When an older adult with mild cognitive impairment (MCI) has poor sleep quality, it can aggravate depression. That can lead to decline in cognitive function, a new study finds.
The authors recommended properly managing sleep and depressive symptoms in those with MCI.
The report was published Wednesday in Scientific Reports.
At baseline, researchers evaluated 134 patients (which eventually dwindled to 122) from 24 communities in China. All were over the age of 60, and the mean age of participants was 70.1 years. They all had MCI, which can be a precursor for dementia, though not all people with it go on to develop dementia.
Researchers used the Patient Health Questionnaire-9, the Pittsburgh Sleep Quality Index and the Montreal Cognitive Assessment Scale to evaluate participants during the interviews. These tools assessed each person’s depressive symptoms, sleep quality and cognitive functions.
The team used multiple statistical models to better understand the relationship between sleep quality, depression and cognitive function.
Researchers have posited a few theories about the relationship between sleep quality and depression in people with MCI. Loss of sleep may lead to decreased inhibitory control of negative emotions by disrupting prefrontal cortex functioning, leading to negative emotions, the authors wrote. The link between depressive symptoms and cognitive functions may arise from dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis seen in depressed patients, and lead to biological changes (including chronic inflammation and increased amounts of amyloid plaques) that are associated with cognitive decline, they noted.
“Overall, this study revealed the mediating role of depressive symptoms in sleep quality affecting cognitive functions in patients with mild cognitive impairment, where the worse sleep quality led to a more severe depressive symptoms resulting in more serious cognitive decline,” the authors wrote. “Interventions for older adults with mild cognitive impairment are suggested to include both sleep disorders and depressive symptoms for consideration.”
The news comes about a week after a recent study published in Alzheimer’s & Dementia found that people with hypertension and amyloid plaque buildup may have a higher risk for cognitive impairment compared with those who have only one risk factor.
