Parkinson’s disease manifests in many ways above and beyond the more commonly known motor symptoms. Estimated to occur in close to 80% of all patients with this illness, are sleep disorders which range from insomnia to frequent awakenings, all adding to the fatigue that also is part of this disease. One type of sleep disorder experienced by some Parkinson’s patients is rapid eye movement (REM) sleep behavior disorder (RBD).
Not that RBD only occurs in Parkinson’s disease. It can commonly occur during withdrawal from alcohol or certain anti-depressant or hypnotic drugs. In other cases it is associated with a number of neurologic conditions including Parkinson’s disease, multi-system atrophy and Lewy body dementia. It is not known with certainty the exact number of patients with Parkinson’s that suffer from RBD but patient reports indicate this behavior in 25% of those surveyed. This number increases to almost 50% when patients are objectively observed while undergoing sleep studies.
REM behavior disorder occurs as its name implies, during REM sleep, which cycles at 90 to 120 minute increments to the time of wakening in the morning. In normal REM sleep, there is rapid eye movement, blood pressure rises and breathing becomes more irregular. Our brain is also highly active and it is in this stage of sleep that we dream. In unaffected individuals there is also a loss of tone in the body’s muscles and essentially we become paralyzed. However in RBD, the muscles remain fully or partially active, allowing patients that are affected to actually move.
Typically RBD presents as dramatic, often violent motor activity and vocalizations during sleep. These behaviors include punching, kicking, jumping, grabbing, talking, yelling, even getting out of bed and can be potentially injurious to both the patient and their bed partner. The activity that occurs can usually be correlated to the dream that is recounted upon waking – in other words, patients are “acting out their dreams”. The subject matter is usually in stark contrast to their normal behaviors or tendencies.
Although this sleep disorder can be found in any age group or gender, it is much more common in older individuals (above the age of 50 years) and in men (80-90%). In some cases the behavior develops slowly, sometimes over a period of several years. It may begin as talking or limb jerking and then with time accelerates to the clinical RBD syndrome. Some patients have a history of childhood night terrors or sleepwalking.
There are a number of other conditions that can be mistaken for RBD including sleep terrors or sleep walking as well as some psychiatric issues like post-traumatic stress disorder and panic attacks or other diseases such as seizures, sleep apnea or periodic limb movement disorder. There are also many different types of sleep disorders in Parkinson’s disease. It is therefore difficult to diagnose RBD by patient history alone. Reports from family or the bed partner are particularly helpful but in order to truly diagnose RBD, you have to undergo polysomnographic (PSG) recording also known as a type of sleep study. While you sleep in a lab setting, many different body functions are measured - brain activity, eye movement, heart rate and rhythm, breathing rate and rhythm along with levels of oxygen and carbon dioxide, snoring, and body muscle movement. Once the specific criteria is met, a diagnosis of RBD can be given.
The specific DSM-5(Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition) criteria for rapid eye movement sleep behavior disorder are as follows[37] :
• Recurrent episodes of arousal during sleep associated with vocalization and/or complex motor behaviors that arise during rapid eye movement (REM) sleep
• On waking from these episodes, the individual is not confused or disoriented and is completely alert
• Either of the following is present: REM sleep without atonia on polysomnographic recordings; or a history suggestive of REM sleep behavior disorder and an established synucleinopathy diagnosis (e.g., Parkinson’s disease, multiple system atrophy)
• The episodes cause significant distress or impairment in social, occupational or other areas of functioning which may include serious injury to self or the bed partner
• The disturbance cannot be explained by the effects of a drug of abuse or medication
The episodes cannot be attributed to another mental disorder or medical condition.
So if you or a loved one are experiencing this type of disruption in your sleep cycle, it is important that you seek medical advice, proper evaluation and symptom management to not only improve your sleep quality but also to protect yourself and the safety of your bed partner.