Effect of triazolam on sleep and arterial oxygen saturation in patients with chronic obstructive pulmonary disease.

We compared the effects of a placebo with 0.125 and 0.25 mg of triazolam (Halcion) on sleep quality, oximetry, and respiratory events during sleep in ten stable outpatients with chronic obstructive pulmonary disease. The subjects had a forced expiratory volume in 1 s ranging from 17% to 76% of the predicted value (mean +/- SD, 38.1% +/- 19%) and a waking arterial oxygen pressure from 46 to 84 mm Hg (mean +/- SD, 67 +/- 12 mm Hg). Polysomnography was done on three nights within a two-week period after the patients received on a "blinded" basis either placebo or 0.125 or 0.25 mg of triazolam. Triazolam produced improvements in total sleep duration, time spent in stage 2 nonrapid eye movement (NREM) sleep, and subjective of sleep quality. For most patients, there was a nighttime drop in arterial oxygen percentage of saturation (SaO2) in the placebo condition, but triazolam did not cause a significant worsening, of the mean SaO2, minimum SaO2, or the number of apneic and hypopneic events. Across all experimental conditions, we documented little desaturation during wakefulness (mean low, 87.2% +/- 10.2%), more during NREM sleep (mean low, 83.2% +/- 12.6%), and most desaturation in REM sleep (mean low, 80.1% +/- 15.7%). We conclude that single-night use of triazolam improved the quality and duration of sleep in patients with chronic obstructive pulmonary disease. In patients without severe waking hypoxemia and without carbon dioxide retention, triazolam did not increase either nocturnal hypoxemia or respiratory events during sleep.

Early central nervous system response to HIV infection: sleep distortion and cognitive-motor decrements.

OBJECTIVE: To repeat and extend findings suggesting that sleep disturbance, excessive daytime sleepiness, and degraded cognitive-motor abilities may be early markers of central nervous system (CNS) involvement in HIV infection. DESIGN: A controlled, cross-sectional, prospective analysis. SETTING: Clinical research center at a teaching hospital and a military health research center. SUBJECTS: Twenty-three HIV-positive (mean CD4+ count, 387 +/- 162 x 10(6)/l) and 13 seronegative men who were Naval personnel or participants of the University of California, San Diego HIV Neurobehavioral Research Center. MAIN OUTCOME MEASURES: Nocturnal and daytime sleep electroencephalogram, electromyogram, and electrocardiogram. Simple and complex cognitive-motor performance assessed via computerized tasks. RESULTS: Comparison of sleep parameters based on HIV status, length of time infected, zidovudine use, and CD4+ count indicated that CD4+ T cells > 400 x 10(6)/l were associated with a distortion in nocturnal sleep characterized by increased stages 3 and 4 non-rapid eye movement (i.e., slow-wave) sleep in the latter portion of the night and reduced nocturnal awakenings. HIV-positive patients were no sleepier in the daytime than controls. Cognitive-motor performance revealed deficits in both accuracy and efficiency for HIV-positive patients. CONCLUSION: Asymptomatic HIV-positive patients with CD4+ counts > 400 x 10(6)/l demonstrate a statistically significant increase in slow-wave sleep during the latter portion of the night and less arousability. CD4+ lymphocyte count in the early phases of HIV infection appears to differentiate between various levels of HIV disease progression with respect to certain CNS measurements of nocturnal sleep and cognitive-motor performance. Sleep structure distortion remains one of the earliest and most consistently replicable physiological signs of HIV infection. This distortion may provide a link to immune function, disease progression, and cognitive-motor disability in HIV infection.

Self-reports versus sleep laboratory findings in 122 drug-free subjects with complaints of chronic insomnia.

The authors compared the sleep laboratory recordings of 122 drug-free subjects who complained of chronic insomnia with the subjects' estimates of their habitual sleep characteristics and their estimated sleep time on the morning after sleeping in the laboratory. Most subjects consistently underestimated the amount of time they slept and overestimated the amount of time it took them to get to sleep in comparison with laboratory data. All subjects consistently underestimated the number of arousals they experienced. The authors discuss the implications of these findings for the treatment and definition of insomnia and for further research.

When people die. Cause of death versus time of death.

