Changes In Sleep Parameters Research Articles

Percentile Reference Charts for Selected Sleep Parameters for 20- to 80-Year-Old Healthy Subjects from the SIESTA Database. Referenzkurven fur ausgewahlte Schlafparameter 20- bis 80-jahriger gesunder Personen aus der SIESTA-Datenbank

One of the aims of the SIESTA project was to establish a normative database of sleep parameters for healthy and sleep-disturbed patients. Reference data for sleep parameters in non-sleep-disturbed subjects are scarce and usually refer to means and standard deviations. However, since most of the parameters do not follow a Gaussian distribution, percentiles of the distribution provide more detailed information. The present results are based on data from 198 healthy, non-sleep-disturbed subjects (104 females) in the age range of 20 to 95 years. For every subject, two consecutive nights were polysomnographically recorded in one of the eight participating clinical centres. Percentile charts were created on the basis of moving averages computed for 10 year age intervals with the presented age being the midpoint of the underlying interval. The resulting percentile curves were smoothed by a spline function. Since sample size in the oldest age groups is comparatively small, the percentile curves are restricted to the age range of 20 to 80 years. Percentile curves have been created for the parameters sleep period time (SPT), total sleep time (TST), sleep onset latency, REM sleep latency, sleep efficiency index, and percentages of NREM1, NREM2, REM sleep, SWS, and WAKE (with reference to SPT). The charts reflect the known changes of sleep parameters with age, e.g. decrease of TST and sleep efficiency with increasing age. The reference charts are intended to be a helpful tool to evaluate selected aspects of sleep quality in sleep-disturbed patients.

Night-to-night variability in periodic leg movements in patients with restless legs syndrome

Background and purpose Although a night-to-night variability in periodic leg movements (PLM) occurrence has been described in patients with primary PLM disorder and sleep apnea syndrome, no study has apparently considered the inter-night effect on PLM index during wakefulness and sleep in patients with Restless Legs Syndrome (RLS). Moreover, no study has examined the night-to-night variability in PLM index according to sleep stage and time of night. We therefore examined changes in PLM index during wakefulness and sleep during two consecutive nights in a group of untreated RLS patients. Patients and methods Twenty-eight drug-free RLS patients, aged 53.4±2.3 yr, with a mean International Restless Legs Syndrome Study Group (IRLSSG) severity score of 20.2±1.6, were studied during two consecutive nights. PLM duration and interval, PLM index during wakefulness (PLMWI), during total sleep time (PLMSI), as well as during each sleep stage were measured. Analysis was also extended to examine PLM occurrence during sleep cycles. Results In the group of patients as a whole, the PLMW and PLMS index, duration and interval did not show significant difference between nights, these measures being consistently similar for both nights. Comparison of PLMS index between different sleep stages did not reveal inter-night differences. Nocturnal variation in PLM number, duration and interval for total recording time and sleep period revealed a progressive decline across the night for PLM index ( P≤0.0001) but no interaction, the changes being similar in first and second nights. However, a large intra-individual variability was present with a correlation coefficient between nights of 0.60 for the PLMWI ( P=0.001) and 0.54 ( P=0.003) for the PLMSI. The individual inter-night changes in PLM index were independent of age, IRLSSG severity score, duration of the disease and changes in sleep parameters. Conclusions This study shows that the index and the nocturnal pattern of PLM occurrence are highly reliable across nights in RLS patients, suggesting that a single-night study may be sufficiently sensitive to confirm diagnosis and associated sleep disturbances in these patients. However, an individual inter-night variability is present, independent of age, severity and duration of the disease, which should be considered in the clinical evaluation.

