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Biomedical subjects

T Roehrs

Publications and source records attributed to T Roehrs.

At least 37 records · Page 2Linked to original sources
PubMed1997

Hypnotic self administration: forced-choice versus single-choice.

Twenty-four men and women with insomnia, age 21-50 years, self administered hypnotics under a single-choice with placebo, single-choice with triazolam (0.25 mg), or forced-choice of placebo versus triazolam (0.25 mg) paradigm. Subjects received 4- sampling nights of placebo or triazolam in the single-choice conditions or 2 nights of each in the forced-choice condition. Then on 7 choice nights they could self administer a capsule, or not, in the single-choice conditions, or were required to choose one of two color-coded capsules in the forced-choice condition. In the single-choice conditions, subjects chose placebo 80% of nights and triazolam 77% of nights, while in the forced-choice condition triazolam was chosen on 86% of nights. Thus, the self administration of triazolam did not vary significantly between single or forced choice conditions, but that of placebo did. Placebo rate was high when it was the only alternative, but low when competing with triazolam. On sampling nights, compared to placebo, triazolam produced a significant increase in total sleep time, a reduction in latency to sleep, wake after sleep onset, and percentage stage 1 sleep. Triazolam, relative to placebo, also improved mood in the morning on some sampling nights. For subjects choosing capsules < 100% of opportunities (n = 14), on nights a capsule was chosen versus nights none was chosen (regardless of whether placebo or triazolam was the choice), self-ratings 30 min before bedtime on the Profile of Mood States vigor scale were significantly higher.

Adult↗
PubMed1997

Alerting effects of methylphenidate under basal and sleep-deprived conditions.

Six men and 3 women on each of 4 days received 10 mg of methylphenidate or placebo (2 times a day) at 0800 and 1200 after 8 hr or 0 hr of sleep. Sleep latency was measured by the Multiple Sleep Latency Test (MSLT) at 0930, 1130, 1330, 1530, and 1730. Participants also completed divided-attention and auditory vigilance tasks at 1000 and 1400 and the Profile of Mood States (POMS) and the Addiction Research Center Inventory (ARCI) after the 0930 and 1330 latency tests. The drug increased mean latency on the MSLT in both sleep conditions. Performance only showed drug effects after prior sleep deprivation. On the POMS, the drug increased Vigor and reduced Fatigue and Depression scale scores, primarily after sleep deprivation. The drug increased the ARCI Amphetamine and Morphine-Benzedrine scores only in the basal state. The ARCI Pentobarbital score was increased by sleep deprivation and decreased by the drug.

Adult↗
PubMed1997

The alerting effects of short and long naps in narcoleptic, sleep deprived, and alert individuals.

Eleven narcoleptic patients and 22 age- and gender-matched normal controls participated in a study to determine the alerting effects of differing nap lengths. All narcoleptic patients had been previously diagnosed [mean sleep latency on the multiple sleep latency test (MSLT) < or = 5 minutes with two or more sleep-onset rapid eye movement periods (SOREMPs)]. Healthy, normal subjects with a mean sleep latency on the screening MSLT > or = 8 minutes were randomly assigned to one of two groups (i.e. sleep-deprived and alert). All subjects completed two experimental night and days with at least 5 days between sessions. On the evening prior to each experimental day, narcoleptic and alert subjects spent 8 hours in bed and sleep-deprived subjects spent 0 hours in bed. The following day, all subjects underwent one of two napping conditions, 15 or 120 minutes in bed. Both naps were terminated at noon. Every subject underwent both conditions and the order of conditions was counterbalanced. From 1215 to 1355 hours all subjects underwent a modified MSLT. At 1500 hours, the subjects had a 1-hour nap. The results showed that the 120-minute nap condition was more beneficial than the 15-minute nap. Narcoleptic and sleep deprived subjects were shown to have comparable levels of sleepiness on the modified MSLT. However, a differential response pattern on their latency to sleep was noted on the 1-hour nap. Sleep-deprived subjects were shown to be differentially more alert following a 120-minute nap opportunity. In contrast, for narcoleptic patients the beneficial effects of the nap were lost when tested 3 hours later. These results show that narcoleptic patients benefit from a longer nap but that these benefits are short-lived.

