Effect of active and passive techniques used in thromboembolic prophylaxis on venous flow velocity in the post-procedure period.

Introduction: Studies have shown that using mechanical thromboembolic prophylaxis methods speeds up venous flow and decreases stasis. These studies examine the post-intervention period of 1-10 min. The length of the effect of procedures to raise venous flow velocity cannot be determined by clinical trials. To apply mathematical techniques to estimate how long mechanical thromboembolism prophylaxis procedures will increase venous flow rate. Methods: In the survey, we examined 25 persons (poststroke patients), with an average age of 57.2 ± 6.3 years. Regarding the proportion of genders, 13 (52%) participants were male and 12 (48%) female. The peak venous blood flow velocity was measured with a HADECO BIDOP ES-100V II type Doppler ultrasound device, using an 8 MHz head, in the femoral vein, at the level of the hip joint. We estimated the change of the venous blood flow velocity from the available sampled data using the method of least squares. For the calculations, we used Microsoft Excel, version Mac Excel 2019. Results: The decrease in peak venous flow velocity can be approximated by a logarithm function. Mathematical calculations show that after active thromboembolic prophylaxis interventions, resting venous flow velocity is restored at 26.8 min on the intact limb and 85.1 min on the hemiparetic side. Resting flow velocity is restored in 131.9 min after passive mobilization of the hemiparetic side and in 137.7 min after the consensual effect. Discussion: An elementary mathematical function can be used to estimate the time to recovery of peak venous flow velocity to resting state from measurements taken 15 min after the intervention. Active and passive mechanical thromboembolic prophylaxis after the intervention has a longer-term effect on venous flow velocity.

Effects of anterior thalamic nucleus DBS on interictal heart rate variability in patients with refractory epilepsy.

OBJECTIVE: Heart rate variability (HRV) changes were investigated by several studies after resective epilepsy surgery/vagus nerve stimulation. We examined anterior thalamic nucleus (ANT)-deep brain stimulation (DBS) effects on HRV parameters. METHODS: We retrospectively analyzed 30 drug-resistant epilepsy patients' medical record data and collected electrocardiographic epochs recorded during video- electroencephalography monitoring sessions while awake and during N1- or N2-stage sleep pre-DBS implantation surgery, post-surgery but pre-stimulation, and after stimulation began. RESULTS: The mean square root of the mean squared differences between successive RR intervals and RR interval standard deviation values differed significantly (p < 0.05) among time-points, showing increased HRV post-surgery. High (0.15-0.4 Hz) and very low frequency (<0.04 Hz) increased, while low frequency (0.04-0.15 Hz) and the LF/HF ratio while awake decreased, suggesting improved autonomic regulation post-surgery. Change of effect size was larger in patients where both activated contacts were located in the ANT than in those where only one or none of the contacts hit the ANT. CONCLUSIONS: In patients with drug-resistant epilepsy, ANT-DBS might positively influence autonomic regulation, as reflected by increased HRV. SIGNIFICANCE: To gain a more comprehensive outcome estimation after DBS implantation, we suggest including HRV measures with seizure count in the post-surgery follow-up protocol.

Weight reduction added to CPAP decreases blood pressure and triglyceride level in OSA: Systematic review and meta-analysis.

Obstructive sleep apnea (OSA) is associated with treatment-resistant hypertension and high cardiovascular risk. Continuous positive airway pressure (CPAP) fails to reduce cardiovascular risks consistently. Obesity and OSA show reciprocal association and they synergistically increase hypertension via different pathways. Our meta-analysis aimed to assess the cardiovascular benefits of combining weight loss (WL) with CPAP (vs. WL or CPAP alone) in OSA. Outcomes included systolic and diastolic blood pressure (BP) and blood lipid parameters. We explored Medline, Embase, Cochrane, and Scopus. Eight randomized controlled studies (2627 patients) were included. The combined therapy decreased systolic BP more than CPAP alone. Weighted mean difference (WMD) for CPAP + WL versus CPAP was -8.89 mmHg, 95% confidence interval (95% CI; -13.67 to -4.10, p < 0.001) for systolic BP. For diastolic BP, this decrease was not significant. In case of blood lipids, the combined treatment decreased triglyceride levels more than CPAP alone (WMD = -0.31, 95% CI -0.58 to -0.04, p = 0.027). On the other hand, addition of CPAP to WL failed to suppress BP further. The certainty of evidence according to GRADE was very low to moderate. In conclusion, our results showed that the addition of WL to CPAP significantly improved BP and blood lipid values in OSA. On the other hand, the addition of CPAP to WL could not significantly improve BP or blood lipid values. Review protocol: PROSPERO CRD42019138998.

