Treatment for Word Retrieval in Semantic and Logopenic Variants of Primary Progressive Aphasia: Immediate and Long-Term Outcomes

Abstract

Purpose Recent studies confirm the utility of speech-language intervention in primary progressive aphasia (PPA); however, long-term outcomes, ideal dosage parameters, and relative benefits of intervention across clinical variants warrant additional investigation. The purpose of this study was to determine whether naming treatment affords significant, lasting, and generalized improvement for individuals with semantic and logopenic PPA and whether dosage manipulations significantly affect treatment outcomes. Method Eighteen individuals with PPA (9 semantic and 9 logopenic variant) underwent lexical retrieval treatment designed to leverage spared cognitive-linguistic domains and develop self-cueing strategies to promote naming. One group (n = 10) underwent once-weekly treatment sessions, and the other group (n = 8) received the same treatment with 2 sessions per week and an additional "booster" treatment phase at 3 months post-treatment. Performance on trained and untrained targets/tasks was measured immediately after treatment and at 3, 6, and 12 months post-treatment. Results Outcomes from the full cohort of individuals with PPA showed significantly improved naming of trained items immediately post-treatment and at all follow-up assessments through 1 year. Generalized improvement on untrained items was significant up to 6 months post-treatment. The positive response to treatment was comparable regardless of session frequency or inclusion of a booster phase. Outcomes were comparable across PPA subtypes, as was maintenance of gains over the post-treatment period. Conclusion This study documents positive naming treatment outcomes for a group of individuals with PPA, demonstrating strong direct treatment effects, maintenance of gains up to 1 year post-treatment, and generalization to untrained items. Lexical retrieval treatment, in conjunction with daily home practice, had a strong positive effect that did not require more than 1 clinician-directed treatment session per week. Findings confirm that strategic training designed to capitalize on spared cognitive-linguistic abilities results in significant and lasting improvement, despite ongoing disease progression, in PPA.

Figures

Figure 1.

Voxel-based morphometry analysis comparing gray and white matter volumes in nine participants with semantic primary progressive aphasia (A) and eight participants with logopenic primary progressive aphasia (B) relative to 30 healthy controls (p < 0.001, uncorrected; covariates include age, sex, and total intracranial volume) Color bars represent t values.

Figure 2.

Performance on trained and untrained sets of words as well as standardized tests over time in the full group of participants with primary progressive aphasia. 95% confidence intervals around the mean were derived using n = 1,000 bootstrapped samples. Significant permutation test, with Bonferroni correction, denoted: * = significant difference relative to pre-treatment; + = significant difference relative to post-treatment. Trained = trained items; Untrained = untrained items; BNT = Boston Naming Test; WAB = Western Aphasia Battery; AQ = Aphasia Quotient; Pre = pre-treatment; Post = post-treatment; 3M = 3 months post-treatment; 6M = 6 months post-treatment; 12M = 12 months post-treatment.

Figure 3.

Performance on trained and untrained sets of words as well as standardized tests over time in participants from each dosage protocol. 95% confidence intervals around the mean were derived using n = 1,000 bootstrapped samples. Significant permutation test, with Bonferroni correction, denoted: for within-group comparisons, * = significant difference relative to pre-treatment; + = significant difference relative to post-treatment. No significant between-groups differences in change scores. LRT1 = Lexical Retrieval Treatment Group 1; LRT2 = Lexical Retrieval Treatment Group 2; Trained = trained items; Untrained = untrained items; BNT= Boston Naming Test; WAB = Western Aphasia Battery; AQ = Aphasia Quotient; Pre = pre-treatment; Post = post-treatment; 3M = 3 months post-treatment; 6M = 6 months post-treatment; 12M = 12 months post-treatment.

Figure 4.

Performance on trained and untrained sets of words as well as standardized tests over time in each clinical subtype. 95% confidence intervals around the mean were derived using n = 1,000 bootstrapped samples. Significant permutation test, with Bonferroni correction, denoted: for within-group comparisons, * = significant difference relative to pre-treatment; + = significant difference relative to post-treatment. No significant between-groups differences in change scores. SvPPA = semantic variant primary progressive aphasia; lvPPA = logopenic variant primary progressive aphasia; Trained = trained items; Untrained = untrained items; BNT= Boston Naming Test; WAB = Western Aphasia Battery; AQ = Aphasia Quotient; Pre = pre-treatment; Post = post-treatment; 3M = 3 months post-treatment; 6M = 6 months post-treatment; 12M = 12 months post-treatment.

Figure 5.

Mean response for post-treatment self-assessment survey (LRT2 participants). Scale: −3 = a lot worse; −2 = worse; −1 = somewhat worse; 0 = unchanged; 1 = somewhat better; 2 = better; 3 = a lot better. lvPPA = logopenic variant primary progressive aphasia; svPPA = semantic variant primary progressive aphasia.