Adult↗
PubMed1997

Minimal rebound insomnia after treatment with 10-mg zolpidem.

This study examined rebound insomnia after discontinuation of chronic use of zolpidem (10 mg), a short elimination half-life imidazopyridine. The zolpidem group was bracketed by a placebo group and a positive control group taking 0.5 mg of triazolam (twice the recommended dose), which is known to produce rebound insomnia. Ninety-nine patients with sleep complaints that were polysomnographically documented participated in the study. After randomization, patients completed a 2-night, single-blind, placebo baseline period, a 28-night double-blind treatment phase, and a 3-night, single-blind, placebo substitution period. Polysomnographic and subjective sleep variables indicated a lack of rebound insomnia for the zolpidem group. The positive triazolam control group had rebound insomnia only on the first discontinuation night. There was no significant correlation between rebound insomnia and the level of initial insomnia, the degree of response to treatment in week 4, or the amount of tolerance that developed during drug use. During the 4-week treatment period, efficacy diminished for both drugs. From these data, it cannot be determined whether the lack of rebound insomnia with zolpidem is a result of drug dose or some property of the drug such as receptor selectivity.

Adult↗
PubMed1996

The reliability of the diagnostic features in patients with narcolepsy.

This study determined the test-retest reliability of the polysomnographic findings in narcolepsy. The diagnosis of narcolepsy was based on clinical symptoms and polysomnographic signs. Control subjects were screened before participation and were split based on their screening multiple sleep latency test (MSLT) into high- and low-MSLT groups. Subjects completed two polysomnographic evaluations with at least 5 days between laboratory tests. Narcoleptics had lower sleep efficiencies and high stage 1% when compared to the low MSLT control group. They had more awakenings and less stage 2% than the control groups. Narcoleptics had a shorter latency to 1 when compared to the high-MSLT group but comparable to that of the low-MSLT group. Narcoleptics had a higher number of sleep-onset rapid eye movement periods (SOREMPs) than both control groups. The MSLT scores were stable across the two evaluations and showed a statistically significant correlation. Twenty-eight of the 30 narcoleptic subjects had two or more SOREMPs on reevaluation. None of the controls had multiple SOREMPs. Thus, multiple SOREMPs were shown to be a reliable finding in patients with narcolepsy.

Adolescent↗
PubMed1996

Hypnotic self administration and dose escalation.

The dependence liability of benzodiazepines in the context of their use as hypnotics (i.e. by insomnia patients as pre-sleep medications) is unresolved. A recent study found that insomniacs self administer capsules at bedtime at a high rate, with triazolam (0.25 mg) taken as often as placebo. This study sought to determine if differential self administration would develop when multiple capsules are available nightly. Eighteen men and women, age 21-45 years, with insomnia complaints (nine with objective sleep disturbance and nine without) were studied, 1 week with placebo and 1 week with triazolam (0.25 mg). The two conditions were administered double-blind and presented in a counter-balanced order with a week between conditions. In each condition, after 3 consecutive sampling nights of the available single capsule for that condition, subjects could self administer 0-3 capsules before bed on the 4 subsequent nights. Triazolam was self administered as many nights as placebo, but the number of placebo capsules self administered was twice that of triazolam capsules. The objective insomniacs self administered more capsules than the subjective insomniacs and neither group differentially choose triazolam over placebo. The number of triazolam capsules taken nightly was stable and the number of placebo capsules variable. It is concluded that insomniacs show no short-term escalation of triazolam dose, but do choose an increased and variable number of placebos, a pattern which is interpreted as being insomnia relief-seeking behavior.

Adult↗
PubMed1996

Nocturnal sleep latencies among alert, alert-deprived and sleepy subjects.

