodes stimulate the same instead of different
goal: patients can distinguish the electrodes
How can we transmit Speech modulation ranges to the nerve ranges?
compression
New development: Stimulation by one electrode and record nerve activity by another activity
Last changed2 days ago