Circadian rhythm of the plasma cortisol level in cases of prolonged coma

Circadian rhythm studies in neuronal ceroid-lipofuscinosis (NCL)

Sleep disorders are common in NCL patients. The patients have problems such as frequent awakenings, difficulties with sleep onset, nightmares, and night terrors. The aim of the study was to examine whether the sleep disturbance in NCL can be explained on the basis of desynchronised circadian rhythms. Therefore we studied diurnal patterns of melatonin, cortisol, body temperature, and motor activity of 14 patients. The group consisted of 8 JNCL patients, 5 INCL children, and one boy with Jansky-Bielschowsky disease of the variant type. There were healthy age- and sex-matched control subjects. The blood samples for serum melatonin and cortisol were collected every 2 hours during 24-hour periods. Body temperature was recorded continuously for a 24-hour period by a polygraph. Diurnal motor activity was measured by wrist actigraphy for 5 days. In most of our patients sleep was fragmented and the sleep phase was irregular. Disturbances in the daily hormonal rhythms occurred only in the minority of the patients and only at an advanced stage of the disease. Although disturbances in the body temperature rhythm were found in about half of the patients, a general failure in the circadian regulatory system does not explain the frequent disturbances of the sleep-wake cycle of the NCL patients.

Melatonin, cortisol and body temperature rhythms in Lennox-Gastaut patients with or without circadian rhythm sleep disorders

The daily rhythms of melatonin, cortisol and body temperature were studied in 16 institutionalized subjects with the Lennox-Gastaut syndrome. The results of 9 subjects with normal daily rhythms of sleep and wakefulness (group 1) were compared with those of 7 subjects with disordered sleep (group 2). Salivary samples were collected and axillary temperature was measured every 2 h during two or three separate 26-h periods. The hormones were measured by radioimmunoassays. The rhythms were characterized with single cosinor analysis. Two subjects in group 1 and six subjects in group 2 had abnormalities in their rhythms of temperature, cortisol or melatonin. All three rhythms were disrupted in two subjects of group 2. These two subjects were the only ones with disrupted cortisol rhythm. The diversity of rhythm pathologies suggested partly separate regulatory mechanisms for each rhythm. The co-occurrence of circadian rhythm sleep disorders with the deteriorated melatonin rhythm raised the question as to whether the sleep disorders of these subjects, like those of subjects with healthy brains, could be relieved by the induction of normal melatonin rhythm.

Twenty-four-hour profiles of growth hormone, prolactin and cortisol in the chronic vegetative state

The 24-h profiles of growth hormone (GH), prolactin (PRL) and cortisol were obtained from 11 patients in the chronic vegetative state in order to gain more insight into the neuroendocrine alterations caused by widespread suprahypothalamic brain damage. Age and sex-matched normal subjects served as a control group. Patients had fewer high-amplitude GH peaks (greater than 20 mU/l: 6 peaks/24 h vs 21 peaks/24-h in controls) and a (non-significant) tendency towards higher basal GH concentrations. PRL concentrations were higher in patients (296 +/- 212 (SD) vs 120 +/- 28 mU/l). Cosinor analysis also showed that 24-h rhythmicity was preserved, but acrophases were more dispersed. A nocturnal PRL acrophase occurred in only three of 11 patients but in 10 of 11 control subjects. The number of PRL peaks was the same in patients and controls. Cortisol concentrations were also higher in patients (298.3 +/- 114.6 vs 193.6 +/- 97.4 nmol/l) with a preserved circadian rhythm. The acrophases, however, were likewise more dispersed. There was no difference in the number of cortisol peaks between patients and controls, but the mean peak duration was shorter in patients (75.4 +/- 28.1 vs 109.5 +/- 28.2 min). The stage of remission was negatively correlated with the 24-h mean and the mean peak amplitude of PRL. No patient showed a normal organization of sleep stages. On visual analysis there was no apparent association between EEG patterns and hormonal parameters. These results suggest that the endocrine hypothalamus is essentially intact in the chronic vegetative state. The observed changes may be due to an altered input from extrahypothalamic brain structures.