Verb therapy & neuromodulation in primary progressive aphasia (Sheppard et al., 2025)

Purpose: The purpose of the study was to evaluate Verb Network Strengthening Treatment (VNeST) paired with the transcranial direct current stimulation (tDCS) of the left inferior frontal gyrus, which was compared to VNeST paired with a sham stimulation in primary progressive aphasia (PPA).

Method: A double-blind, within-subject, sham-controlled crossover design was used. Eight participants with PPA were enrolled. Participants were enrolled in two treatment phases, one with VNeST plus real tDCS and one with VNeST plus sham. Participants received fifteen 1-hr sessions of VNeST in each phase. Linear mixed-effects models were used to compare changes between baseline and two follow-up time points (1 week and 8 weeks posttreatment) in naming trained verbs, untrained verbs, and untrained nouns; sentence production and comprehension; and producing content units and complete utterances in discourse.

Results: VNeST was effective for significantly improving naming trained verbs and producing more complete utterances in discourse at 1 week posttreatment in both tDCS and sham conditions. A significant tDCS advantage yielded generalization of treatment effects to untrained verbs (at 1 week and 8 weeks posttreatment), sentence production (at 1 week posttreatment), and sentence comprehension (at 8 weeks posttreatment). Untrained verb naming and sentence comprehension declined when VNeST was not augmented with tDCS.

Conclusions: Our findings provide emerging evidence that VNeST paired with tDCS can improve word finding, and other language abilities, in people with PPA. VNeST without neuromodulation can improve trained verb naming, but untrained verbs will likely decline faster when VNeST is not augmented with tDCS. Future research is required with a larger sample size to continue investigating the potential of treating word finding with VNeST and tDCS in PPA.

Supplemental Material S1. Six figures depicting individual participant outcomes for trained verb naming, untrained verb naming, noun naming, sentence production, sentence comprehension, and discourse.

Sheppard, S. M., Goldberg, E. B., Sebastian, R., Vitti, E., Ruch, K., Meier, E. L., & Hillis, A. E. (2025). Augmenting verb-naming therapy with neuromodulation decelerates language loss in primary progressive aphasia. American Journal of Speech-Language Pathology, 34(1), 155–173. https://doi.org/10.1044/2024_AJSLP-24-00016