Deborah E. Sewitch

EEG sleep in elderly depressed, demented, and healthy subjects

In a prospective study of EEG sleep patterns in 25 elderly depressives, 25 elderly demented patients, and 25 healthy, elderly control subjects, the sleep of depressives was characterized by reduced REM sleep latency, increased REM percent and first REM period density, and altered temporal distribution of REM sleep, as well as by diminished sleep maintenance (correlated significantly with Hamilton ratings of depression: multiple R = -0.42, p less than 0.05). In contrast, the sleep of demented patients showed reduced REM sleep percent, but normal REM temporal distribution, increased loss of spindles and K-complexes (the latter correlating significantly with severity of cognitive impairment as measured by the Folstein score: multiple R = -0.59, p less than 0.01), and less severe sleep maintenance difficulty than for depressives. An examination of REM latency demonstrated a skewed distribution in depression (i.e., 42% of nights with sleep-onset REM periods), but a normal distribution in the controls and demented subjects. A REM latency cut-off score of 30 min correctly classified 68% of all patients (kappa = 0.36; p less than 0.005), compared with 78% correctly identified in our retrospective study (Reynolds et al. 1983).

Two-Year Follow-Up of Elderly Patients With Mixed Depression and Dementia: Clinical and Electroencephalographic Sleep Findings

In a two‐year follow‐up of 16 patients with mixed symptoms of depression and dementia, eight showed clinical improvement and eight showed deterioration. Improvement at two‐year follow‐up was associated with several baseline measures: a Folstein Mini‐Mental State score of 21 or greater, a Hamilton Depression score of 21 or greater, and a sleep efficiency of less than 75%. These findings suggest that in the elderly with mixed symptoms of depression and dementia, a more favorable outcome is associated with initially greater depressive symptomatology, higher cognitive function, and moderate sleep continuity disturbance (“early morning awakening”).

Body temperature and sleep architecture in response to a mild cold stress in women

Six women participated in a seven consecutive night polygraphic sleep study during which both 24-hour rectal, body temperature and wrist activity were continuously sampled and stored at one-minute intervals. The study was designed to investigate the effects of a mild nocturnal cold stress on thermoregulation and sleep. On nights 4 and 5, subjects slept naked, without any bedcovers (mild cold stress) in a warm (26.7-28.3 degrees C) room. The daily mean rectal temperature and the daily nadir (low point) of the circadian temperature rhythm (CTR) showed a significant decrease between the baseline and cold stress conditions. The lowered nadir resulted in a significant amplitude increase in the daily CTR between the baseline and cold stress conditions. There were no significant changes in activity levels across experimental conditions. The ability to maintain a sleep state was significantly impaired during the cold stress. Stage 4 slow wave sleep increased, while Stage 3 decreased in response to the cold stress condition, and there was an associated lengthening of the first NREM period. These data suggest that challenges to the thermoregulatory system can be used as a vehicle to systematically alter sleep architecture in humans.

Elevated red blood cell/plasma choline ratio in dimentia of the Alzheimer type: Clinical and polysomnographic correlates

In a prospective study we have observed a shift in distribution of red blood cell (RBC)/plasma choline ratios among patients with probable dementia of the Alzheimer type (DAT), compared with healthy controls and depressed patients. Fifteen of 22 DAT patients (68%) showed RBC/plasma choline ratios greater than 1.9, in contrast to 9 of 26 healthy controls (35%) and 7 of 20 depressives (35%). These significant differences confirm and expand earlier observations. The subgroup of DAT patients with elevated RBC/plasma choline ratios is older and more cognitively impaired, shows later onset of dementia, and has less rapid eye movement (REM) sleep than the DAT subgroup with normal RBC/plasma choline ratios. Within the entire group of DAT patients, moreover, the RBC/plasma choline ratio shows a significant inverse correlation with REM sleep latency. These findings are discussed in relation to abnormalities in other nonneural Alzheimer tissues and within the context of cholinergic involvement in both DAT and the timing of REM sleep.

Multiple Sleep Latency Test findings in Kleine-Levin syndrome.

Multiple Sleep Latency Test (MSLT) findings in a case of Kleine-Levin syndrome are reported for the first time. MSLT data indicate sleepiness as severe as in narcolepsy or obstructive sleep apnea and the occurrence of four sleep onset rapid eye movement (REM) periods, with a greater REM propensity at 2:00 p.m. and 4:00 p.m. than at 10:00 a.m. and 12:00 noon. The replication of such findings might suggest that Kleine-Levin syndrome could be considered a form of periodic REM sleep disinhibition. Therefore, the traditional hypothesis of diencephalic dysfunction may require modification to include the role of more caudal brain stem structures specifically activated during REM sleep.

Exercise and Subsequent Sleep in Male Runners: Failure to Support the Slow Wave Sleep-Mood-Exercise Hypothesis

10 male joggers participated in a 3-week experimental protocol designed to look at the effects of three levels of energy expenditure (no exercise, regular exercise, and double exercise) on mood and subsequent nocturnal sleep focusing on REM sleep and delta sleep parameters. Exercise conditions were well discriminated by daily (F(2,18) = 65.8, p less than 0.0000) mean hip activity counts during monitored field exercise and by the mean weekly body weights (F(2,14) = 7.24, p less than 0.007). Subjects slept for 2 nights in the laboratory following each exercise condition and filled out two brief, clinical self-rating scales each night prior to sleep. These two self-rating instruments together index 105 somatic and psychobiological symptoms that are subsumed by the five major clinical symptom clusters of: Depression, Mania, Anxiety, Cognitive Disorganization, and Organicity. There were no significant differences in manually scored whole-night sleep parameters with the exception of REM latency (F(2,18) = 3.63, p less than 0.05), and there were no significant differences in self-ratings of psychobiological symptoms by night or exercise condition. These results are discussed in the context of failure to support either the slow wave sleep-exercise hypothesis or the exercise-mood elevation hypothesis.

Alpha-NREM sleep distributed across the 24-hour day in a legally blind elderly male

A 77-year-old married man was evaluated in our Sleep Evaluation Center for a 6-month history of excessive daytime sleepiness. By reported history and a 2-week sleep diary, he showed a polyphasic sleep-wake rhythm, which, by itself, is not unusual in this age group (Tune, 1969a,b; Webb 1969; Miles and Dement 1980). However, 2 consecutive nights of polysomnography, followed by a Multiple Sleep Latency Test (MSLT), revealed a continuous well-formed alpha rhythm coincident with all NREM sleep recorded. Except for a 40-second fragment on the second night of recording, REM sleep was absent. Delta sleep was the predominant form of NREM sleep recorded in this patient, and it was recorded during the second half of both nights and throughout all four daytime naps (MSLT). To our knowledge, this is the first case description of a sleep-wake rhythm that shows not only a breakdown in the regulation of sleep and waking as distinct states, but also a redistribution of electroencephalographic (EEG) sleep architecture across the 24-hr period.