This research project was based at the Ear Foundation (linked to the Nottingham Implant Programme at Queen’s Medical Centre) and was funded for two years, 2000–2002. As well as myself (with a background in Deaf Studies), the project included a ToD, a psychologist, an implant surgeon, an expert in audiological science, and a health economist. The study coincided in the UK with the publication of the first results of a study by the Institute of Hearing Research funded by MRC, which aimed to establish a ‘reference data-set’ of the situation of deaf children in the UK, against which changes could be measured. This project was based on the BATOD survey of 1998, and covered 12,255 deaf pupils, of which 757 were cochlear implanted. [Fortnum H.M., Marshall D.H., Bamford J.M., Summerfield A.Q. (2002) Hearing-impaired children in the UK: Education setting and communication approach, in Deafness and Education International . 4(3):123–141.] The Study also coincided with the establishment, in 2000, of a national longitudinal study at the University of Edinburgh, the ‘Achievements of Deaf Pupils in Scotland’ (ADPS) project, which has now been tracking the educational circumstances of almost all deaf pupils in Scotland for four years.
The goal of a cochlear implant is to restore auditory perception to levels that become linguistically meaningful. Implantation in very young deaf children—as is preferred—is assumed to deliver a critical improvement in the child’s potential for developing spoken language, as a result of improved auditory perception. Evidence of benefit can be measured at various levels of immediacy: direct (primary) outcomes focus on audition exclusively: the perception of sounds, and in particular those that are phonologically relevant, ie pertain to the perception of speech. Factors here also include measures that pertain to the implant itself: numbers of electrodes inserted, postoperative complications, type of device, speech processing strategy used, etc. Secondary measures might be those that relate to spoken language skills—the extent to which the child is better able to make a link between hearing sound and understanding spoken language, and develop linguistically as a consequence. And finally, measures can relate to associated outcomes, such as changes in behaviour and educational performance. The number of actually intervening variables (variables not associated with the effects of implantation) increases exponentially at each level of outcome analysis. Since the vast majority of the research concentrates on speech perception and speech production, the question in relation to this research is whether the test-designs, and in particular the test environments, are sensitive to the full complexity of language context and opportunity, in particular in relation to the period of development in children. For example, many tests in relation to speech perception are undertaken in controlled laboratory conditions. Moreover, many of the studies fall into the common error of equating ‘language skill’ with spoken language skill exclusively. This affects in particular studies that set up comparisons between children who are exposed to spoken language only, with those in eg. total communication or sign-bilingual programmes—where it is assumed that those children develop slower linguistically because they develop spoken language skills at slower rates. Only three studies in the data-set reference findings in relation to spoken language development explicitly with pre-existing skills in sign language. With regards to Education, it is of interest to note that a number of studies investigate placement. Placement in the mainstream is considered to be a measure of success in using the cochlear implant. However, none of the studies in question attempts to compensate for the numerous deep effects of current educational policy, which explictly favours the inclusion of deaf children in mainstream spoken language settings regardless of language preference or aided condition. In Scotland, only two deafschools now exist independently of local mainstream schools (one in Glasgow and one in Edinburgh), and arguable neither of those deliver sign-bilingual education. [A social science aside] The thing that is of interest to a sociologist about the procedures of Health Economics are the ontological assumptions by which their statistical modelling of the world ends up reflecting the public ordering of social differentiation, between the rich and the poor, between those defined as ‘sick’ or ‘healthy’, and between deaf and hearing. In sum, it is the impossibility of being able to even imagine a deaf perspective that places this ‘science’ in relation to understanding the outcomes of cochlear implantation. From the viewpoint of Deaf Studies, Health Economics is a double contradiction In terms; however, it is exactly its ability to statistically confirm the supposed ‘common sense’ behind the existing status quo that makes Health Economics a powerful social agent.
