REM Sleep Behavior Disorder

One of the amazing things about being human is that we all dream. Dreams occur in the Rapid Eye Movement (REM) stage of sleep. Dreams can take us to worlds unknown, or give us the opportunity to be the world class athlete we always aspired to. However, what would it be like if we acted out some of our dreams? In a small percentage of humans this is a reality due to a condition called REM Sleep Behavior Disorder, or RBD for short.

There are three main aspects of RBD. The first is an alteration of how we have and remember dreams.  Persons suffering from RBD will have very vivid dreams that are at times violent in nature.  These dreams will be remembered for weeks or even months, whereas most people forget dreams within minutes of waking up.  The second is abnormal vocalizations.  These vocalizations can include yelling, screaming, and even full purposeful conversations.  After awakening, patient will often give descriptions of dreams that coincide with what they were saying in their sleep.  The final aspect of RBD is the abnormal movements during sleep.  Most of us do not move during sleep because our brains have a “switch” that temporarily turns off our motor cortex during REM sleep, inducing a partial paralysis.  This is what keeps us from acting out that touchdown dance or big fight we have going on in our dreams.  However, in RBD that “switch” does not work properly and persons will act out certain parts of their dreams, often times in great detail.  These include hitting and kicking motions during sleep when they are dreaming of defending themselves from enemies.

The prevalence of RBD is estimated between 0.38% and 0.5% of the population.  It occurs more often in males and has an average age of onset between 50 to 70 years.  One of the important aspects of RBD is the correlation with future neurodegenerative disorders.  Following a diagnosis of RBD, 38-65% of patients will develop a neurodegenerative disorder within 7-13 years.  The large majority of these will be diagnosed with a dementia, particularly one of the synucleinopathies such as Lewy Body dementia, Parkinson Disease, or Multi-System Atrophy.  One theory that has been proposed is that RBD represents the earliest manifestation of an ascending synucleinopathy that produces additional symptoms as the disease process moves upward in the CNS.

Interestingly enough, medications that are commonly used to treat depression have been linked to developing RBD. These medications are in the classes of selective serotonin receptor inhibitors, tricyclic antidepressants, and serotonin norepinephrine uptake inhibitors.  All of these medications have action at serotonin which has led to the hypothesis that serotonin either plays a part in the pathological process of RBD or it unmasks RBD that was destined to occur at a later date.

Treatment

The goal in treatment of RBD is to minimize danger to the patient and bed partners. The first interventions include decreasing risk by altering the environment. These include:

• Moving sharp objects
• Reorganizing bedroom furniture to decrease the chance of falls
• Placing a mattress or cushion next to the bed
• Using a protective barrier on the side of the bed to decrease risk of falling out of bed
• Using a barrier to separate the patient from the bed partner

Medication interventions are also warranted for the safety of patients and their partners. The most commonly recommended medications in RBD are melatonin and clonazepam.   A trial of clonazepam for patients that do not have medical contraindications is often tried first.  For those that cannot tolerate clonazepam or continue to have symptoms, a trial of melatonin is warranted.  Other medications that have been used to treat RBD include donepezil, rivastigmine, pramipexole, sodium oxybate, and levodopa.

While much is left to understand about RBD it is important to recognize as a clinical syndrome in order to protect patients and their bed partners. A full understanding of what causes RBD and its implications in the development of future neurodegenerative disorder is still under investigation.

Nathan E. Bruce, D.O.

Excerpted article as reprinted from IPA’s newsletter, the IPA Bulletin, Volume 31, Number 3