Making the right connections: Maximizing lexical generalization in lexical impairments in primary progressive aphasia and alzheimer’s disease

Purpose: Positive intervention effects following lexical retrieval interventions are increasingly reported with people with progressive language impairments; however, generalization of therapy gains are less frequently evident and less well understood. This study sought to explore the impact of specific therapy ingredients on generalization outcomes.

Method: Twelve participants with progressive lexical retrieval deficits (four each with semantic variant primary progressive aphasia, logopenic variant primary progressive aphasia, and Alzheimer's disease, amnestic presentation) and their family members participated in a 6-week intervention that aimed to increase access to different word classes (nouns, verbs, and adjectives) through a strategic self-cueing approach. Generalization was actively facilitated through strategy practice in connected speech. Repeated baselines of picture naming and connected speech were conducted prior to intervention and repeated immediately post and at 6 weeks following intervention.

Results: All three diagnostic groups showed significant improvements in naming performance post-intervention for all word classes and for both treated and untreated items, demonstrating consistent treatment effectiveness and generalization at the word level. No changes in the informativeness or efficiency of connected speech were found.

Conclusions: Despite heterogeneity across participants, widespread evidence of both treatment effects and generalization to untreated items was found for all diagnostic groups and word classes. The consistent within-level generalization across all groups is explored here in relation to optimization of strategy use through incorporation of cognitive scaffolds, strategic practice at the connected speech level, and the inclusion of family members. The absence of across-level generalization to connected speech is also explored.