Twenty-seven healthy, asymptomatic subjects participated in a study to determine repeated nocturnal sleep latencies as a function of level of daytime sleepiness. Subjects were screened polysomnographically and were determined to be free of any sleep pathology. Nine subjects had a screening multiple sleep latency test (MSLT) of < or = 5 min and 18 had a MSLT of > or = 10 min. Subjects were assigned to 3 groups, sleepy (MSLT < or = 5 min), alert, and alert sleep-deprived groups (MSLT > or = 10 min). Repeated nocturnal latencies to sleep were determined at 2300, 0110, 0310 and 0510 h on 2 nights with at least 5 days between nights. The results showed a main effect of group on the repeated nocturnal sleep latencies. Post-hoc tests demonstrated longer repeated nocturnal latencies among alert subjects compared to the sleepy and alert sleep-deprived subjects. The latter two groups had comparable sleep latencies. A significant main effect of time of night was also shown. The 0510 h latency was significantly shorter than the latencies at 2300 and 0110 h. The 0310 h latency was significantly shorter than the 0110 h latency and comparable to the 2300 and 0510 h latency. Significant correlations were found between daytime MSLT, repeated nocturnal sleep latencies, and nocturnal sleep time. These results show systematic differences in repeated nocturnal sleep latencies among sleep and alert subjects and extend the already described characteristics of these subjects by comparing them to a group of alert sleep-deprived subjects.

Adult↗
PubMed1996

Auditory awakening thresholds in sleepy and alert individuals.

Twenty-seven healthy men and women with regular sleep-wake habits (and no habitual napping) participated in a study to determine the relation between auditory awakening thresholds (AAT) and multiple sleep latency test (MSLT) scores. Subjects were free of any sleep complaints and were screened polysomnographically. Nine subjects had a screening MSLT of < or = 5 minutes (sleepy group), and 18 subjects had an MSLT of > or = 10 minutes. Subjects were assigned to three groups: a sleepy group, alert group and an alert sleep-deprived group. Subjects underwent 2 nights of AAT testing with at least 5 days in between each study night. AATs were determined at 0100, 0300, 0500 and 0730 hours. There were a total of 209 available AAT determinations, with a comparable number of trials across the groups. Because 68% of AAT determinations were done out of stage 2 non-rapid eye movement (NREM) sleep, the thrust of the analysis was based on the results of this stage of sleep. The AATs were averaged across the two experimental nights. Trials 1 and 2 (first half of the night) and 3 and 4 (second half of the night) were averaged for each subject. There was no main effect of group on AATs. However, there was a significant main effect of time and a significant group by time interaction. The former indicated an overall decline in AATs across the night. More importantly, the three groups had comparable AAT levels during the first half of the night:. Sleepy and alert-deprived subjects, however, failed to show a decline in AATs, whereas the alert group showed a significant decline in the second half of the night. This differential rate of decline in AATs is suggested to be related to the differences in sleep homeostasis among alert and sleepy individuals.

Acoustic Stimulation↗
PubMed1996

Phase advance in moderately sleepy and alert normals.

Phase advanced sleep (by 4 hours) was studied in 28 healthy, normal men and women, aged 21-50 years, without nocturnal sleep or daytime sleepiness complaints. Eleven subjects (6 men and 5 women) with moderately short (< or = 10 minutes) average daily sleep latencies on the multiple sleep latency test (MSLT) were compared to 17 (11 men and 6 women) with relatively long (> or = 12 minutes) latencies. Nocturnal sleep on both a baseline and a shift night differed between the groups. The moderately "sleepy" group had shorter sleep latencies and less wakefulness during sleep than the moderately "alert" group. The phase advanced sleep schedule reduced sleep efficiency in both groups, but the moderately sleepy group showed a lessened effect of the shift. Additionally, sleep efficiency was reduced in the moderately sleepy group only during the first 2 hours of the sleep period, while sleep efficiency was uniformly disturbed in the moderately alert group throughout the night during the phase advance.

Adult↗
PubMed1996

The frequency of multiple sleep onset REM periods among subjects with no excessive daytime sleepiness.

The multiple sleep latency test (MSLT) is a valuable tool in the assessment of excessive daytime sleepiness (EDS). Additionally, multiple sleep onset rapid eye movement periods (SOREMPs) are a frequent occurrence in patients with narcolepsy. To date, however, few studies have evaluated the frequency of SOREMPs in a population of healthy control subjects. Subjects participating in a variety of sleep studies were screened with a nocturnal clinical polysomnogram, followed by the MSLT. Subjects were required to be drug free and have no sleep-related symptoms or medical or psychiatric conditions. Of the 139 subjects who were screened, 24 (17%) had two or more SOREMPs. These individuals were more likely to be male, younger, and sleepier than those with one or zero SOREMPs. The etiology of two or more SOREMPs in healthy controls was not apparent from the clinical or polysomnographic evaluation. Although it is possible that these findings are early signs of narcolepsy, subjects reported being free of any sleep-related complaints. Further investigations into the determinants of multiple SOREMPs and their reliability among asymptomatic populations are warranted.

