Prelingual deafness
Prelingual deafness refers to
Statistics
There are approximately 12,000 children with hearing loss in the United States.[3] Profound hearing loss occurs in somewhere between 4 and 11 per every 10,000 children.[4] In 2017, according to the CDC, of the 3,742,608 babies screened, 3,896 were diagnosed with hearing loss before the age of three months or 1.7 babies per 1,000 births were diagnosed with hearing loss in the United States.[5]
Causes
Prelingual hearing loss can be considered congenital, present at birth, or acquired, occurring after birth before the age of one. Congenital hearing loss can be a result of maternal factors (
Treatment
Hearing aids and cochlear implants may make the child able to hear sounds in their hearing range, but do not restore normal hearing. Cochlear implants can stimulate the auditory nerve directly to restore some hearing, but the sound quality isn't that of a normal hearing ear, suggesting that deafness cannot be fully overcome by medical devices. Some say that the benefits and safety of cochlear implants continues to grow, especially when children with implants receive a lot of oral educational support. It is a goal for some audiologists to test and fit a deaf child with a cochlear implant by six months of age, so that they don't get behind in learning language. In fact, there are expectations that if children get fit for implants early enough, they can acquire verbal language skills to the same level as their peers with normal hearing.[11]
Social and cognitive impact
Children who are prelingually deaf and cannot hear noise beneath 60 decibels—about the intensity level of a vacuum cleaner[12]—do not develop oral language comparable to their peers. Children born with profound hearing impairment, 90 decibels and above (about the level of a food blender),[12] are classified as functionally deaf. These children do not develop speech skills without help from a speech pathologist. Such children display speech comprehension difficulties, even when other modes of language (such as writing and signing) are up to their age level standard.[11] Children who lose their hearing after they have acquired some amount of language, even if it is just for a short while, demonstrate a much higher level of linguistic achievement than those who have not had any language exposure.[11]
In children, this type of hearing loss can lead to social isolation for several reasons. First, the child experiences delayed
Language acquisition
Speech acquisition
Deaf children do not acquire speech the same as hearing children because they cannot hear the language spoken around them.
Cochlear implants
Speech perception can be corrected prior to language acquisition with
Research has continuously found that early implantation leads to better performance than older implantation.
Cochlear implants give deaf individuals the chance to understand auditory messages.[17] Progress was analyzed after several groups of children were given vocabulary and language tests. After three years of practice, the children with the devices did as well as children that had no previous issues with hearing. Specifically, cochlear implants allow children with prelingual deafness to acquire skills similar to children with minimal or mild hearing loss.[19]
Sign language acquisition
There is an innate desire to produce language in both hearing and deaf population. All babies vocalize to communicate.
Sign language, such as American Sign Language (ASL), is a well known form of communication that is linguistic for both hearing and deaf individuals.[17] Deaf children learning a sign language such as ASL go through a series of language milestones from birth through one year of age. These milestones are similar to those of spoken language. A deaf child is aware of their environment, enjoys human interaction, smiles, and enjoys hand play from birth to 3 months of age. From 3–6 months a deaf child also begins to babble, referred to as finger babbling.[21] These gestures of the deaf children do not have real meaning, any more than babble noises have meaning, but they are more deliberate than the random finger flutters and fist clenches of hearing babies.[22] Between 6–12 months, deaf children use manual communication and communicate with gestures, such as pulling and pointing. Many deaf children sign their first word around 8 months and up to 10 or more signs by 12 months.[21]
Reading and short-term memory
Learning three-dimensional grammar, such as in ASL, boosts the child's visual and spatial abilities to higher than average levels.[17] To succeed at learning to read, the deaf child must have a strong language to base it upon. Additionally, communication difficulties with the teacher can impair reading.
Additionally, deaf children performed more poorly in short-term memory spans for written words in comparison to age-matched hearing children simply because they are not as familiar with English words.[17] Short-term memory spans for signs and fingerspelling are also reduced in comparison to age-matched hearing children's span for spoken words. Deaf children vary widely in their developmental experience with sign language, which affects development of short-term memory processes. Children who begin language acquisition at older ages and/or have limited language input during early childhood have underdeveloped sign language skill, which, in turn, affects their short-term memory development.[23] However, with the linguistic element removed, deaf children's performance is equivalent to age-matched hearing children on short-term memory tasks.
