Cochlear implants Flashcards
Role of Directional Microphone in CI
Ext part 1
Picks up acoustic energy
Changes it to electric signal
Electrical signal sent to speech processor
Role of Speech Processor
Ext part 2
Receives electrical signal from mic
Electrical signal changed to coded signal
Coded signal sent to transmitting coil
Role of Transmitting coil
Ext part 3
Receives coded signal from speech processor
Sends to internal receiver-stimulator
Internal Receiver-Stimulator
Internal Part 1
Receives coded signal from transmitting coil
Sends signal to electrode array
Electrode Array
Internal Part 2
Receives coded signal from internal receiver-stimulator
Stimulates Nerve fibers
Nerve fibers send the msg to the brain
Telecoil and FM battery pack for CI
permit wireless connectivity to telephones, public sound systems, MP3 players & Bluetooth systems
CI are regulated by FDA and are
Class III medical devices
Current youngest age requirement for CI
12 mo. and even younger if candidate
patient selection criteria
requirements that must be met prior to proceeding to implantation
open-set recognition
a response format in which parents write down or repeat test stimuli instea of selecting a response from a group of options (no choices)
Moderate bilateral HL adults can be candidates for CI
Yes- for Cochlear brand.
all candidates must undergo haid trial period before CI
true
hearing aid trial in children can be waived if
there is evidence of cochlear ossification
cochlear ossification
build-up of new bone in response to bacterial meningitis that may have caused an infection in cochlea
HINT-C
was developed as an adaptive procedure to find children’s sentence recognition thresholds or the lowst SNR resulting in 50% recognition
possible physical contraindictions for implantation
- deafness due to lesions in the acoustic nerve or central auditory pathway (such as genetic condition called neurofibromatosis)
- external or middle ear infections, TM performations, Chronic mastoiditis, Cholesteatomas which need to be cleared up before implantation surgery
abnormalities that will render CI useless
Mondini anomaly
EVAS
Mondini anomaly
congenital malformation - Profound SNL HL & a flattened cochlea w/ a single turn
EVAS stands for
Enlarged Vestibular Acqueduct Syndrome
EVAS
the opening in temporal bone is arger than normal & pts present with progressive SNL HL
Useful test for CI
- needle electrode is inserted thru TM & placed on the promontory w/ a surface electrode place on opposite cheek
- good sign if pt experiences the small electrical current (means neurons of aud nerve are stimulable)
Promontory stimulation test
Implant is always placed in “better ear” because
better ear has larger population of surviving nerves in the spiral ganglion to be stimulated (Spiral ganglion sends signals from cochlea to brain)
Mastoidectomy (choice in surgery)
partial or complete removal of the mastoid process & bone
facial recess approach (choice in surgery)
way of surgically accessing the middle ear through mastoid bone through a niche lateral to the facial nerve canal
in CI, surgeon must perform
cochleostomy
Cochleostomy
drilling a hole into the basal turn of the cochlea to insert the electrode array into the Scala Tympani
hook-up
initial delivery & fitting of the CI (external parts)
mapping of CI
initial programming of CI
- the setting of the required electrical stimulation by the cochlear implant for hte pt to hear soft & comfortably loud sounds (goal is to determine dynamic range for each electrode)
- ***The process of setting or adjusting the speech processor based on the dynamic range of each electrode
dynamic range
base on the area b/w electrical threshold level (t-level) and maximum comfort level (C-level)
-difference between t & c level for each electrode
T-level
pt can just detect the sensation of hearing at this level
Speech coding strategies examples
SPEAK
CIS
SPEAK
speech coding strategy that breaks the signal into many (e.g.20) bandpass filters, scans for those having the greatest amplitude, and then conveys teh information via low pulse rates
SPEAK
based on the principle that frequency regions w/ greatest amplitude hav ethe most perceptual salience
CIS stands for
continuous interleaved stimulation
CIS
speech coding strategy estimates the envelope of the acoustic wave by codign the amplitude of the signal in 6 to 8 bandpass filters at a high pulse rate (>800pps)
ACE speech coding strategy
combo of SPEAK & CIS
5 communication options
auditory verbal unisensory oral auditory-oral cued speech total communication ASL/ESL
Definition of auditory verbal unisensory
emphasizes auditory skills
focuses on use of remaining hearing with amplification
no manual communication
*child discouraged from relying on visual cues
Definition of Oral Auditory-Oral
Emphasizes auditory skills AND
stresses use of speechreading*
no manual communication
Definition of Cued Speech
Visual communication system of 8 handshapes (cues) that represent different sounds of speech (makes speech clear through vision)
-allows child to distinguish sounds that look same on lips
Definition of Total Comm
-Philosophy of using every and all means to communicate w/ deaf children…including manual lang based on Eng
definition of ASL
manual language that is distinct from spoken Eng. Eng is taught as 2nd lang
Primary goal of Auditory Verbal Unisensory
To develop speech, primarily thru use of aided hearing alone, & comm skills necessary to integrate into hearing community
Primary goal of Oral auditory-oral
To develop speech & communication skills to integrate into Hearing community