Examining Durability and Generalization Following Lexical Retrieval Treatment in an Individual with Semantic Variant of Primary Progressive Aphasia

• Main Author: Kindle Rising
• Format: Article
• Language: English
• Published: Frontiers Media S.A. 2015-05-01
• Series: Frontiers in Psychology
• Subjects: Anomia; primary progressive aphasia; lexical retrieval; Semantic Dementia; treatment outcome; Treatment generalization
• Online Access: http://journal.frontiersin.org/Journal/10.3389/conf.fpsyg.2015.65.00017/full

Introduction: The Semantic Variant of Primary Progressive Aphasia (PPAsv) is characterized by marked anomia, even in the earliest stages of the disease1. Despite the progressive nature of the disorder, there is evidence that lexical retrieval may improve following behavioral treatment2-4. Most approaches focus on stimulation treatment targeting specific lexical items (e.g., verbal repetition paired with written words), but outcomes are typically item specific with limited generalization, and maintenance has not been well characterized2-4. Treatment approaches that attempt to engage relatively spared cognitive processes (phonology, orthography, episodic memory) in addition to maximizing residual semantic abilities may contribute to better generalization and durability2-5. Henry and colleagues (2013)5 described one such approach, which contributed to positive treatment outcomes and generalization in an individual with PPAsv. Additional treatment was conducted with this individual two years after the first course of therapy. Here we report response to treatment at each time point, and describe performance following various intervals without treatment. Method: SV was a 60-year-old man who described increased word finding difficulties over a 1.5-year period. Comprehensive assessment revealed relatively isolated language impairment characterized by severely impaired lexical retrieval. Performance on semantic tasks was significantly below the normal range. An MRI revealed notable atrophy of the left anterior temporal lobe, consistent with PPAsv. SV participated in a two-phase lexical retrieval treatment: The Arizona Lexical Retrieval Cascade and Generative Naming Treatment5. Treatment included self-cueing for naming by engaging residual cognitive processes and further training these strategies in the context of generative naming for semantic categories (e.g., tools, animals). Direct treatment effects and generalization to untrained tasks were documented immediately following each phase, at one and four months following the initial treatment, and again two years later. At that time, SV received a second “dose” of the two-phase lexical retrieval treatment. Outcomes were documented immediately following this second round of treatment and 6-months later. Results: As depicted in Figure 1a & b, SV demonstrated notable gains following the first course of treatment, and maintained performance on treatment tasks for four months. Two years later, performance on trained tasks declined, but did not fall below baseline. SV’s response to the second course of treatment was equally robust, but performance declined slightly after six months. After each round of treatment, SV showed generalized improvement on untrained lexical retrieval tasks, and maintenance up to at least four months. Measures of non-verbal problem solving and general cognition remained relatively unchanged over time (Figure 1c). Conclusions: These findings suggest that ongoing rehabilitation for PPAsv can be beneficial, even as the disease progresses. The optimal length of time between treatment periods is not clear, but SV’s performance indicates that an interval between 6-months and two years should be considered. This case adds to the growing literature suggesting that lexical retrieval treatment capitalizing on strategic use of residual cognitive processes may contribute to generalization, and items trained using this approach may be relatively durable in the face of progressive language decline.