Lecture 15 Flashcards
Place Coding of Sound
Different portions of the basilar membrane are more sensitive to sounds of different frequencies
-Valid for low + high frequencies
Time Coding of Sound
Auditory nerve firing is also ‘‘phase-locked’’, i.e. neurons systematically fire at a given time point of te cycle
-Only valid for low frequencies
Audiometry
Measure of how good or bad someone’s hearing is
-Map out the minimal sound needed
nearly perfect noise clarity
A discrimination of 96% would indicate…
a loss of noise clarity
A discrimination of 84% would indicate…
Treatment Avenues for Hearing Loss
-Hearing aid
-Cochlear implant
-Surgery
-Medication/antibiotics
Hearing Aid
-Sound amplifiers
-Microphone that amplifies sound
Hearing Aid Design
-In-the-ear (ITE) hearing aid
-Behind-the-ear (BTE) hearing aid
Amplifying Hearing Aids
Adjust volume to push certain frequencies
-Directional microphones (focus on speech)
-Noise-cancelling algorithms (cancel background noises)
Hearing Aid Fit Check
Validation of acoustic output at the tympanic membrane
Cochlear Implant (CI)
-Electrode inserted inside cochlea
-Stimulate
-Shoot electricity on the nerve
-Place-coding
-Microphone on outside piece
-Attached to head by magnet
Candidacy for Cochlear Implant
Candidacy assesment for cochlear implant is indicated for patients showing 60/60 (loudness/clarity)
Electro-Acoustic Stimulation (EAS)
-Acoustic stimulation
-Electric stimulation
-Hybrid loss
-Combine both
-Overlap provides a smooth transition
patient is completely deaf
A discrimination of 10% indicates…
Acute phase post-activation of the CI
More reports of high-pitched sound in 18-24 mm electrode users vs. 26-31 mm electrode users
Chronic phase 4-8 years post-activation of the CI
Similar number of reports of high-pitched sound in 18-24 mm electrode users and 26-31 mm electrode users
Anatomy-based Fitting
Electrode contact site as per CT scan
-Realized in the last year 1/2 that we weren’t doing a great job
Anatomy-based fitting improves speech recognition in bilateral CI users
-ABF improves speech recognition in quiet and in noise in experienced bilateral CI users
-2 ears mismatched
-2 cochlear implants
-Neural placisity will not fully adapt in this case
Single-Sided Deafness (SSD)
If electrode of deaf ear is not placed well… patient stps wearing it and says ‘‘not as good as my other ear’’
Hearing Handicap in Single-Sided Deafness
-Recognition deficit for speech signal in the ipsilesional auditory hemifield
-Speech-in-noise recognition deficit
-Sound localization deficit
-Listening effort
Pupillometric Measure of Listening Effort
-Eye tracking
-More cognitive effort = more pupil dialates
Anatomy-based fitting improves speech recognition in EAS CL users
ABF improves speech-in-quiet recognition in patients newly implanted with a unilateral EAS CI
Partial Alleviation of Hearing Handicap by Anatomy-based fitting in bilaterally deaf patients using unilateral CI
-ABF FAILS to improve speech recognition in quiet or in noise in bilaterally deaf patients newly implanted with a unilateral CI, even after 9 months of use
-ABF IMPROVES speech recognition in noise, but not in quiet, in bilaterally deaf patients newly-implanted with unilateral CI
-ABF IMPROVES speech reognition in quiet and in noise when introduced in bilaterally deaf patients wih long-standing use of a unilateral CI
Anantomy-based fitting improves music perception in bilaterally deaf patients using a unilateral CI
-Subjective quality rating of music samples
-Melodic contour identification
-Familiar song appreciation
-Place coding
Fixed Stimulation Rate Across Frequency Channels
Continuous Interleaved Sampling (CIS)
Fine Temporal Structure Processing (FSP)
-Natural sound in environment
-Modern -> makes sure electricity matches this (stimulation)
-speech recognition in quiet or in noise + melody discrimination in newly-implanted or experienced unilateral CI users
-localization of low-frequency noise bursts in experienced bilateral CI users
FSP fails to improve…
fails to improve localization of single words
Introduction of bilateral acoustic input in bilateral CIs users (EAS)…
improves speech recognition in quiet and in noise
Introduction of unilateral acoustic input in unilateral CI users (EAS)…
Adaptation to hearing devices for first-time users
Progressive increase of hearing aids’ gain or cochlear implants’ stimulation levels
Tinnitus
When you experience ringing or other noises in one or both of your ears
-Peripheral neural deficit associated with increased central gain
Hyperacusis
An increased sensitivity to sound and a low tolerance for environmental noise.
Hearing Loss
A person who is not able to hear as well as someone with normal hearing
Tonotopic Mapping
Spatial arrangement of where sounds of different frequency are processed in the brain