Low test-retest reliability of the Epworth Sleepiness Scale within a substantial short time frame.

The Epworth Sleepiness Scale (ESS) is a widely used, validated questionnaire for effectively examining patients' sleepiness in a range of different situations. Test-retest reliability is an important aspect of a questionnaire, which, according to only a few studies, was found to be low in the case of the ESS. All these studies applied long intervals between the tests, thereby increasing the possibility of fundamental change in circumstances, which in turn affect the reliability of the test. The aim of the present study was to investigate the test-retest reliability of the ESS in a short time frame to provide stability of the test circumstances. We also compared the originally used and current accepted statistical methods of test-retest evaluation. We examined 100 unselected patients consecutively referred to the sleep laboratory with the ESS questionnaire, using a test-retest paradigm with an interval of 1 h between two ESS tests. The Lin's concordance coefficient was found to be low, whereas the Pearson's correlation revealed good reliability. Our result provides evidence on the poor test-retest reliability of the ESS, despite the examination protocol excluding changes in test circumstances.

Effect of Active and Passive Mechanical Thromboprophylaxis and Consensual Effect on the Venous Blood Flow Velocity Among Hemiparetic Patients.

Our aim was to measure the venous blood flow velocity (VBFV) in case of hemiparetic patients, after passive and active thromboembolic methods, as well as the consensual effect in the hemiparetic limb following the active venous exercises in the healthy limb. We examined 215 patients, with the median age of 58.0 (55.0-63.0) years. The VBFV was measured with a HADECO BIDOP ES-100 V II type Doppler ultrasound device, using an 8 MHz head, on the femoral vein at the level of the hip joint. For statistical analysis, SPSS version 22 was used. After passive movement, on the hemiparetic side, compared to the value in resting state, the VBFV significantly (12.6; 11.6-13.5 cm/s; P < .001) increased. Following active venous exercises performed on the healthy side, the VBFV significantly (18.0; 15.6-19.6 cm/s; P < .001) increased compared to the value in resting state. Following the active venous exercises performed on the healthy side, the VBFV measured on the hemiparetic side (consensual effect) was significantly (15.1 [14.1-16.5] cm/s; P < .001) higher than the value on the hemiparetic side in resting state. Active and passive mechanical thromboprophylaxis methods can be effective. Movements of the healthy limb significantly increase the VBFV in the inactive limb, and patients can perform it themselves several times a day.

[Pharmacological and nonpharmacological treatment of insomnias with regard to sleep medicine]. / Az insomniák kezelésének helye az alvásmedicinában: gyógyszeres és nem gyógyszeres eljárások.

Insomnia - one of the most prevalent sleep complain - has a great impact on the everyday life. Basically two different form of insomnia can be defined: the insomnia disorder and the co-morbid insomnias. To treat adequately determination of background pathology is essential, which is based on the help of Sleep Medicine Centers. According to the newest guidelines, the treatment of insomnia disorder is based on cognitive behavioural therapies followed by pharmaceutical intervention. In this review we provide the short description of cognitive behavioural therapies and basic principles of hypnotic drugs. Despite the availability of insomnia guidelines the huge variation of the insomnia medication can be seen in the daily practice. Due to the above mentioned reasons we summarize the good clinical practice of hypnotic drug administration for insomnia patients.

Combination of severe facial and cervical vascular malformation with obstructive sleep apnea syndrome: diagnostic and therapeutic approaches.

