Predicting treatment outcomes for bilinguals with aphasia using computational modeling: Study protocol for the PROCoM randomised controlled trial

Abstract

IntroductionBilinguals with aphasia (BWA) present varying degrees of lexical access impairment and recovery across their two languages. Because both languages may benefit from therapy, identifying the optimal target language for treatment is a current challenge for research and clinical practice. Prior research has demonstrated that the BiLex computational model can accurately simulate lexical access in healthy bilinguals, and language impairment and treatment response in bilingual aphasia. Here, we aim to determine whether BiLex can predict treatment outcomes in BWA in the treated and the untreated language and compare these outcome predictions to determine the optimal language for rehabilitation.Methods and analysisThe study involves a prospective parallel-group, double-blind, randomised controlled trial. Forty-eight Spanish–English BWA will receive 20 sessions of semantic treatment for lexical retrieval deficits in one of their languages and will complete assessments in both languages prior and after treatment. Participants will be randomly assigned to an experimental group receiving treatment in the optimal language determined by the model or a control group receiving treatment in the language opposite to the model’s recommendation. Primary treatment outcomes include naming probes while secondary treatment outcomes include tests tapping additional language domains. Treatment outcomes will be compared across the two groups using 2×2 mixed effect models for repeated measures Analysis of variance (ANOVA) on metrics of treatment effects commonly employed in rehabilitation studies (ie, effect size and percentage change).Ethics and disseminationAll procedures included in this protocol (protocol number 29, issue date: 19 March 2019) were approved by the Boston University Charles River Campus Institutional Review Board at Boston, Massachusetts (reference number: 4492E). The results of this study will be published in peer-reviewed scientific journals and will be presented at national and international conferences.Trial registration numberNCT02916524.

Telerehabilitation for Word Retrieval Deficits in Bilinguals With Aphasia: Effectiveness and Reliability as Compared to In-person Language Therapy

“…As this is a double-blind RCT, both the researcher conducting the computational simulations that determine the optimal language of treatment for each patient and the clinicians conducting assessments and treatment are blind to each patient's group assignment. The study protocol of our RCT has been fully described and is available elsewhere ( 30 ).…”

“…The participants in the in-person therapy group attended therapy sessions at one of the recruiting institutions pre-COVID19. In both cases, therapy was conducted by a bilingual clinician with training and experience in providing therapy using both delivery methods in accordance with our established RCT protocol ( 30 ). All participants had normal or corrected-to-normal vision and hearing, and demonstrated sufficient ability to understand and follow study procedures.…”

“…Assessments were completed following our RCT protocol ( 30 ). All participants underwent a comprehensive battery of multiple tests, which were administered separately for each language on alternating English-only and Spanish-only testing sessions to avoid interference between languages.…”

“…All six word sets were included in naming probes administered before, during, and after treatment to evaluate primary treatment outcomes in both languages. A detailed description of the naming probes and related procedures is available elsewhere ( 30 ).…”

“…All patients received therapy in one language targeting critical semantic features of the targeted trained items ( 16 , 30 ), which entails retrieving the critical semantic features of the objects targeted in therapy. Treatment comprised 20 sessions in total (i.e., 2-h sessions twice per week).…”