Chad Nye

Prevalence and natural history of primary speech and language delay: findings from a systematic review of the literature.

The prevalence and the natural history of primary speech and language delays were two of four domains covered in a systematic review of the literature related to screening for speech and language delay carried out for the NHS in the UK. The structure and process of the full literature review is introduced and criteria for inclusion in the two domains are specified. The resulting data set gave 16 prevalence estimates generated from 21 publications and 12 natural history studies generated from 18 publications. Results are summarized for six subdivisions of primary speech and language delays: (1) speech and/or language, (2) language only, (3) speech only, (4) expression with comprehension, (5) expression only and (6) comprehension only. Combination of the data suggests that both concurrent and predictive case definition can be problematic. Prediction improves if language is taken independently of speech and if expressive and receptive language are taken together. The results are discussed in terms of the need to develop a model of prevalence based on risk of subsequent difficulties.

The feasibility of universal screening for primary speech and language delay: findings from a systematic review of the literature

This paper reports on a systematic review of the literature commissioned to examine the feasibility of universal screening for speech and language delay. The results, based on an examination of productivity figures, including positive predictive ability and likelihood ratio, indicate that a number of screening tests are adequate. Sensitivity was generally lower than specificity, and study quality was inversely related to both sensitivity and likelihood ratio, suggesting that it is easier to identify accurately children who do not have language and speech problems than those who do. The review concluded that there is insufficient evidence to warrant the introduction of universal screening at this stage. This paper discusses the type of data that would be needed to address this issue further and recommendations are made for alternative approaches to early identification.

SCREENING FOR PRIMARY SPEECH AND LANGUAGE DELAY: A SYSTEMATIC REVIEW OF THE LITERATURE

Screening young children for developmental conditions such as speech and language delay is considered to be a part of the Child Health Surveillance programme in the UK. It is currently practised in many different ways throughout the country and like screening for other conditions conventionally identified in infancy, has been the subject of some concern for those responsible for providing such services. This systematic review (Law et al. 1998) was hypothesis driven and aimed to: i) establish whether, given the available evidence, there was sufficient evidence to warrant the introduction of universal screening for speech and language delays in children up to seven years of age; ii) identify gaps in the available literature; iii) identify priority areas in need of further investigation and iv); provide evidence-based recommendations for the future provision of services.

A meta-analysis of studies carried out between 1946 and 1988 concerned with the efficacy of speech and language therapy treatment for aphasic patients

An examination of the empirical evidence for the efficacy of speech and language therapy treatment for adult aphasic patients is undertaken with the aid of meta-analysis which affords a statistical method of systematic data summary and synthesis. Patient characteristics and treatment outcomes are correlated to identify factors that contribute to the demonstration of a treatment effect. One of the most striking results of this retrospective study was the identification of the overwhelming failure to report data or include, in experimental controls, variables that might crucially affect outcome.

Botulinum toxin for treating spasmodic dysphonia (laryngeal dystonia): a systematic Cochrane review

Background: Spasmodic dysphonia is a neurological voice disorder characterized by involuntary adductor (towards midline) or abductor (away from midline) vocal fold spasms during phonation which result in phonatory breaks. Botulinum toxin is currently the gold standard of treatment. Objective: To determine the efficacy of botulinum toxin therapy for the treatment of spasmodic dysphonia. Design: Systematic Cochrane review. Search strategy: The search strategy for this review complied with Cochrane standards. We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE (1966 to February 2005), EMBASE (1974 to February 2005), CINAHL (through February 2005), Dissertation Abstracts International (1975 to February 2005) and PsycINFO (1975 to February 2005). The search engine FirstSearch was also used (February 2005). Reference lists for all the obtained studies and other review articles were examined for additional studies. Selection criteria: All randomized control trials where the participants were randomly allocated prior to intervention and in which botulinum toxin was compared to an alternative treatment, placebo or non-treated control group were included. Data collection and analysis: Two reviewers independently evaluated all potential studies meeting the selection criteria noted above for inclusion. Main results: Only one study in the literature met the inclusion criteria. This was the only study identified which reported a treatment/no treatment comparison. It reported significant beneficial effects for fundamental frequency (Fo), Fo range, spectrographic analysis, independent ratings of voice severity and patient ratings of voice improvement. Reviewers conclusions: The evidence from randomized controlled trials supporting the effectiveness of botulinum toxin for management of spasmodic dysphonia is deficient. The lack of supporting evidence from randomized controlled trials results in an inability to draw unbiased generalized conclusions regarding the effectiveness of botulinum toxin for all types of spasmodic dysphonia.

Joint attention interventions for children with autism spectrum disorder: a systematic review and meta-analysis.