The combination of obstructive sleep apnea syndrome and vascular malformation within the head and neck region is a rare condition, and interestingly, only a few cases have recently been published. Propagation of the vascular mass to the larynx and pharynx can cause breathing and swallowing difficulties. Due to these sypmtoms, examination and initiation of appropriate therapy for such patients are indeed challenging. We reviewed the literature available and present our case of a 64 year old woman emphasizing the complaints of sleep apnea syndrome and vascular malformation of the face and neck region. Polygraphic examination detected severe obstructive sleep apnea syndrome. The MR examination of the neck revealed extensive vascular mass narrowing the pharyngo-laryngeal region, thereby causing temporal bone destruction on the right side with intracranial propagation. ENT examination demonstrated significant narrowing of the pharyngeal lumen and the laryngeal aditus caused by multiple hemangiomas. CPAP titration showed the minimalization of the apnea-hypopnea index on the effective pressure level. Regular CPAP usage resulted in diminishing a majority of the patient's complaints. Our examination clearly demonstrates, obstructive sleep apnea syndrome coupled with significantly obstructing vascular malformation in the head and neck region can be effectively treated safely with a CPAP device, if surgical therapy is not possible. We summarized our findings and the data available in the literature to set up recommendations for the appropriate examination and therapy (including mask fit, etc.) of vascular malformations and hemangiomas causing pharyngo-laryngeal obstruction.

[Insomnia and habits to help to fall asleep among adults]. / Insomnia és elalvást segíto szokások felmérése felnottek körében.

INTRODUCTION: The quality of sleep can be influenced by several factors, insomnia in turn has an effect on the state of health. AIM: The aim of our survey is to measure the effects of insomnia, furthermore, the sleep affecting agents and habits to help to fall asleep among adults. METHOD: We collected the online nationwide and the written datas from the South-Transdanubia region, 455 adults filled the questionnaire which contains the Athens Insomnia Scale. RESULTS: 13.4% of participants has insomnia, it is influenced by the quality of diet (p<0.001), comsumption of coffee (p = 0.045) and the physical activity (p = 0.011), what is more in correlation with the prevalency of chronic deseases (p = 0.001) and psychosomatic symptoms (p<0.001). The most frequent causes of sleep disorders are: work-related stress (35.6%), personal-life stress (35.4%) and pain (24.2%). In case of dormition problems most of the participants watch television (52.1%) and read (33%); 7.5% and 11.4% of the responders use sleeping pills and tisane. CONCLUSIONS: We attract attention to the prevalency and effects of insomnia, and the habits to help to fall asleep. Orv. Hetil., 2016, 157(49), 1955-1959.

Differences of brain electrical activity between moderate and severe obstructive sleep apneic patients: a LORETA study.

The effects of initiation of continuous positive airway pressure (CPAP) therapy on electroencephalographic (EEG) background activity were investigated in patients exhibiting both moderate (n = 13) and severe (n = 12) obstructive sleep apnea syndromes in the testing of the potential differences of alterations of brain electrical activity caused by chronic hypoxia between these two groups. A normal control group (n = 14) was also examined. Two EEG examinations were achieved in each group: before and after first-time CPAP therapy. Low-resolution electromagnetic tomography (LORETA) was implemented towards localizing the generators of EEG activity in separate frequency bands. Prior to CPAP treatment, as a common direction of change, analysis with LORETA demonstrated increased activity in comparison with the patient and control groups. In the moderate group, significant changes were detected in the alpha2 band in the posterior cingulate cortex as well as in the beta1 band in the right posterior parietal cortex and the left supramarginal gyrus. In the severe group, significant changes were found in theta and alpha1 bands in the posterior cingulate cortex. Following CPAP treatment, these significant differences vanished in the severe group. In the moderate group, significantly decreased activity was seen in the beta3 band in the right fusiform gyrus. These findings potentially suggest a normalizing effect of CPAP therapy on EEG background activity in both groups of obstructive sleep apnea syndrome patients. Compensatory alterations of brain electrical activity in regions associated with influencing successful memory retrieval, emotional perception, default mode network, anorexia and fear network caused by chronic intermittent hypoxia could possibly be reversed with the use of CPAP therapy.

Dynamic changes in sleep-related breathing abnormalities in bilateral paramedian mesencephalon and thalamus stroke: a follow-up case study.

