Brain Damage Caused by Sleep Apnea Can Be Reversed With Treatment
While studies have shown that severe sleep apnea can cause brain damage and memory loss when left untreated, use of continuous positive airway pressure (CPAP) therapy can actually reverse the damage and improve overall cognition. While these functional alterations of the brain are not yet fully understood, it is clear that some level of neurological disruption occurs in severe or untreated sleep apnea. What has been less certain is the role of PAP therapy in treating those symptoms. But studies conducted by groups such as the American Academy of Sleep Medicine (AASM) have shown strong evidence of reversal for patients treated with PAP therapy. This means that neurological damage caused by periodic apnea events is not only averted by treating the disorder, but that overall cognition will actually regenerate and improve over time. This research underscores the importance of the Healthy Sleep Awareness Project, funded in part by the national plan for Healthy People 2020, which provides science-based, 10-year objectives for improving the health of all Americans.
Sleep Apnea and Cognitive Impairment
In studies involving untreated patients, nearly every participant has shown impairment in most cognitive areas, including mood, alertness, and memory. As far back as the early 2000s studies have affirmed the loss of white matter in OSA patients that develops, at least in part, from gradual injury to neural structures such as the numerous axons that link major systems, or the network of projections to and from the cerebellum. Results show that patients with severe or prolonged untreated sleep apnea have significant reductions in this type of white matter structural integrity, and most often, it occurs in multiple areas of the brain. This qualifies as brain damage, and the symptoms are clear. Patients experience a range of impairments to memory, emotional stability, and alertness as long as the condition persists.
Other markers of damage or inflammation, such as the existence of tau proteins, have been similarly linked to severe sleep-apnea conditions. Tau proteins (or τ proteins, after the Greek letter with the same name) are a group of highly soluble protein isoforms used primarily in maintaining the stability of axons, and are therefore abundant in the neurons of the central nervous system (CNS). Problems of the nervous system such as Alzheimer’s disease and Parkinson’s disease have been associated with tau proteins, and studies have found similar links with OSA. Tau levels tend to be elevated in the blood of patients with moderate to severe OSA, especially among younger patients, suggesting that these biomarkers may be an early sign in the development of chronic sleep-apnea conditions.
These study findings also help to improve our understanding of the nature of episodic memory loss found in individuals diagnosed with sleep apnea. Impairments to episodic memory have a gradual effect on the daily functioning of individuals with sleep apnea, often compounding the dangers of the condition as the patient becomes more sleepy during day hours, and less effective cognitively, even during peak work hours when they should be at the height of their performance. Overall, this gradual deterioration of one’s capabilities can become a very serious health issue in its own right, one of the many reasons why sleep apnea syndromes are considered a primary health concern by medical professionals. Whether or not the cognitive defects are a direct result of sleep apnea events, the fact that strong comorbid relationships exist should give patients and clinics enough of an incentive to expand diagnostic screenings and heighten overall commitment to treatment and continued support.
PAP Therapy and Cognitive Improvement
On average, the AASM found that over the course of 12 months of PAP therapy treatment, an “almost complete reversal” of white matter abnormalities in all affected regions was observed. This has been consistent for all compliant PAP-therapy patients, that is, for all patients who either maintained or surpassed a limit of four nightly hours of therapy throughout 70 percent or more of the 12-month period. In considering that the majority of health professionals in the area of sleep medicine recommend more rigorous PAP therapy regimens for their patients, it is easy to see why researchers would find these study results optimistic. If, for example, a patient maintained a mere four-hour minimum throughout the majority of the year, and yet experienced a full reversal of all brain damage caused by previous years of untreated sleep apnea, the outcome presents a strong case for reversing structural neural injury in OSA in patients.
AASM President Timothy Morgenthaler, Ph.D., a national spokesperson for the Healthy Sleep Awareness Project, reinforced the idea that clinics should widen the screening protocols for OSA, testing anyone with primary symptoms or strong secondary markers associated with the disorder. “Treatment of sleep apnea can be life-changing and potentially life-saving,” Dr. Morgenthaler said. But compliance is key. If patients are compliant, according to the research, PAP therapy is effective for a range of primary and secondary outcomes, many of which can be life threatening. This complete turnaround, both in terms of damage to neural structures and the general purpose of reducing or eliminating apnea events, is a promising long-term outcome for those struggling to adopt the therapy for the first time.
The Healthy Sleep Awareness Project
The Healthy Sleep Awareness Project was established as a cooperative agreement between the AASM and the Centers for Disease Control and Prevention, which for the last 30 years has been part of a national plan for Healthy People 2020, a large-scale strategy for the prevention of major public health concerns. In regard to sleep apnea, this includes a general pledge to increase the medical evaluation of people with symptoms specific to OSA. The plan also vows to reduce vehicular crashes due to drowsy driving, and to improve overall sleep health on a national scale. While it is 2020 now, the plan is still in full stride, and the Healthy Sleep Awareness Project continues to spread awareness to clinics as well as the general public. The great medical benefits that result from our continued study of this life-threatening disorder show us just how valuable these resources can be, giving us even further incentive to expand the science in the direction of public health and the general welfare of the nation.
Healthy People 2020 – https://www.healthypeople.gov/
Healthy Sleep Awareness Project -. http://sleepeducation.org/healthysleep
Journal of Otolaryngology Head and Neck Surgery – https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4992257/
Sleep Medicine – https://www.ncbi.nlm.nih.gov/pubmed/29482817