REM Sleep Disorders May Be an Early Warning Sign of Neurodegenerative Disease

Summary: Researchers report that disturbances in dreaming and specific sleep disorders can precede clear neurological symptoms by many years, offering a potential early indicator of diseases such as Parkinson’s and Lewy body dementia.

REM sleep disturbances could indicate increased risk for neurodegenerative disease later in life.

Dr. John Peever and his team at the University of Toronto have been investigating a fundamental question about human experience: how do we dream? Their work has identified a group of neurons in the brainstem that are active during Rapid Eye Movement (REM) sleep and appear to be essential to the dreaming state. By studying these REM-active neurons in animal models, the researchers have begun to demonstrate not only how dreaming is generated but also how abnormalities in dreaming can signal broader brain health problems.

Since the 1960s, scientists have recognized that the brainstem plays a central role in controlling REM sleep. Building on that foundation, Peever’s research has isolated the specific cells responsible for initiating and maintaining the REM state. In laboratory animals, the team has shown they can trigger the rapid transition into REM sleep by activating these neurons. As Dr. Peever explains, “When we switch on these cells, it causes a rapid transition into REM sleep.” This experimental control provides a clearer window into the mechanisms of dreaming and the neural circuitry that supports it.

Beyond the basic neuroscience, the team has explored the clinical implications of dreaming dysfunction. One REM-related condition of particular interest is REM sleep behaviour disorder (RBD), a condition in which the normal muscle paralysis that accompanies REM sleep is incomplete or absent, causing people to physically act out their dreams. The researchers found a striking association between REM sleep disorders and a class of neurodegenerative conditions known as synucleinopathies. These include Parkinson’s disease and dementia with Lewy bodies.

Analysis of clinical observations reveals that a large proportion of people diagnosed with REM sleep disorder later develop synucleinopathies. According to the team’s findings presented at the 2017 Canadian Neuroscience Meeting, more than 80% of individuals with REM sleep disorder go on to develop such neurodegenerative diseases. Importantly, the sleep disorder often appears many years before the classic motor symptoms, cognitive decline, or other clinical signs associated with these conditions. In some cases, REM disturbances arise as much as fifteen years earlier than other diagnosable symptoms.

The implications of these findings are significant. If REM sleep disorders reliably predict later development of synucleinopathies, clinicians could use sleep assessments as an early screening tool. Early detection could allow patients and healthcare providers to pursue neuroprotective strategies and lifestyle interventions long before irreversible neurological damage occurs. While a preventative treatment for Parkinson’s or Lewy body dementia is not yet available, diagnosing REM sleep disorders early could identify people who would benefit from closer monitoring, lifestyle guidance, or participation in clinical trials aimed at slowing disease progression.

Dr. Peever stresses the potential for preventive action: “Much like we see in people prone to cancer, diagnosing REM disorders may allow us to provide individuals with preventative actions to keep them healthy long before they develop these more serious neurological conditions.” Realizing this potential will require further research to translate basic laboratory discoveries into reliable clinical tests and effective interventions, but the path forward is clearer now that the link between dreaming mechanisms and disease risk has been established.

Funding: This research received support from the Canadian Institutes of Health Research (CIHR) and the Natural Sciences and Engineering Research Council (NSERC) of Canada.

Source: Julie Poupart, Canadian Association For Neuroscience.

Image Source: NeuroscienceNews.com image used for illustrative purposes and noted as public domain in the original release.

Original Research: Findings were presented at the 11th Canadian Neuroscience Meeting in Montreal, Canada, held May 28–31, 2017.

Canadian Association For Neuroscience. “Connecting the Dots Between Dreams and Brain Disease.” NeuroscienceNews. May 30, 2017. Presented at the 2017 Canadian Neuroscience Meeting.