Holzer B

Application of the multiple sleep latency test in disorders of excessive sleepiness

Multiple sleep latency tests were performed in 42 drug-free outpatients with excessive sleepiness: 12 narcoleptics, 9 sleep apneics, 7 primary depressives, and 14 patients with miscellaneous disorders. Among-group comparisons were made by one-way ANOVA for each nap (time-of-day effect) and using four-nap means of EEG sleep variables. Four-nap means were significantly different among groups for percent awake, percent time spent asleep, stage 1 latency, and REM latency. Of 22 significant pairwise comparisons (P less than 0.05, LSD test), 77.3% occurred at 12.00 and 14.00. Depressives showed lower sleep percentage (more arousal) and fell asleep later than narcoleptics or apneics. Patients with miscellaneous disorders occupied a middle position. Sleep percentage was gradually reduced during the day in depressives but remained high or rose further in apneics, narcoleptics, and miscellaneous patients. Naps were SOREMP-positive (sleep onset REM) 60.4% of the time in narcoleptics, 25.0% in apneics, 3.5% in depressives, and 5.4% in miscellaneous patients. SOREMP distribution across naps (10.00, 12.00, 14.00 and 16.00) was 19%, 31%, 19% and 31%, respectively. REM latency was significantly shorter in narcolepsy than in apnea. In summary, results show a continuum of excessive daytime sleepiness (EDS), demonstrating MSLT application in the differential diagnosis of EDS and significant diurnal variation in sleep measures.

REM sleep, naps, and depression

Continued interest in rapid eye movement (REM) sleep abnormalities in depression stimulated comparative studies on daytime naps versus nighttime sleep. In a group of 15 depressed patients, REM latencies in morning and afternoon naps were similar to the shortened REM onset at night. Although REM latency did not vary across the three times, the propensity for REM sleep appeared to be greater in the morning nap than in the afternoon nap and the early portion of nocturnal sleep. Finally, the data suggest that responders to tricyclic treatment tend to be poor sleepers during daytime naps.

Prevalence of sleep apnea and nocturnal myoclonus in major affective disorders: clinical and polysomnographic findings.

We performed screening polysomnography on 86 inpatients with affective disorders and found that 13 (15.1 per cent) had sleep apnea and one had nocturnal myoclonus. The apnea tended to be extremely mild, with an average of 27.8 episodes per patient and with a mean duration of 15.0 seconds. No clinically significant cardiac arrhythmia accompanied the apnea. The apnea was predominantly obstructive or mixed, not central. Only four patients (4.7 per cent) had apnea indices greater than five, and even here the total apnea was considered mild. Much of the apnea (68.3 per cent) occurred during rapid eye movement sleep. While there was no association of apnea with gender or with type of sleep-wake complaint, a significant relationship with age emerged. On the basis of these data, we suggest that routine polysomnographic screening for sleep apnea and nocturnal myoclonus in affective disorders is not indicated. On occasion, however, both an affective disorder and a sleep-apnea syndrome co-exist in the same patient. In such cases, the sleep-wake complaint is usually very prominent and/or long-standing in relation to other psychopathology and requires appropriate polysomnographic evaluation.

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 < 0.05) than in patients with a persistent psychophysiologic disturbance. The percentage of REM sleep was significantly elevated (p < 0.05) in the depressed group, and intermittent wakefulness was decreased (p < 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.

EEG sleep alterations in olivopontocerebellar degeneration

All-night polygraphic recordings of the electroencephalogram, horizontal electrooculogram, and submental electromyogram were performed in two patients with familial olivopontocerebellar degeneration. Sleep was characterized by subnormal measurements of both rapid eye movement (REM) and delta (slow-wave) sleep. Phasic eye movements were reduced out of proportion to tonic components of REM sleep. These findings lend further support to theories linking the pontine nuclei to the primary regulation of sleep in both experimental animals and humans.

MHPG excretion and EEG sleep in primary depression

Measures of daily urinary 3-methoxy-4-hydroxyphenylglycol (MHPG) excretion and electroencephalographic (EEG) sleep data were examined in 30 patients hospitalized for depression. This sample (mean age = 35 years) comprised 17 females and 13 males, all of whom were drug-free for 2 weeks and met Research Diagnostic Criteria for primary depressive disorder. Data analyses were conducted on the entire group, as well as the male, female, unipolar, and recurrent subgroups. No significant relationships were observed between total MHPG excretion and rapid eye movement (REM) or non-REM sleep variables. In particular, the absence of an interrelatedness of MHPG and REM sleep fails to confirm earlier findings in a smaller patient sample. These results, therefore, raise new questions about the proposed role of central noradrenergic activity in the mediation of REM sleep in depression.

MAO activity and EEG sleep in primary depression

Platelet monoamine oxidase (MAO) activity and electroencephalographic (EEG) sleep measures were examined in 56 drug-free hospitalized patients with primary depression as defined by the Research Diagnostic Criteria. The group included 35 females and 21 males with a mean age of 42.6 +/- 1.4 years. Platelet MAO and EEG sleep data were compared for the group as a whole and separately for the unipolar, bipolar, male, and female subgroups. No significant relationships could be demonstrated for the entire group or for the unipolar, male, or female subgroups. However, an inverse relationship between MAO activity and REM sleep percent was noted in the bipolar subgroup (p < 0.02). While changes in REM sleep have been relatively firmly established in primary depression, the relationship of MAO to depression and to REM sleep remains unclear.

EEG SLEEP AND AFFECTIVE DISORDERS: WHAT CAN IT PREDICT?

Our current studies on patients with primary depression have established that early EEG sleep changes on amitriptyline are highly correlated with the final clinical response four weeks after initial drug administration. These immediate changes which include rapid REM suppression (43%) and prolongation of REM latency (187%) suggest an initial alteration in multitransmitter levels which may relate to eventual clinical change. Since catecholaminergic and cholinergic neurons have been implicated in the control and intensity of REM sleep, a more active search for REM sleep-tricyclic drug mechanisms is warranted.