BACKGROUND: Bilateral paramedian thalamic stroke is characterized by hypersomnia, vertical gaze palsy, amnestic alteration, and apathic state. Combined lesion of the paramedian thalamus and mesencephalon bilaterally is extremely rare. Little is known about the breathing disturbances of the particular region due to the lesion. The following describes the specific case of a woman, age 62, with bilateral paramedian thalamic and mesencephalic stroke. Initially, the patient's complaints exhibited altered vigilance and vertical gaze palsy. Notably, following the acute phase, fluctuating hypersomnia was detected. The MRI (brain) revealed an ischemic lesion in the medial part of the mesencephalon and paramedian thalamus, bilaterally. AIMS: The aim of the present study is to elucidate the involvement and characteristics of sleep-related breathing abnormalities in the clinical manifestation of the combined paramedian thalamic and mesencephalic stroke. METHODS: Polysomnographic recordings were accomplished seven times with 1-week interval between the consecutive recordings, toward investigating the early changes of sleep and sleep-related breathing abnormalities. RESULTS: Sleep structure examination featured a decrease in N3 and REM ratio and an increase in N1 and N2 ratio with minimal improvement during the recovery period. In contrast, significant changes were found in the breathing pattern: the initial central apnea dominance was followed by obstructive apneas with a gradual decrease of the total pathological respiratory events. CONCLUSION: In addition to the structural abnormality of the sleep regulating network, sleep-disordered breathing is another possible cause of hypersomnia in patients afflicted with the present localization of the lesion.

Minimal Clinically Important Difference on Parkinson's Disease Sleep Scale 2nd Version.

Background and Aims. The aim of the present study was to determine the estimates of minimal clinically important difference for Parkinson's Disease Sleep Scale 2nd version (PDSS-2) total score and dimensions. Methods. The subject population consisted of 413 PD patients. At baseline, MDS-UPDRS, Hoehn-Yahr Scale, Mattis Dementia Rating Scale, and PDSS-2 were assessed. Nine months later the PDSS-2 was reevaluated with the Patient-Reported Global Impression Improvement Scale. Both anchor-based techniques (within patients' score change method and sensitivity- and specificity-based method by receiver operating characteristic analysis) and distribution-based approaches (effect size calculations) were utilized to determine the magnitude of minimal clinically important difference. Results. According to our results, any improvements larger than -3.44 points or worsening larger than 2.07 points can represent clinically important changes for the patients. These thresholds have the effect size of 0.21 and -0.21, respectively. Conclusions. Minimal clinically important differences are the smallest change of scores that are subjectively meaningful to patients. Studies using the PDSS-2 as outcome measure should utilize the threshold of -3.44 points for detecting improvement or the threshold of 2.07 points for observing worsening.

[Sleep disturbances in Parkinson's disease: characteristics, evaluation and therapeutic approaches]. / Alvászavarok Parkinson-kórban: megjelenés, kivizsgálás, terápiás lehetoségek.

INTRODUCTION: Parkinson's disease is a well known representent of the movement disorder group of neurological disorders. The diagnosis of Parkinson's disease is based on specific symptoms and signs of movement abnormalities. In addition to classic motor symptoms, Parkinson's disease has characteristic non-motor features, and some of these emerges the classic signs. AIM: The authors discuss characteristics and therapeutic interventions in Parkinson's disease related sleep disturbances. METHOD: The authors reviewed and summarised literature data on sleep disorders in Parkinson's disease published in the PubMed database up to January 2015. RESULTS: Sleep problems are important non-motor complains (insomnia, hypersomnia, REM behaviour disorder, sleep apnea and restless legs syndrome). The neurodegenerative process of the brain-stem, the effect of symptoms of Parkinson's disease on sleep and concomitant sleep disorders constitute the background of the patient's complains. CONCLUSIONS: Appropriate diagnosis and therapy of the consequential or concomitant sleep disorders in Parkinson's disease will help to improve the patient's quality of life.

[CHARACTERISTICS AND DIFFERENTIAL DIAGNOSTICS OF SLEEP RELATED PATHOLOGICAL MOVEMENTS. UPDATE 2013]. / ALVÁS ALATTI KÓROS MOZGÁSJELENSÉGEK ÉS AZOK DIFFERENCIÁL DIAGNOSZTIKÁJA. UPDATE 2013.

Wide variety of the movements (from the physiologic body position changes to different pathologic events) can be seen during the sleep period. The most important types of these movements are the sleep related events (from the parasomnias to the restless leg related movements), the movement disorders and the epilepsy related events. To differentiate between these events is required special skill, which is based on appropriate characterisation of the events (for example timing, repetition, pattern), the polysomnographic and video-EEG examination and validated questionnaires (FLEP scale). The appropriate differential diagnostics and therapy must be based on the knowledge of the relationship of the sleep architecture and movement events. This review would like to provide guideline for the understanding and recognizing the nature of the sleep related movements.

