Evidence-based pathways to intervention for children with language disorders.

BACKGROUND: Paediatric speech and language therapist (SLT) roles often involve planning individualized intervention for specific children, working collaboratively with families and education staff, providing advice, training and coaching and raising awareness. A tiered approach to service delivery is currently recommended whereby services become increasingly specialized and individualized for children with greater needs. AIMS: To stimulate discussion regarding delivery of SLT services by examining evidence regarding the effectiveness of (1) intervention for children with language disorders at different tiers and (2) SLT roles within these tiers; and to propose an evidence-based model of SLT service delivery and a flowchart to aid clinical decision-making. METHODS & PROCEDURES: Meta-analyses and systematic reviews, together with controlled, peer-reviewed group studies where recent systematic reviews were not available, of interventions for children with language disorders are discussed, alongside the differing roles SLTs play in these interventions. Gaps in the evidence base are highlighted. MAIN CONTRIBUTION: The service-delivery model presented resembles the tiered model commonly used in education services, but divides individualized (Tier 3) services into Tier 3A: indirect intervention delivered by non-SLTs, and Tier 3B: direct intervention by an SLT. We report evidence for intervention effectiveness, which children might best be served by each tier, the role SLTs could take within each tier and the effectiveness of these roles. Regarding universal interventions provided to all children (Tier 1) and those targeted at children with language weaknesses or vulnerabilities (Tier 2), there is growing evidence that approaches led by education services can be effective when staff are highly trained and well supported. There is currently limited evidence regarding additional benefit of SLT-specific roles at Tiers 1 and 2. With regard to individualized intervention (Tier 3), children with complex or pervasive language disorders can progress following direct individualized intervention (Tier 3B), whereas children with milder or less pervasive difficulties can make progress when intervention is managed by an SLT, but delivered indirectly by others (Tier 3A), provided they are well trained and supported, and closely monitored. CONCLUSIONS & IMPLICATIONS: SLTs have a contribution to make at all tiers, but where prioritization for clinical services is a necessity, we need to establish the relative benefits and cost-effectiveness at each tier. Good evidence exists for SLTs delivering direct individualized intervention and we should ensure that this is available to children with pervasive and/or complex language disorders. In cases where service models are being provided which lack evidence, we strongly recommend that SLTs investigate the effectiveness of their approaches.

Effectiveness of intervention with visual templates targeting tense and plural agreement in copula and auxiliary structures in school-aged children with complex needs: a pilot study.

This pilot study aims to evaluate the effectiveness of a school-based intervention using visual strategies for improving accurate use of auxiliary and copula marking in singular and plural, past and present tense by students with moderate learning disability and complex needs. Eleven students, aged 10-14 years, in a specialist school based in the UK, participated in the study. A within participants design was used which included testing at baseline, pre- and post-intervention to consider progress with intervention as compared with progress during a baseline period of similar length. The experimental intervention consisted of eight, bi-weekly, 20 minute sessions, over a four week period, in small groups, in a classroom setting. Half of the participants focused on the auxiliary and half on the copula, but all were tested on both. Techniques included the use of visual templates and rules (the Shape CodingTM system) to support explicit instruction. Eight participants made greater progress during the intervention term than during the baseline term and this was significant at a group level (d = 0.92). A comparison of progress to zero was not significant during the baseline period (d = 0.15) but was during the intervention period (d = 1.07). Progress also appeared to generalise from the targeted to non-targeted structure. This pilot study therefore provides preliminary evidence that older students with complex needs can make progress with morphology when intervention includes explicit instruction and visual templates and that generalisation may be observed.

Intervention research: Appraising study designs, interpreting findings and creating research in clinical practice.

Speech-language pathologists (SLPs) are increasingly required to read, interpret and create evidence regarding the effectiveness of interventions. This requires a good understanding of the strengths and weaknesses of different intervention study designs. This paper aims to take readers through a range of designs commonly used in speech-language pathology, working from those with the least to most experimental control, with a particular focus on how the more robust designs avoid some of the limitations of weaker designs. It then discusses the factors other than research design which need to be considered when deciding whether or not to implement an intervention in clinical practice. The final section offers some tips and advice on carrying out research in clinical practice, with the hope that more SLPs will become actively involved in creating intervention research.

Effectiveness of 1:1 speech and language therapy for older children with (developmental) language disorder.

