Health Technology Assessment 2007; Vol 11: number 25
Executive SummaryView/Download full monograph in Adobe Acrobat format (745 kbytes)
J Boyle,1* E McCartney,2 J Forbes3 and A O'Hare4
1 Department of Psychology, University of Strathclyde, UK
2 Division of Speech and Language Therapy, Department of Educational and Professional Studies, University of Strathclyde, UK
3 Public Health Sciences Section, Division of Community Health Sciences, University of Edinburgh, UK
4 Department of Reproductive and Developmental Medicine, University of Edinburgh, UK
* Corresponding author
Some 30–60% of children with primary language impairment (PLI) that cannot be accounted for in terms of non-verbal ability, behaviour or emotional problems, hearing or neurological impairments may experience difficulties in school achievement or social, emotional or behaviour problems that persist to adolescence and beyond. Children with PLI that persists to school age provide a stable basis for determining the relative effectiveness of modes of speech and language therapy and their cost-effectiveness.
This trial aimed to address the following research questions.
This randomised controlled trial had a 2 × 2 factorial design (direct/indirect versus individual/group therapy) together with a control group that received existing levels of community-based speech and language therapy and served as a comparator for the economic analysis. All postintervention language outcome measures were blind assessed. A short-run economic evaluation across the four different modes of therapy was carried out using the primary outcome measure. A comparable method was used for estimating the costs of providing services in the community for children allocated to the control group.
Research intervention took place in school settings, with some of the children randomised to group therapies transported to join a group in a different school.
Participants were identified by community speech and language therapy services in Glasgow, Edinburgh and the Lothians. They were initially assessed by members of the project team and thereafter by SLTs blind to intervention mode. Children met the following eligibility requirements:
A therapy manual was constructed that provided a range of procedures and activities for intervention in areas identified by a search of the research and professional literature for examples of language therapies of proven effectiveness. SLTs planned activities for children seen by therapists and SLTAs, using the manual.
Primary outcome measures of the study were standardised scores on tests of expressive and receptive language. Secondary outcome measures were scores on a test of receptive vocabulary, together with questionnaire, rating scale and focus group data from parents, teachers, project SLTs and SLTAs, and an audit of therapy sessions.
There was no evidence that the five modes involved in the project were different at the onset in terms of primary outcome measures, although there were significant gender differences. The results from both the intention-to-treat analyses of the outcomes from the 161 children randomised who met the eligibility criteria and the protocol analyses of the outcomes from the 152 children for whom postbaseline data were available revealed that there were no significant postintervention differences between direct and indirect modes of therapy on the one hand, or between individual and group modes on the other on any of the primary language outcome measures, after adjustment for the effects of severity of language impairment at pretest. However, there was evidence of some benefits from direct therapy from an SLT in secondary outcome measures. Parents and teachers were positive about the childrens progress and their experience of the project. All four intervention modes were acceptable to parents and schools.
Intervention delivered three times a week for 30–40 minutes over a 15-week period also yielded significant improvements in age-corrected standardised scores for expressive language, although not for receptive language, relative to those receiving community-based SLT services. Children with specific expressive language delay were more likely to show improvement than those with mixed receptive–expressive difficulties, and non-verbal IQ was not a significant moderating variable.
The within-trial economic evaluation identified indirect therapy, particularly indirect group therapy, as the least costly of the modes investigated in the study, with direct individual therapy as the most costly option. This is unsurprising given the differences in the ratio of trained professional staff to children and in the cost of labour between different staff grades. However, these cost differences should not be overinterpreted as these estimates were based on the pattern of resource use inherent in the trial design with allowance for how the different modes of therapy could be delivered in practical settings.
Well-trained, well-supported and well-motivated SLTAs can act as effective surrogates for SLTs in the delivery of services within primary schools to children with PLI who do not to require the specialist skills of an SLT. Generalising the central estimates of the relative cost of different therapy modes to other educational/health systems is possible, but the precise differences reported in resource use need to be qualified by the level of programme intensity and other characteristic features of education and therapy services that may differ from those observed in this trial.
Boyle J, McCartney E, Forbes J, O'Hare A. A randomised controlled trial and economic evaluation of direct versus indirect and individual versus group modes of speech and language therapy for children with primary language impairment. Health Technol Assess 2007;11(25).
The Health Technology Assessment (HTA) programme, now part of the National Institute for Health Research (NIHR), was set up in 1993. It produces high-quality research information on the costs, effectiveness and broader impact of health technologies for those who use, manage and provide care in the NHS. 'Health technologies' are broadly defined to include all interventions used to promote health, prevent and treat disease, and improve rehabilitation and long-term care, rather than settings of care.
The research findings from the HTA Programme directly influence decision-making bodies such as the National Institute for Health and Clinical Excellence (NICE) and the National Screening Committee (NSC). HTA findings also help to improve the quality of clinical practice in the NHS indirectly in that they form a key component of the 'National Knowledge Service'.
The HTA Programme is needs-led in that it fills gaps in the evidence needed by the NHS. There are three routes to the start of projects.
First is the commissioned route. Suggestions for research are actively sought from people working in the NHS, the public and consumer groups and professional bodies such as royal colleges and NHS trusts. These suggestions are carefully prioritised by panels of independent experts (including NHS service users). The HTA Programme then commissions the research by competitive tender.
Secondly, the HTA Programme provides grants for clinical trials for researchers who identify research questions. These are assessed for importance to patients and the NHS, and scientific rigour.
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Reports are published in the HTA monograph series if (1) they have resulted from work for the HTA Programme, and (2) they are of a sufficiently high scientific quality as assessed by the referees and editors.
Reviews in Health Technology Assessment are termed 'systematic' when the account of the search, appraisal and synthesis methods (to minimise biases and random errors) would, in theory, permit the replication of the review by others.
The research reported in this monograph was commissioned by the HTA Programme as project number 99/36/04. The contractual start date was in April 2002. The draft report began editorial review in December 2005 and was accepted for publication in January 2007. As the funder, by devising a commissioning brief, the HTA Programme specified the research question and study design. The authors have been wholly responsible for all data collection, analysis and interpretation, and for writing up their work. The HTA editors and publisher have tried to ensure the accuracy of the authors' report and would like to thank the referees for their constructive comments on the draft document. However, they do not accept liability for damages or losses arising from material published in this report.
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