In patients with mild cognitive impairment (MCI), sleep habits are associated with gray matter atrophy and changes in functional connectivity, according to study results published in Alzheimer & Dementia.
Previous studies have shown that poor quality sleep can increase the risk of Alzheimer’s in patients with MCI. The aim of the current study was to determine the association between sleep habits and gray matter atrophy and functional connectivity in patients with MCI.
This case-control study included 38 patients with MCI and 38 age-matched controls. All study participants completed structural magnetic resonance imaging (MRI) to assess brain atrophy and functional MRI at rest to determine functional connectivity.
Researchers used Sleep Continuity on the Alzheimer’s Scale, a self-reported questionnaire, to classify patients with MCI as “good” sleepers (20 patients) and “bad” sleepers (18 patients). They then performed independent component analyzes to identify the networks in standard mode (DMN) and frontoparietal region (FPN) and calculated Z-score cards for each patient and modality. In addition, they calculated a composite Z-Score card across the modalities for each participant and each network.
In both patients with MCI who were classified as good or bad sleepers, the connectivity DMN values within the precuneus were significantly higher than the atrophy. Connectivity FPN values that exceed the atrophy in frontal, temporal and parietal regions, however, were only documented in MCI sleepers.
When study researchers compared composite Z-score cards between poor and good sleepers with MCI, they documented significant FPN connectivity scores that exceeded right lower frontal gyrus atrophy in good sleepers.
Ultimately, these results could “indicate different sleep-induced slopes in brain atrophy and connectivity within the FPN network. These results could provide new targets and substitute outcomes for interventions to restore sleep disorders in MCI, ”the study’s researchers concluded.
Wennberg AMV, Pini L., Mitolo M. et al. Sleep-dependent relationship between atrophy and functional connectivity with mild cognitive impairment. Alzheimer’s dementia. Published online on December 7, 2020. doi: 10.1002 / alz.040387
Alzheimer’s disease and dementia