SLEEP

Pilcher, June, J.;Bergmann, Bernard, M.;Refetoff,, Samuel;Fang, Victor, S.;Rechtschaffen,, Allan

doi: 10.1093/sleep/14.3.201pmid: 1896721

Summary: Previous studies of rats subjected to total sleep deprivation by the disk-over-water method had shown a large increase in energy expenditure (EE) and an initial increase followed by a later decrease in body temperature (Tb). It had been proposed that the increase in Tb resulted from regulation toward a higher temperature or setpoint, that the later decline in Tb resulted from excessive heat loss, and that the increase in EE supported both of these thermoregulatory changes. To evaluate this proposed role of the increase in EE, we examined whether blunting the EE rise in sleep-deprived rats by making them hypothyroid attenuated and/or shortened the initial increase in Tb and accelerated the later decline in Tb. Rats made hypothyroid by propylthiouracil administration (TxD rats) were totally sleep deprived and compared to hypothyroid yoked control (TxC) rats and to previously studied, untreated, totally sleep-deprived (TSD) rats. Neither TxD nor TxC rats showed large increases in EE like those of TSD rats. TxD rats did not initially increase Tb, as TSD rats had. Presumably, TSD rats had been able to support an initially elevated Tb, in spite of excessive heat loss, by large increases in EE, although even these increases were eventually insufficient. TxD rats showed much earlier and greater declines in Tb than TxC and TSD rats, eventually becoming severely hypothermic. These results support the interpretation that the large increase in EE previously seen in TSD rats had been compensatory for deprivation-induced thermoregulatory deficits. TxD rats survived an average of 17.1 days, which was not significantly different from survival time in TSD rats. However, there were differences in mortal processes between the two groups. TxD rats died or were sacrificed after chronic, severe hypothermia without observable signs of other morbid pathology. TSD rats had not shown similarly low Tb until just prior to death, but had shown signs of severe pathology, including severely debilitated appearance, disheveled fur, and severe lesions on their tails and on the plantar surfaces of their paws. These signs were diminished or absent in TxD rats, possibly due to blunted EE, lower Tb, or other effects of hypothyroidism. Because the skin changes seen in TSD rats were minimal in TxD rats, they could not have been responsible for the excessive heat loss. Sleep deprivation, Function of sleep, Thermoregulation, Thyroid hormones, Energy expenditure This content is only available as a PDF. © 1991 Association of Professional Sleep Societies

Follenius,, M.;Krieger,, J.;Krauth, M., O.;Sforza,, F.;Brandenberger,, G.

doi: 10.1093/sleep/14.3.211pmid: N/A

Summary To assess the effect of obstructive sleep apnea treatment on plasma renin activity (PRA) and plasma aldosterone seven male patients were studied under two conditions: untreated and treated with nasal continuous positive airways pressure (CPAP). PRA and plasma aldosterone were measured at 10-min intervals for both nights. CPAP treatment diminished the urinary and Na+ excretion, whereas plasma volume increased. The mean levels of PRA and aldosterone were significantly enhanced by the treatment, increasing respectively from 1.5 ± 0.3 to 3.0 ± 0.7 ngAI ml−hr− (p < 0.05) and from 8.0 ± 1.0 to 12.0 ± 1.7 ng.100 ml− (p < 0.05). PRA curves reflected the overall sleep structure as similarly described in normal subjects. The apnea−induced sleep disturbance led to flat PRA profiles and the restoration of a normal sleep pattern by treatment restored the PRA oscillations related to the sleep cycles and consequently restored aldosterone oscillations. The mean amplitude of these oscillations increased respectively from 1.0 ± 0.1 to 1.8 ± 0.4 ngAI ml−hr− and from 5.4 ± 1.2 to 10.9 ± 1.9 ng.100 ml−. These results suggest that CPAP treatment modifies the nocturnal patterns of PRA and aldosterone by increasing their mean levels and their oscillation amplitude. This indicates increased secretion, which contributes to the normalization of urine and Na output. Sleep apnea, Plasma renin activity, Aldosterone This content is only available as a PDF. © 1991 Association of Professional Sleep Societies

