Lynn S. Taska

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).

Sleep in narcolepsy and depression. Does it all look alike

Depression has been reported to be frequent in narcolepsy and has been considered to be variously a reaction to chronic sleepiness or an endogenous expression of the pathophysiology of narcolepsy. Supporting the latter possibility are reports of similarities between the nocturnal rapid eye movement (REM) sleep of narcoleptics and inpatients with endogenous depression. In a comparison of 25 consecutive narcoleptics and 25 age-matched outpatient primary depressives, significant group differences were found in nocturnal EEG sleep measures of sleep continuity, sleep architecture, and REM sleep. Twenty per cent of the narcoleptic sample met Research Diagnostic Criteria (RDC) for a past history of major or chronic intermittent depression, but 60 per cent did not meet RDC criteria for any present or past psychiatric disorder. These findings mandate a cautious reevaluation of the nature of depressive symptoms in narcolepsy and leave open the question of whether there are common neurobiological control mechanisms in narcolepsy and depression.

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.

EEG sleep "abnormalities" in preadolescent boys with a diagnosis of conduct disorder.

The electroencephalographic sleep of conduct-disordered and normal boys was compared using both standard and automated measurement techniques. While the standard sleep summary measures were not particularly robust in demonstrating group differences, automated measures revealed quite striking differences in delta sleep activity. Delta wave counts were significantly higher in conduct-disordered subjects than in normal subjects. These findings clearly support future applications of automated techniques to child samples and, if replicable and specific to conduct-disordered subjects, strongly suggest that an abnormality in the expression of slow-wave sleep may be present in at least some of these children.

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.