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Biomedical subjects

T Roth

Publications and source records attributed to T Roth.

At least 181 records · Page 10Linked to original sources
PubMed1988

Daytime alertness in patients with chronic insomnia compared with asymptomatic control subjects.

Despite the subjective reports of patients with difficulty initiating and maintaining sleep (DIMS) that they are impaired during the day, consistent differences in daytime functions have not been found between normal sleepers and patients with insomnia. The present study compares polysomnography and Multiple Sleep Latency Test (MSLT) data from 70 clinic patients seeking evaluation for chronic insomnia with data from a group of 45 asymptomatic sleepers. The DIMS group was found to sleep significantly less than the control group; yet they were also significantly more alert than the control group the following day, as measured by MSLT. Within the insomnia diagnostic subgroups, a correlation of -0.67 (p less than 0.05) was found between nocturnal total sleep time and mean MSLT. The results are interpreted as supporting the existence of a tendency towards physiological hyperarousal in patients with chronic insomnia. This tendency may be exacerbated by other factors (e.g., personality disorder, periodic leg movements) also associated with insomnia.

Adult↗
PubMed1988

Test-retest reliability of the MSLT.

The test-retest reliability of the Multiple Sleep Latency Test (MSLT) was evaluated in 14 healthy normal subjects. Each slept a single night in the laboratory (8 h time in bed) and received the MSLT the following day (1000, 1200, 1400, and 1600 h) on two occasions separated by 4-14 months. Mean sleep latency (four tests) was highly reliable from MSLT to MSLT (r = 0.97, p less than 0.001). The test-retest reliability did not change as a function of the interval of time between tests or as a function of the level of sleepiness (range = 4-20 min) within the population. However, as the number of tests comprising the MSLT was reduced below three, the reliability was reduced such that only 50% or less of the variance could be predicted.

Adult↗
PubMed1988

The effects of acute sleep restriction and extension on sleep efficiency.

This study employed a repeated measures design to assess the relationship between sleep efficiency and time-in-bed (TIB). Fourteen subjects underwent three TIB conditions: (5 hour, 8 hour, and 11 hour), which were presented in a Latin Square design. Subjects slept a total of six nights (two nights per condition) while being monitored by a wrist actigraph to determine sleep time. Sleep efficiencies (sleep time/TIB) were analyzed with a two-way repeated-measures ANOVA. The main effect of night was not significant. The main effect of TIB and the interaction of nights and TIB were significant. In the 11-hour condition, sleep efficiency fell from night one to night two, and on night two both the 5-hour and the 11-hour conditions were significantly different from the 8-hour condition. Analysis of total sleep time (TST) yielded the same results with the addition of a significant night-to-night difference in the 5-hour condition. It was concluded that sleep efficiency systematically changes with an extension or restriction of TIB from 8 hour.

Adult↗
PubMed1988

Increased daytime sleepiness enhances ethanol's sedative effects.

Thirty healthy men, 21 to 35 years old, received either 8.7, 13.0 or 17.4 mmol/kg (0.4, 0.6, or 0.8 g/kg) ethanol after 8 hours time in bed (TIB), one night of 5 hours TIB, and four nights of 5 hours TIB. Ethanol, administered as 80-proof vodka mixed 1:4 with tonic water, was consumed over 30 minutes (0900 to 0930 hours). Sleep latency was measured at 1000, 1200, 1400, and 1600 hours using standard sleep laboratory methodology. Breath ethanol concentration (BEC) was determined prior to each latency test. Mean latency to sleep on the four tests decreased from day 1 (8 hours TIB) to day 5 (fourth day of 5 hours TIB). On day 1 mean latency after 8.7 mmol/kg differed from that after 17.4 mmol/kg, with the 13.0 mmol/kg latency intermediate between the other two. On day 2 and day 5 during sleep restriction these dose differences were diminished. Latency on day 5 after 8.7 mmol/kg was similar to that of 13.0 mmol/kg on day 2, which was similar to that of 17.4 mmol/kg on day 1. The BEC did not change from day 1 to day 5 and significant dose differences between each dose remained consistent from day to day. These data show that increased basal levels of sleepiness enhance ethanol's sedative effects for even moderate ethanol doses.

Adult↗
PubMed1988

Mortality and apnea index in obstructive sleep apnea. Experience in 385 male patients.

Although obstructive sleep apnea (OSA) has been studied in detail for over a decade, the mortality of this disorder is unclear. We calculated cumulative survival in 385 male OSA patients. We found that those with an apnea index (AI) greater than 20 had a much greater mortality than those with AI = less than 20. The probability of cumulative eight-year survival was .96 +/- 0.02 (SE) for AI = less than 20 vs. 63 +/- 0.17 for AI greater than 20 (p less than .05). This difference in mortality related to AI was particularly true in the patients less than 50 years of age in whom mortality from other causes is not common. None of the patients treated with tracheostomy or nasal CPAP died. Eight of the patients treated with uvulopalatopharyngoplasty (UPPP) died and the cumulative survival of the UPPP-alone treated group was not different from the survival curve of untreated OSA patients with an apnea index of greater than 20. We conclude that OSA patients with an apnea index of greater than 20 have a greater mortality than those below 20 and that UPPP patients be restudied after therapy. If the latter patients are found not to have marked amelioration of their AI, then they should be treated by nasal CPAP or tracheostomy.

Actuarial Analysis↗
PubMed1988

Daytime sleepiness in young adults.

