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A systematic review of treatment-induced neuroplasticity following anomia rehabilitation
Poster B52 in Poster Session B and Reception, Thursday, October 6, 6:30 - 8:30 pm EDT, Millennium Hall
Tijana Simic1,2,3, Marie-Ève Desjardins1,2,3, Melody Courson1,2, Bérengère Housé1,2, Simona Maria Brambati1,2,3; 1Centre de Recherche de l’Institut Universitaire de Gériatrie de Montréal (CRIUGM), Canada, 2Département de Psychologie, Université de Montréal, Canada, 3Hôpital du Sacré-Cœur de Montréal (HSCM), Montréal, Canada
Studies have shown the efficacy of anomia rehabilitation, both in the short- and long-term (e.g., Breitenstein et al., 2017), and there is a growing body of evidence reporting on neural changes associated with treatment-induced recovery from anomia. However, these patterns of neural change vary widely, and the specific mechanisms underlying treatment-induced neuroplasticity remain unclear (Kiran et al., 2019). The present is a systematic review of the literature reporting pre- to post-treatment changes in brain structure and/or function that are associated with naming improvement. Electronic searches of six databases were conducted, including CINAHL, Cochrane Trials, Embase, Ovid MEDLINE, MEDLINE-in-Process and PsycINFO. Two independent raters assessed all abstracts and full texts against pre-specified inclusion criteria. Single-case, case-series and group studies were accepted if they reported original data on adult participants (aged ≥ 18 years) with post-stroke aphasia and conducted magnetic resonance imaging (MRI) pre- and post- behavioural anomia treatment. Initial search results yielded 2302 unique citations. A total of 33 studies were accepted for review: 21 single-case or case-series designs (N=62), and 12 group studies (N=161). Most studies employed a functional MRI (fMRI) approach: event-related (n=21), block (n=10) and resting-state fMRI (n=3). Two studies employed diffusion MRI. The quality of reporting neuroimaging procedures, appraised by two independent raters, was variable across studies. Whereas sequence characteristics were adequately described, studies were heterogeneous in their reporting of image preprocessing and statistical analysis procedures. Study characteristics and main results (including whole-brain stereotactic coordinates) were extracted. Data synthesis focused primarily on whole-brain contrasts showing neural changes after therapy, particularly those correlated with naming improvement. A variety of therapy techniques were administered, including phonological and/or semantic cueing, naming plus movement therapy, and constraint-induced language therapy. All studies reported pre- to post-treatment improvements in naming. Only two group studies reporting whole-brain data directly associated these naming improvements with neural activation changes. Our findings suggest that anomia therapy induced functional activation changes primarily in the left-hemisphere, within- and outside of the naming network. Also, increased functional connectivity between left hemisphere regions was associated with language improvement. Across studies, most consistent increases in activation following therapy were in the bilateral precunei, which may be important to anomia rehabilitation. Our findings also suggest that treatment-induced neural changes may be specific to the type of treatment administered. Phonological treatment studies primarily reported activation in dorsal stream structures, whereas semantic and constraint-induced treatment studies primarily reported activation of the left middle frontal gyrus and basal ganglia. Combined naming plus gesture treatments which were designed to activate the right hemisphere (i.e., with left hand movements), primarily reported rightward shifts in activation, particularly in the right motor and premotor regions. In other treatment types, a leftward shift in activation was observed post- compared to pre-treatment. The present review underscores the heterogeneity of MRI results in the literature. It is important for future research to make direct links between the neural- and behavioural changes induced by anomia therapy. In addition, future use of standardized MRI procedures may improve the interpretability of findings in aphasia rehabilitation research.
Topic Areas: Language Therapy, Disorders: Acquired