Study shows that patients with DLB have reduced sleep efficiency and RBD.

REM in sleep medicine stands for Rapid Eye Movement. REM sleep behaviour disorder (RBD) is a disorder that is characterised by abnormal muscle tone, which results in a troublesome release. The release can be an enactment of, particularly unpleasant, altered, and hostile dreams.

The aggressive nature of the movements in sleep can be violent, risky, or even life-threatening. RBD occurs naturally in mammals and birds. Pontine lesions can also cause it; lesions are an injury on the pons part of the brain. The wounds can be due to tumour, ulcer, or disease.

There are two forms of RBD, acute and chronic. Acute RBD starts as a result of drug and alcohol abuse, medical toxicity, or drug withdrawal. A patient who has no neurological disease but has a REM sleep behaviour gets an Idiopathic RBD diagnosis. Idiopathic RBD is male predominant and chronically progressive.

Currently, studies have been done trying to link the connection between Dementia with Lewy Body (DLB) and REM sleep behaviour disorder. DLB is the second most common type of dementia that is caused as a result of protein deposit in the nerve cells of the brain. The nerve cells are responsible for memory, thinking, and motor control.

The Study

A study of the relationship between RBD and other sleep disorders in DLB was done on patients with mild dementia signs. Patients with isolated RBD incidents seen on video polysomnography, moderate to severe dementia were not selected for the study. The patients chosen for the study had to be on medication for at least a month.

First, neurologists carried out a thorough neurological test-taking information on the demographic location and current medication the patient was taking. The patients were then referred to the hospital, where they underwent further assessment on their sleep. The evaluation was completed with a questionnaire and video polysomnography.

A sleep-wake assessment was done on the patients complete with their bed partners. The observation covered the sleeping habits, which include sleep onset insomnia, snoring, waking up earlier than supposed to, recalling unpleasant dreams, and vocalisations in sleep. The characteristic of the sleep pattern of every patient was rated, and those with a score of above 5 had impaired sleep.

The level of sleepiness during the day was also tested using the Epworth Sleepiness Scale. The test is administered as a questionnaire and the patients how likely he is to dose off during different situations in the day. Patients with a score of 10 and above were considered to be excessively sleepy.

An audio-visual polysomnography test was also done in the study. Any changes in the patient’s respiration and motor activity were recorded. The recording processes included:

• Encephalography- checking the brain’s electrical activity non-invasively using electrodes placed on the scalp
• Electrooculography- is a technique of measuring the potential difference between the cornea and retina which is used in recording movements of the eye
• Electrocardiography (ECG)- is a technique of measuring the electrical activity of the heart by electrodes placed on the skin
• Electromyography (EMG- is checking on the electrical activity of the muscle tissues by using electrodes attached on the skin surface or inserted in the muscle
• Nasal and oral thermistor, and an oximeter- used to check on changes in respiration

The results

35 patients, including 23 men and 12 women between 61 and 92 years old were selected for the test.  The data collected from the tests were represented as percentage, mean, frequency, and standard deviation. When recording the motor activity and respiration, a difference between the values on the EMG during REM sleep and the occipital rate while awake. RBD diagnosis was made by checking the positive predictive value and negative predictive value.

During the test, one patient was noted to be picking things from the air after the lights were turned off for the video-polysomnography. The patient’s EEG showed the same activity as during wakefulness but with closed eyes. The video-polysomnography indicated RBD.

The study helped in establishing a clear picture of what REM sleep is like in DLB and the presence of RBD in some patients. It was clear from the research that patients with DLB have reduced sleep efficiency and RBD.

Final words

For the diagnosis of RBD, a video-polysomnography is essential. The sad thing is that only a small number of patients seek professional help for their sleep disorders. We must understand sleep disorder to avoid any injuries or accidents while asleep.