Physiologic events initiating REM sleep in patients with the postpolio syndrome

Rapid Eye Movement Sleep Sawtooth Waves Are Associated with Widespread Cortical Activations

Sawtooth waves (STW) are bursts of frontocentral slow oscillations recorded in the scalp electroencephalogram (EEG) during rapid eye movement (REM) sleep. Little is known about their cortical generators and functional significance. Stereo-EEG performed for presurgical epilepsy evaluation offers the unique possibility to study neurophysiology in situ in the human brain. We investigated intracranial correlates of scalp-detected STW in 26 patients (14 women) undergoing combined stereo-EEG/polysomnography. We visually marked STW segments in scalp EEG and selected stereo-EEG channels exhibiting normal activity for intracranial analyses. Channels were grouped in 30 brain regions. The spectral power in each channel and frequency band was computed during STW and non-STW control segments. Ripples (80-250 Hz) were automatically detected during STW and control segments. The spectral power in the different frequency bands and the ripple rates were then compared between STW and control segments in each brain region. An increase in 2-4 Hz power during STW segments was found in all brain regions, except the occipital lobe, with large effect sizes in the parietotemporal junction, the lateral and orbital frontal cortex, the anterior insula, and mesiotemporal structures. A widespread increase in high-frequency activity, including ripples, was observed concomitantly, involving the sensorimotor cortex, associative areas, and limbic structures. This distribution showed a high spatiotemporal heterogeneity. Our results suggest that STW are associated with widely distributed, but locally regulated REM sleep slow oscillations. By driving fast activities, STW may orchestrate synchronized reactivations of multifocal activities, allowing tagging of complex representations necessary for REM sleep-dependent memory consolidation.SIGNIFICANCE STATEMENT Sawtooth waves (STW) present as scalp electroencephalographic (EEG) bursts of slow waves contrasting with the low-voltage fast desynchronized activity of REM sleep. Little is known about their cortical origin and function. Using combined stereo-EEG/polysomnography possible only in the human brain during presurgical epilepsy evaluation, we explored the intracranial correlates of STW. We found that a large set of regions in the parietal, frontal, and insular cortices shows increases in 2-4 Hz power during scalp EEG STW, that STW are associated with a strong and widespread increase in high frequencies, and that these slow and fast activities exhibit a high spatiotemporal heterogeneity. These electrophysiological properties suggest that STW may be involved in cognitive processes during REM sleep.

Currents issues in cardiorespiratory care of patients with post-polio syndrome

ABSTRACT Post-polio syndrome (PPS) is a condition that affects polio survivors years after recovery from an initial acute attack of the poliomyelitis virus. Most often, polio survivors experience a gradual new weakening in muscles that were previously affected by the polio infection. The actual incidence of cardiovascular diseases (CVDs) in individuals suffering from PPS is not known. However, there is a reason to suspect that individuals with PPS might be at increased risk. Method A search for papers was made in the databases Bireme, Scielo and Pubmed with the following keywords: post polio syndrome, cardiorespiratory and rehabilitation in English, French and Spanish languages. Although we targeted only seek current studies on the topic in question, only the relevant (double-blind, randomized-controlled and consensus articles) were considered. Results and Discussion Certain features of PPS such as generalized fatigue, generalized and specific muscle weakness, joint and/or muscle pain may result in physical inactivity deconditioning obesity and dyslipidemia. Respiratory difficulties are common and may result in hypoxemia. Conclusion Only when evaluated and treated promptly, somE patients can obtain the full benefits of the use of respiratory muscles aids as far as quality of life is concerned.

Analysis of sleep characteristics in post-polio syndrome patients

The main post-polio syndrome (PPS) symptoms are new weakness, new atrophy, fatigue, pain and sleep disturbances. Polysomnography is the gold standard for sleep analysis.

OBJECTIVE

To analyze sleep patterns in PPS patients.

METHOD

Sixty patients (mean age 46.8+/-11.3 years) at the Federal University of São Paulo (UNIFESP/EPM) complaining of sleep disturbances were evaluated by means of polysomnography, performed at the Sleep Institute.

RESULTS

Sleep efficiency was lower due to high sleep latency and arousal index. The apnea and hypopnea index (AHI) and the periodic limb movements (PLM) index were higher. Sleep architecture was also impaired. There were no abnormalities of oxygen saturation, carbon dioxide levels, respiratory rate or heart rate.

CONCLUSION

New post-polio sleep disturbances were isolated symptoms. It appears that these symptoms were not due to post-polio features, but rather, that they were due to dysfunction of the surviving motor neurons in the brainstem. Abnormal dopamine production, which is responsible for many sleep-related breathing disorders and abnormal movements, may also have been implicated in the present findings.

Role of ultrasound in the airway management of critically ill patients

Ultrasound imaging of the upper airway in critically ill patients offers a number of attractive advantages compared with competitive imaging techniques or endoscopy. It is widely available, portable, repeatable, relatively inexpensive, pain-free, and safe. In this review article, I describe ultrasonographic anatomy of the upper respiratory organs and present the main potential applications of ultrasonography in airway management. The role of ultrasound in endotracheal tube placement, including preintubation assessment, verification of tube position, double-lumen intubation, and extubation outcome, are explained. Also, ultrasound-guided percutaneous tracheostomy, the role of ultrasound in using the laryngeal mask airway, and upper airway anesthesia are described.

