The immediate effects of nasal continuous positive airway pressure treatment on sleep pattern in patients with obstructive sleep apnea syndrome

We studied the immediate effects of continuous positive airway pressure (CPAP) applied nasally on the pattern of sleep in 12 patients, aged 30-58 years, with obstructive sleep apnea syndrome. All patients demonstrated a moderate to severe syndrome on the control night; apnea index ranged 28-83 apneas/h sleep. Nasal CPAP completely abolished all obstructive apneas and allowed apnea-free breathing in all 12 patients. Nasal CPAP had a marked effect on the sleep pattern. It significantly reduced stage I/II non-rapid eye movement (NREM) sleep and markedly increased stage III/IV NREM and REM sleep on the first treatment night. Stage I/II NREM sleep decreased from a control of 62.7 +/- 2.3% to 29.1 +/- 2.3% on the first treatment night. Stage III/IV NREM sleep increased from a control of 6.7 +/- 1.6% to 31.5 +/- 1.6%. The rebound in this sleep stage was especially marked in 3 patients aged 55-58 years. REM sleep increased from a control of 18.4 +/- 2.0% to 30.6 +/- 2.0% on the first treatment night. There was an increase in REM density. All patients were treated for another 2 nights and their sleep pattern analyzed on the third night. All sleep stages were still significantly different to the control night. The possible mechanisms involved are discussed.     

Efficacy of uvulopalatopharyngoplasty (UPPP) and modifications in sleep structure in the sleep apnea syndrome (SAS)

Thirty-four patients (32 male, 2 female; mean age 53 +/- 7 years) with confirmed sleep apnea syndrome (SAS) were studied before and after uvulopalatopharyngoplasty (UPPP). Clinical symptoms were tiredness, excessive daytime sleepiness and snoring. All patients were overweight. Patients underwent a thorough physical and oropharyngeal examination and polysomnography before and 3 months after surgery. On the basis of post-operative results, patients are divided into 3 groups: --group 1: 16 cured patients: apnea index (A.I./h) 38 +/- 17 before and 4.4 +/- 4 apneas/h sleep after surgery. Improved nocturnal hypoxemia: mean minimum oxyhemoglobin saturation (SAO2) before and after UPPP in NREM sleep 83 +/- 4% v. 90 +/- 4% in REM sleep 76 +/- 11% v. 85 +/- 7%. Uninterrupted sleep is restored; --group 2: 8 improved patients: A.I./h of 64 +/- 11 before and 20 +/- 6 after UPPP: improved nocturnal hypoxemia: mean minimum SAO2 in NREM sleep 74 +/- 10% before and 86 +/- 6% after UPPP: in REM sleep 59 +/- 9% before and 79 +/- 6% after UPPP, lower amount and percentage of fragmented sleep; --group 3: 10 non-improved patients: A.I./h unchanged 55 +/- 22% before and 50 +/- 20% after UPPP. Persistent nocturnal hypoxemia: mean minimum SAO2 in NREM sleep 76 +/- 13 before and 81 +/- 12% after UPPP: in REM sleep 63 +/- 16% before and 65 +/- 24% after UPPP. Sleep remains fragmented. In this last group patients are more overweight and all suffer from severe SAS with greater nocturnal oxyhemoglobin desaturation. Surgical treatment by UPPP is shown to be effective for 70% of our patients. Better results are obtained when SAS is less severe and overweight less important.     

Influence of nocturnal hypoxemia on the function of the visual tract in the course of the obstructive sleep apnea syndrome

