Psychobiology and Pathologies of Human Sleep

Abstract

This review is principally devoted to major sleep pathologies which pose exemplary problems for cardiology, neurology, psychiatry, physiology, internal, and pulmonary medicine. Fundamental information about the psychobiology and biorhythmic aspects of normal nocturnal slumber is presented and related to polygraphic findings on sleep pathology. Clinically significant increases in blood pressure, respiratory rate, cardiac irregularities and gastric acid secretion all occur in phase with the nocturnal sleep cycle. Exacerbations of duodenal ulcer and coronary-artery disease including cardiac arrhythmias at night have all been shown to coincide with REM sleep. Stereotyped abnormal leg movements associated with nocturnal myoclonus are due to activity of anterior tibialis or quadriceps muscles and occur episodically during the entire sleep period especially in the NREM-stages. Sleepiness has frequently been observed to accompany hypothyroidism and stages 3-4 are drastically reduced. The major symptoms of narcaolepsy are excessive daytime sleepiness and cataplexy. Drugs which suppress REM sleep such as monamine oxidase inhibitors and tricyclic antidepressants are effective in treating cataplexy. Central nervous system stimulants, particularly methylphenidate, are are recommended as the optimal treatment for controlling narcoleptic sleep attacks. The major treatment of upper airway sleep apnea is currently surgical. Successful therapy has been achieved in the central sleep apnea syndrome with imipramine and chlorimipramine. Although both respiratory problems disturb sleep about equally, central apnea leads to insomnia, while upper airway apnea is accompanied by hypersomnia. When tracheostomy is indicated it reduces the central apnea and obstructive apneic episodes during sleep. Polygraphic recording of human sleep has yielded extensive information about the nocturnal perturbations associated with clinical conditions characterized by physiological disregulation. The continued application of polysomnography possesses considerable promise for progress in diagnosis and treatment of those pathological states which lead to sleep continuity disturbances or are exacerbated by sleep itself. Attention to naturally occurring circadian and ultradian variations in the sleep-wakefulness rhythm would appear mandatory for comprehensive assessment and effective alleviation of impaired functioning related to temporal disruptions.