Get latest articles and stories on Health at LatestLY. According to recent Alzheimer's research from UVA Health, increased light sensitivity may be responsible for "sundowning," or the exacerbation of symptoms in the late afternoon, as well as for sleep disturbances that are thought to hasten the disease's progression. Health News | Heightened Light Sensitivity May Contribute to Alzheimer's 'sundowning' and Cause Disease Advancement: Study.