A sample of 4,920 disease-related deaths from New York City for 1979 (8.7 percent of all relevant data from New York City's files) showed a 60 percent rise in death rate beginning at 2 A.M. and reaching a peak at 8 A.M. A smaller peak was also noted at 6 P.M. The rise in human mortality beginning at 2 A.M. and peaking at 8 A.M. might be explained by: artifact of deaths occurring anytime during the night that are discovered after daybreak, effect of less efficient health care between 2 A.M. and 8 A.M., and disease processes that somehow increase risk of death between 2 A.M. and 8 A.M. An attempt was made to differentiate among these possibilities by comparing time of death for various subsamples. The bimodal pattern appeared only in the temporal distribution of deaths of persons over 65 years of age; deaths of persons under 65 did not show significant temporal concentration. There were also prominent differences in the distribution of deaths for different reported causes of death. Ischemic heart disease, which numerically accounted for over 50 percent of the sample, showed peak mortality at 8 A.M. for both males and females. Hypertensive disease showed a significant peak in mortality at 1 A.M. for females only. Cerebrovascular disease peaked significantly at 6 A.M. with a significant peak only for males. The age and disease specificity of the 2 A.M. to 8 A.M. rise in death is consistent with a disease-related explanation for the bimodal circadian pattern in mortality. The quality and efficiency of health care could be improved with more precise information on peak periods of risk for specific morbid conditions.

Nonselective and selective benzodiazepine receptor agonists--where are we today?

Insomnia is problematic for many individuals, causing them to seek treatment. There is a long history of therapies aimed at restoring normal sleep patterns, each having its advantages and disadvantages. This review traces the history of insomnia drug therapies from chloral hydrate and the barbiturates through the benzodiazepines and explores the newest selective benzodiazepine receptor agonists, including zolpidem and zaleplon. The mechanisms of action of the benzodiazepine receptor agonists are compared and contrasted. A pharmacokinetic comparison is presented showing the importance that parameters such as dose, onset of action, lipophilicity, metabolites, half-life, and receptor-binding affinity have on clinical effects. The possible adverse effects of sleep aids are discussed, including residual sedation and psychomotor impairment, daytime anxiety, anterograde amnesia and cognitive impairment, rebound insomnia, and drug tolerance and dependence. Effects on sleep efficiency and staging are also discussed. Recommendations for the primary care physician on the selection of hypnotics are also provided. Benzodiazepine receptor agonists are often appropriate agents in the treatment of insomnia; however, individual drug and patient considerations are important in matching the most appropriate agent to the individual patient. Zolpidem and zaleplon, newer selective benzodiazepine receptor agonists, offer additional treatment options.

Daytime sleepiness and cognitive functioning in sleep apnea.

Our earliest findings relating sleepiness to cognitive function revealed that, among patients with the symptom of excessive somnolence, sleep apneics were the most impaired on cognitive tasks. Although the multiple sleep latency test (MSLT) has been the standard diagnostic test for assessing daytime sleepiness, the maintenance of wakefulness test (MWT) has clinical advantages over the MSLT when the assessment of daytime alertness is the primary goal. A number of studies on patients with sleep apnea and narcolepsy indicate that the MWT is more sensitive to treatment-related improvements in sleepiness. However, sleep tendency, as measured by the MSLT, and ability to remain awake, as measured by the MWT, probably represent the same physiological process viewed from different perspectives. Some patients, particularly those who have received suboptimal treatment, will show no treatment-related improvement in daytime sleepiness if they are evaluated only by the MSLT. We believe that the MWT and MSLT measure different aspects of the central problem of abnormal sleep tendency. The MWT may be a useful adjuvant daytime test in clinical situations where it is necessary to quantify degree of impairment or effectiveness of treatment.

Evaluation of treatment with stimulants in narcolepsy.

This paper briefly reviews sleep laboratory studies on the treatment efficacy of methylphenidate, pemoline, dextroamphetamine and methamphetamine. The literature indicates that 1) methylphenidate, dextroamphetamine, pemoline and methamphetamine objectively improve somnolence as measured by the Multiple Sleep Latency or Maintenance of Wakefulness Tests (MSLT or MWT); 2) pemoline, at doses up to 112.5 mg, is less effective in controlling somnolence than methylphenidate, dextroamphetamine and methamphetamine; 3) there are dose-dependent improvements in performance that parallel MSLT and MWT data; and 4) at the highest doses of stimulants studied to date, narcoleptics, although improved, still did not function on MSLT or MWT and most performance tests at levels comparable to those of control subjects. Future research designs should address issues of placebo effect, practice effects and the degree to which alertness and performance measures can be pharmacologically brought up to levels comparable to those of normal control subjects.

