Episodic and working memory function in Primary Progressive Aphasia: A meta-analysis
Neuroscience & Biobehavioral Reviews , Volume 92 p. 243- 254
Objective: The 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. Method: Effects 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. Results: Memory 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. Conclusions: Memory 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.