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Biomedical subjects

Peretz Lavie

Publications and source records attributed to Peretz Lavie.

At least 37 records · Page 2Linked to original sources
PubMed2003

The prevalence of glaucoma in patients with sleep apnea syndrome: same as in the general population.

PURPOSE: An association of glaucoma and sleep apnea syndrome (SAS) has been widely reported. We investigated the largest group of patients with SAS thus far to determine the prevalence of glaucoma among these patients. DESIGN: Cross-sectional study. METHODS: An institutional study. STUDY POPULATION: A total of 228 patients with SAS. OBSERVATION PROCEDURES: Sleep studies determined the respiratory disturbance index (RDI) during night sleep. Ocular examination included intraocular pressure (IOP) measurement, optic disk evaluation, and Humphrey visual field examination. MAIN OUTCOME MEASURES: The SAS was diagnosed as an RDI > 10. The RDI was graded to determine the severity of SAS: mild (RDI, 10-19), moderate (RDI, 20-39), and severe (RDI > 40). Open-angle glaucoma was diagnosed when a glaucomatous visual field defect matched the optic disk changes, irrespective of IOP levels. RESULTS: Nineteen participants had mild SAS (mean +/- standard deviation, RDI = 15 +/- 3), 129 had moderate SAS (RDI = 28 +/- 5), and 80 had severe SAS (RDI = 54 +/- 11). Open-angle glaucoma was found in five SAS subjects, a prevalence of 2% (95% confidence interval, 0.7% to 5%). There was no correlation between RDI and the presence of glaucoma (chi-square = 1.18; degrees of freedom = 2; P =.6) or between the RDI and the IOP (r = -0.067; P =.316). CONCLUSION: The prevalence of glaucoma in SAS patients was similar to that in the general Caucasian population.

Adult↗
PubMed2003

An automatic ambulatory device for detection of AASM defined arousals from sleep: the WP100.

OBJECTIVES AND BACKGROUND: Arousals from sleep are associated with increased sympathetic activation and therefore with peripheral vasoconstriction. Sleep fragmentation in the form of multiple arousals is associated with daytime somnolence and cognitive impairment; however, manual scoring of arousal is time consuming and problematic due to relatively high inter-scorer variability. We have recently shown that automated analysis of in-lab recorded peripheral arterial tone (PAT) signal and the pulse rate derived from it can accurately assess arousals from sleep as defined by the American Academy of Sleep Medicine (AASM). In the current study we sought to extend these findings to the Watch_PAT100 (WP100), an ambulatory device measuring PAT, oximetry and actigraphy. METHODS: Sixty-eight subjects (61 patients referred to the sleep lab with suspected obstructive sleep apnea and seven healthy volunteers, mean age 46.3+/-14.2 years) underwent a whole night polysomnography (PSG) with simultaneous recording of PAT signal by the ambulatory WP100 device. The PSG recordings were blindly manually analyzed for arousals based on AASM criteria, while PAT was scored automatically based on the algorithm developed previously. RESULTS: There was a significant correlation between AASM arousals derived from the PSG and PAT autonomic arousals derived from the WP100 (R=0.87, P<0.001), with a good agreement across a wide range of values. The sensitivity and specificity of PAT in detecting patients with at least 20 arousals per hour of sleep were 0.80 and 0.79, respectively, with a receiver operating characteristic curve having an area under the curve of 0.87. CONCLUSIONS: We conclude that automatic analysis of peripheral arterial tonometry signal derived from the ambulatory device Watch_PAT100 can accurately identify arousals from sleep in a simple and time saving fashion.

Adult↗
PubMed2003

Sleep complaints are not corroborated by objective sleep measures in post-traumatic stress disorder: a 1-year prospective study in survivors of motor vehicle crashes.

Disturbed sleep is a common complaint among patients with post-traumatic stress disorder (PTSD). However, laboratory studies of sleep in PTSD have provided inconsistent evidence of objective sleep disturbances. A major shortcoming of most previous studies is the fact that they were performed retrospectively in patients with chronic PTSD, often complicated by comorbid psychiatric disorders and drug abuse. Thus, little is known about the development of sleep disturbances in recently traumatized subjects. In this study, 102 motor vehicle collision (MVC) survivors were followed from the time of collision throughout 1 year. Nineteen subjects hospitalized for elective surgery served as a comparison group. Subjective quality of sleep was assessed using the mini-Sleep Questionnaire and the Sleep Habit Questionnaire. In addition, a 48-h actigraphic recording was obtained 1 week, 3 and 12 months after the collision. At 12 months, a structured clinical interview (SCID) was administered to reach a formal diagnosis of PTSD. Twenty-six of the MVC survivors, but none of the comparison subjects, met the diagnostic criteria for PTSD. While MVC survivors with PTSD reported markedly poorer sleep as reflected by significantly higher scores on the mini-Sleep Questionnaire, there were no significant differences between the three groups on the actigraphic measures that were largely normal. These results, which were obtained in subjects with no evidence of active psychiatric symptoms at the time of trauma and free of psychotropic or hypnotic medications, further support previous polysomnographic (PSG) studies suggesting that altered sleep perception, rather than sleep disturbance per se, may be the key problem in PTSD.