Relative efficacy of drugs for the treatment of sleepiness in narcolepsy.

A survey was conducted on 10 polysomnographic studies on the pharmacologic treatment of the sleepiness of narcolepsy. Three studies employed the 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.

Treatment of narcolepsy with methamphetamine.

Eight pairs of subjects (each consisting of a narcoleptic and a control matched on the basis of age, sex, educational background and job) were evaluated under the following double-blind, randomized treatment conditions: baseline, placebo, low dose and high dose methamphetamine. Subjects were drug-free for 2 weeks prior to beginning the protocol. Methamphetamine was the only drug taken during the protocol and was given in a single morning dose of 0, 20 or 40-60 mg to narcoleptics and 0, 5 or 10 mg to controls. The protocol was 28 days long, with each of the four treatment conditions lasting 4 days followed by 3 days of washout. Nighttime polysomnography and daytime testing were done during the last 24 hours of each treatment condition. Daytime sleep tendency was assessed with the multiple sleep latency test (MSLT). Daytime performance was assessed with performance tests including a simple, computer-based driving task. Narcoleptics' mean MSLT sleep latency increased from 4.3 minutes on placebo to 9.3 minutes on high dose, compared with an increase from 10.4 to 17.1 minutes for controls. Narcoleptics' error rate on the driving task decreased from 2.53% on placebo to 0.33% on high dose, compared with a decrease from 0.22% to 0.16% for controls. The effects of methamphetamine on nocturnal sleep were generally dose-dependent and affected sleep continuity and rapid eye movement (REM) sleep. Elimination half life was estimated to be between 15.9 and 22.0 hours. Mild side effects emerged in a dose-dependent fashion and most often involved the central nervous system and gastrointestinal tract. We concluded that methamphetamine caused a dose-dependent decrease in daytime sleep tendency and improvement in performance in both narcoleptics and controls. Methamphetamine at doses of 40-60 mg allowed narcoleptics to function at levels comparable to those of unmedicated controls.

The treatment of excessive somnolence with stimulant drugs.

Controlling the symptom of excessive sleepiness is an important responsibility of sleep medicine. Our group has reported that methamphetamine, given in the morning at doses of 40-60 mg, allowed narcoleptics to function throughout the day at normal levels of sleep tendency and psychomotor functioning as measured by multiple sleep latency and performance testing. These findings are important because they are the first to show normalization of function in narcolepsy with pharmacotherapy and because the dose of stimulant utilized was more than twice the maximum recommended by the manufacturer. Because it is possible to essentially eliminate the disabling sleepiness of narcolepsy, at least in the short term, we suggest that the following principles be applied in the therapeutic use of stimulant drugs: 1) Pathological sleepiness warrants aggressive treatment when sustained alertness is necessary for individual or public safety; 2) Stimulant drugs are important in the therapeutic approach to patients with pathological sleepiness; 3) The prime goal, although sometimes unachievable, should be symptom-free daytime functioning. It is important that, during therapy, a period of symptom-free daytime functioning be achieved for a frame of reference for evaluating future treatments; 4) Treatment efficacy should be assessed periodically with objective techniques such as the multiple sleep latency test or the maintenance of wakefulness test; 5) In some cases, stimulant doses may exceed the manufacturer's recommendations. However, the clinician should be guided by the prime goal of therapy, the patient's needs and the patient's ability to tolerate the chosen therapy.

HLA haplotypes, polysomnography, and pedigrees in a case series of patients with narcolepsy.