BACKGROUND AND PURPOSE: In patients with obstructive sleep apnea (OSA) syndrome the episodes of upper airway obstruction lead to hypoxemia during sleep. The aim of the study was to establish the influence of sleep hypoxemia on the function of the visual tract in OSA patients. MATERIAL AND METHODS: The latency and amplitude of wave P100 of visual evoked potentials have been studied in 35 patients with OSA syndrome (mean apnea index 48+/-19). The diagnosis of OSA was established on the basis of continuous recordings of the respiratory function during sleep with additional full polysomnography in 17 patients. RESULTS: Mean absolute latency of P100 was longer in OSA patients than in healthy controls (117.0+/-8.8 ms vs. 104.3+/-4.6 ms, p<0.001). The differences in the amplitude of P100 were not significant (5.9+/-2.6 mV in OSA patients and 7.62+/-3.04 mV in healthy persons). In 60% of patients the latency of P100 exceeded 118 ms; in this group of patients the mean SaO2 during sleep apneas was lower than in patients with normal P100 latency (46+/-15% vs. 69+/-10%, p<0.05). Full polysomnographic studies revealed that in patients with prolonged latencies as compared with patients with normal P100 latencies there were lower: minimal SaO2 during NREM sleep (63+/-12% vs. 78+/-8%, p<0.05), as well as mean and minimal SaO2 during REM sleep (53+/-15% vs. 80+/-5% and 46+/-15% vs. 69+/-10%, p<0.05), without differences in apnea index or apnea duration. CONCLUSIONS: In patients with OSA syndrome the electrophysiological abnormalities suggesting damage of the optical tract may develop probably as a consequence of profound sleep hypoxemia.     

Half of patients with obstructive sleep apnea have a higher NREM AHI than REM AHI

BACKGROUND AND PURPOSE: To determine the percentage of sequential patients with obstructive sleep apnea with a higher non-rapid eye movement (NREM) apnea-hypopnea index (AHI) than rapid eye movement (REM) AHI and those with a higher REM AHI than NREM AHI, and to look for factors that might influence the AHI to be higher in one of these two groups versus the other and thus ascertain the factors that cause an AHI to be higher in NREM than REM. A high body mass index (BMI) and a supine body position are well known as exacerbating factors for obstructive sleep apnea (OSA). Males, as well as older individuals, are generally more predominantly affected with OSA than females. Usually OSA is worse in REM sleep than in NREM sleep, although this is not always true. METHODS: A retrospective study of sequential patients from one month's admission to a single sleep laboratory was conducted. We determined the age, sex, BMI, body position, duration of apnea, amount of time spent in REM and oxygen desaturation in patients who had a higher NREM AHI than REM AHI versus those who had a higher REM AHI than NREM AHI. To minimize variability, the sleep studies were scored by a single individual. RESULTS: A higher NREM AHI than REM AHI was found in 50% of the 66 patients with OSA. Males predominated in each group and there was no age difference between the groups. Although AHI for both groups tended to become higher with an increase in BMI, the BMI was not statistically different between the two experimental groups. OSA was worse in the supine position in both experimental groups consistent with previous literature. Percentage of time spent in REM or the duration of the apnea did not determine whether a patient fell into the NREM AHI>REM AHI group versus the REM AHI>NREM AHI. The severity of oxygen desaturation was not significantly different between the NREM AHI>REM AHI versus the REM AHI>NREM AHI group. However, when we combined and analyzed the two groups as a whole, the apneas were longer in REM, consistent with previous literature. CONCLUSIONS: Although it is well known that OSA is generally worse in REM sleep because of the degree of desaturation and duration of apnea, a higher NREM AHI than REM AHI is found in up to one half of individuals. Most of the usual predictors for severity of OSA as a whole did not discriminate these groups. Further work needs to be done to determine the factors that discriminate these two groups and thus make AHI higher in NREM than REM.     

Sleep disorders in Wilson’s disease

Background: Wilson’s disease (WD) is an autosomal recessive inherited disease with copper accumulation; neurodegeneration is associated with dopaminergic deficit. The aim of the study is to verify sleep co‐morbidity by questionnaire and objective sleep examinations (polysomnography, multiple sleep latency test). Methods: Fifty‐five patients with WD (22 hepatic, 28 neurological, five asymptomatic form) and 55 age‐ and sex‐matched control subjects completed a questionnaire concerning their sleep habits, sleep co‐morbidity, Epworth sleepiness scale (ESS), and answered screening questions for rapid eye movement (REM) behaviour disorder (RBD‐SQ). Twenty‐four patients with WD and control subjects underwent polysomnographic examination. Results: Unlike the controls, patients with WD were more prone to daytime napping accompanied by tiredness and excessive daytime sleepiness, cataplexy‐like episodes and poor nocturnal sleep. Their mean ESS as well as RBD‐SQ was higher than that of the controls. Total sleep time was lower, accompanied by decreased sleep efficiency and increased wakefulness. Patients with WD had lower latency of stage 1 and stage 2 of non‐rapid eye movement (NREM) sleep and less amount of NREM sleep stage 2. One‐third of the patients with WD were found to have short or borderline multiple sleep latency test (MSLT) values independent of nocturnal pathology (sleep apnoea, periodic leg movements and/or restless leg syndrome). Conclusions: Patients with WD often suffer from sleep disturbances (regardless of the clinical form). The spectrum of sleep/wake symptoms raises the suspicion that altered REM sleep function may also be involved.     

