Effects of sleep deprivation on daytime sleepiness in primary insomnia.

STUDY OBJECTIVES: This study investigated changes in MSLT scores and recovery sleep following total sleep deprivation in subjects with insomnia as compared to normal sleepers. DESIGN: Matched-groups design. SETTING: A sleep disorders center in a large medical center. PARTICIPANTS: Ten individuals with psychophysiological insomnia and ten age- and sex-matched normal sleepers served as subjects. INTERVENTIONS: Subjects underwent total sleep deprivation after baseline polysomnography and MSLT. A post-deprivation MSLT was obtained, as well as polysomnography on the recovery night and an MSLT after the recovery night. MEASUREMENTS AND RESULTS: Both groups showed significant decreases in MSLT scores following total sleep deprivation, as compared to baseline. Both groups had significantly shorter scores on a nighttime MSLT compared to a daytime MSLT. The insomnia group also showed a significant increase in total sleep time on the recovery night compared to baseline. CONCLUSIONS: The MSLT is sensitive to changes in sleepiness associated with total sleep deprivation in individuals with primary insomnia.

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.

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.

Sleep disorders in patients on continuous ambulatory peritoneal dialysis.

Sleep complaints, habits, and medical history were surveyed in 81 patients chronically receiving continuous ambulatory peritoneal dialysis. Seventy-three percent of the sample reported insomnia, and 52% reported unintentional napping during the day. Behavioral factors (such as caffeine or alcohol use) or the severity of concurrent medical disease did not account for the sleep problems. Eighteen of these patients subsequently underwent polysomnography and objective measurement of daytime sleepiness. Clinically significant sleep apnea syndrome was present in 11. The presence of sleep apnea was associated with increased levels of psychological distress and daytime sleepiness. Periodic leg movements during sleep were also frequently observed but had minimal effect on sleep quality. Implications of these findings for clinical practice are discussed.

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.

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.

Sleepiness and ethanol effects on simulated driving.

Twelve healthy young men were assessed in each of four experimental conditions presented in a Latin Square design: 8-hr time in bed (TIB) and placebo, 4-hr TIB and placebo, 8-hr TIB and ethanol, and 4-hr TIB and ethanol. After consuming ethanol (0.6 g/kg) or placebo (0900-0930 hr) with 20% supplements at 1030 and 1100 hr, subjects were tested for sleepiness (Multiple Sleep Latency Test at 1000, 1200, 1400, and 1600 hr) and divided attention (1030 hr) performance on day 1, and for simulated driving and divided attention (1000-1200 and 1400-1600 hr) performance on day 2. In the morning testing, with breath ethanol concentrations (BECs) averaging 0.049%, sleepiness was increased, divided attention reaction times increased (on both days), and simulated driving performance was disturbed in the ethanol and 4-hr TIB relative to placebo. Similarly in the afternoon, with BECs averaging 0.013%, the ethanol and 4-hr TIB condition increased sleepiness and disrupted divided attention and simulated driving performance. The results show that sleepiness and low-dose ethanol combine to impair simulated automobile driving, an impairment that extends beyond the point at which BEC reaches zero. They provide a possible explanation for the incidence of alcohol-related automobile accidents at low BECs.

Long-term study of the sleep of insomnia patients with sleep state misperception and other insomnia patients.

OBJECTIVE: The objectives were 1) to investigate differences among patients with subjective insomnia (sleep state misperception), patients with objective findings of insomnia, and normal volunteers and 2) to assess the consistency of the sleep findings during a 2-month period. METHOD: Twenty-one subjects were studied. Subjects with sleep state misperception (N = 7) had insomnia complaints for more than 1 year, no objective sleep disturbance, and sleep efficiency of 90% or greater (on the diagnostic screening sleep recording), while subjectively estimating that sleep time was less than 6.5 hours. Subjects with objective insomnia (N = 7) met the same subjective criteria, but objectively sleep efficiency was 85% or less. Normal subjects (N = 7) had no insomnia complaints and objective sleep efficiency of 90% or greater. All subjects were recorded on 2 consecutive nights three times with a 3-week period between each pair of nights (6 standard all-night polysomnographic sessions of 8 hours). A subjective sleep questionnaire was administered after each sleep recording night. RESULTS: Sleep stage variables (percentages) were similar between the two insomnia groups, and both were different from the normal subjects. Sleep continuity variables were disturbed in the objective insomnia group, but they were similar in the sleep state misperception and normal groups. Both insomnia groups rated their sleep as inadequate on the questionnaires and differed from the normal subjects. The distinct sleep patterns of each of the three groups did not vary over the 6 nights of assessment. CONCLUSIONS: Sleep state misperception may be a prodromic or transitional state of sleep dysfunction between normal sleep and the sleep pattern of objective insomnia.

Rebound insomnia in normals and patients with insomnia after abrupt and tapered discontinuation.