An ongoing study of the genetics of narcolepsy ascertains families through a case series of narcoleptic probands using diagnostic criteria consisting of 1) clinical history of excessive somnolence, 2) a mean sleep latency on the multiple sleep latency test (MSLT) of less than 7.9 minutes, 3) the rapid eye movement (REM) sleep-related symptom of cataplexy, 4) nocturnal polysomnography ruling out sleep apnea syndrome, and 5) two or more transitions to REM sleep on the MSLT. All probands and first-degree relatives received clinical and laboratory evaluations as well as human leukocyte antigen (HLA) typing. Demographic characteristics of the 32 probands are as follows: 17 males and 15 females; mean age was 42.1 years (range 13-70 years). The polysomnographic data confirmed daytime sleepiness and increased tendency for REM sleep for the 32 probands. Nocturnal polysomnographic results are as follows: sleep latency, 3.2 minutes; total sleep time, 442 minutes. MSLT results are as follows: sleep latency, 3.1 minutes; REM latency, 6.9 minutes; number of REM periods, 3.2. HLA typing revealed the presence of the HLA haplotypes, DRB1*15 and DQB1*0602, in 21 narcoleptic probands, with two African-Americans having the DQB1*0602 but not the DRB1*15 allele. Among the 57 relatives of the 32 probands, 1/31 females and 7/26 males were found to be affected with narcolepsy (p < 0.02), which suggests a higher diagnostic rate in male relatives. The 21 probands who were positive for the DRB1*15 and DQB1*0602 haplotypes did not differ from the 10 probands who were negative for these alleles in terms of their nocturnal sleep parameters, MSLT findings, or clinical presentation. Three families with multiple individuals affected with narcolepsy are presented. Two families have more than one affected individual who does not have the high-risk HLA haplotype. In one of these families, the disease is segregating independently of any HLA haplotype. In the third family, there is cosegregation with HLA DRB1*15 and DQB1*0602. One family contains a pair of DNA-confirmed, monozygotic twins with narcolepsy who are discordant for cataplexy and have the HLA DR14(Dw9)/DQB1*0503 and DR4(Dw4)/DQB1*0302 haplotypes.

Forty-eight-hour polysomnographic evaluation of narcolepsy.

Eleven narcoleptic and 11 control subjects completed five multiple sleep latency test (MSLT) procedures with instructions to "fall asleep" while supine and five maintenance of wakefulness test (MWT) procedures with instructions to "remain awake" while comfortably sitting. Narcoleptic subjects had a shorter sleep latency and a higher frequency of sleep onset REM periods (SOREMPs) on both daytime tests than controls. Each group had a longer sleep latency on the MWT than MSLT. For patients with narcolepsy, the differences between the two daytime procedures suggest the tests measure distinct aspects of sleep-wake tendency. Sleep latency on the MSLT did not correlate with sleep latency on the MWT for narcoleptic subjects. Furthermore, the number of SOREMPs during the MSLT for narcoleptic subjects did not correlate with the number of SOREMP during the MWT. Measures of nocturnal REM sleep for narcoleptic subjects correlated with sleep latency on the MSLT. In particular, REM latency at night was highly predictive of the magnitude of hypersomnia for patients with narcolepsy. Sleep latency at night tended to relate to sleep latency on the daytime tests for controls. Patients with narcolepsy had a shorter sleep latency, more frequent arousals, and a shorter REM latency than control subjects across the 2 nights of study.

Treatment of narcolepsy: objective studies on methylphenidate, pemoline, and protriptyline.

Methylphenidate, pemoline, and protriptyline were studied for their treatment efficacy in narcolepsy. A low, intermediate, and high dose level of each drug was studied for 1 week. For methylphenidate the doses were 10, 30, or 60 mg/day; for pemoline, 18.75, 56.25, or 112.5 mg/day; and for protriptyline 10, 30, or 60 mg/day. The order of dose levels was random from subject to subject and the daily dose was divided into thirds and taken in identically appearing capsules morning, noon, and afternoon. Subjects were 6 narcoleptic patients studied on methylphenidate (5 women and 1 man; mean age 54.5 + 11.7 years), 7 narcoleptic patients studied on pemoline (5 women and 2 men; mean age 43.0 + 7.1 years), and 4 narcoleptic patients studied on protriptyline (2 women and 2 men; mean age 42.5 + 16.9 years). Testing consisted of day-long sessions occurring at the end of each dose level and involving a clinical status questionnaire as well as maintenance of wakefulness, Wilkinson addition, and Digit-Symbol Substitution tests. Results were compared with 9 control subjects with no sleep disorder (5 women and 4 men; mean age 39.2 + 8.4 years) who were given placebo that was purported to be a "stimulant drug" and tested in a similar manner. Results demonstrated profound differences in ability to stay awake and perform between narcoleptic patients and controls. Data also suggested that methylphenidate significantly improves ability to stay awake. Pemoline seems to improve ability to perform. Protriptyline does not significantly alter ability to stay awake or to perform.

