Disorders Of Excessive Somnolence Research Articles

HLA-DR2 and Dw2 in narcolepsy and in other disorders of excessive somnolence without cataplexy.

Studies on HLA antigens were conducted in several patient populations with the following findings: (a) All 135 Japanese narcoleptic patients, eight of whom were considered to have "symptomatic" narcolepsy, were found to be HLA-DR2 and HLA-DQw1 positive. All 17 members of a subgroup of the original population were also found to be HLA-Dw2-positive. It was concluded that HLA-DR2 is a prerequisite for the development of narcolepsy and that the diagnosis of narcolepsy can be excluded if HLA-DR2 or HLA-Dw2 is negative. The distinction between idiopathic and symptomatic narcolepsy needs to be reconsidered. (b) Haplotype studies in three families with narcoleptic members enabled detection of children at high risk for narcolepsy. (c) Of the 54 patients with disorders of excessive daytime sleepiness other than narcolepsy, those with essential hypersomnia (EHS) had a higher frequency of HLA-DR2; the others had a lower frequency. The DR2-positive EHS group could include members with an incomplete form of narcolepsy; the DR2-negative EHS group had disorders essentially different from narcolepsy, although both positive and negative groups manifested hypnagogic hallucinations, sleep paralysis, and sleep onset REMs. Two further studies were conducted in subgroups of the original narcoleptic population studied. In a subgroup of 30 patients who underwent lymphocyte subset studies, no T-cell abnormalities were detected; it is unlikely that an autoimmune mechanism is involved in the development of narcolepsy. In a subgroup of 33 narcoleptic patients, Southern's blot analysis of DNA using a DQ beta probe revealed three specific restriction fragments. Further studies are necessary to locate the DNA locus that carries the susceptibility gene for narcolepsy.

Absence spells: Hyperventilation syndrome as a previously unrecognized cause

Absence spells in adults have been recognized in association with disorders of excessive somnolence, transient ischemia of the temporal lobes, and seizure disorders. A 66-year-old man who presented with a history of absence spells for more than 20 years is described. After diagnosis of a hyperventilation syndrome without an associated seizure disorder, educational and behavioral therapy without the use of medication has produced a long, continuing remission of these spells. The hyperventilation syndrome continues to present in many ways, often without recognition by physicians for prolonged periods. The case presented exemplifies this problem and may be the first report of absence spells caused by hyperventilation.

Flow-volume curves reflect pharyngeal airway abnormalities in sleep apnea syndrome.

Twenty-nine patients with disorders of excessive somnolence were evaluated with standard nocturnal polysomnography, fiberoptic laryngoscopy, and flow-volume curves. Twenty-two had evidence of obstructive sleep apnea (OSA) by polysomnography and most had abnormal flow-volume curves, supporting earlier observations. Three of 7 patients without obstructive sleep apnea also had abnormal curves. Fiberoptic nasopharyngoscopy was performed in the OSA group while awake to evaluate the upper airway. Sixteen patients of the OSA group demonstrated pharyngeal obstruction; 14 of those with visualized airway obstruction had flow-volume abnormalities. In the 6 patients of the OSA group with no significant visual obstruction, 5 had normal curves. The flow-volume curve appears to correlate with direct visual assessment of upper airway patency during wakefulness in those patients demonstrating obstruction during sleep.

Sleep and its disorders.

The advances in research on sleep an biological rhythms have recently been applied to the diagnosis and treatment of sleep disorders. A new clinical specialty has developed with the establishment of sleep disorder centers and a diagnostic classification of sleep and arousal disorders. This new nosological approach has evolved from an extensive base of new scientific information concerning descriptive polygraphic and analysis of clinical case series. Four major categories have been defined: (a) disorders of initiating and maintaining sleep (insomnias), (b) disorders of excessive somnolence, (c) disorders of the sleep-wake schedule, and (d) dysfunctions associated with sleep. Within this comprehensive classification certain major pathophysiological advances are described for the "insomnias." These include polysomnographic identification of altered sleep stage patterns in the major effective illnesses, insomnias related to hypnotic drugs and alcohol, sleep disturbances associated with sleep-induced respiratory impairment, and sleep-related periodic movements during sleep (nocturnal myoclonus). Excessive daytime somnolence is primarily associated with the hypersomnia sleep-apnea syndrome and with narcolepsy. The relationship between biological rhythms (chronobiology) and disorders of the human sleep-wake schedules is very actively investigated. The recognition that sleep length, internal organization, and timing within neurophysiological circadian time-keeping systems has lead to better diagnosis of these sleep-wake disorders and new chronotherapeutic regimens. Finally, increasing identification and description of "parasomnias," i.e. dysfunctions associated with sleep, has led sleep research into important new areas that are of general physiological interest. It is now clear that sleep disorders medicine has become a new scientific and clinical discipline in its own right.

Sleep disturbances in a series of elderly patients: polysomnographic findings.

A group of 27 elderly patients with complaints of either chronic insomnia or excessive daytime sleepiness were studied in the Sleep Evaluation Center of Western Psychiatric Institute and Clinic during the period January 1977-June 1979. On the basis of anamnestic data from patients and bedroom partners, together with polysomnographic findings, sleep disturbances were classified according to the nosology of the Association of Sleep Disorders Centers. Of the 27 patients, 19 had disorders of initiating or maintaining sleep (DIMS), 7 had disorders of excessive somnolence (DOES), and 1 had parasomnia (episodic nocturnal wandering). Of the 19 DIMS patients, two-thirds had either a primary affective disorder (depression) or a persistent psychophysiologic disturbance. Of the 7 DOES patients, 6 had a primary sleep disorder such as a sleep apnea syndrome or narcolepsy-cataplexy. Additional electroencephalographic sleep data are presented on elderly patients with primary nonpsychotic depression. The latency of rapid eye movements (REM) in the depressed patients was shorter (p less than 0.05) than in patients with a persistent psychophysiologic disturbance. The percentage of REM sleep was significantly elevated (p less than 0.05) in the depressed group, and intermittent wakefulness was decreased (p less than 0.01). The causes of sleep disturbance in the elderly are both heterogeneous and complex. The need for accurate differential diagnosis and a multiaxial approach is stressed.