Disturbed sleep in children with Tourette syndrome: A polysomnographic study

Objective: To evaluate objective data on sleep quantity/quality and motor activity during night sleep in children with Tourette syndrome (TS). Method: Polysomnography of 17 unmedicated TS children (ages: 7;11–15;5, mean: 11;10 years) without comorbid attention-deficit hyperactivity disorder (ADHD) was compared with 16 age-, sex- and IQ-matched healthy controls. Sleep analyses according to the procedure of Rechtschaffen and Kales were supplemented by counting epochs with short arousal-related movements (≤15 s), thus allowing to calculate correlations between motor activity and sleep parameters. Results: Children with TS demonstrated changes in sleep parameters, including longer sleep period time, longer sleep latency, reduced sleep efficiency, and prolonged wakefulness after sleep onset. Their sleep profiles showed significantly more time awake and less sleep stage II. However, REM sleep variables, slow-wave sleep, and number of sleep stage changes were unaffected. Movement time was similar in both groups, but epochs with short arousal-related movements were increased in TS. Further analyses showed no significant correlations between sleep parameters and nighttime nontic movements, level of psychopathology or tic severity during daytime. Periodic limb movements during sleep (PLMS) were only seen in one TS patient (low PLMS index of 7.8/h). Conclusions: Children with TS have disturbed sleep quality with increased arousal phenomena, which both may be intrinsic to the disorder and might trigger tics and other behavioral problems during daytime. This indicates the need for sleep evaluation in patients with TS.

Sleep during Ramadan intermittent fasting

During the month of Ramadan intermittent fasting, Muslims eat exclusively between sunset and sunrise, which may affect nocturnal sleep. The effects of Ramadan on sleep and rectal temperature (Tre) were examined in eight healthy young male subjects who reported at the laboratory on four occasions: (i) baseline 15 days before Ramadan (BL); (ii) on the eleventh day of Ramadan (beginning of Ramadan, BR); (iii) on the twenty-fifth day of Ramadan (end of Ramadan, ER); and (iv) 2 weeks after Ramadan (AR). Although each session was preceded by an adaptation night, data from the first night were discarded. Polysomnography was taken on ambulatory 8-channel Oxford Medilog MR-9000 II recorders. Standard electroencephalogram (EEG), electro-oculogram (EOG) and electromyogram (EMG) recordings were scored visually with the PhiTools ERA. The main finding of the study was that during Ramadan sleep latency is increased and sleep architecture modified. Sleep period time and total sleep time decreased in BR and ER. The proportion of non-rapid eye movement (NREM) sleep increased during Ramadan and its structure changed, with an increase in stage 2 proportion and a decrease in slow wave sleep (SWS) duration. Rapid eye movement (REM) sleep duration and proportion decreased during Ramadan. These changes in sleep parameters were associated with a delay in the occurrence of the acrophase of Tre and an increase in nocturnal Tre during Ramadan. However, the 24-h mean value (mesor) of Tre did not vary. The nocturnal elevation of Tre was related to a 2-3-h delay in the acrophase of the circadian rhythm. The amplitude of the circadian rhythm of Tre was decreased during Ramadan. The effects of Ramadan fasting on nocturnal sleep, with an increase in sleep latency and a decrease in SWS and REM sleep, and changes in Tre, were attributed to the inversion of drinking and meal schedule, rather than to an altered energy intake which was preserved in this study.

8-OH-DPAT and MK-801 affect epileptic activity independently of vigilance

Vigilance and parallel occurrence of epileptic activity after administration of the 5-HT 1A agonist 8-OH-DPAT and the NMDA receptor antagonist MK-801 were studied in the genetic absence epilepsy model WAG/Rij rats. Spike-wave discharges (SWD) were present predominantly in passive awake and light slow wave sleep (SWS1) either in control animals or after treatments. Injection of 8-OH-DPAT (20.0 μg/rat i.c.v.) caused marked increase and MK-801 (10.0 μg/rat i.c.v.) decrease in SWD densities, thus the ratios of SWD in passive awake and in SWS1. SWD densities of MK-801 plus 8-OH-DPAT in combination were similar to those of CSF+CSF treated control rats. Both 8-OH-DPAT and MK-801 transiently increased the duration of active awake, increased latency and decreased duration of rapid eye movement (REM) sleep. 8-OH-DPAT increased the amount of SWD despite the decrease in the duration of SWS1. MK-801 decreased the amount of SWD despite the lack of significant change in duration of passive awake or SWS1. Pre-treatment with MK-801 reversed 8-OH-DPAT- induced increase in duration of SWD without any effect on 8-OH-DPAT-induced changes in sleep parameters. Our studies provide evidence that 8-OH-DPAT-induced epileptic activity is independent of its effect on sleep, and that interaction of serotonergic and glutamatergic systems plays a role in the generation of SWD, but not in the regulation of vigilance and sleep.

