The neurocognitive disorder Alzheimer’s disease affects an estimated 5 million Americans. Its prevalence is expected to triple by 2060. People affected by Alzheimer’s disease have increasing problems with memory, judgement and doing daily tasks of living as the disease progresses. Various studies have indicated that obstructive sleep apnea (OSA) is associated with an increased risk of developing Alzheimer’s disease and that people with OSA have increased levels of certain biomarkers (e.g., amyloid beta protein) associated with Alzheimer’s disease. Scientists have recently noted increased levels of biomarkers associated with Alzheimer’s disease in young children with OSA.
An overlooked symptom in people with obstructive sleep apnea (OSA) is olfactory dysfunction (i.e., impairment in the sense of smell) such as an inability to detect or distinguish between odors. A finding that the sense of smell improves soon after a person with OSA begins continuous positive airway pressure (CPAP) treatment corroborates a possible link between olfactory dysfunction and OSA.
The advent of actigraphy in the 1990s made it possible to indirectly record a person’s sleep-wake cycles based on the person’s activity level, with increased activity indicating wakefulness and decreased activity indicating sleep. In actigraphy, a device — an actigraph — which is typically worn on the wrist, continually records movement data over a prolonged time — one week or more.