Atomoxetine improves sleepiness and global severity of illness but not the respiratory disturbance index in mild to moderate obstructive sleep apnea with sleepiness

BACKGROUND AND PURPOSE: Norepinephrine reuptake inhibitors such as protriptyline have been shown to improve sleepiness in sleep apnea, with or without improvement in the respiratory disturbance index (RDI). This study was performed to evaluate whether the selective norepinephrine reuptake inhibitor atomoxetine improves sleepiness, the clinical global impression (CGI) of severity of illness, and the RDI in patients with mild to moderate obstructive sleep apnea with excessive sleepiness. METHODS: Patients aged 18-60 years with RDI (including apneas, hypopneas with desaturations and hypopneas with arousals) >5/h sleep, apnea-hypopnea index (AHI; including apneas, hypopneas with 4% desaturations, but not apneas with arousals) <15/h sleep, and excessive sleepiness (Epworth Sleepiness Scale [ESS]>or=10) received open-label treatment with atomoxetine 40-80 mg HS for 4 weeks, with repeat polysomnography at the end of treatment. Of 20 patients screened, 17 started treatment and 15 completed treatment. RESULTS: ESS improved from 15.3 to 10.5 and CGI improved from 4.3 to 3.1 (both significant at p<0.01), but there was no significant change in RDI. ESS and CGI improved in a linear fashion across the weeks of treatment. Sleep efficiency and % stage rapid eye movement (REM) sleep were decreased, and % stage 1, awakenings and wake after sleep onset were increased. CONCLUSIONS: Atomoxetine improved sleepiness and the CGI in patients with mild to moderate obstructive sleep apnea with sleepiness. However, it did not improve the RDI.     

Total durations of respiratory events are modulated within REM and NREM sleep by sleeping position and obesity in OSA patients

BackgroundSupine sleeping position and obesity are well-known risk factors for obstructive sleep apnea (OSA) and modulate the risk for OSA-related daytime symptoms. Although respiratory event durations are associated with OSA-related severe health consequences, it is unclear how sleeping position, obesity, and daytime sleepiness are associated with respiratory event durations during REM and NREM sleep. We hypothesize that irrespective of the apnea-hypopnea index (AHI), respiratory event durations differ significantly between various OSA subgroups during REM and NREM sleep.MethodsOne night in-lab polysomnographic recordings were retrospectively analyzed from 1910 untreated suspected OSA patients. 599 patients (AHI ≥ 5) were included in study and divided into subgroups based on positional dependency, BMI, and daytime sleepiness (Epworth Sleepiness Scale and Multiple Sleep Latency Test). Differences in total hypopnea time (THT), total apnea time (TAT), and total apnea-hypopnea time (TAHT) within REM and NREM sleep between the subgroups were evaluated.ResultsDuring REM sleep, positional OSA patients had lower THT (OR = 0.952, p < 0.001) and TAHT (OR = 0.943, p < 0.001) than their non-positional counterparts. Compared to normal-weight patients (BMI < 25 kg/m²), obese patients (BMI ≥ 30 kg/m²) had lower THT, TAT, and TAHT (ORs = 0.942–0.971, p ≤ 0.009) during NREM sleep but higher THT (OR = 1.057, p = 0.001) and TAHT (OR = 1.052, p = 0.001) during REM sleep. No significant differences were observed in THT, TAT, and TAHT between patients with and without daytime sleepiness.ConclusionRegardless of the AHI, respiratory event durations vary significantly between OSA sub-groups during REM and NREM sleep. Therefore, to personalize OSA severity estimation the diagnosis should be tailored based on patient's demographics, clinical phenotype, and PSG characteristics.     

