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.