Late-life changes in sleep are thought to contribute to cognitive dysfunction and progression of Alzheimer’s Disease. Sleep disruption impairs multiple aspects of cognition. This connection may occur through slow-wave sleep which characterizes the deepest, most restorative stage of sleep. Slow-wave sleep is commonly associated with memory in both young and older adults. Intriguingly, during slow-wave sleep, beta amyloid, a precursor for Alzheimer's disease, is cleared from the fluid surrounding the brain, suggesting a direct link between slow-wave sleep and prevention of neurodegeneration. Accordingly, treatments that enhance slow-wave sleep in older adults are thought to be promising for preventing and delaying neurodegeneration. Slow-wave sleep can be enhanced through wake activities in a use-dependent pattern. For instance, brain stimulation during wakefulness can lead to a robust increase in slow-waves during subsequent sleep. Brain stimulation outside the sleep field has been shown to benefit memory in patients with depression and mild cognitive impairment (MCI). Slow-wave sleep regulates brain plasticity and reorganizes neural connections to enhance relevant memories and the function of brain networks involved in memory. Thus, slow-wave sleep may drive memory enhancement through brain stimulation. This pilot study will compare increases in slow-wave sleep and memory performance before and after brain stimulation over the dorsolateral prefrontal cortex in older adults with MCI. It will assess whether brain stimulation increases slow-wave sleep and memory in MCI, and explore whether slow-wave sleep increases are associated with memory improvements.
University of Pittsburgh