Episodic and working memory function in Primary Progressive Aphasia: A meta-analysis

Abstract

ObjectiveThe distinction between Primary Progressive Aphasia (PPA) variants remains challenging for clinicians, especially for the non-fluent (nfv-PPA) and the logopenic variants (lv-PPA). Previous research suggests that memory tests might aid this differentiation. This meta-analysis compares memory function among PPA variants. MethodEffects sizes were extracted from 41 studies (N = 849). Random-effects models were used to compare performance on episodic and working memory tests among PPA patients and healthy controls, and between the PPA variants. ResultsMemory deficits were frequently observed in PPA compared to controls, with large effect sizes for lv-PPA (Hedges’ g = −2.04 [−2.58 to −1.49]), nfv-PPA (Hedges’ g = −1.26 ([−1.60 to −0.92], p < .001)), and the semantic variant (sv-PPA; Hedges’ g = −1.23 [−1.50 to −0.97]). Sv-PPA showed primarily verbal memory deficits, whereas lv-PPA showed worse performance than nfv-PPA on both verbal and non-verbal memory tests. ConclusionsMemory deficits were more pronounced in lv-PPA compared to nfv-PPA. This suggests that memory tests may be helpful to distinguish between these PPA variants.