- What domains of cognition/perception are known to be enhanced by experience with sign language?
Processing Motion in the periphery
• Deaf signers are perceptually sensitive to handshape categories that are relevant to sign language.
• Deaf signers develop special abilities for perceiving aspects of sign language that are similar to the abilities that speakers develop for perceiving speech.
Processing motion in the periphery
• Deafness (auditory deprivation) enhances the ability to detect movement in the periphery of vision
• Sign language exposure during development shifts motion processing to the left hemisphere
• Enhanced ability to discriminate between transitional and purposeful movements
Left hemisphere bias for processing of motion
Sign language exposure during development shifts motion processing to the left hemisphere
– Deafness (not sign language experience) creates an enhanced ability to detect motion in the periphery
AFFECTED DOMAINS OF VISUAL SPATIAL COGNITION:
• Mental rotation and image generation
• Memory for spatial locations
• Face discrimination and processing of facial features
• Motion analysis and brain organization for motion
- What domains of cognition/perception are known to be unaffected by experience with sign language?
• Neither sign language experience nor deafness affects low-level motion perception ability
(VISUAL/SPATIAL COGNITION) OTHER UNAFFECTED AREAS:
Memory for visual images
Face recognition and gestalt face processing
Motion detection thresholds
- What aspects of face processing are enhanced in signers?
• Deaf adults and children who are fluent signers perform better than non-signers on tests of face discrimination
-Enhanced face discrimination is not observed for upside-down faces
• Experience with sign language affects mechanisms specific to face processing, rather than general visual abilities
******Signers were significantly more accurate than non-signers in detecting changes in the eyes and mouth features *******
- Do deaf individuals “see” better (i.e., have better visual acuity)?
• No evidence that deaf people “see better”
Visual acuity is not better
Motion detection and coherence thresholds unaffected
- How can we tease apart effects of deafness (auditory deprivation) from effects of sign language experience?
Use hearing signers (CODAs/bimodal bilinguals) - fluent signers that grew up in a Deaf household.
- What criteria are used to determine whether someone is a candidate for cochlear implant surgery?
Sensorineural hearing loss - a candidate for CI
Damage to the cochlea or its connection to the auditory nerve
Conductive hearing loss= not a candidate
Children and adults with profound (90-120 dB) or severe (70-90 dB) hearing loss
Receive little or no beneﬁt from hearing aids (preferred for those with mild to moderate hearing loss)
A functioning auditory nerve
“Appropriate” educational environment (often interpreted as speech only)
- How are cochlear implants different from hearing aids?
Cochlear implants help differentiate sound and pitches. The differentiation of pitches and sound are done by the insertion of electrons into the cochlear. The more electrodes inserted, the wider range of pitches a person can hear. The max number of electrodes is 24.
Hearing aids amplify sounds so they can be heard by damaged ears while Cochlear Implants “replace” hair cells that send information to the brain
- How well do cochlear implants work?
From age appropriate language after a few years, to short term language delays, to long term delays
As a group CI children lag behind their hearing peers in speech/language development
Exclusive use of spoken communication before implantation was NOT associated with better language outcomes
• All CI children performed better than expected, based on their pre-implantation scores
• Most did not reach age-appropriate levels after 3 years
• Huge variability in outcomes
- Does the NAD oppose CIs and advise against them?
No, they only want to supply the public with information on cochlear implants so they can make an informed decision.