Rebound insomnia was studied in subjects, aged 25-50 years, with insomnia complaints and normal sleep, insomnia complaints and disturbed sleep, and normal sleep with no complaints (N = 21, n = 7 per group). Standard sleep recordings were collected on a baseline night and after abrupt discontinuation of 6 nights of 0.50 mg triazolam, tapered discontinuation (3 nights of 0.50 mg, 2 nights of 0.25 mg, and 1 night of 0.125 mg triazolam) and 6 nights of placebo. Significantly disturbed sleep on the discontinuation night compared to the baseline night was found. The relative degree of rebound insomnia was greater in the abrupt condition than in either the tapered or placebo conditions. The tapered condition reduced sleep time by half that of the abrupt condition which was twice the reduction found in the placebo condition. An overall (regardless of group or condition) difference in baseline versus discontinuation sleep was found, suggesting that pill discontinuation itself leads to sleep disturbance. Subjects did not differ in rebound insomnia as a function of pre-existing sleep disturbance.

Rebound insomnia and hypnotic self administration.

Twenty-one (three groups of seven), men and women, 25-50 years of age were studied to determine whether or not rebound insomnia would increase the likelihood of self administering a benzodiazepine (triazolam 0.25 mg) hypnotic. The groups compared were patients with insomnia and disturbed sleep, insomnia and normal sleep, and healthy normals. Rebound insomnia, by both subjective and polysomnographic assessment, was induced. The experience of rebound insomnia did not increase the likelihood of self administering a benzodiazepine hypnotic in any of the groups. There were clear group differences in pill self administration with normals rarely and insomnia patients frequently, but not differentially (placebo versus active drug) self administering pills.

Rebound insomnia: duration of use and individual differences.

This study assessed consistency, duration of use, and individual difference in rebound insomnia. Eleven healthy men, 20-30 years old, with normal sleep by both subjective and polysomnographic criteria, received each of four treatments in a double-blind Latin Square design (triazolam 0.50 mg for 1, 6, and 12 nights and placebo for 12 nights), followed by two placebo discontinuation nights. Triazolam increased sleep compared with placebo without differences in effects between the first and last nights of treatment. On discontinuation following active drug, sleep efficiency was reduced compared with placebo, but duration of administration did not alter the likelihood or intensity of rebound insomnia. Those subjects (5) showing poorer sleep on discontinuation from the 12-night treatment also had poorer sleep in the 1- and 6-night treatment. Subjects with rebound insomnia had poorer baseline sleep and a greater drug effect than did subjects without.

HLA DR2 in narcolepsy with sleep-onset REM periods but not cataplexy.

To determine the association of HLA DR2 in patients with narcolepsy without cataplexy, a case-control study was performed. Patients receiving the diagnosis of narcolepsy without cataplexy had excessive daytime sleepiness (EDS) and polysomnographic findings consistent with narcolepsy but no clinical evidence of cataplexy. Of 28 patients identified, 12 agreed to return for HLA typing. Respondents did not differ from nonrespondents in demographic, clinical, or sleep laboratory data. The comparison group was 503 individuals, those 30 years and older, on the Michigan Kidney Transplant Registry. The odds ratio obtained from logistic regression indicated a strong association between narcolepsy without cataplexy and HLA DR2. To control for potential confounding variables, multivariate models were constructed to explore the joint effects of HLA DR2 and each one of the covariates (age, sex, and race), their possible combinations, and the effect of all three covariates. The odds ratios decreased minimally and the association between the disease and HLA DR2 remained significant.

Subjective and polysomnographic characteristics of patients diagnosed with narcolepsy.

In order to better characterize the subjective and polysomnographic findings in patients with narcolepsy, a follow-up questionnaire was mailed to all patients diagnosed with the disorder at the Henry Ford Hospital Sleep Disorders and Research Center. The questionnaire inquired regarding the present, previous, and change in status for the constellation of narcolepsy symptoms. Memory problems, problems of daytime function, and nocturnal sleep disturbance were included among the questions related to the symptomatic constellation. By definition, all patients were symptomatic of daytime sleepiness and were diagnosed with narcolepsy only if there were two or more rapid eye movement (REM) onsets documented on the polysomnographic evaluation. A high percentage of patients reported nocturnal sleep disturbance, which was one of the symptoms with the latest reported onset. Retrospective comparison of questionnaire responses to the clinical polysomnography revealed significantly more sleep maintenance difficulties in the group of patients reporting this symptom on the questionnaire. Patients with disturbed nocturnal sleep reported taking more naps during the day, although the Multiple Sleep Latency Test (MSLT) failed to show differences in sleep latency. Interestingly, this group of patients was found to have a significantly higher number of sleep onset REM episodes on the MSLT. Finally, the findings are discussed as they compare to studies that required the presence of cataplexy as part of their inclusion criteria.

Psychometric profiles of patient populations with excessive daytime sleepiness.