Use of the Epworth Sleepiness Scale in Chinese patients with obstructive sleep apnea and normal hospital employees

OBJECTIVE: To determine the use of the Epworth Sleepiness Scale (ESS) in Chinese patients with obstructive sleep apnea syndrome (OSA) and normal hospital employees. METHODS: Our sample consisted of 61 healthy controls and 100 patients with OSA. The test-retest reliability, internal consistency, and concurrent validity of the Chinese version of the ESS were analyzed. We also compared the ESS scores between controls and patients, studied the association between the ESS score and the apnea-hypopnea index (AHI) and minimum oxygen saturation (mO(2)), and examined to what extent the ESS score was predictive of mean sleep latency of the Multiple Sleep Latency Test (MSLT). RESULTS: The Chinese version of the ESS was found to have satisfactory reliability and validity. The mean+/-S.D. of ESS scores in normals was 7.5+/-3.0; in patients, it was 13.2+/-4.7. The ESS score had a negative association with mean sleep latency of the MSLT (rho=-0.42, P=0.0001) but no correlation with the AHI and mO(2). ESS scores of 14 and above significantly predicted a low mean sleep latency of the MSLT. CONCLUSION: The ESS should be included as one of the methods for assessing sleepiness in clinic samples of patients with OSA. Our data showed that the ESS was useful to separate patients with and without pathological degree of objective daytime sleepiness as determined by the MSLT.     

Epilepsy and obstructive sleep apnea

A few publications documented the coexistence of epilepsy and obstructive sleep apnea (OSA). The extent, nature, and clinical relevance of this association remain poorly understood. We retrospectively reviewed the database of our sleep center to identify patients with both sleep apnea and epilepsy. Characteristics of epilepsy, sleep history, presence of excessive daytime sleepiness [Epworth Sleepiness Scale (ESS)] and polysomnographic data were assessed. The effect of continuous positive airway pressure (CPAP) on seizure reduction was prospectively analyzed after a median interval of 26 months (range: 2-116 months) from the diagnosis of OSA. OSA was found in 29 epilepsy patients (25 men and 4 women) with a median age of 56 years (range: 37-79). The median apnea hypopnea index was 33 (range: 10-85), the oxygen desaturation index was 12 (range 0-92), and 52% of the patients had an ESS score >10. In 27 patients, epilepsy appeared 1 month to 44 years prior to the diagnosis of OSA. In 21 patients, the appearance of OSA symptoms coincided with a clear increase in seizure frequency or the first appearance of a status epilepticus. Treatment with CPAP was continued with good compliance in 12 patients and led to a significant reduction of both ESS scores and seizure frequency in 4 patients. Our data suggest the importance of considering diagnosis and treatment of OSA in epilepsy patients with poor seizure control and/or reappearance of seizures after a seizure-free interval.     

Residual subjective daytime sleepiness under CPAP treatment in initially somnolent apnea patients: a pilot study using data mining methods

BACKGROUND AND PURPOSE: Despite correct treatment with positive airway pressure (PAP), obstructive sleep apnea (OSA) patients sometimes remain subjectively somnolent. The reliability of the Epworth Sleepiness Scale (ESS) has been established for healthy subjects and patients under stable conditions; the ESS may eventually vary among treated OSA patients, biasing the results of a cross-sectional analysis of persisting sleepiness. The objective of this study was to depict the evolution of subjective vigilance under treatment using an index of ESS variability (DeltaESS). METHODS: In 80 OSA patients (apnea-hypopnea index [AHI]=54+/-26/h), initially somnolent (ESS=15+/-3) and treated with auto-titrating PAP (APAP) (oxyhaemoglobin desaturation index 3% [ODIapap]=3.4+/-2.2/h; daily APAP use=5.3+/-1.5 h) during 434+/-73 days, ESS scores were regularly collected four times every 109+/-36 days. DESS was calculated and data mining methods (Segmentation and Decision Tree) were used to determine homogeneous groups according to the evolution of ESS scores. RESULTS: When assessed cross-sectionally, 14-25% of the subjects were recognized as somnolent, depending on the moment when ESS was administered. Using data mining methods, three groups were clearly identifiable: two without residual somnolence - group 1, n=38 (47%), with high DeltaESS=-2.9+/-0.8, baseline ESS=16.3+/-3.3, AHI=58.5+/-26.1/h, mean ESSapap=5.1+/-2.4 and group 2, n=31 (39%), with low DeltaESS=-1.1+/-0.5, baseline ESS=13.2+/-1.4, AHI=53+/-27.3/h, mean ESSapap=8.8+/-1.9; and one with persisting sleepiness; group 3, n=11 (14%), with low DeltaESS=-0.3+/-0.8, baseline ESS=16.3+/-3, AHI=38.7+/-10.8/h, mean ESSapap=14.1+/-1.9. Compliance to PAP was high and comparable in the three groups. Age and body mass index (BMI) did not differ. CONCLUSION: Data mining methods helped to identify 14% of subjects with persisting sleepiness. Validation needs to be done on a larger population in order to determine predictive rules.     