Accidents, Traffic↗
PubMed2003

Evaluation of a portable device based on peripheral arterial tone for unattended home sleep studies.

BACKGROUND: Diagnosis of obstructive sleep apnea syndrome (OSAS) by ambulatory systems is a growing practice in view of the large number of patients awaiting correct diagnosis. The Watch PAT100 (WP100) [Itamar Medical; Caesarea, Israel] is a portable device based on the peripheral arterial tone (PAT) signal, and is designed for unattended home sleep studies. OBJECTIVES: To evaluate the efficacy, reliability, and reproducibility of the WP100 device for the diagnosis of OSAS as compared to in-laboratory, standard polysomnographic-based manual scoring. DESIGN AND METHODS: One hundred two subjects (78 men; 69 patients with OSAS and 33 normal volunteers; mean +/- SD age, 41.4 +/- 15.2 years; body mass index, 26.8 +/- 5.5) underwent in-laboratory full polysomnography simultaneously with WP100 recording. Fourteen subjects also underwent two additional unattended home sleep studies with the WP100 alone. The polysomnography recordings were blindly scored for apnea/hypopnea according to the American Academy of Sleep Medicine criteria (1999), and the polysomnography respiratory disturbance index (RDI) [PSG-RDI] was calculated. The WP100 data were analyzed automatically for the PAT RDI (PRDI) by a proprietary algorithm that was previously developed on an independent group of subjects. RESULTS: Across a wide range of RDI levels, the PRDI was highly correlated with the PSG-RDI (r = 0.88, p < 0.0001), with an area under the receiver operating characteristic curve of 0.82 and 0.87 for thresholds of 10 events per hour and 20 events per hour, respectively. The PRDI scores were also highly reproducible, showing high correlation between home and in-laboratory sleep studies (r = 0.89, p < 0.001). CONCLUSION: The WP100 may offer an accurate, robust, and reliable ambulatory method for the detection of OSAS, with minimal patient discomfort.

Adult↗
PubMed2003

Plasma levels of nitric oxide and L-arginine in sleep apnea patients: effects of nCPAP treatment.

Sleep apnea syndrome has been shown to be associated with decreased levels of circulating nitric oxide (NO) after waking up from sleep. In this study we investigated overnight plasma concentrations of NO in sleep apnea patients before and after nasal continuous positive airway pressure (nCPAP) treatment and the effects of nCPAP on morning levels of L-arginine. In experiment 1, NO concentrations measured hourly during sleep were found to be significantly lower in a group of eight sleep apnea patients in comparison with six age-similar snorers and six normal young adults. In experiment 2, overnight NO concentrations were compared in 5 sleep apnea patients before and 9.3 +/- 3.9 mo after treatment with nCPAP. A significant increase in NO concentrations was found in four out of five patients, and a significant increase in L-arginine was found in all five patients after treatment. In experiment 3, removal of nCPAP for a single night in seven sleep apnea patients caused a significant decrease in morning levels of NO and L-arginine. These results demonstrate that sleep apnea is associated with a chronic state of diminished circulating NO concentrations that can be ameliorated by nCPAP treatment.

Adult↗
PubMed2003

Pituitary-gonadal function in men with obstructive sleep apnea. The effect of continuous positive airways pressure treatment.

OBJECTIVES: Decreased libido and a decline in morning serum testosterone levels were reported in men with obstructive sleep apnea (OSA). Our study aimed to evaluate the pituitary-gonadal axis in middle age men with OSA before and after treatment with nasal continuous positive airway pressure (CPAP). MATERIAL AND METHODS: Measurement of the nocturnal serum luteinizing hormone (LH) and testosterone levels and sleep recordings before and after nine months of CPAP treatment in five men with OSA aged 49.5+/-5.2 years. Patients were evaluated during nocturnal sleep at base line and during CPAP treatment. Serum LH and testosterone levels were determined at 20 minutes interval between 1900h and 0700h with concomitant determination of sleep quality, respiration and oxygen saturation. RESULTS: At base line, patients had higher RDI and PaO2<90%, lower mean and integrated (AUC) values of LH and testosterone. During CPAP treatment, RDI and PaO2<90% were normal. Mean and AUC values of testosterone and LH increased. CONCLUSIONS: OSA in men is associated with dysfunction of the pituitary-gonadal axis. The central suppression of nocturnal testosterone in these patients is partially corrected during chronic CPAP treatment.

