Open AccessPreserved network functional connectivity underlies cognitive reserve in multiple sclerosis
Author(s) -
Fuchs Tom A.,
Benedict Ralph H. B.,
Bartnik Alexander,
Choudhery Sanjeevani,
Li Xian,
Mallory Matthew,
Oship Devon,
Yasin Faizan,
Ashton Kira,
Jakimovski Dejan,
Bergsland Niels,
Ramasamy Deepa P.,
WeinstockGuttman Bianca,
Zivadinov Robert,
Dwyer Michael G.
Publication year - 2019
Publication title -
human brain mapping
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.005
H-Index - 191
eISSN - 1097-0193
pISSN - 1065-9471
DOI - 10.1002/hbm.24768
Subject(s) - cognitive reserve , cognition , neuroscience , neuropsychology , white matter , psychology , multiple sclerosis , effects of sleep deprivation on cognitive performance , atrophy , functional connectivity , resting state fmri , audiology , medicine , magnetic resonance imaging , cognitive impairment , psychiatry , radiology
Abstract Cognitive reserve is one's mental resilience or resistance to the effects of structural brain damage. Reserve effects are well established in people with multiple sclerosis (PwMS) and Alzheimer's disease, but the neural basis of this phenomenon is unclear. We aimed to investigate whether preservation of functional connectivity explains cognitive reserve. Seventy‐four PwMS and 29 HCs underwent neuropsychological assessment and 3 T MRI. Structural damage measures included gray matter (GM) atrophy and network white matter (WM) tract disruption between pairs of GM regions. Resting‐state functional connectivity was also assessed. PwMS exhibited significantly impaired cognitive processing speed ( t = 2.14, p = .037) and visual/spatial memory ( t = 2.72, p = .008), and had significantly greater variance in functional connectivity relative to HCs within relevant networks ( p < .001, p < .001, p = .016). Higher premorbid verbal intelligence, a proxy for cognitive reserve, predicted relative preservation of functional connectivity despite accumulation of GM atrophy (standardized‐β = .301, p = .021). Furthermore, preservation of functional connectivity attenuated the impact of structural network WM tract disruption on cognition (β = −.513, p = .001, for cognitive processing speed; β = −.209, p = .066, for visual/spatial memory). The data suggests that preserved functional connectivity explains cognitive reserve in PwMS, helping to maintain cognitive capacity despite structural damage.