The Hearing or Visually Impaired Child

Peter Hindley

Alison Salt

Models of Deafness, Visual Impairment, and Deaf-Blindness: Culture and Disability

Deafness and severe visual impairment (SVI) are low-incidence conditions which, alone and in combination, can have a significant effect on a child’s development and mental wellbeing. Less severe degrees of hearing and visual impairment are more common but have a less significant impact on child development. This chapter provides an overview of hearing and visual impairment and a more detailed account of deaf, SVI, and deaf-blind children’s development and mental health. Two Web sites (www.raisingdeafkids.org and www.boystownhospital.org) provide an overview of deafness and an online research facility. The American Federation for the Blind website (www.afb.org) is a useful source of information as well.

The sensory impairments can be defined in a variety of ways. Two key models are used, medical and cultural. Medical definitions of sensory impairments focus on the severity of impairment, the site and type of impairment, the age of onset of the impairment and the presence or absence of additional disabilities. The cultural model of sensory impairment challenges the notion that a deaf or visually impaired person is disabled. Cultural models focus on the social experience of deafness or blindness and the strengths of deaf and blind communities and individuals (Table 1.7.2.1).

Being a deaf, SVI, or deaf-blind young person does not necessarily increase the risk of developing mental health problems. Three sets of factors, which are linked to sensory impairments, do. First are the consequences of being deaf,
SVI, or deaf-blind in a world which is oriented to the needs of hearing and sighted people. The goodness or poorness of fit between the needs of sensorially impaired children and their environment has an impact from early in the child’s life—in particular, since the vast majority of deaf and SVI children are born into hearing and sighted families, how the family adjusts to the needs of their deaf or SVI child. Second, brain insults and other physical illnesses linked to the cause of deafness or blindness may confer additional neuropsychological vulnerabilities. Third, children with sensory impairments are more vulnerable to all forms of abuse and neglect.

TABLE 1.7.2.1 DEFINITIONS OF SENSORY IMPAIRMENT

Hearing Impairment	Visual Impairment	Deaf-Blindness
Severity: mild <40dB in better ear; moderate <70dB; severe <95dB; profound 96dB<(BSA 1988)	Severity: Partially sighted; low vision; legally blind (<20/200 Snellen or 20° visual field); totally blind (AFB 1995)	Severity: either deafness and any visual impairment or legally blind and any hearing impairment
Age of onset: congenital, early onset, acquired and progressive	Age of onset: congenital, early onset and acquired	Age of onset: congenital, early onset and acquired
Site: conductive or sensorineural	Site: peripheral or central	Site: conductive or sensorineural HI and peripheral or central VI
Descriptors: Children with profound deafness in the better ear are commonly called deaf. Children with moderate to severe deafness are commonly called hard of hearing.		Children with combinations of visual impairment and deafness are called deaf-blind.
Cultural: use of sign language, experiencing the world visually, identification with other deaf people, attitude of majority community— “assimilating” or “oppositional” (4)	Cultural: constructing the world as a narrative, not as a gestalt (67)	Cultural: use of hand-on signing or hands on finger-spelling. Identification with other deaf-blind people and experience of oppression

Deaf, Hard of Hearing and Hearing-Impaired Children

Epidemiology and Etiology of Hearing Impairment

Hearing impairment affects approximately 17/1,000 children under the age of 18 in the United States (1). The most common forms of hearing loss are those resulting from middle ear effusions, although these are often time limited. It is not always possible to establish the age of onset of hearing impairment, but among children with permanent hearing impairment just under 60% have congenital hearing loss and approximately 25% acquired hearing loss (2). Genetic causes are the most common causes of permanent sensorineural hearing loss, followed by the complications of severe prematurity and intrauterine and postnatal infections (Table 1.7.2.2).

Otitis Media with Effusion, Unilateral Deafness, and Hard of Hearing Children

Acute otitis media (AOM) affects about 2/3 of children in the age range 6–24 months. AOM is very uncommon after 6 years of age. About 45% of children with AOM have a middle ear effusion (MEE) one month after an episode of AOM and approximately 10% have one three months after an episode of AOM. MEE can cause hearing loss, and where this is greater than 20 dB loss, surgical insertion of PEC tubes is indicated. Chronic MEE with hearing impairment can cause language delay in children (www.e-medicine.com). Unilateral deafness affects approximately 1/1,000 live births (3), of which approximately 35% have profound unilateral hearing impairment. Hearing impairment as a result of MEE and as a result of unilateral sensorineural deafness can cause significant difficulties for the child in the classroom and in conversational settings. Common effects of these forms of hearing impairment include: localization of sound; understanding what people say when there is other noise at the same time; paying attention in class; following directions in class; and learning new concepts. The possibility of an undetected hearing impairment should always be considered in children referred for attention problems.

Children with moderate to severe hearing impairment need an initial multidisciplinary assessment by audiologists, pediatricians, speech and language therapists, teachers of the deaf, and where appropriate, geneticists. The main intervention for these children will be the provision of hearing aids with support from teachers of the deaf to ensure that classroom provision and teaching practice meet the individual child’s needs. Hearing aids amplify the sound being transmitted to the middle ear. Digital hearing aids allow specific adjustments to be made to improve comfort and amplify specific frequencies, but they need careful fitting (4).

Despite their advantages, digital hearing aid users still face a variety of problems. Children can still experience excessive amplification of background noise, which makes noisy environments particularly difficult. Recruitment, perceiving greater increases in sound loudness than would be expected (e.g., a sound at 70 dB is tolerable but intolerable at 110 dB), can cause pain and distress. Finally, acoustic feedback, leading to high-pitched whistling, can occur if hearing aids are not fitting properly. This is a particular problem for young children who are growing rapidly.