REM sleep episodes during the maintenance of wakefulness test in patients with sleep apnea syndrome and patients with narcolepsy.

Twelve patients with sleep apnea, 12 narcoleptic patients, and 10 controls were given 20-min opportunities to remain awake while sitting comfortably. Test sessions were administered at 10:00, 12:00, 14:00, 16:00, and 18:00. Apneic and narcoleptic subjects were less capable of maintaining wakefulness than controls. Patients with sleep apnea had an average of 1.4 daytime rapid eye movement (REM) episodes with the peak incidence at 14:00. Narcoleptics also had sleep onset REM periods (mean of 2.7), whereas none of the controls had REM episodes during the daytime testing. Narcoleptic and control groups differed in the probability of REM occurring at each session. There were time-of-day differences in the probability of REM occurring between patient groups. The amount of stage REM the night preceding testing was unrelated to the occurrence of REM episodes during the day in either patient group. In addition, there were notable differences in the frequency of sleep onset REM periods when patients were sitting as opposed to being supine during nap studies. Sleep latency and frequency of REM episodes on the maintenance of wakefulness test were independent of the subject's age. The maintenance of wakefulness test proved unsatisfactory as a diagnostic procedure, but appeared useful as an adjunct procedure in the evaluation of treatment efficacy of hypersomnia.

Nocturnal myoclonus: treatment efficacy of clonazepam and temazepam.

Clonazepam (1 mg h.s.) and temazepam (30 mg h.s.) were studied in 10 patients diagnosed as having insomnia with nocturnal myoclonus. Each subject underwent two nocturnal polysomnographic recordings while drug-free, two during treatment with clonazepam, and two during treatment with temazepam. Treatment sessions were 7 days long, and recordings were done on nights 6 and 7 of the treatment sessions. A 14-day washout period separated the treatment sessions. The order of drugs used in the first and second treatment sessions was randomized. Objective and subjective sleep laboratory data showed that both drugs improved the sleep of patients with insomnia in association with nocturnal myoclonus. Neither drug significantly reduced the number of nocturnal myoclonic events. Sleep changes were consistent with those produced by sedative benzodiazepines in general. Thus, the data support clinical reports that clonazepam, a benzodiazepine marketed for the indication of seizure, is useful in improving sleep disturbances associated with nocturnal myoclonus. Temazepam, a benzodiazepine marketed for the indication of insomnia, was found to be a suitable alternative to clonazepam in the treatment of insomnia associated with nocturnal myoclonus. The present data and other studies suggest the need for a model that explains why leg movements and sleep disturbances may wax and wane independently.

Narcolepsy and its treatment with stimulants. ASDA standards of practice.

This review is part of the standards of practice recommendations. It has been commended and reviewed by the Board of the ASDA. It reflects recommendations of the Board for the practice of sleep medicine in North America. The subcommittee is responsible for the presented write-up.

Genetic factors in canine narcolepsy.

The mating of narcopleptic Doberman pinschers yielded 30 puppies in five litters, all of which developed the disease between 1 and 4 months of age. Pedigrees of the Doberman probands are indicative of an autosomal recessive mode of transmission. An analysis of the pedigree of five affected Labrador retriever littermates suggests a similar mode of transmission. Crosses of affected dogs in two other breeds (miniature poodles and beagles) have resulted in all-unaffected F1 generations, thus allowing rejection of the simplest genetic hypothesis of a fully penetrant autosomal or sex-linked dominant or recessive gene.

The mandibular repositioning device: role in the treatment of obstructive sleep apnea.

The role of oral appliances in the routine treatment of obstructive sleep apnea (OSA) is not well defined. This prospective study attempts to clarify the clinical role of a specific oral appliance, the mandibular repositioning device (MRD). This study evaluated the demographic, polysomnographic, and cephalometric radiographic findings predictive of treatment success or failure with the MRD. Twenty-nine patients were diagnosed with mild to severe OSA by nocturnal polysomnography. The majority of these patients were intolerant to nasal continuous positive airway pressure (CPAP) and all were fitted with a MRD. Twenty-three of these patients were compliant initially with MRD use and received post-treatment nocturnal polysomnogrpahy at a mean of 104 days after receiving the device. The respiratory disturbance index (RDI) decreased with MRD use (37 +/- 23 versus 18 +/- 20 events/hour, p < 0.001), and 16 of the 23 patients (69%) were considered responders (decrease in RDI > or = 50% and posttreatment RDI < or = 20). Measurements of subjective and objective daytime sleepiness, nocturnal oxygen desaturation, and snoring were all improved with MRD use. A pre-treatment RDI > 40 was present in four of the seven (67%) non-responders. Age, body mass index, and cephalometric radiographic measurements were not predictive of treatment outcome. Sixteen of 23 patients (70%) continue to use the MRD after 3.4 +/- 0.7 years. This study suggests that the MRD is useful in the long-term treatment of patients with OSA of mild to moderate severity.

