Sleep and Be Well

Mysteries of the slumbering psyche.

The Tigers Come at Night

REM sleep behavior disorder

Patients sometimes have symptoms that are so distressing that they are afraid to discuss them. They are ashamed or are afraid that they will be labeled as crazy. They are sitting in front of you, but they are holding something back. Sometimes a single question breaks down the defensive barrier and the story comes pouring out.

Figure caption: Dream Caused by the Flight of a Bee Around a Pomegranate a Second Before Awakening (Salvador Dali, 1944).
But the tigers come at night,

With their voices soft as thunder,

As they tear your hope apart,

As they turn your dream to shame.

From I Dreamed a Dream, Les Misérables, ©. 1985 Alain Boublil Music, Cameron Mackintosh Producer

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Attacked by Tigers

The patient in front of me was a 35-year-old nurse who was referred for sleepwalking. Her history was typical of many sleepwalking patients. She started to wander in her sleep at age 4 or 5. She did not remember having had the episodes; she was told by family members that she had wandered around the house. She had many such episodes the next few years, but shortly after age of 10 the episodes seemed to disappear.

At about age 20 sleepwalking returned. She was at university. Maybe it was the late nights. Maybe it was the lack of sleep. Maybe it was the night shifts. Sleepwalking had returned with a vengeance. The episodes occurred from once a month to several nights a week. They seemed related to stress. Sometimes she would awaken on her own during an episode. Sometimes others would awaken her. Sometimes she would be told the next day that she had wandered. Sometimes she would notice the next morning that she must have sleepwalked. Food had been eaten in the kitchen. Clothes had been placed in the laundry hamper. She never remembered anything. Although this was embarrassing for her, it did not bother her a great deal. The sleepwalking seemed a source of humor for others.

Then about the age of 30, she told me that the sleepwalking had become much more severe. The episodes happened every night. She was in my office because she wanted a medication to get rid of the sleepwalking. She was now afraid to go to sleep. Her family doctor didn't know what to do.

Sometimes a clinician can tell that they are not hearing the whole story. This was one of these moments. She was avoiding my eyes. Why was she here today when she had been sleepwalking for much of her life and very frequently the last 15 years?

Then came the question. I asked in a very matter of fact way, as though I ask every patient: "Are you dreaming you are being attacked by animals and do you fight back?"

Her eyes widened. She stared straight at me and answered, "Yes, how did you know?" She must have thought I was telepathic.

It was not telepathy.  It was because I thought that this was no longer sleepwalking. I thought that is was now an entirely different problem, REM sleep behavior disorder, a condition in which people react physically to what they are dreaming, and in my experience, most often they are reacting to animals. She then told me that her now nightly dream was that she was being attacked by tigers and that she sometimes tried to run away from them and sometimes tried to fight them off. People observing her would note that she would moan sometimes kick and punch out, and when she awoke, she appeared frightened and sometimes was sweating.

Soccer Dream

A 67-year-old attorney relayed a dream he had that he was a soccer goalie and he lunged to stop a shot from the other team. The next thing he recalled was awakening on the floor, next to a wall with a splitting headache. In his sleep he had leaped out of bed and his head struck a wall. He had symptoms of grogginess and headache for about three weeks. He had suffered a concussion. These acting out dreams occurred infrequently.

What patients with RBD dream about.
What is REM Sleep Behavior Disorder?

Rapid eye movement (REM) sleep was described for the first in 1953. The characteristics of this state include vivid dream imagery and atonia, the latter term meaning loss of muscle tone, or paralysis. There is paralysis during REM so that one could not physically respond to the content of dreams. Starting in 1965 a series of experiments in cats showed that lesions to certain parts of the central nervous system could cause “REM without atonia.” In other words the system maintaining paralysis during REM not longer worked. Such cats would react physically to dreams and would, for example, at times demonstrate walking or attacking behavior. “ . . . cats with such lesions would slowly raise their heads, move their limbs at all joints, make several attempts to rise and eventually leap violently.”

Scientists predicted that this condition might exist in humans and indeed was described in 1986.

Causes

We have learned a great deal about what may cause this condition (for more detail see page 216-221 of the just published 2nd edition of Atlas of Clinical Sleep Medicine). In some cases there is no explanation, but in many cases the disease is associated with damage to parts of the central nervous system (example is multiple sclerosis), the accumulation of abnormal molecules in the nervous system (examples include amyloid in Alzheimer disease and alpha-synuclein in Parkinson disease, but there are several other neurodegenerative diseases ). In some cases the condition is related to medications (examples include antidepressants).

What do people with RBD dream about?

Almost 90% of the dreams of patients with this condition are violent. They dream they are being attacked by people they usually don’t know and whose faces may be indistinct or absent. In about a third the dreams involve being attacked by animals, such as tigers, panthers, wolves, dogs, and bears. Most of the time the patient has never had the type of experience they are dreaming about. The patients usually remember the dreams when they awaken.

How do they respond to the dreams?

A vast array of behaviors may be observed. These can injure the patient or the bed partner. These include screaming, singing, punching, kicking, jumping and running. I have had patients who tried to choke their bed partners.

How are patients treated?

Such patients are best referred to a sleep specialist to confirm the diagnosis (which often requires an overnight sleep test) and to start treatment and follow the outcome of treatment. The first patient was started on a small dose of clonazepam and the number and severity of the episodes decreased dramatically. She occasionally still had the terrible dream, but she was quite satisfied with the outcome. The second patient was reassured because the episodes were so rare. Some cases are challenging and do not respond well to treatment. It is indeed gratifying to hear that the patient is no longer being attacked by animals in their dreams.

Readings

Henley K, Morrison AR. A re-evaluation of the effects of lesions of the pontine tegmentum and locus coeruleus on phenomena of paradoxical sleep in the cat. Acta Neurobiol Exp (Wars). 1974;34(2):215-32.

Schenck CH, Bundlie SR, Patterson AL, Mahowald MW. Rapid eye movement sleep behavior disorder. A treatable parasomnia affecting older adults. JAMA. 1987;

3;257(13):1786-9.

Kryger M, Avidan A, Berry R. Atlas of Clinical Sleep Medicine. 2nd Edition. Elsevier, Philadelphia. 2014. Page216 to 221.

Meir H. Kryger, M.D., is a professor of Medicine at the Yale School of Medicine and editor of Principles and Practice of Sleep Medicine, 5th Edition, and Kryger’s Sleep Medicine Review.

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