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Differential effects of confluent and non‐confluent white matter hyperintensities on functional connectivity in mild cognitive impairment
Author(s) -
Kumar Dilip,
Vipin Ashwati,
Wong Benjamin,
Ng Kok Pin,
Kandiah Nagaendran
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.038512
Subject(s) - hyperintensity , default mode network , audiology , cognition , cognitive impairment , psychology , neuropsychology , white matter , neuroscience , functional connectivity , magnetic resonance imaging , medicine , radiology
Abstract Background Emerging evidence suggests that confluent WMH results in greater cognitive impairment compared to non‐confluent WMH. However, the mechanism linking confluent WMH and early cognitive impairment is not clearly understood. We studied the effects of confluent and non‐confluent WMH on whole‐brain functional connectivity (FC) across 164 regions of interest (ROI) in subjects with Mild Cognitive Impairment (MCI). Method Sixty‐three MCI subjects with T1‐weighted MRI, T2‐weighted MRI, resting‐state functional MRI (rs‐fMRI) and neuropsychological data were studied. Subjects were classified as confluent WMH (C‐WMH) or non‐confluent WMH (NC‐WMH) using the Staal’s criteria on the Fazekas WMH scale. Group‐level ROI‐to‐ROI FC trends and differences at differential WMH subtypes were computed using standard rs‐fMRI analysis. Result Subjects with C‐WMH exhibited increased inter‐regional FC in the fronto‐parietal, fronto‐occipital, parieto‐occipital, and temporo‐parietal regions of the salience, dorsal‐attention, default‐mode, and visual networks. Increased intra‐regional FC in the frontal lobe was also observed in C‐WMH. In contrast, only intra‐regional FC changes were seen in the frontal and temporal lobes in NC‐WMH. Performance on the Montreal Cognitive Assessment correlated positively with increased inter‐regional FC only in the C‐WMH group, suggesting that increased connectivity was associated with better global cognition in MCI subjects with C‐WMH. Conclusion C‐WMH in subjects with MCI is associated with widespread increased inter‐regional FC changes which correlates with better performance in global cognition. These findings provide novel insights into divergent functional alterations related to the confluence of WMH in MCI.