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White matter integrity linked to memory retrieval deficits in posterior cortical atrophy
Author(s) -
Overman Margot Juliette,
Zamboni Giovanna,
Butler Christopher,
Ahmed Samrah
Publication year - 2020
Publication title -
alzheimer's and dementia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.713
H-Index - 118
eISSN - 1552-5279
pISSN - 1552-5260
DOI - 10.1002/alz.041942
Subject(s) - splenium , episodic memory , psychology , white matter , posterior cortical atrophy , recall , corpus callosum , diffusion mri , cingulum (brain) , fractional anisotropy , audiology , neuroscience , dementia , cognitive psychology , magnetic resonance imaging , medicine , disease , pathology , cognition , radiology
Background Posterior cortical atrophy (PCA) is an atypical form of Alzheimer’s disease characterised by visuospatial abilities, with episodic memory traditionally thought to be relatively preserved. However, recent work suggests that verbal memory is impaired at clinical presentation (Ahmed et al., 2016) associated with changes in functional connectivity of parietal attention networks (Veldsman et al., 2018). It is currently unclear how structural connectivity changes may contribute to memory functioning within this patient group. Here, we examine the relationship between white matter integrity and verbal episodic memory in PCA. Method Eighteen patients with PCA and eighteen healthy controls underwent diffusion tensor imaging (DTI) MRI scanning. Episodic memory of patients was assessed with the Free and Cued Selective Reminding Test with Immediate Recall (FCSRT‐IR). Voxel‐wise statistical analyses of fractional anisotropy and mean diffusivity measures in patient and control groups were carried out using tract‐based spatial statistics. Relationships between white matter microstructure and memory performance were examined with partial correlations controlling for age. Result There was no difference in encoding of verbal items between patients and healthy controls. However, PCA patients presented with significant impairments of memory retrieval on the FCSRT‐IR. In line with previous neuroimaging research, white matter degeneration in PCA was restricted to posterior regions of the cortex. Within the patient group, reduced integrity of the splenium of the corpus callosum was associated with less free recall of task items. Conclusion This study demonstrates that splenial atrophy may contribute to deficits in episodic memory retrieval in PCA. The findings have implications for supporting diagnostic profiling in PCA. References: Ahmed, S., Baker, I., Husain, M., Thompson, S., Kipps, C., Hornberger, M., Hodges, J.R., & Butler, C.R. (2016). Memory impairment at initial clinical presentation in posterior cortical atrophy. Journal of Alzheimer’s Disease, 52 : 1245 – 1250. Veldsman, M., Zamboni, G., Butler, C., & Ahmed, S. (2018). Attention network dysfunction underlies memory impairment in posterior cortical atrophy. NeuroImage: Clinical, 22 : 101773.