Children of deaf parents
Mothers who are deaf themselves model signs during face-to-face interactions with their deaf babies. They mold the hands of their babies to form shapes of signs. They exaggerate their facial expressions and provide models in the direct line of vision of their deaf babies.[21] Caregivers of both hearing children and deaf children reinforce the child's early attempts at communication, thus encouraging further and more elaborate communication.
Deaf students who have deaf parents outperform their deaf peers who have hearing parents on every subtest of the WISC-R performance scale.
Neuropsychological function
Deaf children often have enhanced perceptual skills to compensate for the impaired auditory input, and this continues throughout adulthood. Congenitally deaf adults who used sign language showed ERPs that were 5-6 times larger than those of hearing adults over the Left and Right occipital regions and ERPs 2-3 times larger than hearing participants over the left temporal and parietal regions (which are responsible for linguistic processing).[24] Because both hearing and deaf adults using ASL showed larger ERPs occipital regions, the heightened response to visual stimuli is also due to knowing and using sign language and not only due to deafness.
Both hearing and deaf adults using ASL also show larger ERPs over the left than right hemisphere. Since the
Sociocultural factors
Deaf children from a lower socioeconomic status are at a high risk for not being exposed to accessible language at the right time in early childhood. This is because in most countries poverty translates into a lack of access to the educational and clinical services that expose deaf children to language at the appropriate age.[17]
Academic achievement of deaf students is predicted to a large extent by the same factors that predict the academic achievement of normally hearing students, such as social class and the presence of additional handicapping conditions. This means that deafness, by itself, does not determine academic success or failure but rather interacts with many other factors in complex ways.[17]
Early intervention
The deaf children of hearing parents may not have significant exposure to any language in early childhood. Because of their sensory loss, these children perceive little of their parents' speech. Because in most cases the parents do not sign the children are also not exposed to a conventional sign language.[25] Until recently, education of deaf emphasized speech training and the deaf children also were not exposed to sign language in school.
Not being exposed to accessible language at a certain time in early childhood combined with lack of access to the educational and clinical services that expose deaf children to language at the appropriate age are all factors that contribute to language acquisition of prelingually deaf individuals.[17]
See also
- Congenital hearing loss
- Deaf history
- Deafness
- Hearing impairment
- Language exposure for deaf children
- List of notable deaf people
- Models of deafness
- The Butterflies of Zagorsk
- The Language Instinct
References
- ^ CDC (2019-03-21). "Types of Hearing Loss | CDC". Centers for Disease Control and Prevention. Retrieved 2020-03-18.
- ^ "Speech and Language Developmental Milestones". NIDCD. 2015-08-18. Retrieved 2020-03-18.
- ^ CDC (2017-10-23). "Research and Tracking of Hearing Loss in Children | CDC". Centers for Disease Control and Prevention. Retrieved 2020-03-18.
- ^ "Deafness and HearingLoss". Retrieved 2012-04-11.
- ^ CDC (2019-12-04). "Summary of Infants Not Passing Hearing Screening Diagnosed by 3 Months". Centers for Disease Control and Prevention. Retrieved 2020-03-06.
- ^ a b "Deafness and hearing loss". www.who.int. Retrieved 2020-03-18.
- ^ "Audiology Information Series: Childhood Hearing Loss" (PDF). ASHA. Retrieved 18 March 2020.
- PMID 22652773.
- ^ "Hearing Loss at Birth (Congenital Hearing Loss)". Retrieved 2012-04-11.
- ^ "Hearing Loss at Birth (Congenital Hearing Loss)". American Speech-Language-Hearing Association. Retrieved 2020-03-18.
- ^ ISBN 978-0-205-59303-3.
- ^ a b "Noise Sources and Their Effects". Retrieved 2012-04-11.
- PMID 15448056.
- ^ "Effects of Hearing Loss on Development". American Speech-Language-Hearing Association. Retrieved 2020-03-18.
- S2CID 60995200.
- ^ ISBN 0-86377-308-7.
- ^ ISBN 9780444503602.
- S2CID 30550367.
- ^ S2CID 59361619.
- PMID 25368567.
- ^ a b c Andrews J, Logan R, Phelan J (2008). "Milestones of Language Development". Advance for Speech-Language Pathologists and Audiologists. 18 (2): 16–20.
- ^ Angier, Natalie (1991-03-22). "Deaf couples' babies found to babble with hands Study compares practice to learning sounds". Retrieved 2024-02-10.
- JSTOR 29774278.
- ^ PMID 9448260.
- JSTOR 29774278.