BACKGROUND A core social-communication deficit in children with autism spectrum disorder (ASD) is limited joint attention behaviours-important in the diagnosis of ASD and shown to be a powerful predictor of later language ability. Various interventions have been used to train joint attention skills in children with ASD. However, it is unclear which participant, intervention and interventionist factors yield more positive results. AIMS The purpose of this systematic review and meta-analysis was to provide a quantitative assessment of the effectiveness of joint attention interventions aimed at improving joint attention abilities in children with ASD. METHODS & PROCEDURES The researchers searched six databases for studies meeting the inclusion criteria at two levels: title/abstract and full-text stages. Two independent coders completed data extraction using a coding manual and form developed specifically for this research study. Meta-analysis procedures were used to determine the overall effects of several comparisons including treatment type, treatment administrator, intervention characteristics and follow-up. MAIN CONTRIBUTION Fifteen randomized experimental studies met inclusion criteria. All comparisons resulted in statistically significant effects, though overlapping confidence intervals suggest that none of the comparisons were statistically different from each other. Specifically, treatment administrator, dosage and design (control or comparison, etc.) characteristics of the studies do not appear to produce significantly different effects. CONCLUSIONS & IMPLICATIONS The results of this meta-analysis provide strong support for explicit joint attention interventions for young children with ASD; however, it remains unclear which children with ASD respond to which type of intervention.

Transition Services for Youth with Autism: A Systematic Review.

Purpose As the number of individuals diagnosed with autism spectrum disorders (ASDs) rises, attention is increasingly focused on employment outcomes for individuals with ASD who are exiting public school settings. This review aimed to identify what works in transition programs to help students with ASD obtain competitive employment after graduation. Method Authors combed through the literature to find all research that could definitively identify interventions that predictably led to employment for transitioning youth. Results: While no definitive conclusions can be drawn based upon the current review, the authors identified qualitative research that addressed elements of potential successful employment placements for individuals with ASD. Discussion Future research efforts are needed to develop studies that utilize rigorous experimental designs to determine the relative effectiveness of the various interventions being utilized in transition programming for students with ASD. This review is published in its entirety in the Campbell Collaboration Library of Systematic Reviews.

Understanding high quality research designs for speech language pathology

As innovative methods, strategies, or curriculum are introduced to assist clients with speech and language disorders, many Speech-Language Pathologists (SLPs) may question the effectiveness of the intervention and more specifically whether the results that they are seeing are the result of the intervention (i.e., cause/effect). Several research designs allow researchers to examine causality including the most widely known, the randomized controlled trial (RCT). While not all situations are suited to applying the RCT, other high quality designs may be used that still lend evidence of causality even when randomization is not possible. The purpose of this paper is to provide a brief summary and illustrations of randomized controlled trials (RCT) and quasi-experimental design (QED) that are appropriate for the study of treatment effectiveness in speech-language pathology research, present potential barriers to quality randomization, and provide guidelines to help identify RCTs.

Assessing methodological quality of randomized and quasi-experimental trials: A summary of stuttering treatment research

The purpose of this study is to provide a detailed analysis of the methodological quality of experimental and quasi-experimental group designed studies in the area of stuttering intervention. A total of 23 randomized controlled trials (RCT) and quasi-experimental studies of treatment in the area of stuttering were identified and retrieved from an electronic search of nine databases and 13 individual journals. Using the Downs and Black Checklist each study was coded for reporting, external validity, internal validity, and internal validity confounding. Results of the coding indicated that while overall reporting was reasonably complete, the quality of the external and internal validity scores was found to be substantively incomplete. This lack of clarity and completeness of reporting issues related to the external and internal validity makes the interpretation of the findings of individual study results problematic and seriously effects the replicability of the individual study. Implications of these findings are suggested for both researchers and clinicians.

Methodological quality of intervention research in speech–language pathology: Analysis of 10 years of group-design studies

The aim of this work was to critically examine the methodological quality of recent treatment research in speech–language pathology, focusing specifically on group-design studies (randomized, controlled trials and quasi-experimental-design studies). We also considered whether methodological quality differed as a function of a particular studys treatment focus (i.e. literacy, language, speech, fluency, voice), the age group studied (pre-school-age child; school-age child; adult), the year of publication, or the publishing journal. In total, 53 treatment studies published in the last 10 years in three journals of the American Speech–Language–Hearing Association (ASHA) were selected for analysis using Downs and Blacks (1998) reliable, valid rating tool for examining methodological quality. The results indicated that the quality of the treatment studies was highly variable in terms of the 25 indicators of quality studied, and that there were few systematic differences in quality attributable to treatment focus, age group studied, year of publication, or the publishing journal. Implications for evidence-based practice and study reporting are discussed.