快速动眼睡眠型和非快速动眼睡眠型阻塞性睡眠呼吸暂停综合征患者的临床特征分析

目的 比较快速动眼睡眠(REM)型和非REM(NREM)型阻塞性睡眠呼吸暂停综合征(OSA)患者的临床特征、多导睡眠监测(PSG)参数和血清学指标间的差异.方法 收集2018年1月至2019年6月住院且PSG提示总呼吸暂停低通气指数(AHI)≥5的OSA患者129例.统计REM期AHI值(AHIREM)和NREM期AH...     

The impact of obstructive sleep apnea and daytime sleepiness on work limitation

BACKGROUND: Many patients with obstructive sleep apnea (OSA) participate in the work force. However, the impact of OSA and sleepiness on work performance is unclear. METHODS: To address this issue, we administered the Epworth Sleepiness Scale (ESS), the Work Limitations Questionnaire (WLQ), and an occupational survey to patients undergoing full-night polysomnography for the investigation of sleep-disordered breathing. Of 498 patients enrolled in the study, 428 (86.0%) completed the questionnaires. Their mean age+/-standard deviation (SD) was 49+/-12 years, mean body mass index (BMI) was 31+/-7 kg/m(2) mean apnea hypopnea index (AHI) was 21+/-22 events/h, and mean ESS score was 10+/-5. Subjects worked a mean of 39+/-18 h per week. The first 100 patients to complete the survey were followed up at two years. RESULTS: In the group as a whole, there was no significant relationship between severity of OSA and the four dimensions of work limitation. However, in blue-collar workers, significant differences were detected between patients with mild OSA (AHI 5-15/h) and those with severe OSA (AHI>30/h) with respect to time management (limited 23.1% of the time vs. 43.8%, p=0.05) and mental/personnel interactions (17.9% vs. 33.0%, p=0.05). In contrast, there were strong associations between subjective sleepiness (as assessed by the ESS) and three of the four scales of work limitation. That is, patients with an ESS of 5 had much less work limitation compared to those with an ESS 18 in terms of time management (19.7% vs. 38.6 %, p<0.001), mental-interpersonal relationships (15.5% vs. 36.0%, p<0.001) and work output (16.8% vs. 36.0%; p<0.001). Of the group followed up, 49 returned surveys and 33 who were using continuous positive airway pressure (CPAP) showed significant improvements between the initial and second follow-up in time management (26% vs. 9%, p=0.0005), mental-interpersonal relationships (16% vs. 11.0%, p=0.014) and work output (18% vs. 10%; p<0.009). CONCLUSION: We have demonstrated a clear relationship between excessive sleepiness and decreased work productivity in a population referred for suspected sleep-disordered breathing. Screening for sleepiness and sleep-disordered breathing in the workplace has the potential to identify a reversible cause of low work productivity.     

