The pragmatic skills of profoundly deaf children.

This study investigated the ability of normally hearing students and two groups of profoundly deaf students, one using oral and one using signed communication, to employ a series of pragmatic skills required for effective face-to-face interaction. Specifically considered were the ability of listeners to request clarification, the ability of speakers to respond to requests, and the strategies speakers use at times of communication breakdown. Differences were found between the two groups suggesting that the profoundly deaf students had difficulty consistently using appropriate, productive pragmatic behaviors in their face-to-face dyadic interactions.

Patterns of persistent otitis media in the first year of life in aboriginal and non-aboriginal infants.

Australian Aboriginal infants experience very early otitis media (OM). A previous study reported that OM with effusion (OME) or acute OM (AOM) was observed in the first 8 weeks of life in 95% of 22 Aboriginal infants, but that OME was seen in only 30% of 10 non-Aboriginal infants. Tympanic membrane perforation was reported for 1 Aboriginal subject at 8 weeks of age. This requires further investigation, because early OM onset has been demonstrated in non-Aboriginal groups to increase the risk of chronic and persistent ear disease in later childhood. This prospective study used otoscopy and tympanometry to describe the course of OM in infants examined repeatedly from soon after birth. Disease course was described in two ways, based upon earlier findings from other studies of Aboriginal schoolchildren. First, patterns of disease in the first year were identified; non-Aboriginal infants had occasional episodes of OME or AOM from which they recovered spontaneously, usually within 1 month; Aboriginal infants had persistent AOM, OME, or tympanic membrane perforation with discharge that rarely, if ever, resolved to normal. Second, conditional probabilities were calculated for ear state transitions at consecutive ear examinations, and a model of the course of OM was proposed for the Aboriginal infants. Results also suggested that binaural patterns of chronic OM described previously in Aboriginal schoolchildren may already be established in the first year of life. These findings will help service providers determine when to intervene to avoid the chronic consequences of early OM.

Onset of otitis media in the first eight weeks of life in aboriginal and non-aboriginal Australian infants.

Otitis media (OM) is highly prevalent among Aboriginal Australians, in whom eardrum perforations with discharge have been reported in the first 3 months of life. Only one published study, however, has described middle ear status at birth or prior to eardrum perforation in young Aboriginal infants. This prospective study used otoscopy, tympanometry, and hearing tests to compare middle ear status and hearing sensitivity in Aboriginal and non-Aboriginal neonates. Immobile eardrums were observed immediately after birth, but mobility generally appeared within the first week. At examinations at 6 to 8 weeks of age, OM with effusion or acute OM was observed in 95% of 22 Aboriginal infants, but OM with effusion was seen in only 30% of 10 non-Aboriginal infants. There was a clinic record of unilateral perforation in 1 Aboriginal infant only. Hearing impairment was demonstrated by auditory brain stem response in 5 ears, all with evidence of middle ear abnormalities. Improved knowledge and diagnosis of the signs and symptoms of OM will contribute to improvements in the provision of early medical intervention to populations at high risk for early OM.

Bacterial colonization of the nasopharynx predicts very early onset and persistence of otitis media in Australian aboriginal infants.

Otitis media (OM) develops in the first months of life and persists throughout childhood in many rural Aboriginal children. We have followed Aboriginal and non-Aboriginal infants from birth to determine the relationship of the early onset of OM to nasopharyngeal colonization with respiratory pathogens. Aboriginal infants were colonized with multiple species of respiratory bacteria (Moraxella catarrhalis, Haemophilus influenzae, Streptococcus pneumoniae) at a rate of 5% per day and the timing of colonization predicted the onset of persistent OM in individual Aboriginal infants. Non-Aboriginal infants became colonized by M. catarrhalis alone at the slower rate of 1% per day and experienced transient episodes of OM in the absence of colonization. We attribute early bacterial colonization in most Aboriginal infants to high rates of cross-infection due to overcrowding, poor hygiene and high rates of bacterial carriage. Early age of infection and the multiplicity of bacterial types may contribute to prolonged carriage and to eustachian tube damage leading to persistent OM. Thus Aboriginal infants are "otitis-prone" and might qualify for prophylactic antibiotics.

Middle ear measures as predictors of hearing loss in Australian aboriginal schoolchildren.

This study sought to establish the value of tympanometry and otoscopy for predicting significant conductive hearing loss in remote-area Aboriginal children, and also to measure the range of hearing loss which can be expected with middle ear disease, with or without a tympanic membrane (TM) perforation. A field study is reported of 255 Aboriginal children aged up to 16 years who were examined with pneumotoscopy and tympanometry and whose hearing was tested under controlled acoustic conditions. Results showed that pneumatic otoscopy for detection of middle ear effusion and identification of perforations resulted in the best rate of prediction of significant conductive hearing loss. Furthermore, the hearing of children with perforated TMs (mean pure-tone average 30.0 dB; S.D. 11.1) was significantly worse than those in which tympanometry suggested middle ear effusion (mean pure-tone average 20.3 dB; S.D. 9.6), and both differed significantly from ears showing normal tympanograms (mean pure-tone average 11.2 dB; S.D. 5.9). Implications for community-based hearing screening and classroom management of affected children are discussed.

Reflectometric screening for otitis media: inconsistencies in a sample of Australian aboriginal children.