Adult↗
PubMed2002

Correlation differences in heartbeat fluctuations during rest and exercise.

We study the heartbeat activity of healthy individuals at rest and during exercise. We focus on correlation properties of the intervals formed by successive peaks in the pulse wave and find significant scaling differences between rest and exercise. For exercise the interval series is anticorrelated at short-time scales and correlated at intermediate-time scales, while for rest we observe the opposite crossover pattern--from strong correlations in the short-time regime to weaker correlations at larger scales. We also suggest a physiologically motivated stochastic scenario to provide an intuitive explanation of the scaling differences between rest and exercise.

Biophysical Phenomena↗
PubMed2002

Autonomic arousal index: an automated detection based on peripheral arterial tonometry.

Arousals from sleep are associated with increased sympathetic activation and are therefore associated with peripheral vasoconstriction. We hypothesized that digital vasoconstrictions as measured by peripheral arterial tonometery (PAT), combined with an increase in pulse rate, would accurately reflect arousals from sleep, and can provide an autonomic arousal index (AAI). Based on a previously studied group of 40 sleep apnea patients simultaneously recorded by both polysomnography (PSG) and PAT systems, an automated algorithm using the PAT signal (and pulse rate derived from it) was developed for detection of arousals from sleep. This was further validated in a separate group of 96 subjects (85 patients referred with suspected obstructive sleep apnea and 11 healthy volunteers mean age 46.2+/-14.4 years, BMI 28.5+/-5.4 kg/m2). All underwent a whole night PSG with simultaneous PAT recording. The PSG recordings were blindly manually analyzed for arousals based on American Academy of Sleep Medicine (AASM) criteria, while PAT was scored automatically. There was a significant correlation between PSG and PAT arousals (R=0.82, p<0.0001) with a good agreement across a wide range of values, with a ROC curve having an area under the curve (AUC) of 0.88. We conclude that automated analysis of the peripheral arterial tonometry signal can detect EEG arousals from sleep, in a relatively quick and reproducible fashion.

Arousal↗
PubMed2002

Plasma vascular endothelial growth factor in sleep apnea syndrome: effects of nasal continuous positive air pressure treatment.

Sleep apnea syndrome is associated with recurrent episodic hypoxia during sleep, which has been implicated in the development of cardiovascular morbidity. Hypoxia is the major stimulus of vascular endothelial growth factor (VEGF), which is a potent angiogenic cytokine. In the present article we describe the results of three experiments in which plasma concentrations of VEGF were measured in patients with sleep apnea. In Experiment 1, apnea-hypopnea index was found to be a significant independent predictor of morning VEGF concentrations in 85 male subjects investigated in the sleep laboratory, of whom 47 had an apnea-hypopnea index greater than 20. In Experiment 2, VEGF concentrations measured hourly during the sleep period were found to be significantly higher in a group of five sleep apnea patients compared with six age-similar snorers and six normal young adults (129.1 +/- 43.4 versus 74.6 +/- 11.5 and 32.5 +/- 12.8 pg/ml, respectively [p < 0.007]). In Experiment 3, VEGF concentrations were compared in patients with sleep apnea before and 1 year after nasal continuous positive airway pressure treatment. A significant decrease in VEGF concentrations was found only in patients in whom nocturnal hypoxia improved after treatment (57.1 +/- 62.5 versus 39.6 +/- 46.9 pg/ml, p < 0.01). There was no comparable improvement in patients who did not accept treatment (53.9 +/- 23.6 versus 54.0 +/- 21.5 pg/ml, ns). These results raise the possibility that VEGF may contribute to the long-term adaptation of sleep apnea syndrome to recurrent nocturnal hypoxia.

Adult↗
PubMed2002

Residual effects of daytime administration of melatonin on performance relevant to flight.