The majority of hard of hearing children who have received appropriate audiological and educational intervention will develop effective spoken language. They are likely to experience a degree of language delay and may have pragmatic and syntactic deficits. This is also true of many, but not all, deaf children who receive early (i.e., before two years) cochlear implantation (see below).

TABLE 1.7.2.2 PREVALENCE AND ETIOLOGY OF SENSORY IMPAIRMENT

Hard of Hearing and Deafness

SVI and Blindness

Prevalence:

Early onset: 101/100,000

Early onset: 4/10,000

Acquired: 21/100,000¹

Acquired: 2/10,000²

Additional impairments:

Total: 20–40%³

Total: 77%²

Visual: 4%

Mental retardation: 8%
Emotional and behavioral: 4%

n.b.: mortality of 10% in SVI/blind with additional or SVI/Blind+²

Learning: 9%

Etiology and timing (%s)¹:

	Early onset	Acquired
Genetic	44.7	24.7
Prenatal	4.0	1.0
Perinatal	17.6	11.3
Postnatal	0.0	41.2
CFA*	2.9	0.0
Other	1.0	3.0
Missing	25.7	18.6

Etiology and timing (%s)²:
SVI/Blind SVI/Blind+
Prenatal 83.3 54.5
Neonatal+ 2.9 21.7
Perinatal
Childhood 7.8 20.8
All
Hereditary 33
Hypoxia/ischaemia 18
Tumour 4
Infection 3
Hydrocephalus 3
Injury (AI and NAI) 3
Systemic 2
Other 5
Unknown 25
Cause and timing unknown 9
n.b. % > because some children have multiple aetiology

Site (%s):

Sensorineural 91.5

SVI/Blind SVI/Blind+

Conductive 8.5

Cerebral/visual 5.9 60.1
Pathway
Optic nerve 16.7 31.3
Retina 60.8 19.1
Whole globe 9.8 5.7
Other anterior** 22.6 8.9
Other 2.9 1.5
n.b. % >100 because some children have multiple sites

*Cranio-facial abnormalities
**Uvea, lens, cornea, and glaucoma
¹Data from Davis A & Mencher G. Epidemiology of permanent hearing impairment. In: Newton VE, editor. Paediatric Audiological Medicine. London and Philadelphia: Whurr Publishers; 2002. pp. 65–90.
²Data from Rahi JS & Cable N on behalf of the British Childhood Visual Impairment Study Group. Severe visual impairment and blindness in children in the UK. The Lancet. 2003; 362: 1359–65.
³Data from Knoors H & Vervloed PJ. Educational Programming for Deaf Children with Multiple Disabilities. In: Marschark M & Spencer PE, editors. The Oxford Handbook of Deaf Studies, Language and Education. Oxford and New York: Oxford University Press; 2003. pp. 82–96.

Cultural Aspects of Deafness

There are historical references to deaf people and the use of sign language dating back to the classical period (5), but the modern study of the cultural aspects of deafness began in the 1960s with Bob Stokoe’s (6) studies of American Sign Language (ASL). The Deaf community came to be defined by a series of key experiences. Central among these were the use of sign language, experiencing the world visually and the experience of oppression by the majority culture (7). More recent studies have suggested that the types of community that emerge, e.g., distinct and separate deaf communities, merged communities of deaf and hearing people, or single deaf people within hearing communities, depend in part on the attitude of the majority hearing community toward deafness (4). Majority communities can be seen on a continuum. At one end are those that make no distinction between the role and function of deaf and hearing people, so-called assimilating communities. These tend to occur in rural communities and lead to merged communities of deaf and hearing people, such as the community described in nineteenth century Martha’s Vineyard (8). At the other end of the continuum are communities in which the role and function of deaf people is significantly restricted and their cultural practices, such as the use of sign language, are suppressed. These are so called oppositional communities. Most industrial communities of the nineteenth and twentieth century shared these characteristics and lead to the distinct deaf communities described by Meadow-Orlans and Erting.

A key feature of oppositional deaf communities is cultural discontinuity; 90–95% of deaf children are born into hearing families (deaf children of hearing parents [DOH]), the vast majority with no previous experience of deafness (9). Approximately 90% of deaf parents have hearing children (10). Historically DOH children joined the deaf community through key experiences such as attending residential schools and joining deaf clubs. Changes in education legislation and practice have lead to the vast majority of American deaf children being educated in mainstream classes or special education classes in mainstream schools. Early intervention and cochlear implants are changing the experiences of deaf children and their hearing families. At the same time, fewer deaf people seem to be active in formal social organizations such as deaf clubs and changes in communication technology (email, close captioning and video-telephony) are making communication much easier.

Sign Languages

Sign languages are naturally occurring languages that develop whenever significant numbers of deaf people come together (11). In the Western world, prior to formal education, this occurred in areas with high rates of congenital deafness, such as Martha’s Vineyard. This continues to happen in parts of the developing world, such as Yucatan (4). Formal education of deaf children began in Europe in the sixteenth and seventeenth centuries and was first established in the United States in 1817.

The American founders of deaf education brought French teachers of the deaf from Paris. American Sign Language (ASL) origins appear to be in Langue des Signes Française, the native sign language of Martha’s Vineyard and the sign language of North American Indians (Sherman and Wilcox 2003). There are strong linguistic and neurological arguments to support the contention that language originally emerged from early gesture and that sign language antedates spoken language (11).

ASL, like other natural sign languages, differs both syntactically and lexically from spoken English. Fischer and Huslt (12

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