Bilateral Subthalamic Stimulation can Improve Sleep Quality in Parkinson's Disease.

BACKGROUND: Sleep problems are among the most common non-motor symptoms of Parkinson's disease (PD). The PD Sleep Scale 2nd version (PDSS-2) improved the original PDSS by adding more items on different aspects of sleep problems, making it a more robust tool to evaluate the severity of sleep disturbances. However, previous studies on deep brain stimulation (DBS) have not used the PDSS-2. OBJECTIVE: To determine if the PDSS-2 could detect improvement reliably in sleep problems after bilateral subthalamic nucleus DBS for PD. METHODS: In this prospective study, 25 consecutive patients undergoing DBS implantation were enrolled. Patients were examined twice: 1 week prior to the DBS implantation (baseline) and 12 months postoperatively. Severity of PD symptoms were assessed by the Movement Disorders Society Unified PD Rating Scale (MDS-UPDRS) and the Non-Motor Symptoms Scale (NMSS). Presence and severity of sleep disturbances were specifically measured by PDSS-2. RESULTS: Total score of MDS-UPDRS improved from 81 (median, interquartile-range: 63-103) to 55 points (median, IQR: 46-75, p <  0.001). Health-related quality of life, measured by PDQ-39, also improved from 29 (IQR: 18-40) to 15 (IQR: 9-28) points (p = 0.002). Most domains of NMSS also improved. At baseline 13 patients reported sleep problems, but 1 year after DBS implantation only 3 did (p = 0.012). Although only 6 out of 15 items showed a significant decrease after DBS implantation, the total score of PDSS-2 decreased from 24 (IQR: 17-32) to 10 (IQR: 7-18) points (P <  0.001). CONCLUSIONS: Based on our results, PDSS-2 can detect improvements in sleep quality reliably after DBS implantation.

[SLEEP DISORDERED BREATHING AND EPILEPSY: RELATIONSHIPS AND THERAPEUTIC CONSIDERATIONS]. / AZ ALVÁSFÜGGO LÉGZÉSZAVAROK ÉS EPILEPSZIA: KAPCSOLÓDÁSI PONTOK ÉS TERÁPIÁS MEGFONTOLÁSOK.

The importance of the sleep related breathing disorders (obstructive sleep apnea syndrome, central sleep apnea, and Cheyne-Stokes breathing) in the pathophysiology crebro- and cardiovascular disorders is well known. The relationship of sleep related breathing abnormalities and epilepsy is also important but underestimated in the daily practice. The relation is bidirectional. The breathing abnormalities in sleep may play important role in generating epileptic seizure, but the adverse effect of seizure and antiepileptic therapy (generation of apneas and hypopneas) may worsen the seizure control. The effect of new therapies (vagal nerve and deep brain stimulation) on the sleep architecture and sleep disordered breathing must be examined and discussed. Here we present a brief case of epileptic patient with deep brain stimulation therapy on sleep as well. The examination of the sleep related breathing abnormalities in epilepsy patient may help improve the effectiveness of antiepileptic therapy.

Is the MDS-UPDRS a Good Screening Tool for Detecting Sleep Problems and Daytime Sleepiness in Parkinson's Disease?

Movement Disorder Society-sponsored Unified Parkinson's Disease Rating Scale (MDS-UPDRS) has separate items for measuring sleep problems (item 1.7) and daytime sleepiness (1.8). The aim of our study was to evaluate the screening sensitivity and specificity of these items to the PD Sleep Scale 2nd version (PDSS-2) and Epworth Sleepiness Scale (ESS). In this nationwide, cross-sectional study 460 PD patients were enrolled. Spearman's rank correlation coefficients were calculated between the individual items, domains, and the total score of PDSS-2 and item 1.7 of MDS-UPDRS. Similarly, the items and the total score of ESS were contrasted to item 1.8 of MDS-UPDRS. After developing generalized ordinal logistic regression models, the transformed and observed scores were compared by Lin's Concordance Correlation Coefficient. Only item 3 difficulties staying asleep and the "disturbed sleep" domain of PDSS-2 showed high correlation with "sleep problems" item 1.7 of the MDS-UPDRS. Total score of PDSS-2 had moderate correlation with this MDS-UPRDS item. The total score of ESS showed the strongest, but still moderate, correlation with "daytime sleepiness" item 1.8 of MDS-UPDRS. As intended, the MDS-UPDRS serves as an effective screening tool for both sleep problems and daytime sleepiness and identifies subjects whose disabilities need further investigation.