Evening and morning blood gases in patients with obstructive sleep apnea

BACKGROUND AND PURPOSE: The purpose of this study was to see if blood oxygen levels deteriorate overnight during obstructive sleep apnea (OSA). Before and after sleep, arterial blood gases (ABGs) in OSA subjects and controls were drawn during a diagnostic night, as well as during a continuous positive airway pressure (CPAP) night for the OSA subjects. PATIENTS AND METHODS: Subjects, both male and female, were referred to our sleep laboratory for symptoms of daytime somnolence. Subjects consisted of a control group (N=13) with a mean apnea hypopnea index (AHI) of 3.3 events/h and a study group (N=22) with a mean baseline AHI of 57 events/h. RESULTS: With the subject supine, resting room air ABGs were drawn at 'lights out' on the evening before (PM) nocturnal polysomnography and in the morning (AM) at discontinuation ('lights on') of the sleep study. In controls, PM PaO(2) (79.4+/-9.7 mmHg) was not significantly different from AM PaO(2) (80.2+/-8.9 mmHg, P=0.5). In apneic subjects, the PM PaO(2) was 78.7+/-7.2 mmHg compared to an AM PaO(2) of 72.6+/-8.3 mmHg (P<0.05). The AM PaO(2) after a night of CPAP treatment in the OSA subjects was 77.5+/-10.2 mmHg compared to the PM PaO(2) of 76.0+/-6.0 mmHg (NS). The PM and AM PaCO(2)s were not different in controls or in study subjects under baseline conditions. However, during titration with nasal CPAP, the PaCO(2) was significantly higher in the morning after CPAP treatment [43.1+/-4.8 vs. 46.1+/-4.8 mmHg, respectively (P<0.05)]. CONCLUSIONS: OSA subjects showed a fall in overnight resting oxygenation. This could be accounted for by overnight deterioration of gas exchange and is ameliorated by CPAP.     

Analysis of the first night effect and sleep parameters in medically refractory epilepsy patients

OBJECTIVES: To assess the first night effect (FNE) and compare sleep stage proportions to normative values in a sample of medically refractory epilepsy patients. PATIENTS AND METHODS: Sleep parameters of 53 epilepsy patients, ages (18-56, mean: 34+/-12, 25 females 28 men), who underwent two consecutive nights of polysomnography (PSG) were compared. Non-rapid eye movement (NREM) stage 3 and NREM stage 4 were combined as slow wave sleep (SWS). Sleep efficiency, sleep latency, rapid eye movement (REM) latency, number of stage shifts, total minutes and proportion of total sleep time for stage 1, stage 2, SWS, and REM sleep were compared between the 2 nights. RESULTS: SWS was the only parameter that differed between nights 1 and 2 for both total minutes (P=0.02) and proportion of total sleep time (P=0.01), although the means for both nights were within the normative range. Comparing sleep proportions to normative values indicates that our patients had increased NREM stage 1 and decreased REM sleep. CONCLUSIONS: We observed a minimal FNE in this sample of epilepsy patients manifested by reduced SWS. Multiple PSGs to accommodate the FNE may not be necessary in this population.     

Vagus nerve stimulation reduces daytime sleepiness in epilepsy patients

BACKGROUND: Given that vagal afferents project to brainstem regions that promote alertness, the authors tested the hypothesis that vagus nerve stimulation (VNS) would improve daytime sleepiness in patients with epilepsy. METHODS: Sixteen subjects with medically refractory seizures underwent polysomnography and multiple sleep latency tests (MSLT) and completed the Epworth Sleepiness Scale (ESS), a measure of subjective daytime sleepiness, before and after 3 months of VNS. Most subjects (>80%) were maintained on constant doses of antiepileptic medications. RESULTS: In the 15 subjects who completed baseline and treatment MSLT, the mean sleep latency (MSL) improved from 6.4 +/- 4.1 minutes to 9.8 +/- 5.8 minutes (+/- SD; p = 0.033), indicating reduced daytime sleepiness. All subjects with stimulus intensities of < or =1.5 mA showed improved MSL. In the 16 subjects who completed baseline and treatment ESS, the mean ESS score decreased from 7.2 +/- 4.4 to 5.6 +/- 4.5 points (p = 0.049). Improvements in MSLT and ESS were not correlated with reduction in seizure frequency. Sleep-onset REM periods occurred more frequently in treatment naps as compared to baseline naps (p < 0.008; Cochran-Mantel-Haenszel test). The amount of REM sleep or other sleep stages recorded on overnight polysomnography did not change with VNS treatment. CONCLUSIONS: Treatment with VNS at low stimulus intensities improves daytime sleepiness, even in subjects without reductions in seizure frequency. Daytime REM sleep is enhanced with VNS. These findings support the role of VNS in activating cholinergic and other brain regions that promote alertness.     

