title: Sleep disturbance in mild cognitive impairment is associated with alterations in the brain's default mode network.
abstract: This study aimed to identify default mode network (DMN) functional connectivity deficits in patients with mild cognitive impairment (MCI) and sleep disturbance, relative to those with MCI and no sleep disturbance. A control group was included to aid in identifying DMN changes specific to MCI. A cross-sectional, single-center study was performed at the Brain and Mind Research Centre in Sydney, Australia. Participants (95 adults over the age of 65: 38 controls and 57 meeting criteria for MCI) underwent resting-state functional MRI along with comprehensive neuropsychological, medical, and psychiatric assessment. Self-report data were collected including sleep quality assessment via the Pittsburgh Sleep Quality Index. A total score of greater than 5 on the Pittsburgh Sleep Quality Index was used to signify the presence of significant sleep disturbance, as per commonly used methodology. Using this criterion, 53% (n = 30) of our MCI group were classified as sleep-disturbed. Whereas the total group of MCI subjects and controls demonstrated no significant differences, sleep-disturbed MCIs demonstrated increased connectivity between temporal and parietal regions, and decreased connectivity between the prefrontal cortex and the temporoparietal junction relative to sleep-disturbed controls. Relative to those MCIs without sleep disturbance, sleep-disturbed MCI participants demonstrated significantly diminished DMN connectivity between temporal and parietal regions, a finding that was particularly pronounced in amnestic MCI. Sleep disturbance in MCI is associated with distinct alterations in DMN functional connectivity in brain regions underpinning salient memory and sleep systems. Future studies may build on these results via experimental manipulation and objective measurement of sleep. (PsycINFO Database Record
authors.affiliation: Healthy Brain Ageing Clinic, The University of Sydney.
authors.forename: Andrew C
authors.initials: AC
authors.lastname: McKinnon
authors.affiliation: Healthy Brain Ageing Clinic, The University of Sydney.
authors.forename: Jim
authors.initials: J
authors.lastname: Lagopoulos
authors.affiliation: Healthy Brain Ageing Clinic, The University of Sydney.
authors.forename: Zoe
authors.initials: Z
authors.lastname: Terpening
authors.affiliation: Woolcock Institute of Medical Research.
authors.forename: Ron
authors.initials: R
authors.lastname: Grunstein
authors.affiliation: Healthy Brain Ageing Clinic, The University of Sydney.
authors.forename: Ian B
authors.initials: IB
authors.lastname: Hickie
authors.affiliation: Department of Psychology, Macquarie University.
authors.forename: Jennifer
authors.initials: J
authors.lastname: Batchelor
authors.affiliation: Healthy Brain Ageing Clinic, The University of Sydney.
authors.forename: Simon J G
authors.initials: SJ
authors.lastname: Lewis
authors.affiliation: Healthy Brain Ageing Clinic, School of Psychology, Charles Perkins Centre, The University of Sydney.
authors.forename: Shantel
authors.initials: S
authors.lastname: Duffy
authors.affiliation: Healthy Brain Ageing Clinic, The University of Sydney.
authors.forename: James M
authors.initials: JM
authors.lastname: Shine
authors.affiliation: Healthy Brain Ageing Clinic, School of Psychology, Charles Perkins Centre, The University of Sydney.
authors.forename: Sharon L
authors.initials: SL
authors.lastname: Naismith
mesh_terms: D000368:Aged; D001315:Australia; D001921:Brain / Q000503:physiopathology; D001931:Brain Mapping / Q000706:statistics & numerical data*; D060825:Cognitive Dysfunction / Q000473:pathology / Q000523:psychology; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D009415:Nerve Net / Q000473:pathology*; D009483:Neuropsychological Tests / Q000706:statistics & numerical data; D012893:Sleep Wake Disorders / Q000150:complications*