Biomedical subjects

P Blamey

Publications and source records attributed to P Blamey.

8 recordsLinked to original sources

PubMed2002

Comparison of methods in speech acquisition research.

The paper examines the effect of choices involved in speech acquisition research among children with impaired hearing. Choices involving transcription method, sampling procedures, subject selection and statistical approaches affect the outcome of any research. Two recent papers used different methodological approaches to examine the conversational speech samples of children with impaired hearing and arrived at differing conclusions about their rates of improvement. To compare these results, a further data set was examined using both methodologies. The analyses indicated a closer alignment of results than was immediately obvious from the two previous studies, suggesting that the different results were primarily due to differences in methodology.

Child↗

PubMed2000

The development of speech perception in children using cochlear implants: effects of etiologic factors and delayed milestones.

HYPOTHESIS: Speech perception outcomes for cochlear implantation of children vary over a wide range, and it is hypothesized that central pathologic states associated with certain causes of hearing impairment account for a substantial part of the variance. STUDY DESIGN: A retrospective analysis was carried out to ascertain the relationships between speech perception, etiologic factors, and central pathologic states as indicated by preoperative delayed motor milestones and/or cognitive delays. SETTING: Data were obtained from the pre- and postoperative records of patients attending a hospital cochlear implant clinic. PATIENTS: Results for 75 consecutive patients up to age 5 years who underwent implantation were included in the study. INTERVENTION: Patients received a 22-electrode cochlear prosthesis and were seen by the clinic for regular tune-up and assessments. Home- and school-based habilitation was recommended by the clinic. MAIN OUTCOME MEASURES: Speech perception measures were classified on a five-point scale to allow for different evaluation procedures at different ages and developmental stages. RESULTS: The incidence of motor and cognitive delays were fairly evenly spread across etiologic factors, except for cytomegalovirus, which had a much higher than average incidence. Children with motor and/or cognitive delays were significantly slower than other children in the development of speech perception skills after implantation. Etiologic factors did not have a statistically significant effect on speech perception outcome. CONCLUSIONS: It is likely that central pathologic states account for a substantial part of the variance among children using cochlear implants. Specific indicators of central pathologic states should be used to assess a child's prognosis in preference to less specific information based on etiologic factors alone.

Child, Preschool↗

PubMed1997

Are spiral ganglion cell numbers important for speech perception with a cochlear implant?

OBJECTIVE: Studies of factors affecting the survival of ganglion cells in adults with profound hearing loss and speech perception in cochlear implant users are reviewed in order to assess the hypothesis that ganglion cell numbers have a strong influence on the level of speech perception achieved by adult implant users. DATA SOURCES: All histopathologic data have been published as tables or figures in refereed papers. Speech perception data were collected from published papers and directly from clinics and from Cochlear Corporation's database. STUDY SELECTION: Histopathologic studies with reasonably large groups of patients were selected. The speech perception data were from the largest study available. DATA EXTRACTION: All data used have been published in refereed journals of high repute. No other assessment of quality or validity was available to the author. DATA SYNTHESIS: Trends in the speech perception data were compared qualitatively and quantitatively with trends in the histopathologic ganglion cell data. CONCLUSIONS: The analysis found no strong evidence that spiral ganglion cell numbers have a strong influence on the level of speech perception achieved with a cochlear implant. A possible explanation for this surprising result may be that the minimum number of cells required for good speech perception is quite low, and the majority of implant users exceed this minimum requirement.

Adolescent↗

PubMed1997

Phoneme acquisition in the first 4 years of implant use.

OBJECTIVE: To investigate the phonetic inventory development in a group of profoundly hearing impaired children fitted with the 22-electrode cochlear implant (Cochlear Ltd, NSW, Australia) at < or = 5 years of age. BACKGROUND: The cochlear implant provided access to auditory perceptual information that was not previously available. Investigation into the speech production skills of these children postimplant is of interest because the speech of these young profoundly hearing-impaired children is in a constant state of development. METHOD: Phonetic inventories of nine children were monitored at preimplant and over the first 4 years of implant use using spontaneous speech samples collected at regular intervals for each child. Progress of phoneme acquisition was measured using two different criteria: targetless and target production. RESULTS: At 4 years postimplant, 87% of all phonemes had been acquired as targetless productions and 62% of all phonemes had been acquired as target productions. All monophthongs were acquired as target phonemes, but only 38% of the diphthongs and 54% of all consonants were acquired as targets over the time of the study. The average time taken for a phoneme to progress from targetless acquisition to target acquisition was 21.6 months, although variation among phonemes was evident. CONCLUSIONS: Overall, the data suggest similar trends in the order of phoneme acquisition when compared to normally-hearing children, although it would appear that the process of acquisition in children with cochlear implants occurs at a slower rate.