Mitler, Merrill, M.;Hajdukovic,, Roza

doi: 10.1093/sleep/14.3.218pmid: 1680245

Summary: A survey was conducted on 10 polysomnographic studies on the pharmacologic treatment of the sleepiness of narcolepsy. three studies emplyedthe MSLT and 7 employed the MWT as their polygraphic measure of sleep tendency. Statistically and clinically significant therapeutic changes were apparent for pemoline, modafinil, dextroamphetamine and methylphenidate. Codeine, ritanserin and protriptyline did show statistically significant effects. The common feature among the drugs that did produce clinically significant improvements seems to be facilitatory action on central catecholaminergic transmission. Within this group of drugs, only methylphenidate and dextroamphetamine brought MWT sleep latencies to approximately 70% of normal levels. Narcolepsy, Methylphenidate, Amphetamine, Pemoline, CNS stimulants, Multiple Sleep Latency Test, Maintenance of Wakefulness Test This content is only available as a PDF. © 1991 Association of Professional Sleep Societies

Åkerstedt,, Torbjöm;Kecklund,, Göran;Knutsson,, Anders

doi: 10.1093/sleep/14.3.221pmid: 1896723

Summary: Twenty-five three-shift workers in a process industry were subjected to ambulatory polysomnography during one afternoon and one night shift. The electroencephalographic (EEG) recordings were analyzed with spectral analysis. Subjective sleepiness increased during the night work but did not reach an extreme level. Five subjects fell asleep during night work and the involuntary naps were preceded by a few minutes of increased alpha (8–11.9 Hz) power density. Alpha and theta activity occurred in very short bursts. The hourly mean EEG alpha power density increased significantly but moderately during the night shift and correlated with subjective ratings of sleepiness. Theta power density (4–7.9 Hz) did not increase during the night shift, nor did it correlate with subjective sleepiness. It was suggested that the shift workers could prevent much of the polysomnographic manifestations of sleepiness by various types of activity (including succumbing to sleep). It was also suggested that averaging power density values across long time periods might not be an optimal strategy for detection of sleepiness, but rather some method of emphasizing the occurrence of alpha or theta bursts. Ambulatory monitoring, Electroencephalogram (EEG), Sleepiness, Shift work, Spectral analysis This content is only available as a PDF. © 1991 Association of Professional Sleep Societies

Chesson, Andrew, L.;Levine, Steven, N.;Kong,, Lung-Suen;Lee, Stephen, C.

doi: 10.1093/sleep/14.3.226pmid: N/A

Summary A patient with Kleine-Levin syndrome had polysomnography and neuroendocrinological assays performed during asymptomatic (ASMP) and symptomatic (SMP) 24-hr periods. During the SMP, sleep data revealed poor nocturnal sleep efficiency, increased sleep fragmentation and reduced stages 3, 4 and rapid eye movement (REM). No sleep onset REM episodes were seen. Sleep staging in the ASMP was normal. Blood samples were obtained every 20 min and assayed for thyroid-stimulating hormone (TSH), cortisol (CORT), prolactin (PRL) and growth hormone (GH). Patterns of secretion, 24-hr mean and total integrated concentrations, and mean sleep period time values during the ASMP and SMP were compared. The mean 24-hr level of TSH was increased and GH decreased in the SMP. Comparing sleep period time in the SMP to the ASMP, values for TSH and PRL were increased and GH and CORTwere reduced in the SMP. These hormone changes support the hypothesis that reduced hypothalamic dopaminergic tone is present in the SMP compared to the ASMP in Kleine-Levin patients. Kleine, Levin, Sleep, Pituitary hormones, Dopamine, Hypothalamic, hypophyseal system This content is only available as a PDF. © 1991 Association of Professional Sleep Societies

Horne, J., A.;Donlon,, J.;Arendt,, J.

