Neural Correlates of Cognitive Performance in Alzheimer’s Disease- and Lewy Bodies-Related Cognitive Impairment

Article type: Research Article

Authors: Chung, Seok Jong^{a; 1} | Jeon, Seun^{b; 1} | Yoo, Han Soo^a | Lee, Yang Hyun^a | Yun, Mijin^c | Lee, Seung-Koo^d | Lee, Phil Hyu^a | Sohn, Young Ho^a | Evans, Alan C.^b | Ye, Byoung Seok^{a; *}

Affiliations: [a] Department of Neurology, Yonsei University College of Medicine, Seoul, South Korea | [b] McGill Center for Integrative Neuroscience, Montreal Neurological Institute, McGill University, Montreal, Canada | [c] Department of Nuclear Medicine, Yonsei University College of Medicine, Seoul, South Korea | [d] Department of Radiology, Yonsei University College of Medicine, Seoul, South Korea

Correspondence: [*] Correspondence to: Byoung Seok Ye, MD, PhD, Department of Neurology, Yonsei University College of Medicine, 50 Yonsei-ro, Seodaemun-gu, Seoul, 03722, South Korea. Tel.: +82 2 2228 1601; Fax: +82 2 393 0705; E-mail: romel79@gmail.com.

Note: [1] These authors contributed equally to this work.

Abstract: Background:Clinicopathological studies have demonstrated that the neuropsychological profiles and outcomes are different between two dementia subtypes, namely Alzheimer’s disease (AD) and Lewy bodies-related disease. Objective:We investigated the neural correlates of cognitive dysfunction in patients with AD-related cognitive impairment (ADCI) and those with Lewy bodies-related cognitive impairment (LBCI). Methods:We enrolled 216 ADCI patients, 183 LBCI patients, and 30 controls. Cortical thickness and diffusion tensor imaging analyses were performed to correlate gray matter and white matter (WM) abnormalities to cognitive composite scores for memory, visuospatial, and attention/executive domains in the ADCI spectrum (ADCI patients and controls) and the LBCI spectrum (LBCI patients and controls) separately. Results:Memory dysfunction correlated with cortical thinning and increased mean diffusivity in the AD-prone regions, particularly the medial temporal region, in ADCI. Meanwhile, it only correlated with increased mean diffusivity in the WM adjacent to the anteromedial temporal, insula, and basal frontal cortices in LBCI. Visuospatial dysfunction correlated with cortical thinning in posterior brain regions in ADCI, while it correlated with decreased fractional anisotropy in the corpus callosum and widespread WM regions in LBCI. Attention/executive dysfunction correlated with cortical thinning and WM abnormalities in widespread brain regions in both disease spectra; however, ADCI had more prominent correlation with cortical thickness and LBCI did with fractional anisotropy values. Conclusions:Our study demonstrated that ADCI and LBCI have different neural correlates with respect to cognitive dysfunction. Cortical thinning had greater effects on cognitive dysfunction in the ADCI, while WM disruption did in the LBCI.

Keywords: Alzheimer’s disease, cognition, Lewy body, neural correlate

DOI: 10.3233/JAD-190814

Journal: Journal of Alzheimer's Disease, vol. 73, no. 3, pp. 873-885, 2020