Adult↗
PubMed1996

A two-week sleep extension in sleepy normals.

Thirty-four healthy, normal young men and women (21-35 years), with no sleep complaints and a normal screening polysomnogram, some with short (< or = 6-minute) and some with long (> or = 16-minute) average daily sleep latencies on a screening multiple sleep latency test, were studied on two baseline nights (8 hours) and in the "sleepy" group, for 14 consecutive nights of extended (10-hour) or habitual (7.8 +/- 0.7-hour) bedtimes. The screening differences between the groups in average daily sleep latency were consistently seen on the two further baseline nights and days. The extension of bedtime in sleepy subjects was followed by an increase in average daily sleep latency relative to randomly chosen sleepy subjects maintained on their habitual sleep schedule for the 14 nights. The increase in average daily sleep latency was associated with a gradual reduction in sleep efficiency over the 14 nights. Some (36%) of the sleepy subjects did not have increased average sleep latencies during the 10-hour bedtime extension. Those showing no increase in average daily sleep latency had an immediate drop in sleep efficiency when the bedtime was increased to 10 hours, suggesting they were unable to sleep longer during the extension. Their short average daily sleep latency was a result of causes other than chronic insufficient sleep.

Adult↗
PubMed1995

Zolpidem in the treatment of transient insomnia: a double-blind, randomized comparison with placebo.

Transient insomnia may be induced by stress, sleep in unfamiliar surroundings, jet lag and other factors. Zolpidem, a novel imidazopyridine hypnotic, has been shown to have hypnotic properties in most patients without significantly affecting next-day performance. Using the first-night effect in a sleep laboratory as a model of transient insomnia, this placebo-controlled, double-blind, parallel-group study evaluated the efficacy and safety of zolpidem in 462 normal volunteers. Zolpidem was tested at doses of 5, 7.5, 10, 15 and 20 mg, and statistical analysis of 7.5 mg and 10 mg was compared with placebo (unbalanced randomization). Compared with placebo, the 7.5 mg and 10 mg doses of zolpidem decreased sleep latency and increased sleep duration and maintenance (i.e. reduced number of awakenings). Zolpidem (7.5 mg or 10 mg) had no significant effect on next-day psychomotor performance. No statistically significant differences in the overall side-effect profiles were found between 7.5-mg and 10-mg zolpidem dose groups and placebo. This study demonstrates that zolpidem at 7.5 mg and 10 mg is effective in the treatment of transient insomnia.

Adult↗
PubMed1995

Neuropsychological function in obstructive sleep apnea syndrome (OSAS) compared to chronic obstructive pulmonary disease (COPD).

Forty-nine men, 25 with obstructive sleep apnea syndrome (OSAS) and 24 with chronic obstructive pulmonary disease (COPD), were evaluated with a standard 8-hour nocturnal polysomnogram, multiple sleep latency test the following day and a neuropsychological test battery. The OSAS patients had more respiratory disturbances per hour of sleep, more stage 1 sleep and greater daytime sleepiness than COPD patients. The OSAS patients were as impaired as the COPD patients in neuropsychological test functioning, with the pattern of impairment nonspecific as to hypoxemic-sensitive versus sleepiness-sensitive tasks, with two exceptions. The OSAS patients performed more poorly on a test requiring sustained attention and considered sensitive to sleepiness, whereas the COPD patients performed more poorly on a test requiring motor skills and sensitive to hypoxemia. These deficits in psychomotor and attention appear to be specifically related to patients group (OSAS vs. COPD), but the other deficits found in complex reasoning and memory are nonspecific.

Attention↗
PubMed1995

Hypersomnolence and neurocognitive performance in sleep apnea.