BACKGROUND: Evidence of the effectiveness of therapy for older children with (developmental) language disorder (DLD), and particularly those with receptive language impairments, is very limited. The few existing studies have focused on particular target areas, but none has looked at a whole area of a service. AIMS: To establish whether for students with (developmental) language disorder attending a specialist school, 1:1 intervention with an SLT during one school term improves performance on targeted areas, compared with untreated control areas. Also, to investigate whether gender, receptive language status, autism spectrum disorder (ASD) status, or educational Key Stage affected their response to this intervention. METHODS & PROCEDURES: Seventy-two students (aged 9-17 years, 88% of whom had receptive language impairments) and all speech and language therapists (SLTs) in our specialist school for children with Language Disorder, most of whom have DLD participated in this study over one school term. During this term, the SLTs devised pre- and post-therapy measures for every student for each target they planned to treat 1:1. In addition, for each target area, a control measure was devised. The targets covered a wide range of speech, language and communication areas, both receptive and expressive. Post-therapy tests were administered 'blind'. OUTCOMES & RESULTS: During the term, SLTs and students worked 1:1 on 120 targets, the majority in the areas of expressive and receptive language. Targets and controls did not differ pre-therapy. Significant progress was seen both on targets (d = 1.33) and controls (d = 0.36), but the targeted areas improved significantly more than the controls with a large and clinically significant effect size (d = 1.06). There was no effect of language area targeted (targets improved more than their controls for all areas). Participants with versus those without receptive language difficulties, co-occurring ASD diagnosis or participants in different educational Key Stages did not differ significantly in terms of the progress they made on target areas. CONCLUSIONS & IMPLICATIONS: Direct 1:1 intervention with an SLT can be effective for all areas of language for older children with (D)LD, regardless of their gender, receptive language or ASD status, or age. This adds to the relatively limited evidence base regarding the effectiveness of direct SLT intervention for school-aged children with (D)LD and for children with receptive language impairments. If direct 1:1 intervention can be effective with this hard-to-treat group, it may well also be effective with younger children with (D)LD. Thus, direct SLT services should be available for school-aged children with (D)LD, including older children and adolescents with pervasive difficulties.

Improving comprehension in adolescents with severe receptive language impairments: a randomized control trial of intervention for coordinating conjunctions.

BACKGROUND: Little evidence exists for the effectiveness of therapy for children with receptive language difficulties, particularly those whose difficulties are severe and persistent. AIMS: To establish the effectiveness of explicit speech and language therapy with visual support for secondary school-aged children with language impairments focusing on comprehension of coordinating conjunctions in a randomized control trial with an assessor blind to group status. METHODS & PROCEDURES: Fourteen participants (aged 11;3-16;1) with severe RELI (mean standard scores: CELF4 ELS = 48, CELF4 RLS = 53 and TROG-2 = 57), but higher non-verbal (Matrices = 83) and visual perceptual skills (Test of Visual Perceptual Skills (TVPS) = 86) were randomly assigned to two groups: therapy versus waiting controls. In Phase 1, the therapy group received eight 30-min individual sessions of explicit teaching with visual support (Shape Coding) with their usual SLT. In Phase 2, the waiting controls received the same therapy. The participants' comprehension was tested pre-, post-Phase 1 and post-Phase 2 therapy on (1) a specific test of the targeted conjunctions, (2) the TROG-2 and (3) a test of passives. OUTCOMES & RESULTS: After Phase 1, the therapy group showed significantly more progress than the waiting controls on the targeted conjunctions (d = 1.6) and overall TROG-2 standard score (d = 1.4). The two groups did not differ on the passives test. After Phase 2, the waiting controls made similar progress to those in the original therapy group, who maintained their previous progress. Neither group showed progress on passives. When the two groups were combined, significant progress was found on the specific conjunctions (d = 1.3) and TROG-2 raw (d = 1.1) and standard scores (d = 0.9). Correlations showed no measures taken (including Matrices and TVPS) correlated significantly with progress on the targeted conjunctions or the TROG-2. CONCLUSIONS & IMPLICATIONS: Four hours of Shape Coding therapy led to significant gains on comprehension of coordinating conjunctions which were maintained after 4 months. Given the significant progress at a group level and the lack of reliable predictors of progress, this approach could be offered to other children with similar difficulties to the participants. However, the intervention was delivered one-to-one by speech and language therapists, thus the effectiveness of this therapy method with other methods of delivery remains to be evaluated.

Non-word repetition in adolescents with specific language impairment (SLI).