There is a general consensus that melatonin possesses time-dependent hypnotic effects, but there is no information yet whether it has residual effects on neurobehavioral performance, especially after daytime administration. In the present study we investigated the possible residual effects of 3 mg melatonin on performance relevant to flight and on subjective feelings of sleepiness, arousal, activation and affect after a daytime nap, as a function of nap length. Fifteen reserve pilots of the Israeli Air Force participated in the study. The experiment consisted of four sessions during which either melatonin or placebo was administered at 16:00 h. In two conditions, subjects were allowed to sleep for 2 h (17:00-19:00 h) whereas in the other two only a 0.5-h nap was allowed. After the naps they started performing a flight simulator task every 2 h. Sleep efficiency significantly increased and sleep latency significantly decreased in both melatonin conditions compared to placebo. Flight performance was only mildly affected in the 0.5-h nap condition. Subjective assessment of sleepiness significantly differed between the two treatment conditions, only in the 0.5-h nap condition. Subjects felt sleepier 2-4 h after melatonin administration. To conclude, our data suggest that administration of melatonin before a brief daytime nap (about 0.5 h) may be associated with mild residual effects on psychomotor performance and may significantly affect subjective feeling of sleepiness for 2-4 h.

Adult↗
PubMed2002

Increased adhesion molecules expression and production of reactive oxygen species in leukocytes of sleep apnea patients.

Obstructive sleep apnea (OSA) is associated with increased cardiovascular morbidity and mortality. Free radicals and adhesion molecules were implicated in the pathogenesis of atherosclerosis leading to cardiovascular disorders. Therefore, we investigated the link between CD15, CD11c, CD11b, and CD64 expression on leukocytes and their ability to generate reactive oxygen species (ROS) in patients with OSA and control volunteers. We also studied the effects of hypoxia in vitro on monocytes from control subjects and the ability of monocytes from both groups to adhere to human endothelial cells in culture. The effect of nasal continuous positive airway pressure (nCPAP) treatment was studied as well. We found that OSA was associated with increased expression of adhesion molecules CD15 and CD11c on monocytes, increased adherence of monocytes in culture to human endothelial cells, increased intracellular ROS production in some monocyte and granulocyte subpopulations, and upregulation of CD15 expression due to hypoxia in vitro in monocytes of control subjects. Furthermore, nCPAP treatment was associated with downregulation of CD15 and CD11c monocyte expression and decreased basal ROS production in CD11c+ monocytes. Monocyte adherence to endothelial cells decreased as well. Our findings provide one of the possible mechanisms for explaining the high rate of cardiovascular morbidity in patients with sleep apnea.

Adult↗
PubMed2002

Oscillations in peripheral arterial tone in congestive heart failure patients: a new marker for Cheyne-Stokes breathing.

Cheyne-Stokes breathing (CSB), which is a prevalent finding in congestive heart failure (CHF) patients, has been shown to be of prognostic value. The oscillations in respiration were shown to be associated with oscillations in sympathetic nerve activation. We tested the hypothesis that the peripheral arterial tone (PAT) as measured by a novel finger plethysmograph can be used to detect CSB. Using a novel technique to measure the PAT, we monitored 10 patients with advanced CHF simultaneously with conventional polysomnographic recordings for either 1 or 2 nights. Records were scored for CSB during 3-min periods based on either respiratory effort and nasal-buccal airflow or on the PAT signal alone. The PAT sensitivity and specificity for the detection of periods containing CSB were 91 and 91% for the entire recording, 90.7 and 92.9% for non-REM sleep, 90.7 and 70% for REM sleep, and 73 and 97.3% for awake periods, respectively. PAT is a reliable marker of CSB in CHF patients. The novel finger plethysmograph can be used for screening and monitoring CSB.

Adult↗
PubMed2002

Sleep complaints as early predictors of posttraumatic stress disorder: a 1-year prospective study of injured survivors of motor vehicle accidents.

OBJECTIVE: Disturbed sleep is a common complaint among patients with posttraumatic stress disorder (PTSD) that appears in the reexperiencing and hyperarousal symptom clusters in DSM-IV. The causal relationship between sleep complaints and PTSD is unclear. METHOD: Self-reported insomnia and excessive daytime sleepiness were assessed in 102 victims of motor vehicle accidents and 19 comparison subjects 1 week and 1, 3, 6, and 12 months after the trauma. At 12 months the Structured Clinical Interview for DSM-III-R was administered to determine diagnoses of PTSD. RESULTS: Twenty-six of the accident victims but none of the comparison subjects met the criteria for PTSD. Logistic regression models indicated that sleep complaints from 1 month on were significant in predicting PTSD at 1 year. CONCLUSIONS: These results suggest that on the basis of sleep complaints as early as 1 month after the trauma, it is possible to detect subjects who will later develop chronic PTSD.