The aim of the research was to help develop a common understanding of the state of the research, in a situation where much of the debate around cochlear implantation is fuelled by personal accounts and often over-generalised references to research findings. The review in particular cross-references research efforts that are focussed on similar outcomes and record similar measures, but it also provides a helpful overview of where most of the research is located, the extent to which it takes account of the very wide range of factors that affect outcome, and how the current body of evidence in relation to paediatric cochlear implantation is oriented, specifically in relation to the potential life-trajectories and real-life circumstances of deaf people.
Although thereview focussed on articles published in the English language, it included articles from Western European countries. The small numbers of articles included from outside the UK, US, Canada and Australia as much reflects the smaller numbers of children implanted in other countries (France and Germany perhaps excepted) as the fact that their findings are published in languages other than English. A number of articles had to be removed from the initial searches because their titles or abstracts were also given in English, but the actual text was not. All implanted children now have multi-channel implants, which may contain up to 24 electrodes. The criterion relating to sample size means that most qualitative research was lost to the project, since many of those concern case-studies. Therefore the review is greatly biased towards evidence from the so-called exact sciences, which tend to favour quantitative approaches, as compared to the more qualitative approaches commonplance in the humanities. This will also help to explain to a considerable extent why most of the research was located in medical science journals.
BEI: British Education Index ERIC: Education Resource Information Centre (US) CINAHL: Citation Index of Nursing and Allied Health Literature IBSS: International Bibliography of the Social Sciences
Speech recognition and speech perception measures account for the most widely reported findings, and the fact that most studies report a very wide range of individual performance suggests something of the ‘fit’ (or lack thereof) between meassures and findings. Moreover, selective reporting of findings (the bottle being half-full or half-empty) also helps to account for the optimism behind evidence on benefit. For example, in one study it is reported that 82% of the cochlear implanted children can “understand conversation” without lipreading 6 years post implantation (in controlled circumstances with a known speaker). By contrast, the finding that only 27% of the subjects can conduct a telephone conversation (even with a known speaker) is not singled out for discussion, not even in relation to the questions it raises about lipreading (comment on Nikolopoulos 1999, N=103) Another study focussed on placement effects on spoken language outcomes for children with an implant (Geers at al. 2000). It reports that those in oral settings outperform those in total communication settings, but the finding does not bother to compensate for the fact that the children in the oral setting received twice the amount of oral rehabilitation, nor for the fact that the pedagogy of total communication settings is not exclusively focussed around spoken language outcomes. Wide individual variation also suggests something of the considerable extent to which the research remains innocent about standard socio-economic and demographic measures—including such factors as gender, ethnicity, class, and geographic (in particular postcode) location, not only that of the home but also that of the school. Such facts flag up critically the weaknesses of the research drawing almost exclusively on medical rather than social or cultural models of deafness.
1. This presentation was ﬁrst delivered at the University of Central Lancashire (Deaf Studies Seminar) in Preston, 22 February 2005 ___________ Updated for a seminar at Queen Margaret University College, 24 October 2005 .
2. The order of those things we know about deaf pupils with cochlear implants Ernst Thoutenhoofd [email_address] Moray House School of Education University of Edinburgh 2005 slide
3. International literature review, 1994–2002 Thoutenhoofd, E.D., Archbold, S.M., Gregory, S., Lutman, M.E., Nikolopoulos, T.P. and Sach, T.H. (2005) Paediatric cochlear implantation: Evaluating Outcomes. London, England: Whurr. ISBN 1-86156-366-3 . Project funded by Cochlear International. slide
4. Areas of interest Language and communication (spoken and sign languages). Family and social life. Education, placement and attainment. Health economics. slide
5. Purpose To summarise the current knowledge on this topic and identify gaps in the literature. To make recommendations for future research in the area, identifying aspects of beneﬁt not previously taken into account. slide
