Somnambulism

Fumiko Konno

One of the interesting sleep disorder is sleep walking. The medical, or more scientific, term for sleep walking is somnambulism. The characteristic symptoms are walking or exhibiting other activities while seemingly still asleep. (1) I became interested in researching this topic, because I sleep walk. I sleep walk only when I am under stress, which is not often. However, it is one of my primary concerns because I exhibit an extremely violent behavior. I began my research by looking for the relationship between somnambulism and the brain. I found that they are related, but the details are still under research. Then, I looked for the cause, however, since the detailed mechanism of the brain during sleep walking is not defined, a specific cause and effect was also not clearly defined. Thus, this paper will include the information that the researchers have obtained so far, the type of experiments that have been done, and the problems in obtaining more information about somnambulism.

The term somnambulism comes from the Latin words for sleep (somnus) and walking (ambulus). A typical sleepwalking episode is rather short. Sleepwalkers may simply appear awake, or exhibit complicated activity such as driving a car, while asleep. (2)

The researchers have been using a device called the Electroencephalogram (EEG) to understand sleep and sleep disorders. This device measures the electromagnetic waves that are emitted from the brain at various locations around the head. These waves are amplified and fed to a plotter, which plots the amplitude of the waves over time. This device identified four stages of sleep.(3)

The first sleep state, before the four stages, is pre-sleep. The EEG reading of an active and awake person shows mainly beta waves, which are low-amplitude, high frequency waves. Beta waves are associated with conscious thought. As a person begins to fall asleep, the EEG reading becomes punctuated with alpha waves, which are regular waves of higher amplitude. Alpha waves are associated with a relaxed mind. The first stage of sleep shows similar beta waves as the first sleep state, except at a lower frequency. As time progresses within stage 1, there is a gradual lowering of frequency and simultaneous increase of amplitude. The second stage of sleep show two characteristic waves. K-complexes consist of a single large amplitude wave, and Sleep spindles are 1-2 second bursts of very high frequency irregular waves. The third stage shows infrequent intrusion of delta waves, which have high amplitude and a low frequency. During the fourth stage, the delta waves predominates. These stages last about 90 minutes in total. Stages 3 and 2 occurs quickly before the entire cycle repeats with one exception. The first stage is accompanied by Rapid Eye Movement (REM).(3)

REM sleep is usually accompanied by vivid dreaming. Sleep walking occurs during stages 3 and 4, the deepest state of sleep. This observation lead to the conclusion that the sleepwalkers are not acting out their dreams. (4) The precise dysfunctional mechanism of the brain and the cause of somnambulism are not determined. First of all, to design a testable model is difficult. The second reason is that the use of EEG biofeedback has been restricted largely to drug-refractory cases of epilepsy. However, it has been used to investigate various neurological conditions such as hyperactivity, attention deficit disorder, and specific learning disabilities. Recently, EEG biofeedback's clinical application has broadened to include sleep disorders.(5) The research studies of the above disorders by EEG biofeedback have identified a 12-14Hz rhythm in the EEG, observed over the Rolandic(sensorimotor) cortex. It is associated with the inhibition of the motor activity, and was labeled as the SensoriMotor Rhythm (SMR). One treatment that is used on patients with sleep disorders enhances the SMR rhythm by means of biofeedback training. This results in a more normal and peaceful sleep. Patients with hyperactivity disorders also sleep walk. Treating these patients with the biofeedback training also reduces sleep walking. Hence, there might be a correlation between the mechanism of these two disorders. In the case of hyperactivity, the observable anomaly generally consists of an excessive low-frequency activity with insufficient beta activity. This activity is related to arousal.(5) Sleep walking can also be defined as the arousal during a deep sleep. If so, then the brain waves of the sleep walking state must be the same as the characteristic brain waves shown by the hyperactive patient. Various possible causes of somnambulism are known, however, none are definite. For example, stress and anxiety can cause sleep walking, however, the precise mechanism in which these two affect our bodies are not known. I think that to further study or research the dysfunctional mechanism of somnambulism, one must also consider the psychological aspect along with the brain. During my investigation on this topic, I had tremendous difficulty in finding any resources specifically about somnambulism. Also, many of the information that I have found were very indecisive and not definitive. Thus, I could not satisfy my original goal in finding the cause and the mechanism of this disorder. This is definitely a topic, which I would like to keep investigating.

1. http://www.healthanswers.com/database/ami/converted/000808. html

2. http://www.ail.org/Media/Dreams/VisualDreams/disorders/walking.html

3. http://web.mit.edu/ravir/OldFiles/Public/Academic/Sleep2

4. http://www.vnh.org/GMO/ClinicalSection/105Somnambulism.html

5. http://www.primenet.com/~thielbl/na_sig1.html

Comments made prior to 2007

Concerning Somnabulism, I've just read this article and am considering the stress angle. In a an episode where I had significant emotinal trauma both cortex regions were receiving signals from the temporal reigion in a memory recall instance whereupon each side was receiving entirely separate but related signals. The signals were of a nature as to trigger lower brain functions involving primal instict. These forebrain functions are in close proximity to the parietal reigion which involves spatial perception. In regards to this it was not neccary for occipital visual discrimination to work in order for sumnabulism. Usually at work in tandem with the parietal, during low frequency reflexive temporal transmission, visual reality is secondary to a type of sonar. I found that visuals were percieved only during brief encounters with objects ... BIT, 15 August 2006