Two symptom clusters are prominent obstructive sleep apnea syndrome: excessive daytime sleepiness and neurocognitive difficulties. This article reviews studies that have attempted to determine the etiology and interrelation of these two symptom clusters. The research has clearly determined that the cause of the daytime sleepiness of obstructive sleep apnea syndrome is the fragmentation of sleep by the brief arousals that terminate each apneic event rather than the nocturnal hypoxemia that also occurs in obstructive sleep apnea syndrome. However, the daytime sleepiness and nocturnal hypoxemia appear to both contribute to the neurocognitive impairments of obstructive sleep apnea syndrome, and each seems to affect specific aspects of neurocognitive performance. The extent to which treatment reverses the neurocognitive impairments of obstructive sleep apnea syndrome is yet to be fully determined. The initial study suggests that the impairments are not completely reversed with treatment.

Humans↗
PubMed1995

Effects of theophylline on nocturnal sleep and daytime sleepiness/alertness.

To study the short-term effects of theophylline on sleep and wakefulness, 24 healthy men and women, aged 21 to 35 years, received each of three doses, 0, 3, and 6 mg/kg, of theophylline double-blind in a Latin Square design, administered to 12 subjects at 9 AM and to the other 12 at 11 PM. After the daytime administration, sleep latency was tested at 10 AM, 12 Noon, 2 PM, and 4 PM and divided attention and auditory vigilance performance were tested at 10:30 AM and 2:30 PM. After the nighttime administration, a standard 8-h polysomnogram was collected. On a separate day all subjects received a single 6-mg/kg dose at 9 AM and blood samples were drawn at 8:30 and 10:30 AM, 12:30 PM, 2:30 PM, and 4:30 PM. The serum theophylline levels for the 6-mg/kg dose peaked at 11.0 micrograms/mL and declined to 8.1 micrograms/mL by 4:30 PM. In the daytime administration, daytime mean sleep latency was increased by both doses and performance was improved by the high dose but not the low dose. In the nighttime administration, nocturnal sleep onset was delayed and total wake time was increased by the high dose but not the low dose. The low dose increased the amount of light stage 1 sleep without producing wakefulness.

Adult↗
PubMed1994

Sedative, memory, and performance effects of hypnotics.

The sedative, amnestic, and performance disruptive effects of benzodiazepine (Bz) receptor selective and non-selective hypnotics were studied in 23 healthy, normal subjects, aged 26.8 +/- 1.0 years. Triazolam (0.25 and 0.50 mg), zolpidem (10 and 20 mg) and placebo were administered, double-blind, at bedtime in a repeated measures design. During an awakening 90 min later (at approximate peak concentration of each drug) a 30-min performance battery which included memory, vigilance, and psychomotor tasks was completed. Each drug and dose impaired memory (both immediate and delayed), vigilance, and psychomotor performance relative to placebo. Among active drugs impairment was greatest with zolpidem 20 mg, next triazolam 0.50 mg, then zolpidem 10 mg, and finally triazolam 0.25 mg. Next morning delayed recall was also impaired by all drugs and doses (i.e. anterograde amnesia). The amnestic and performance-disruptive effects paralleled the relative hypnotic effects of the drugs and doses. No receptor selectivity in these pharmacodynamic effects was observed.

Adult↗
PubMed1994

Experimental sleep fragmentation.

Thirty-six healthy young men and women (age range 21-35 years) were studied in an experimental model of sleep fragmentation. On 2 nights sleep was disrupted by presenting tones to produce brief electroencephalogram (EEG) arousals (without shortening sleep time) and daytime function was assessed the following day with the Multiple Sleep Latency Test and a divided attention performance test. The fragmentation of sleep produced significant disruption of nocturnal sleep and reduced daytime alertness. Adaptation in EEG-defined arousals occurred from the 1st to the 2nd night of fragmentation. Threshold (measured indirectly) characteristics of EEG-defined arousals were somewhat different than those of previous studies requiring behavioral awakening. The percent of tone series producing arousal, number of tones necessary for arousal and duration of the arousal all reflected heightened thresholds in stage 3/4 and rapid eye movement (REM) sleep compared to stage 1 and stage 2 sleep. In the last 3 hours of sleep versus the first 3 hours, arousals occurred less frequently, required more tones to produce, resulted in shorter durations and in fewer sleep stage changes, except for REM sleep where the converse was the case.

Acoustic Stimulation↗