Patients with narcolepsy have more psychiatric symptoms than normal controls as measured by psychometric tests. However, it is unclear whether these findings are specific to narcolepsy, as some studies have suggested, or related to excessive daytime sleepiness (EDS) or to chronic illness. We compared a group of 56 narcoleptics to age- and sex-matched controls with EDS. A group of 48 individuals with normal sleep architecture was also used as an additional control group. Both the narcoleptic group and the EDS-control group had significantly greater scores on Minnesota Multiphasic Personality Inventory scales but were not different from each other. Our data suggest that the psychopathology associated with narcolepsy is not specific and may be generalized among patients with disorders of excessive sleepiness.

Response to CPAP and UPPP in apnea.

Ninety-two consecutive patients with obstructive sleep apnea syndrome (OSAS) were studied before and six weeks after treatment with either nasal continuous positive airway pressure (CPAP) or uvulopalatopharyngoplasty (UPPP) (n = 46 per group). Assignment of patients to treatment was based on clinical considerations and patient preference. Patients were assessed by nocturnal polysomnography and performance on the Multiple Sleep Latency Test (MSLT) the following day. Before treatment, the CPAP and UPPP groups did not differ in sleep-related respiratory disturbance, oxygenation during sleep, fragmentation of sleep, or the level of excessive daytime sleepiness indicated by the MSLT. Both treatments produced significant improvement on all measures. However, improvement in UPPP patients was significantly less consistent than that of CPAP patients. To the extent that UPPP successfully reversed the respiratory disturbance (i.e., 50% reduction in respiratory events index), sleep continuity and daytime sleepiness were improved to a degree comparable to that of patients treated with CPAP.

Recovery of alertness after CPAP in apnea.

Excessive daytime sleepiness is the most common symptom in OSAS. Administering CPAP improves breathing during sleep. We evaluated the time course of the recovery of alertness following CPAP therapy in OSAS patients. Thirty-nine patients with OSAS were treated with CPAP and evaluated after one, 14, or 42 nights of treatment, 13 patients being randomly assigned to each group. All received a diagnostic polysomnogram and MSLT before treatment. The three groups had similar baseline values for nocturnal respiratory disturbance, oxygenation during sleep, fragmentation of sleep, and level of EDS. CPAP treatment was associated with a significant improvement in sleep-related respiration, oxygenation, and sleep fragmentation. The EDS showed significant improvement after one night, and further significant improvement after 14 nights, but no further significant improvement after 42 nights. The differential rate of improvement in nocturnal parameters compared with that of primary complaint of EDS suggests that OSAS patients experience a chronic functional sleep loss. As with sleep deprivation, recovery of alertness in OSAS requires several nights of normal sleep.

Sleep extension, enhanced alertness and the sedating effects of ethanol.

Twelve, healthy young men (mean age 25.6 years) consumed either ethanol (0.75 g/kg producing a peak breath ethanol concentration, BEC, of 0.060% on average) or placebo at 0900-0930 hr after spending 8 hr time-in-bed (TIB) the previous night and once again after 7 or 8 consecutive nights of 10 hr TIB. Latency to sleep onset (on the Multiple Sleep Latency Test, a standard measure of daytime sleepiness/alertness) was tested at 1000, 1200, 1400 and 1600 hr and divided attention performance was assessed at 1100 hr. Ethanol reduced sleep latency and divided attention performance and the sleep extension improved both sleep latency and divided attention performance. Sleep extension attenuated the sedating effects of ethanol; sleep latency after extending sleep did not differ between placebo and ethanol. While the effects of ethanol on performance still were detectable after sleep extension, the level of performance was at the 8-hr TIB placebo level. BEC peak and decline (determined before each latency test) did not change with the sleep extension. Hence, reduced BECs do not account for the reduction in the disruptive effects of ethanol with sleep extension.

Predictors of objective level of daytime sleepiness in patients with sleep-related breathing disorders.

Excessive daytime sleepiness, the most prevalent symptom associated with the OSAS, is hypothesized to result from either fragmentation of sleep or hypoxemia during sleep. Measures of nocturnal sleep, respiration during sleep, and daytime sleepiness in 466 patients with apnea were collected to evaluate these two hypotheses. The various parameters were submitted to correlation and multiple regression analyses to predict daytime sleepiness as measured by the MSLT. The RAI, which measures the number of arousals from sleep associated with respiratory disturbances (best fragmentation correlation), produced a higher correlation with MSLT scores than did TMES (best hypoxemia correlation); however, the measures were highly intercorrelated, and multiple regression analyses to determine which parameters independently predicted MSLT showed the single best predictor to be the RAI. Additional independent variance in MSLT score was explained by TST and PSG1. Measures of hypoxemia provided little or no independent predictive information. These data support the hypothesis that sleep fragmentation is an important determinant of daytime sleepiness in patients with apnea.