BACKGROUND: Non-word repetition (NWR) difficulties are common, but not universal, among children with specific language impairment (SLI). However, older children and adolescents with SLI have rarely been studied. Studies disagree on the relationship between NWR difficulties and difficulties with other areas of language and literacy. There is also no consensus about the underlying reason for the difficulties (some) children with SLI have with NWR. Some scholars argue that difficulties with phonological short-term memory or storage cause NWR and other language difficulties, whereas others argue that difficulties with NWR may be due more to difficulties with phonological representations. AIMS: To investigate NWR abilities and their relationship to other language and literacy abilities in a group of older children with SLI and typically developing controls. To investigate the relative effects of increasing phonological complexity and the number of syllables on the ability of the participants to repeat non-words. METHODS & PROCEDURES: An NWR test (The Test of Phonological Structure; TOPhS), which systematically varies phonological complexity, was administered to 15 participants with SLI (aged 11-15 years), 30 language and 15 age controls. Standardized language and literacy tests and a specific test of verb agreement and tense marking (Verb Agreement and Tense Test; VATT) were also administered. OUTCOMES & RESULTS: The participants with SLI showed a bimodal distribution: half achieved age-appropriate NWR, while half scored significantly below language and age controls (d > 7). The two groups of participants with SLI (high versus low scorers) only differed in NWR (d > 5) and agreement (d > 3) and tense marking (d > 2.5), not on the standardized language and literacy measures administered. NWR was also highly correlated with verb agreement (r= 0.97) and tense marking (r= 0.89) among participants with SLI, but not among controls (r= 0.16 and 0.30 respectively). Phonological complexity was related to NWR accuracy, particularly among participants with SLI. The number of syllables had no independent effect on NWR performance for any group. CONCLUSIONS & IMPLICATIONS: Some children with SLI (who have good NWR) have language difficulties unrelated to any of the factors underlying NWR. Others have a (probably additional) deficit which affects NWR and also leads to greater difficulties with verb agreement and tense marking. The results indicate that difficulties with this particular NWR test are more likely to be due to a deficit with phonology per se, rather than with phonological short-term memory or storage.

Effectiveness of semantic therapy for word-finding difficulties in pupils with persistent language impairments: a randomized control trial.

BACKGROUND: Word-finding difficulties (WFDs) in children have been hypothesized to be caused at least partly by poor semantic knowledge. Therefore, improving semantic knowledge should decrease word-finding errors. Previous studies of semantic therapy for WFDs are inconclusive. AIMS: To investigate the effectiveness of semantic therapy for secondary school-aged pupils with WFDs using a randomized control trial with blind assessment. METHODS & PROCEDURES: Fifteen participants with language impairments and WFDs (aged 9;11-15;11) were randomly assigned to a therapy versus waiting control group. In Phase 1 the therapy group received two 15-min semantic therapy sessions per week for 8 weeks with their usual speech and language therapist. Therapy for each participant targeted words from one of three semantic categories (animals, food, clothes). All participants were tested pre- and post-phase 1 therapy on the brief version of the Test of Adolescent Word Finding (TAWF), semantic fluency and the Test of Word Finding in Discourse (TWFD). In Phase 2 the waiting control group received the same therapy as the original therapy group, which received therapy targeted at other language areas. Testing after Phase 2 aimed to establish whether the waiting control group made similar progress to the original therapy group and whether the original therapy group maintained any gains. OUTCOMES & RESULTS: The original therapy group made significant progress in standard scores on the TAWF (d= 0.94), which was maintained 5 months later. However, they made no progress on the semantic fluency or discourse tests. Participants in the waiting control group did not make significant progress on the TAWF in Phase 1 when they received no word-finding therapy. However, after Phase 2, when they received the therapy, they also made significant progress (d= 0.81). The combined effect of therapy over the two groups was d= 1.2. The mean standard scores on the TAWF were 67 pre-therapy and 77 post-therapy. CONCLUSIONS & IMPLICATIONS: Four hours of semantic therapy on discrete semantic categories led to significant gains on a general standardized test of word finding, enabling the participants to begin to close the gap between their performance and that of their typically developing peers. These gains were maintained after 5 months. A small amount of therapy can lead to significant gains even with secondary aged pupils with severe language difficulties. However, further studies are needed to find ways of improving word-finding abilities in discourse.

Intervention for verb argument structure in children with persistent SLI: a randomized control trial.

PURPOSE: The authors aimed to establish whether 2 theoretically motivated interventions could improve use of verb argument structure in pupils with persistent specific language impairment (SLI). METHOD: Twenty-seven pupils with SLI (ages 11;0-16;1) participated in this randomized controlled trial with "blind" assessment. Participants were randomly assigned to 1 of 3 therapy groups: syntactic-semantic, semantic, and control. All pupils received 9 weekly half-hour individual therapy sessions. They were assessed on a specifically designed video test pretherapy, posttherapy, and at follow-up. RESULTS: Pupils receiving the syntactic-semantic and semantic therapies made significant progress (d>1.0), which was maintained at follow-up and generalized to control verbs. Both therapies improved linking of arguments to syntax, and the syntactic-semantic therapy tended to increase use of optional arguments. Pupils receiving the control therapy made no progress. CONCLUSION: Both methods of argument structure therapy were effective. Comparisons of their effectiveness in specific areas led to the hypotheses that the pupils' initial difficulties with linking resulted from ill-defined semantic representations, whereas their limited use of arguments may have resulted from syntactic difficulties. When therapy is theoretically grounded, it can inform theories, be time limited, and be effective for older children with SLI.