doi: 10.1093/sleep/14.3.233pmid: N/A

Summary Melatonin output covaries with sleepiness, with both peaking early morning. Bright white light suppresses this output, but it is not known if such treatment ameliorates nighttime sleepiness during sleep deprivation. However, sleep-deprived subjects find such light irritating. Humans are particularly sensitive to green light, and melatonin output is more readily suppressed by this hue. A pilot study using different green light regimens showed that sleep-deprived subjects well tolerated 2,000 lux green light given 10 min hourly, and that this dose reduced nighttime melatonin output. The main study gave this light treatment vs. a low intensity red/green light control, from 1900 hr for 11 hr, to two groups of subjects (n = 6 each) sleep deprived for 36 hr. Urine was collected at 6-hr intervals during sleep loss and on a baseline day. Vigilance performance, subjective sleepiness, and oral temperature were monitored during sleep loss. The experimental condition suppressed urine 6-hydroxymelatonin sulfate (aMT6s) output between 0000 hr and 0600 hr, and increased it 0600-1200 hr; but there was no change in total 24-hr values. The control condition had no such effects. The oral temperature rhythm remained unchanged. Vigilance and subjective sleepiness were improved significantly relative to control values during 0000-0600 hr; these improvements were maintained somewhat over the 0600-1200-hr period, contrary to what one might expect if the delayed melatonin surge at this time was increasing sleepiness. Although the bright green light helped counteract sleepiness, any causal link with changes in melatonin output seem tenuous. Sleep deprivation, Melatonin Performance, Body temperature, Light-Sleepiness This content is only available as a PDF. © 1991 Association of Professional Sleep Societies

Stewart, Malcolm, W.;Stewart, Lara, A.

doi: 10.1093/sleep/14.3.241pmid: 1896725

Summary: Sudden infant death syndrome (SIDS) has been associated with premorbid respiratory irregularities that may contribute to the subsequent occurrence of SIDS (e.g. by chronic hypoxia). Conventional apnea alarms will detect periods of extended apnea but not other chronic respiratory irregularities that could contribute to SIDS. The effect of a brief, quiet, repetitive auditory stimulus on the sleep respiratory behavior of infant dogs and pigs was assessed. Stimulus presentation was associated with an increase in the sleep respiration rate irrespective of the stimulus presentation rate being faster or slower than the baseline respiratory rate, and irrespective of the pattern of presentation being regular or random. These results suggest that apnea monitoring systems may be improved by an additional function in which less extreme respiratory irregularities initiate the time-limited presentation of a quiet, repetitive, auditory stimulus, aimed at normalizing the respiratory pattern. This function could enhance the preventative role of the alarm systems by reducing the development of pathology that may promote some instances of SIDS. SIDS, Infant respiration, Sleep respiration, Sleep apnea This content is only available as a PDF. © 1991 Association of Professional Sleep Societies

Bliwise, Donald, L.;Keenan,, Sharon;Bumburg,, Deborah;Mattice,, Cynthia;Minkley,, Pamela;Pursley,, Ann;Zelonis,, John

doi: 10.1093/sleep/14.3.249pmid: 1896726

Summary: This study investigated inter-rater reliability for scoring periodic leg movements in sleep (PLMS) and related phenomena. Five highly experienced polysomnographic technologists each scored 24 nocturnal polysomnograms, the majority of which contained an appreciable number of PLMS. Results indicated high inter-rater reliability for some variables but more modest reliability for others. We discuss these findings in terms of efforts of standardization in polysomnographic scoring of sleep disorders. Periodic leg movements, Nocturnal myoclonus, Reliability, Electroencephalogram This content is only available as a PDF. © 1991 Association of Professional Sleep Societies

Lord,, Susie;Sawyer,, Beverley;O&apos;Connell,, Dianne;King,, Madeleine;Pond,, Dimity;Eyland,, Ann;Mant,, Andrea;Holland, J., T.;Hensley, Michael, J.;Saunders, Nicholas, A.

doi: 10.1093/sleep/14.3.252pmid:

Demirozu, M., C.;Chediak, A., D.;Nay, K., N.;Cohn, M., A.

doi: 10.1093/sleep/14.3.259pmid: N/A

Summary Nasal continuous positive airway pressure (CPAP) “splints” the airway and prevents inspiratory collapse of the upper airway in patients with obstructive sleep apnea. Nine nasal CPAP machines were compared for their ability to maintain airway pressure at various simulated inspiratory flows. Each machine was connected to a vacuum system at 20, 40, and 60 Umin flow after it was initially set at test pressures of 5, 10, or 15 cm H2O and the system or “mask” pressures were measured. In all machines, mask pressure fell during simulated inspiration and the declines in mask pressure were as high as 5 cm H2O. Because machines varied in their ability to maintain a test pressure, it is recommended that the nasal CPAP machine used in the home be the same as that which was tested in the sleep laboratory. If a different machine is used, it may require adjustment to assure efficacy. Sleep apnea treatment, Nasal continuous positive airway pressure, Sleep disordered breathing This content is only available as a PDF. © 1991 Association of Professional Sleep Societies