Obstructive sleep apnea is common in medically refractory epilepsy patients

BACKGROUND: Previous reports have documented the coexistence of obstructive sleep apnea (OSA) and epilepsy and the therapeutic effects of treatment on seizure frequency and daytime sleepiness. The authors' objective was to determine the prevalence of OSA and its association with survey items in a group of patients with medically refractory epilepsy undergoing polysomnography (PSG). METHODS: Thirty-nine candidates for epilepsy surgery without a history of OSA underwent PSG as part of a research protocol examining the relationship of interictal epileptiform discharges to sleep state. Subjects also completed questionnaires about their sleep, including validated measures of sleep-related breathing disorders (Sleep Apnea Scale of the Sleep Disorders Questionnaire [SA/SDQ]) and subjective daytime sleepiness (Epworth Sleepiness Scale [ESS]). RESULTS: One-third of subjects had OSA, defined by a respiratory disturbance index (RDI) > or = 5. Five subjects (13%) had moderate to severe OSA (RDI > 20). Subjects with OSA were more likely to be older, male, have a higher SA/SDQ score, and more likely to have seizures during sleep than those without OSA (p < 0.05). Seizure frequency per month, the number or type of antiepileptic drugs (AED) prescribed, the localization of seizures (temporal versus extratemporal), and the ESS were not statistically different between the two groups. CONCLUSIONS: In our sample, previously undiagnosed obstructive sleep apnea was common, especially among men, older subjects, and those with seizures during sleep. The impact of treating OSA on seizure frequency and daytime sleepiness in medically refractory epilepsy patients warrants further controlled study.     

Comparative analysis of multiple sleep latency tests (MSLT) parameters and occurrence of dreaming in patients with daytime sleepiness of narcoleptic and non-narcoleptic origin

OBJECTIVE: To compare MSLT parameters in two groups of patients with daytime sleepiness, correlated to the occurrence and onset of dreams. METHOD: Patients were submitted to the MSLT between January/1999 and June/2002. Sleep onset latency, REM sleep latency and total sleep time were determined. The occurrence of dreams was inquired following each MSLT series. Patients were classified as narcoleptic (N) or non-narcoleptic (NN). RESULTS: Thirty patients were studied, 12 were classified as narcoleptics (N group; 40%), while the remaining 18 as non-narcoleptic (NN group; 60%). Thirty MSLT were performed, resulting in 146 series. Sleep was detected in 126 series (86%) and dreams in 56 series (44.44%). Mean sleep time in the N group was 16.0+/-6.3 min, while 10.5+/-7.5 min in the NN group (p<0.0001). Mean sleep latency was 2.0+/-2.2 min and 7.2+/-6.0 min in the N and NN group, respectively (p<0.001). Mean REM sleep latency in the N group was 3.2+/-3.1min and 6.9+/-3.7 min in the NN group (p=0.021). Dreams occurred in 56.9% of the N group series and 28.4% in that of the NN group (p=0.0009). Dream frequency was detected in 29.8% and 75% of the NREM series of the N and NN groups, respectively (p=0.0001). CONCLUSION: Patients from the N group, compared to the NN group, slept longer and earlier, demonstrated a shorter REM sleep onset and greater dream frequency. NN patients had a greater dream frequency in NREM series. Thus, the occurrence of dreams during NREM in the MSLT may contribute to differentially diagnose narcolepsy and daytime sleepiness.     

Continuous sleep EEG monitoring in PD patients with and without sleep attacks

The pathogenesis of sleep attacks in Parkinson's disease (PD) is still unresolved. We investigated seven matched pairs of PD patients with and without a history of sleep attacks using continuous sleep EEG recording. According to the event marker altogether 12 sleep attacks were identified in three patients with a history of sleep attacks. All sleep attacks were characterized by NREM stage 1 and 2 sleep, whereas no sleep onset REM episodes were recorded. Five sleep attacks fulfilled our criteria for microsleep episodes lasting less than 120 s. The cumulative duration of microsleep episodes during the day was 27.7+/-20 min in patients with a history of sleep attacks vs. 6.4+/-4.1 min in patients without a history of sleep attacks (p=0.03), i.e., the majority of microsleep episodes were not perceived by the patients. In summary, our study suggests that sleep attacks are intrusions of NREM stage 1 and 2 sleep into wakefulness and can be identical to microsleep episodes. Future studies should systematically address the awareness of short sleep episodes in patients with PD and other disorders with increased daytime sleepiness.     