This paper evaluates reflectometry, or acoustic otoscopy, as an objective test for the mobility of intact tympanic membranes in Australian Aboriginal children, who are a population at high risk for otitis media. Reflectometry, pneumotoscopy and tympanometry were compared in 395 ears in 198 Aboriginal children living in remote communities in Northern Australia. A strong interaction was found between pneumotoscopy and tympanometry (P < 0.001), there was some interaction between pneumotoscopy and reflectometry (breakpoint 5.0) (P < 0.05) and there was no significant interaction between reflectometry and tympanometry. Results showed that intra-observer and inter-observer agreement for measures of reflectivity were 0.87 and 0.83, respectively. Unexpected differences between reflectivity measures for right (mean 5.4 units) and left (mean 4.9 units) ears and for different test locations were attributed to procedural artifact or training effects. It was concluded that, despite its practical advantages, reflectometry cannot be recommended as a screening tool for tympanic membrane (TM) immobility in this population.

Social and environmental factors in 10 aboriginal communities in the Northern Territory: relationship to hospital admissions of children.

OBJECTIVE: To identify social and environmental differences associated with differences in admission rates of children from 10 rural Aboriginal communities in the Northern Territory. DESIGN: Between March 1986 and December 1987, records of hospital admissions of the cohort of children for 1976-1985 were examined retrospectively; cross-sectional measurements of 74 historical, social and environmental characteristics of each community were collected. SAMPLE: All 1961 children born between 1 January 1976 and 31 December 1985 and still living in the 10 communities. METHOD: Scores on social and environmental factors for each community were generated by factor analysis. Generalised linear interactive modelling was used to investigate the association between these scores and admission rates. RESULTS: Mean admissions per child-year at risk were higher in Central Australian communities (range, 0.41-0.93) than Top End communities (0.26-0.38). Factor I accounted for 30% of the social and environmental differences between communities: communities with a high score on this factor had more houses, fewer shared toilets, more electrical appliances, better personal hygiene and a history of mission administration. High scores on this factor were predictive of lower admission rates and the factor explained most of the differences in admission rates between the Top End and Central Australian communities. Factor VI, correlated with dilapidated dwellings and fewer Aboriginal Health Workers, explained some differences in admission rates between six Top End communities. CONCLUSIONS: Social and environmental factors correlated with the degree of community development are associated with the health of Aboriginal children. Improved development programs should be community-controlled and evaluated to identify the social, educational, behavioural and environmental changes that are most effective in improving health.

A multiple-electrode intracochlear implant for children.

A multiple-electrode intracochlear implant that provides 21 stimulus channels has been designed for use in young children. It is smaller than the adult version and has magnets to facilitate the attachment of the headset. It has been implanted in two children aged 5 and 10 years. The two children both lost hearing in their third year, when they were still learning language. Following implantation, it was possible to determine threshold and comfortable listening levels for each electrode pair. This was facilitated in the younger child by prior training in scaling visual and electrotactile stimuli. Both children are regular users of the implant, and a training and assessment program has been commenced.

Preliminary results for the cochlear corporation multielectrode intracochlear implant in six prelingually deaf patients.

The preliminary results from this study indicate that some prelingually deaf patients may get worthwhile help from a multiple-electrode cochlear implant that uses a formant-based speech processing strategy. It is encouraging that these improvements can occur in young adults and teenagers. The results for two children are also encouraging. A 10-year-old child obtained significant improvement on some speech perception tests. It was easy to set thresholds and comfortable listening levels on a 5-year-old child, and he is now a regular user of the device. There are, however, considerable variations in performance among the prelingual patients, which may be related to the following factors: whether they have had some hearing after birth, the method of education used, the motivation of the patient, and age at implantation.

Child variables influencing maternal speech style. Deaf and hearing children.

This study investigated maternal speech to age-matched and linguistically matched deaf and hearing 2-yr-old and 5-yr-old infants. Maternal speech features that were examined included complexity, selected utterance, and sentence types, repetitions, expansions, utterance acceptability, and fluency. Results revealed more significant differences in maternal speech to age-matched hearing and deaf children than to linguistically matched child groups. In addition, child deafness itself seemed to account for other characteristics of maternal speech, and their possible effects on the communicative development of the deaf child were discussed.

The deaf child: habilitation with and without a cochlear implant.

The rationale underlying the habilitation of deaf children through the use of cochlear implants is discussed. Areas of child development which are especially relevant in the habilitation process are highlighted. The need for rigorous ongoing evaluation is emphasized.

Critical bands following the selective destruction of cochlear inner and outer hair cells.

Critical bandwidths and absolute intensity thresholds were measured in cats before and after kanamycin treatment which induced selective inner and outer hair cell losses. Hair cell losses were measured from cochleograms constructed from surface preparations of the organ of Corti. Results suggested that, for the test frequencies and stimulus intensities employed, critical bandwidths were not affected for frequencies tonotopically located in cochlear regions where only outer hair cells were lost. Critical bands were widened or not measurable only when inner hair cell losses exceeding 40% were also associated with complete loss of outer hair cells. The experiment suggests that cochlear frequency selectivity can be mediated by inner hair cells alone.

Frequency discrimination following the selective destruction of cochlear inner and outer hair cells.

Frequency discrimination was measured behaviorally before and after drug-induced lesions of cochlear hair cells in the cat. Discrimination was unaffected by complete loss of outer hair cells provided that at least 50% of inner hair cells were intact. Thus, inner hair cells are important for frequency discrimination, and they can function normally in this regard without the influence of outer hair cells.