6. Coverage (selection criteria for inclusion) Published in English. Research conducted after 1994, in order to exclude single-channel implants. Sample sizes of ≥12 children or parents. Databases were searched twice, at start and end of the project. The review covers 145 accounts, from 248 originally identified. slide
7. Journal spread Most articles appeared in medical journals, and searches through Medline were the most productive. Other sources were BEI/ERIC, CINAHL, IBSS, PsycInfo and Web of Science. 104 key words and reported measures were listed against the collection of articles. slide
8. Key ﬁndings Speech recognition and speech perception are the most researched outcomes. Studies generally report wide variation in individual performance. Demographic reporting focuses mostly on audiological, implant and placement measures. slide
9. General ﬁnding “ Relative to the huge range of factors that may affect outcome […], there is a more general under-analysis of demographic sample characteristics and few attempts at factoring out intervening variables. Hence any number of outside factors might help to explain individual variation.” (:21) slide
10. General conclusion Outcomes may be divided into 3 categories: Robust outcomes eg improved auditory performance Inconclusive/contradictory outcomes eg language development; placement Outcomes with little or no research eg educational outcomes; quality of life 10 of 17 slides
11. Selected conclusion “… the perceptual effect of the implant is equivalent, on average, to an improvement of about 28dB in hearing thresholds.” (Blamey et al. 2001:264) “… the average language delay will be about 4 or 5 years by the time the children enter secondary school at about age 12 years.” (ibid:283) slide
12. Achievements of Deaf Pupils in Scotland Project (ADPS), 2000–2005 Marian Grimes, Emily Healy, Ernst Thoutenhoofd. Data collection funded by Scottish Executive Education Department (2000–2004) and the National Deaf Children’s Society (2005) A D P S slide
13. Further details http://www.education.ed.ac.uk/adps/ http://www.ssc.mhie.ac.uk/ slide
14. The goal of ADPS The ADPS project is longitudinal in intent, tracking the educational situation and performance of most deaf pupils in Scotland speciﬁcally in order to identify factors that help explain the over-time expression of adverse effect on achievement. Questionnaire return rates for the four years are well over 95%. slide
15. The ADPS population, 2000–2005 2,030 pupils in the database 6,108 year records 22,724 attainment records Details at 24 October 2005. Nb: the information on the slides that follow is ‘work in progress’, much in the spirit of this seminar/workshop. The tables have not been checked by the ADPS team, and therefore any errors that may exist are entirely my own. For data published through the project, consult the ADPS website. slide
16. Cochlear implant details ( October 2005 ) slide
17. Full-time placement: profound/ci ( October 2005 ) slide 2.5 = deaf pupils with profound bilateral deafness, without ci. 3.5 = deaf pupils with ci.
18. Selected cohort yrs 1–3 : hearing loss and ci N= 124 (yr1); 137 (yr2); 116 (yr3) slide
19. Notes to slide 18 slide Details as at 22 February 2005. ‘Year 1’ is school year 2000–01. The hearing loss descriptors represent: UL (all unilateral hearing loss), 1 (within normal limits), 2 (mild hearing loss), 3 (moderate hearing loss), 4 (severe hearing loss), 5 (profound hearing loss), CI (cochlear implanted pupils). The dataset was since recoded for hearing loss, so that these details have now been replaced with a different ordinal scale. The table does not offer the number of pupils within each category, but the “% average” gives the percentage of those who have achied at the given level for any of the three subjects, against the total number of pupils within that category of hearing loss. Level ‘A’ is the threshold (base) level of attainment targeted at the start of Primary. Progression towards Level F is assumed to be continuous from P2 to S2. Figures exclude pupils in SEN settings, but include those pupils in deaf schools for whom their year group is known (ie sufficient basis exists for those pupils to progress). Figures also exclude those for whom outcomes were not reported or not known.
20. Reading age yr 1 : chronological age (all pupils & ci disaggregated) N=792 (ci=69) slide
21. Notes to slide 20 slide Details as at 22 February 2005. ‘Year 1’ is school year 2000–01. Figures include all pupils for whom reading age assessments were reported, regardless of placement or SEN. The column headings list chronological (actual) age, in bands -- there may be a skewing effect on the data due to banding, which is not investigated. The vertical rows list the reported reading age, expressed in years above or below chronological age. The ‘all pupil’ figures (in black) include those of the ci pupils (in red). Note that the figures report the number of reading age test instances, not the number of pupils -- ie, in some instances, more than one reading age assessment may have been reported for a pupil, and all have been included.