Night-shift work in antarctica: Sleep characteristics and bright light treatment

Changes in sleep parameters during and after night-shift and the effects of bright white (2500–3000 1x) and dim red (>500 1x) light treatment on re adaptation after night-shift during winter were studied in 14 men on the British Antarctic Survey Base of Halley (75° south). Subjects kept daily sleep diaries and mood ratings from one week before to three weeks after night-shift and received either full-spectrum white or dim red light treatment from 1100 to 1300 h daily during the first week after night-shift. Plasma melatonin (for 24 h at the end of weeks 1, 2 and 4), and urinary 6-sulfatoxymelatonin (aMT6s, for 48 h weekly) were measured. A significant (MANOVA; p < 0.05) improvement in sleep was seen during night shift (latency and duration) and with bright light treatment (latency). Melatonin and aMT6s rhythms delayed by 7–8 h during night-shift. The white light group readapted slowly, apparently by phase delay, as assessed by aMT6s measurement. The red light group readapted slightly, but significantly (ANOVA, p < 0.01) faster than the white light group.

Sleep polygraphic effects of trimipramine in depressed patients. Preliminary report.

Preliminary results are presented from an ongoing study in hospitalised depressed patients. Changes in sleep parameters were assessed on days 1 to 3 and 12 to 14 of a 4-week study in which patients received trimipramine 150 mg on day 1 and 100 mg thereafter. On days 1 to 3 and 12 to 14, 7 depressed patients had a significantly increased total sleep time and sleep efficiency index and a significantly decreased total wake time and number of intrasleep wake episodes per hour of sleep. Trimipramine treatment had no significant effect on REM sleep, percentage of REM sleep, REM duration and REM sleep stability index. However, a significant increase in REM latency was noted on days 1 to 3 but not on days 12 to 14. These polygraphic data suggest that trimipramine effects a very rapid and maintained sleep improvement in these depressed patients without significant alterations to the parameters of REM sleep.

Effect of housing in an enriched environment on the size of the cerebral cortex in young and old rats

To assess whether or not environmental changes may continue to affect measures relating to cortical size, the size of the cerebral cortex of young adult (7 to 8 months) and old (32 to 33 months) “standard” and “enriched” rats were compared. Enriched rats were housed in large cages during 10 weeks and had access to many different objects; age-matched controls remained in standard laboratory cages. Effects on the cerebral cortex were small; a significant increase in cortical thickness at one, albeit different, site in both age groups was observed. Significant correlations were not present between environmentally induced changes in sleep parameters (recorded in the same rats prior to the present experiment) and the small change in cortical size. The results do, however, support the hypothesis that a certain amount of plasticity of the cerebral cortex is preserved in old age.

Little sleep-promoting effect of three sleep substances diurnally infused in unrestrained rats

Delta-sleep-inducing peptide (2.5 nmol), prostaglandin D 2 (0.36 nmol) and uridine (10 pmol) were intraventricularly infused for 10 h at daytime in otherwise saline-infused freely moving male rats. In contrast to a nocturnal infusion which may result in marked sleep-promoting effects, such a diurnal infusion brought about almost no change in sleep parameters. It is postulated that the requirement of sleep in rats might be fully achieved at the environmental light period to cancel the effect of the exogenously administered sleep substances. It is proposed that an endogenous sleep substance should be characterized by a property not to cause excessive sleep at the time when sleep is physiologically saturated.

Model insomnia, noise, and methylphenidate, used for the evaluation of hypnotic drugs

Experimental sleep disturbance (model insomnia) was produced by intermittent white noise and the administration of 10 mg of methylphenidate (MPD). The effects of flurazepam (FZP) 15 mg and triazolam (TZM) 0.25 mg on these models was investigated. All night sleep polygraphy was performed on 8 normal male subjects under each of the following 9 conditions: baseline, TZM 0.25 mg, FZP 15 mg, white noise alone, noise and TZM, noise and FZP, MPD alone, MPD and TZM, and MPD and FZP. A reduction in total sleep time and stage were (S-REM) and an increase in the wakening stage were observed with both noise and MPD. Stage 4 sleep was reduced only by MPD. Administration of TZM or EZP did not cause any significant change in sleep parameters. These drugs in combination with noise or MPD resulted in almost complete recovery of the sleep disturbance induced by noise or MPD, except for a reduction in S-REM. These results indicate that model insomnia, particularly MPD insomnia, will assist in the evaluation of hypnotic drugs.