Test-retest validity of Parkinson's disease sleep scale 2nd version (PDSS-2).

BACKGROUND AND AIMS: The aim of the present study was to measure the test-retest validity of Parkinson's Disease Sleep Scale 2nd version (PDSS-2) on PD patients with stable medication and motor symptoms over the period of 4 weeks. METHODS: The subject population consisted of 92 PD patients. Besides PDSS-2, Unified PD rating scale, Montgomery-Asberg Depression Rating Scale and EQ-5D were assessed at baseline and 4 weeks later. RESULTS: The total score of PDSS-2 decreased from 19.06 ± 10.78 points to 18.00 ± 9.34 points (p > 0.05). For the total score of PDSS-2 the Intra-class and Lin's Concordance Correlation Coefficients were 0.782 and 0.799. The average difference between the baseline and follow-up total PDSS-2 scores was -1.06 points with the 95% confidence interval of -7.96 and +5.84 points. CONCLUSIONS: Our data supports that the items and the total score of PDSS-2 have acceptable test-retest reliability over a four week period on patients with stable PD symptoms and pharmacological therapy.

Effects of CPAP-therapy on brain electrical activity in obstructive sleep apneic patients: a combined EEG study using LORETA and Omega complexity : reversible alterations of brain activity in OSAS.

Effects of initiation of continuous positive airway pressure (CPAP) therapy on EEG background activity were investigated in patients with obstructive sleep apnea syndrome (OSAS, N = 25) to test possible reversibility of alterations of brain electrical activity caused by chronic hypoxia. Normal control group (N = 14) was also examined. Two EEG examinations were done in each groups: at night and in the next morning. Global and regional (left vs. right, anterior vs. posterior) measures of spatial complexity (Omega complexity) were used to characterize the degree of spatial synchrony of EEG. Low resolution electromagnetic tomography (LORETA) was used to localize generators of EEG activity in separate frequency bands. Before CPAP-treatment, a significantly lower Omega complexity was found globally and over the right hemisphere. Due to CPAP-treatment, these significant differences vanished. Significantly decreased Omega complexity was found in the anterior region after treatment. LORETA showed a decreased activity in all of the beta bands after therapy in the right hippocampus, premotor and temporo-parietal cortex, and bilaterally in the precuneus, paracentral and posterior cingulate cortex. No significant changes were seen in control group. Comparing controls and patients before sleep, an increased alpha2 band activity was seen bilaterally in the precuneus, paracentral and posterior cingulate cortex, while in the morning an increased beta3 band activity in the left precentral and bilateral premotor cortex and a decreased delta band activity in the right temporo-parietal cortex and insula were observed. These findings indicate that effect of sleep on EEG background activity is different in OSAS patients and normal controls. In OSAS patients, significant changes lead to a more normal EEG after a night under CPAP-treatment. Compensatory alterations of brain electrical activity in regions associated with influencing sympathetic outflow, visuospatial abilities, long-term memory and motor performances caused by chronic hypoxia could be reversed by CPAP-therapy.

Characteristic changes in brain electrical activity due to chronic hypoxia in patients with obstructive sleep apnea syndrome (OSAS): a combined EEG study using LORETA and omega complexity.

EEG background activity of patients with obstructive sleep apnea syndrome (OSAS, N = 25) was compared to that of normal controls (N = 14) to reflect alterations of brain electrical activity caused by chronic intermittent hypoxia in OSAS. Global and regional (left vs. right, anterior vs. posterior) measures of spatial complexity (Omega) were used to characterize the degree of spatial synchrony of EEG. Low resolution electromagnetic tomography (LORETA) was used to localize generators of EEG activity in separate frequency bands. Comparing patients to controls, lower Omega complexity was found globally and in the right hemisphere. Using LORETA, an increased medium frequency activity was seen bilaterally in the precuneus, paracentral and posterior cingulate cortex. These findings indicate that alterations caused by chronic hypoxia in brain electrical activity in regions associated with influencing emotional regulation, long-term memory and the default mode network. Global synchronization (lower Omega complexity) may indicate a significantly reduced number of relatively independent, parallel neural processes due to chronic global hypoxic state in apneic patients as well as over the right hemisphere.