Most of us think that poor sleep has little consequence, with perhaps a little tiredness the next day. Wrong. Consider the research that is finding a link between REM-stage sleep disorder and Parkinson’s Disease.
Parkinson’s disease and dementia have been linked to a lack of REM-sleep. This has been illustrated in several studies. In much of the research, the REM-stage deficiency precedes Parkinson’s and dementia onset by a number of years (Arnulf et al. 2008).
REM means “rapid eye movement.” It takes place during several episodes of deep sleep during the night. This is when most of our dreams take place.
In one study (Bugalho et al. 2010), out of 75 Parkinson’s patients assessed, 41 of them were suffering from REM-stage sleep disorders. The researchers admitted, however, that this did not account for the possibility that the patients had past REM-sleep disorders or REM-sleep deficiencies in years past that had become resolved. The researchers stated emphatically: “Our results suggest that RBD is very frequent in the early stages of PD.”
In addition, the “non-tremor motor sub-type” of Parkinson’s patients was associated with a past history of REM-sleep disorder. Those outside of this sub type – the tremor motor sub-type – were more likely to have current REM-sleep disorder, instead of a past REM disorder. In other words, those who slept better did not have as bad a tremors as those who had a REM-stage sleep disorder.
Other research has connected Parkinson’s disease to REM-sleep disorders that had been occurring for over fifteen years. In one study from Mayo Clinic researchers (Claassen et al. 2010), 27 patients who had suffered from REM-sleep deficiency for over 15 years, 63% of the patients eventually developed dementia, 74% developed autonomic motor dysfunction, and 13 (48%) developed Parkinson’s disease.
The extremely interesting thing is that during REM-sleep, a Parkinson’s patient will often not have any of the Parkinson’s symptoms they have when they are awake. They will suddenly begin to talk and move without the characteristic motor tremors (Arnulf 2010). This illustrates the connection between motor skills and REM sleep, and hints at the reason a person who is not getting enough REM-sleep might develop Parkinson’s.
Those with REM sleep behavior disorder (or RBD) will often act out their REM-dreams with violent movements and motions (Trotti 2010). This illustrates that the normal, almost catatonic state during which REM-sleep occurs for most of us is replaced by violent movements during REM sleeping.
REM-sleep is critically connected with dopamine availability. A lack of REM-sleep over time will significantly depress dopamine levels. Dopamine works within our brain to help regulate motor function. When we don’t get enough REM-sleep, dopamine receptors and dopamine synthesis are both affected. The result is a lack of smooth motor movement. This in turn begins to disrupt REM sleep further, as rapid eye movement is synchronized by dopamine. As REM-sleep becomes disrupted in RBD, the risk of further dopamine-related problems and motor problems increases over time.
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