Disorders of excessive daytime somnolence: polygraphic and clinical data for 100 patients.

A consecutive series of 100 sleep apnea free patients with the complaint of excessive daytime somnolence (EDS) were evaluated; data from medical histories, physical examination, personality inventories, and polysomnography [nocturnal polysomnography (NPSG) and daytime multiple sleep latency testing (MSLT)] were tabulated. Significant differences were found between narcoleptic and non-narcoleptic patients in a number of parameters, including EDS severity, mean sleep latency on MSLT, sleep latency on NPSG, latency to REM sleep at night, number of REM sleep at night, number of REM sleep segments throughout the night, the total number of nocturnal myoclonic jerks (as well as the number occurring per hour of NREM and REM sleep), and the number of arousals and wake periods preceded by a myoclonic jerk. Significant differences in sleep latency during MSLT and NPSG testing were found between different EDS diagnostic groups of non-narcoleptic patients. The majority of patients in the MSLT group with long sleep latencies were in the diagnostic groups of EDS associated with psychophysiological and/or psychiatric problems or with drug abuse; patients with a diagnosis of idiopathic central nervous system hypersomnia or EDS associated with disturbed nocturnal sleep formed the majority of the MSLT group with short sleep latencies. The non-narcoleptic patients in a MSLT group with short sleep latencies had significantly shorter sleep latencies at night, more sleep cycles, higher sleep efficiency, and earlier REM sleep than patients with long sleep latencies.

Effects of low energy emission therapy in chronic psychophysiological insomnia.

The treatment of chronic psychophysiological insomnia presents a challenge that has not been met using currently available pharmacotherapy. Low energy emission therapy (LEET) has been developed as a potential alternative therapy for this disorder. LEET consists of amplitude-modulated electromagnetic fields delivered intrabuccally by means of an electrically conducting mouthpiece in direct contact with the oral mucosa. The effect of LEET on chronic psychophysiological insomnia was assessed with polysomnography (PSG) and sleep rating forms on a total of 106 patients at two different centers. Active or inactive LEET was administered for 20 minutes in late afternoon three times a week for a total of 12 treatments. Primary efficacy endpoints evaluating the results were changes from baseline in PSG-assessed total sleep time (TST) and sleep latency (SL). Secondary endpoints were changes in sleep efficiency (SE), sleep stages, and reports by the subjects of SL and TST. There was a significant increase in TST as assessed by PSG between baseline and post-treatment values for the active treatment group (76.0 +/- 11.1 minutes, p = 0.0001). The increase for the inactive treatment group was not statistically significant. The TST improvement was significantly greater for the active group when compared to the inactive group (adjusted for baseline TST; p = 0.020. R1 = 0.20). There was a significant decrease in SL as assessed by PSG between baseline and post-treatment values for the active treatment group (-21.6 +/- 5.9 minutes, p = 0.0006), whereas the decrease noted for the inactive treatment group was not statistically significant. The difference in SL decrease between the two treatment groups was marginally significant (adjusted for baseline SL and center, p = 0.068, R2 = 0.60). The number of sleep cycles per night increased by 30% after active treatment (p = 0.0001) but was unchanged following inactive treatment. Subjects did not experience rebound insomnia, and there were no significant side effects. The data presented in this report indicate that LEET administered for 20 minutes three times a week increased TST and reduced SL in chronic psychophysiological insomnia. LEET is safe and well tolerated and it effectively improved the sleep of chronic insomniacs given 12 treatments over a 4-week period by increasing the number of sleep cycles without altering the percentage of the various sleep stages during the night. The therapeutic action of LEET differs from that of currently available drug therapies in that the sleep pattern noted in insomniacs following LEET treatment more closely resembles nocturnal physiological sleep. This novel treatment may offer an attractive alternative therapy for chronic insomnia.