The daytime sleepiness of a large sample (n = 129) of healthy, young (age 18-29) adults with no sleep-wake complaints was measured and compared with that of a sample (n = 47) of older (age 30-80) healthy, normal sleeping, subjects. Each spent 8 h in the laboratory on 1 night and received the Multiple Sleep Latency Test (MSLT) the following day. Sleep latency was measured at 1000, 1200, 1400, and 1600 h. Mean sleep latency ranged from 2 to 20 min within each group, but the shape of the distribution of latency between groups was different. The mean latency of young subjects (particularly college students) was shorter than that of the older subjects, with the differences occurring between the sleepiest 80% of each distribution. Among the college students, those with higher nocturnal sleep efficiencies (the previous night) were sleepier the following day than those with lower sleep efficiencies. The relation between nocturnal sleep efficiency and daytime sleepiness suggests that the increased sleepiness of average young adults is due to mild sleep restriction.

Adult↗
PubMed1987

Circadian fluctuation of plasma epinephrine in supine humans.

Previous studies have demonstrated circadian fluctuations of systemic catecholamines in man. However, methodological differences and conflicting results with epinephrine are apparent. In the present study, plasma and urinary epinephrine and norepinephrine and plasma cortisol were studied in healthy young adult males over 24 hr with 20 min plasma sampling and EEG monitoring of sleep. Plasma epinephrine did not have a circadian variation in supine subjects. Urinary epinephrine levels and small urinary circadian variations were increased by normal posture and activity. Sleep and sleep stage were not associated with different plasma epinephrine levels, and no ultradian fluctuation was observed. Levels of norepinephrine and cortisol were normal. Based on all studies to date, it appears that basal plasma epinephrine has either a very small amplitude or no circadian rhythm, but that changes in posture and activity or the rest/activity cycle may modify this pattern.

Activity Cycles↗
PubMed1987

Sedative effects of antihistamines.

The central effects of a newly developed, long-acting H1 antihistamine, loratadine (10 and 40 mg), were compared with those of a standard H1 antihistamine, diphenhydramine (50 mg three times a day) with measures of performance and daytime sleepiness (multiple sleep latency test). Sixteen healthy adults (six women and 10 men), 19 to 35 years of age, received each of the drugs and placebo for 2 days, separated by 5 days at home. Each day, the drug or placebo was administered at 8 A.M. and 12 and 4 P.M. Diphenhydramine was administered in three equal doses (50 mg), and loratadine was administered in a single dose followed by two placebo doses. Mean latency to sleep on tests done at 9 and 11 A.M. and 1, 3, and 5 P.M. was reduced significantly with diphenhydramine compared to placebo, whereas neither loratadine dose reduced sleep latency. Performance measured at 9:30 P.M. and 1:30 P.M. with a battery of tests, including reaction time, vigilance, digit symbol substitution, and symbol copying tasks demonstrated a significant reduction in symbols copied and digits substituted after diphenhydramine compared to both loratadine doses. These results demonstrate that loratadine (10 and 40 mg doses) did not have clinically significant central nervous system activity, whereas diphenhydramine increases sleepiness and disrupts performance efficiency.

Adult↗
PubMed1987

Hypercapnia and sleep O2 desaturation in chronic obstructive pulmonary disease.

There is a wide clinical spectrum in chronic obstructive pulmonary disease (COPD). The extremes of this spectrum, the "pink puffer" (PP) and "blue bloater" (BB) stereotypes differ in their degree of sleep hypoxemia and pulmonary hypertension. Most patients cannot be characterized as either PP or BB. The data amassed in the recent nocturnal oxygen therapy trial provide an opportunity to see to what extent differences in sleep oxygenation and hemodynamics in a large hypoxemic COPD population are related to awake hypoxemia and hypercapnia. From a large hypoxemic COPD population sleep SaO2 was examined in those with (PaCO2 greater than 44 mm Hg) and without (PaCO2 less than or equal to 44 mm Hg) hypercapnia. Hypercapnic patients (mean PaCO2 49.8 mm Hg) had the same PaO2 and degree of airflow obstruction as normocapnic patients (PaCO2 37.4 mm Hg) but had far greater sleep hypoxemia (measured by mean sleep SaO2, low sleep SaO2, and awake-low sleep SaO2, p less than 0.05). In addition, arterial blood gases of the large sleep O2 desaturaters were compared with those of the small desaturaters; PaO2 was similar in both groups, whereas PaCO2 was different (p less than 0.01). Two common subsets of hypoxemic patients were also compared; one was hypercapnic and overweight, the other normocapnic and hyperinflated. We found that patients in the hypercapnic group had far worse sleep hypoxemia, although they had better lung function. We conclude that hypercapnia is a marker for sleep O2 desaturation in hypoxemic COPD.

Aged↗
PubMed1987

Experimental sleep fragmentation in normal subjects.

Recent research has suggested that sleep fragmentation in the absence of sleep loss is an important cause of excessive daytime sleepiness in certain clinical populations (e.g., sleep apnea syndrome or periodic leg movements). This study experimentally varied the number and rate of arousals in sleep to define more clearly the relation of sleep fragmentation and daytime sleepiness. Five male subjects participated in the study. Data from each were recorded for three consecutive nights (one baseline followed by two experimental nights) under three experimental conditions. All nocturnal polysomnograms were followed by a Multiple Sleep Latency Test (MSLT) the next day. The experimental conditions consisted of three different schedules of arousal produced by series of tones presented to subjects over headphones. The MSLT showed statistically significant changes after two nights of fragmented sleep, but the three fragmentation schedules did not differ from each other. Arousal threshold also changed significantly with sleep fragmentation from night one to night two.

Adolescent↗