My Science School

Somnambulism is a psychiatric sleep disorder termed under ‘parasomnia’. Parasomnia, a disorder of transition from one sleep stage to another (arousal or partial arousal) can be marked by bizarre or sensual behaviour. Sleep is basically defined as that stage of unconsciousness from which the person can be aroused by sensory stimuli. Sleep can be broadly classified into two types, the slow wave sleep (Non-REM) and the Rapid Eye Movement (REM).  Normally the sleep that one gets is of the slow wave type. This is the deep restful type of sleep experienced in the first hour of sleep, in which the consolidation of the dreams in memory does not occur.

However a normal night of sleep, bouts of REM sleep lasting 15-30 minutes usually appear on the average of every 90 minutes, the first such period occurring 80-100 minutes after the person falls asleep. It is usually associated with active dreaming.

 The brain is highly active in REM sleep. Despite the extreme inhibition of the peripheral muscles, a few irregular muscle movements’ in particular rapid movements of the eye occur.

In the case of Non-REM sleep, the brain waves are very slow. But in the REM type of sleep the eyes undergo rapid eye movements despite the fact that the person is still asleep.

Sleepwalking, somnambulism, is the disorder of the non REM stage of sleep. It is the automatic execution of a sequence of complex behaviours that may include dressing, eating or bathroom visits as well as walking while asleep. It is a fairly common occurrence in childhood and adolescence, but may signify psychological disturbances in adulthood. The frequent episodes of which, more often experienced of which more often experienced by boys has its onset typically between 6-12 years of age.

Sleepwalking usually disappears after adolescence, but many reappear in the 3rd or 4th decade. There seems to be a heredito familial trend. The disorder has been associated with epilepsy, CNS infections and traumas, genito urinary complaints, psychopathology, sleep talking, nocturnal eneuresis and nightmares.

The treatments include besides other things education and appropriate sleep habits, avoiding sleep deprivation and compensatory slow wave sleep rebound by providing guidelines for a regular sleep wake schedule, taking day time naps to decrease pressure for slow wave sleep at night, use of hypnosis and benzodiazepine family of medications in some cases, providing safe environments for sleep and psychotherapy and non REM suppressing psychotropic medications.

      In fact in one review, psychotherapy was recommended to a carefully selected subgroup of patients, only one-third of group were willing to try it. However, of those patients who began psychotherapy 75 per cent rated it as beneficial.