Postpolio syndrome: a challenge to the health-care system

The practical eradication of poliomyelitis in industrialized countries marks one of the most important achievements of world health policy. Yet, disability induced by polio not only continues to exist among survivors with paralytic sequelae, but may also be further accentuated in a considerable number of affected subjects by the development of postpolio syndrome (PPS). PPS aggravates the motor sequelae already present in such subjects and reduces their functional capacity to the point where it affects their activities of daily living and worsens their quality of life. Inasmuch as development of PPS questions the concept of poliomyelitis as a static disease it poses a challenge not only to health professionals but also to policy-makers tasked with providing the necessary health-care measures and appropriate resources. This study sought to review research on this syndrome and to draw up some recommendations that might prove useful to the health authorities for decision-making purposes.

Post-Polio Syndrome

Post-polio syndrome (PPS) is the term used for the new late manifestations that occur in patients 30 to 40 years after the occurrence of acute poliomyelitis. PPS has been recognized for over 100 years, but is more common at the present time because of the large epidemics of poliomyelitis in the 1940s and 1950s. PPS is manifested by neurologic, musculoskeletal, and general manifestations. Neurologic manifestations include new weakness, muscle atrophy, dysphagia, dysphonia, and respiratory failure. Musculoskeletal manifestations include muscle pain, joint pain, spinal spondylosis and scoliosis, and secondary root and peripheral nerve compression. General manifestations include generalized fatigue and cold intolerance. New muscle weakness of a mild-to-moderate degree responds well to a nonfatiguing exercise program and pacing of activity with rest periods to avoid muscle overuse. Generalized fatigue may be treated with energy conservation and weight loss programs and lower extremity orthoses. Pharmacologic agents also may be helpful, but have not been beneficial in controlled trials. Bulbar muscle weakness includes dysphagia, dysphonia, sleep disorders, and chronic respiratory failure. Dysphagia may be improved with instruction on compensatory swallowing techniques. Dysphonia is treated with voice exercise therapy and voice amplification devices. Sleep disorders are treated similarly to sleep disorders in non-PPS patients. Respiratory failure may be treated with continuous positive airway pressure, bilevel positive airway pressure, and nasal ventilation, or tracheotomy and permanent ventilation if necessary. Musculoskeletal (muscle and joint) pain is treated with weight loss, pacing of activities, use of assistive devices, and prescribing anti-inflammatory medications and physical therapy techniques. Cardiopulmonary conditioning can be improved without muscle overuse with cycle or arm ergometer exercise or dynamic aquatic exercise.

Sawtooth wave density analysis during REM sleep in normal volunteers

OBJECTIVE

Sawtooth waves (STW) are a characteristic EEG feature of REM sleep but their source and function are unknown. We previously reported stereotypical properties of STW at stage REM onset, and alterations in bulbar postpolio syndrome. This study analyzes STW features throughout REM, in order to test the hypothesis that sawtooth wave activity may be predictable and have a consistent relationship across REM periods.

METHODS

Twenty polysomnographic recordings were scored for occurrence, duration, and frequency of STWs. STW density was calculated based on the number of bursts/min REM and duration of STW activity/min REM. The density measurements were statistically analyzed to assess for differences across REM periods.

RESULTS

STW density mean was 0.97 bursts/min REM (95% CI [0.85, 1.09]); 6.85 s/min REM (95% CI [5.95, 7.76]). STW frequency range was 1.5-5 Hz, mean 2.5 Hz. STWs occurred in bursts with a mean duration of 7 s (range 2-26 s). There was a lower density of bursts of STW activity per minute in the first REM period compared to the second, third, and fifth cycles.

CONCLUSIONS

This study reports STW density characteristics throughout REM sleep in normal subjects. Our density measurements suggest a difference in STW activity between the first REM period and later periods. Analysis of STW and related phenomena may increase the understanding of REM sleep mechanisms and may be useful to evaluate brainstem function during normal and pathological sleep.

Impaired sequence learning in carriers of the DYT1 dystonia mutation

Previous positron emission tomography (PET) studies have shown that nonmanifesting carriers of the DYT1 dystonia mutation express an abnormal pattern of resting glucose metabolism. To determine whether motor behavior is impaired in these subjects, we compared movement and sequence learning in 12 clinically unaffected DYT1 carriers with 12 age-matched controls. Regional differences in brain function during task performance were assessed with simultaneous H(2) (15)O/PET. We found that motor performance was similar in the DYT1 and control groups, with no significant differences in movement time and spatial accuracy measured during each of the tasks. In contrast, sequence learning was reduced in gene carriers relative to controls (p < 0.01). PET imaging during motor execution showed increased activation in gene carriers (p < 0.001, uncorrected) in the left premotor cortex and right supplementary motor area, with concomitant reduction in the posterior medial cerebellum. During sequence learning, activation responses in DYT1 carriers were increased in the left ventral prefrontal cortex, and lateral cerebellum. These findings suggest that abnormalities in motor behavior and brain function exist in clinically nonmanifesting DYT1 carriers. Although localized increases in neural activity may enable normal movement execution in these subjects, this mechanism may not compensate for their defect in sequence learning.

Paralytic vs. "nonparalytic" polio: distinction without a difference?

Nonparalytic polio (NPP) is commonly thought to be synonymous with "abortive polio," in which the poliovirus neither entered the central nervous system nor damaged neurons. Described are two epidemic illness-"The Summer Grippe" and Iceland disease-apparently caused by a low virulence but neuropathic type 2 poliovirus. Studies show that neuronal lesions in the brain and spinal cord and muscle weakness were common in NPP, and epidemiologic studies document late-onset weakness and fatigue in 14% to 42% of NPP survivors. These findings indicate that clinicians should not require a history of paralytic polio, electromyographic evidence of denervation, and new muscle weakness for the diagnosis of "Postpolio Syndrome" but should be aware that NPP, and possibly even poliovirus-induced "minor illnesses," can be associated with acute central nervous system damage and late-onset muscle weakness and fatigue.