Infants with Congenital Deafness: On the Importance of Early Sign Language Acquisition

Article excerpt

Two boys who both had a profound bilateral hearing impairment met at a specialized sign preschool Their preconditions were quite different, since in one of them the hearing impairment was detected in the maternity ward with the aid of otoacoustic emissions, and habilitation had begun at age 4 months. The other boy's impairment was not detected until age 2 years; habilitation was thus much delayed. Data were collected on the two boys using interviews with parents and teachers, observation, and video recording in the children's own environment at home and in the specialized sign preschool Characteristic differences between the boys are described regarding their social and linguistic development relating to the time of detection of the hearing impairment. This illustrates the importance of early detection and habilitation so as to avoid separation of individuals into different groups with differing social and academic prospects, depending on the lack of early linguistic stimulation and consequent poor language acquisition. Giving children the possibility of developing a language is the primary consideration.

Linguistic proficiency is a central requirement for human life: spoken language for the hearing and sign language for the Deaf. Infants have a communicative competence that was previously unknown, and this competence is common to both hearing and deaf children (Jusczyk & Hohne, 1997; Trevarthen & Marwick, 1986). The newborn child is able to perceive verbal sound patterns, and language development begins in early infancy (Marcus, Vijayan, Bandi Rao, & Vishton, 1999). In deaf children, language development proceeds in a manner that is equivalent to that of the hearing, starting with manual babbling and evolving into linguistic expressions (Petitto & Marentette, 1991). It is well known that the sign language of the Deaf is an advanced language rich in shades of meaning (Sacks, 1989). However, more than 94% of parents of children with severe to profound hearing impairment have normal hearing, which makes communication between parents and child difficult. Since education in sign language can begin only when the hearing impairment is detected, deaf children with hearing parents thus start from a clearly disadvantageous position. During the very important early period of language development, these deaf children thus do not receive any natural language stimulation.

The conventional methods for hearing screening have not been sensitive enough, and a childhood hearing impairment often remains undetected until the child's different behavior and failing speech development make it evident. Apparently, when conventional methods are used, detection of severe to profound hearing impairments in children occurs belatedly in all communities (Bamford & Davis, 1998). The only way to enable early detection and an early start of habilitation is universal neonatal hearing screening, with the aid of auditory brain stem evoked responses (aABR) or otoacoustic emissions (OAE) (Davis, Bamford, Wilson, Ramkalawan, Forshaw, & Wright, 1997; Kemp & Ryan, 1993; Mason, Davis, Wood, & Farnsworth, 1998). In a National Institutes of Health consensus statement (1993), universal neonatal hearing screening was recommended. The European Consensus Programme (1998) recommends hearing screening of infants, and general perinatal screening is now practiced at several centers in the United States and Europe.

There is strong evidence that the benefits of early intervention made possible by neonatal hearing screening outweigh the anxiety caused by a false positive test result (Magnuson & Hergils, 1999; Watkin, Baldwin, Dixon, & Beckman, 1998). It is now recognized that early detection of hearing loss is essential if children are to have the chance to achieve their potential language skills. Of all the variables that were investigated in a thorough longitudinal study of children with profound hearing impairment (Levitt, McGarr, & Geffner, 1987), it was found that the age when intervention began exerted the largest influence on the development of language and communication skills. …