Child Language↗

PubMed1997

Speech perception in noise with implant and hearing aid.

OBJECTIVE: To compare the perception of speech in quiet and in noise by adults using a cochlear implant on its own or a cochlear implant and hearing aid together. STUDY DESIGN: Repeated measures. SETTING: Laboratory study using subjects' own speech processors. PATIENTS: Two groups of cochlear implant users (Australian and American) with some residual hearing in the non-implanted ear (pure tone average thresholds at 500 Hz, 1 kHz, and 2 kHz of 75-112 dB HL). INTERVENTION(S): Conventional hearing aid and cochlear implant in opposite ears. MAIN OUTCOME MEASURES: Speech perception was evaluated using recorded lists of CUNY sentences and lists of CNC words in quiet and in background noise. RESULTS: Speech scores were significantly higher with implant and hearing aid together compared to implant alone. The binaural advantage was greater in background noise than it was in quiet for CUNY sentences in the American listeners. CONCLUSION: Severely-to-profoundly hearing impaired adults may benefit from combined fitting of implants and conventional hearing aids in opposite ears.

Adult↗

PubMed1996

Within-subject comparison of speech perception benefits for congenitally deaf adolescents with an electrotactile speech processor and a cochlear implant.

This study assessed speech perception benefits for three congenitally deaf adolescents who used an electrotactile speech processor (Tickle Talker(TM)) and subsequently went on to use a Nucleus Minisystem 22 cochlear implant. Both devices provided significant and comparable benefits for all children in the device plus lipreading condition. All children benefited from the additional information provided by either the Tickle Talker(TM) or the cochlear implant, and were able to perceive speech information with these devices that was not available through either aided residual hearing or lipreading. None of the three children were able to understand open-set words or sentences using either hearing aids alone or Tickle Talker(TM) alone, without the aid of lipreading. Two of the children showed significant open-set speech perception benefits while using their cochlear implant alone.

Adolescent↗

PubMedDate not supplied

Contralateral masking in cochlear implant users with residual hearing in the non-implanted ear.

Contralateral masking was investigated in cochlear implant users with residual hearing in the non-implanted ear. Threshold elevations for acoustic probes were observed when electrical maskers were presented in the opposite ear. Also, threshold elevations for electrical probes were observed when acoustic contralateral maskers were presented. The amount of threshold shift expressed in decibels charge or decibels sound pressure level produced by either contralateral acoustic or electric maskers was within the range found in normal listeners for similar stimuli (i.e. 4-8 dB). There was a correlation between the sensation level of acoustic maskers and the maximum amount of masking observed which is consistent with data for normally hearing subjects. The width of the masking patterns was similar to that expected from forward masking patterns in severely sensorineurally impaired ears and implanted ears. The maximum amount of acoustic masking tended to occur for electrode positions that were more basal than expected from characteristic frequency positions. However, where a relatively high-frequency 4-kHz masker could be used, there was a good match between the characteristic frequency position of the maximum threshold elevation and that of the masker.

Adult↗

PubMedDate not supplied

Factors affecting auditory performance of postlinguistically deaf adults using cochlear implants.

A model of auditory performance and a model of ganglion cell survival in postlinguistically deafened adult cochlear implant users are suggested to describe the effects of aetiology, duration of deafness, age at implantation, age at onset of deafness, and duration of implant use. The models were compared with published data and a composite data set including 808 implant users. Qualitative agreement with the model of auditory performance was found. Duration of deafness had a strong negative effect on performance. Age at implantation had a slight negative effect on performance, increasing after age 60 years. Age at onset of deafness had little effect on performance up to age 60. Duration of implant use had a positive effect on performance. Aetiology had a relatively weak effect on performance.

Adolescent↗