Accidents, Traffic↗
PubMed2002

Decreased pituitary-gonadal secretion in men with obstructive sleep apnea.

Decreased libido is frequently reported in male patients with obstructive sleep apnea (OSA). The decline in morning serum testosterone levels previously reported in these patients was within the normal adult male range and does not explain the frequent association of OSA and sexual dysfunction. We determined serum LH and testosterone levels every 20 min between 2200-0700 h with simultaneous sleep recordings in 10 men with sleep apnea and in 5 normal men free of any breathing disorder in sleep. The mean levels and area under the curve of LH and testosterone were significantly lower in OSA patients compared with controls [LH, 24.9 +/- 10.2 IU/liter.h vs. 43.4 +/- 9.5 (P < 0.005); testosterone, 67.2 +/- 11.5 nmol/liter.h vs. 113.3 +/- 26.8 (P < 0.003)]. Four of 10 patients had hypogonadal morning (0700 h) serum testosterone levels. Analysis of covariance (ANCOVA) revealed that the 2 groups differed significantly in the amount of LH and testosterone secreted at night independent of age or degree of obesity. After partialing out body mass index, there was a significant negative correlation between the amounts of LH and testosterone secreted at night and the respiratory distress index, but not with degree of hypoxia. Our findings suggest that OSA in men is associated with dysfunction of the pituitary-gonadal axis. The relation between LH-testosterone profiles and the severity of OSA suggests that sleep fragmentation and, to a lesser extent, hypoxia in addition to the degree of obesity and aging may be responsible for the central suppression of testosterone in these patients.

Adult↗
PubMed2002

No evidence of sleep disturbance in post-traumatic stress disorder: a polysomnographic study in injured victims of traffic accidents.

BACKGROUND: Disturbed sleep is a common complaint among patients with PTSD. This complaint can be found in both the reexperiencing and hyperarousal symptom clusters in the DSM-IV. However, laboratory studies of sleep in PTSD have provided inconsistent evidence of objective sleep disturbances. Shortened REM latency, reduced sleep efficiency, restless sleep and increased prevalence of sleep apnea have been reported, but were not confirmed by all. A major shortcoming of most previous studies is the fact that they were done retrospectively in patients with chronic PTSD, often complicated by psychiatric comorbidity and drug abuse. Thus, little is known about the development of sleep disturbances in recently traumatized subjects. METHOD: Eight injured victims of traffic accidents with PTSD and 6 injured victims without PTSD participated in a 3-night polysomnographic study one year after the accident. RESULTS: No significant differences between PTSD and non-PTSD patients were noted on any of the PSG measures. In addition, the two groups did not differ significantly from each other with respect to awakening thresholds during REM sleep. CONCLUSION: Considering that the present sample was free of active psychiatric comorbidity at the time of trauma and free of hypnotic medications, these results strengthen previous PSG studies suggesting that altered sleep perception, rather than sleep disturbance per se, may be the key problem in PTSD. More research is needed in order to examine whether this problem is specific to sleep or generalizes to other domains as well.

Accidents, Traffic↗
PubMed2000

Post-traumatic stress disorder and sleep-what a nightmare!

According to DSM IV criteria, sleep disturbances are incorporated in the definition of post-traumatic stress disorder (PTSD). These include the re-experiencing symptoms (nightmares, criteria B) and a hyperarousal state (difficulty initiating and maintaining sleep, criteria D). PTSD patients commonly complain of sleep disturbances. Moreover, insomnia, restless sleep and trauma-related dreams might be the primary complaint of some patients. However, although subjective sleep disturbances are considered characteristic of PTSD, sleep laboratory studies have provided inconsistent evidence of objective sleep disorders. A variety of sleep architectures and sleep patterns has been reported in PTSD. However, only a few studies have controlled for comorbidities. Thus, uncertainty exists to what extent the sustained complaints of sleep disturbances in chronic PTSD are specifically related to the impact of exposure to traumatic stress, or rather are a consequence of comorbid disorders. Specific changes in REM sleep suggest a pathophysiologic role of REM sleep abnormality in PTSD (e.g. anxiety dreams, increased REM density, exaggerated startle response, decreased dream recall and elevated awakening thresholds from REM sleep). However, again, studies have failed to show consistent changes in percentage of REM sleep or in REM latency. There might be a coexistence of pressure to REM along with inhibitory forces of REM that result in high variability of REM parameters across patients. Alternatively, changes in REM sleep might reflect the effect of comorbid psychiatric disorders that results in inconsistent findings between patients. The current review tries to address these issues based on recent studies carried out in this field.

Journal Article↗