Disrupted Sleep Cycles May Be Related to Parkinson's

Detecting circadian rhythm disruptions may help early diagnosis of Parkinson's.
Utku Kucukduner

Parkinson's is a progressive neurodegenerative disease that affects neural functioning; resulting in slowed movement (bradykinesia), tremors, muscle rigidity, and postural instability. Scientists discovered a link between disrupted circadian rhythm and Parkinson's in a recent study.

Study found that elderly males with irregular or weak circadian rhythm are more prone to developing Parkinson's disease. A study conducted in UC San Francisco Weill Institute for Neurosciences analyzed 11 years' worth of data on about 2,930 community-dwelling men. 

Chicken or the egg, that's the problem

The findings suggest that these circadian disruptions may foresign neurodegeneration underway that will eventually lead to a Parkinson's diagnosis.

The authors of the study note that further investigation so as to determine whether it is the disruption of rhythm itself a cause for neurodegeneration or if it is an effect caused by Parkinson's itself. Further investigation may pave the way for a novel preventive treatment paradigm; strengthening circadian rhythm to lower the risk of Parkinson's.

After Alzheimer's, Parkinson's is the second most common neurodegenerative disease. In the US alone there are over half a million officially diagnosed patients.


Patients are often over the age of 60. As of now, there is no preventive treatment yet, but more and more medication for management are hitting the market each year.

The possibility of forecasting the Parkinson's

Parkinson's takes years to develop, even decades perhaps, so Leng notes: "earlier signs might be critical in understanding the disease and its mechanisms" and adds "This is the first large, long-term study to find that disrupted circadian rhythms might be linked to Parkinson's that emerges years later."

Disrupted Sleep Cycles May Be Related to Parkinson's
Source: koto_feja/iStock

The participants have originally enrolled in a different study "Osteoporotic Fractures in Men Study (MRoS)" in 2000. At the beginning of the study, none of the men had 

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Researchers monitored the participants' circadian rhythm at three separate 24 hour-long periods with an actimeter, a device resembling a watch that records movements of the wrist with great precision. Later, this data was compared to Parkinson's prevalence. At follow-up evaluations, 78 of 2,930 were found to develop Parkinson's.

The takeaway

The study found that those with the lowest circadian robustness were three times at more risk of developing Parkinson's when compared to those with the highest.

Animal models of Parkinson's also demonstrate that neurodegeneration onsets long before symptoms do. Leng also adds that circadian rhythm disruptions cause increased inflammation and metabolic changes and thus there's a possibility of these changes may be contributing to neural degeneration itself.

Leng also does not rule out the possibility that disruptions in circadian rhythm, already known to cause metabolic changes and inflammation, might contribute to neurodegenerative disease in itself.

Leng and the team hope to investigate whether weakened circadian rhythms trigger inflammation or the abnormal accumulation of proteins seen in affected brain tissue in both Parkinson's and Alzheimer's.

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