Effect of 2-chloroadenosine on cerebrovascular reactivity to hypercapnia in newborn pig.

The effect of local administration of vasodilative concentrations of the adenosine receptor agonist 2-chloroadenosine (2-CADO) on the hyperemic responses of the pial and parenchymal microcirculations to graded hypercapnia was determined. The cranial window and brain microdialysis-hydrogen clearance techniques were utilized in two groups of isoflurane-anesthetized newborn pigs to measure changes in pial diameters and local CBF, respectively, in response to graded hypercapnia in the absence and presence of 2-CADO. Progressive size-dependent dilations of pial arterioles [small = 41 +/- 7 microns (mean +/- SD), intermediate = 78 +/- 13 microns, and large = 176 +/- 57 microns in diameter] occurred in response to graded hypercapnia alone (PaCO2 = 58 and 98 mm Hg) and to superfusions of 2-CADO (10(-5) M) during normocapnia; the magnitude of the dilative response to each of these stimuli was inversely proportional to vessel size. When hypercapnia was induced concomitantly with 2-CADO superfusion, the dilative effects of each stimulus were directly additive. Similarly, local microdialysis infusion of 10(-5) M 2-CADO, which doubled CBF during normocapnia, did not affect the hyperemic response of the parenchymal circulation to graded hypercapnia (PaCO2 = 69 and 101 mm Hg). Our findings are consistent with the participation of adenosine in the mediation of cerebral hypercapnic hyperemia. If, however, adenosine is not involved in this dilative response, our results indicate that concomitant vascular and neuromodulatory actions induced by adenosine receptor stimulation do not affect the mechanism responsible for the hypercapnic hyperemic response.     

Craniofacial abnormalities in Chinese patients with obstructive and positional sleep apnea

BACKGROUND: Obstructive sleep apnea (OSA) is a common disorder characterized by recurrent episodes of a complete or partial collapse of the upper airway during sleep. Traditionally, the disease is diagnosed by overnight polysomnography. Studies have shown correlation between parameters of cephalometry and severity of sleep apnea. We wish to determine the variable of craniofacial dimensions in the upper airway that contribute to OSA, and to investigate the significance of craniofacial measurements in positional and non-positional sleep apnea patients. METHODS: From July 2002 to June 2006, we studied 84 males and 15 females who came to the sleep center because of daytime sleepiness. All the participants underwent overnight polysomnography and lateral cephalograms, performed by an experienced technician. RESULTS: Craniofacial measurements of gnathion-gonion, anterior superior hyoid to mandibular plane (MP-H), posterior nasal spine (PNS) to the velum tip (SPL), widest point of the soft palate (SPW), and the product of PNS to the velum tip and widest point of the soft palate (product of soft palate (SPP)=SPL x SPW) were positively related to the apnea/hypopnea index (AHI). The velum tip to the pharyngeal wall parallel to the Frankfurt horizontal (PAS) was negatively related to the AHI. We further divided the study subjects into 4 groups according to AHI value (group 1, AHI<5; group 2, 5 or=30). Age, body mass index (BMI), neck circumference (NC), distances of PAS, SPL, SPW, SPP and angle of sella-nasion-infradentale (SNB) were significantly different depending on the degree of severity of sleep-disordered breathing (SDB). Patients who were older, with a high BMI and longer MP-H distance, had more daytime sleepiness (Epworth sleepiness scale, ESS). Furthermore, lower AHI values and longer PAS measurements were found in the positional sleep apnea group when compared to the non-positional sleep apnea group. After adjusting for confounding factors of age, BMI and NC, we found that BMI, MP-H distance and PAS measurement were correlated with severity of OSA. CONCLUSIONS: Cephalometry could be a useful and inexpensive clinical tool to evaluate Chinese patients with OSA. MP-H and PAS should be measured in Chinese patients with OSA. MP-H was correlated with ESS. The PAS measurement was narrower in non-positional OSA patients compared to positional OSA patients.