Changes in Neurocognitive Architecture in Patients with Obstructive Sleep Apnea Treated with Continuous Positive Airway Pressure.

BACKGROUND: Obstructive sleep apnea (OSA) is a chronic, multisystem disorder that has a bidirectional relationship with several major neurological disorders, including Alzheimer's dementia. Treatment with Continuous Positive Airway Pressure (CPAP) offers some protection from the effects of OSA, although it is still unclear which populations should be targeted, for how long, and what the effects of treatment are on different organ systems. We investigated whether cognitive improvements can be achieved as early as one month into CPAP treatment in patients with OSA. METHODS: 55 patients (mean (SD) age: 47.6 (11.1) years) with newly diagnosed moderate-severe OSA (Oxygen Desaturation Index: 36.6 (25.2) events/hour; Epworth sleepiness score (ESS): 12.8 (4.9)) and 35 matched healthy volunteers were studied. All participants underwent neurocognitive testing, neuroimaging and polysomnography. Patients were randomized into parallel groups: CPAP with best supportive care (BSC), or BSC alone for one month, after which they were re-tested. FINDINGS: One month of CPAP with BSC resulted in a hypertrophic trend in the right thalamus [mean difference (%): 4.04, 95% CI: 1.47 to 6.61], which was absent in the BSC group [-2.29, 95% CI: -4.34 to -0.24]. Significant improvement was also recorded in ESS, in the CPAP plus BSC group, following treatment [mean difference (%): -27.97, 95% CI: -36.75 to -19.19 vs 2.46, 95% CI: -5.23 to 10.15; P=0.012], correlated to neuroplastic changes in brainstem (r=-0.37; P=0.05), and improvements in delayed logical memory scores [57.20, 95% CI: 42.94 to 71.46 vs 23.41, 95% CI: 17.17 to 29.65; P=0.037]. INTERPRETATION: One month of CPAP treatment can lead to adaptive alterations in the neurocognitive architecture that underlies the reduced sleepiness, and improved verbal episodic memory in patients with OSA. We propose that partial neural recovery occurs during short periods of treatment with CPAP.

Cardiac arrest due to a missed diagnosis of Boerhaave's syndrome.

A 91-year-old presented with a rare cause of cardiac arrest. He was initially admitted with severe back pain following vomiting and diagnosed with probable aspiration pneumonia. On day 3 of admission, he was discovered in cardiac arrest and cardiopulmonary resuscitation was started. On intubation, a left-sided pneumothorax and subcutaneous emphysema were noted. Needle decompression showed gastric fluid leaking from the cannula. The patient regained a cardiac output, and a subsequent CT scan confirmed a large pneumomediastinum with air tracking to the neck and chest, and bilateral pneumothoraces. A diagnosis of Boerhaave's syndrome was made. The patient was transferred to the intensive care unit but did not survive. This case demonstrates the importance of looking for and treating the rarer reversible causes of cardiac arrest, and of maintaining a high index of suspicion for Boerhaave's syndrome. Despite its rarity, Boerhaave's syndrome is often misdiagnosed on initial presentation, leading to delayed treatment and poor outcomes.

Sleep apnoea and the brain: a complex relationship.

Intermittent hypoxia, reoxygenation, and hypercapnia or hypocapnia occur in both adults and children during untreated apnoea and hypopnoea, along with changes in cerebral blood flow and sleep fragmentation. These effects can result in cognitive deficits with functional effects on work and school efficiency. The assessment of how obstructive sleep apnoea affects cognition depends on the specificity and sensitivity of the tests, which are rarely developed specifically for obstructive sleep apnoea. In this Review, we discuss both the neural adaptive and maladaptive processes in response to hypoxaemia. The net result on cognitive and emotional performance depends on the stage of this dynamic process, effects on other body systems, cognitive reserve, and idiosyncratic susceptibility. We also explore the contribution of fragmented sleep, and the disruption of sleep structure, with focus on the effect at different times in the development of disease. This Review will address the gap in the underlying pathophysiology of new clinical and translational findings, and argue their contribution to the inherent complexity of the association between obstructive sleep apnoea and the brain.

Upper airway factors that protect against obstructive sleep apnoea in healthy older males.

The prevalence of obstructive sleep apnoea (OSA) increases with age, yet the risk factors for OSA in older people remain poorly understood. This study aimed to define the age-related changes in upper airway morphology in carefully matched groups of healthy older (>60 years, n=11) and younger (<40 years, n=14) males, using direct (magnetic resonance imaging (MRI)) and indirect (acoustic reflection) imaging. The median (interquartile range) combined retropalatal and retroglossal pharyngeal length was greater in older than in younger males (older 8.8 (7.8-9.0) cm, younger 7.8 (7.0-8.3) cm; p=0.03), as was the soft palate cross-sectional area (older 43.1 (36.0-48.8) cm(2), younger 35.3 (30.5-40.5) cm(2); p=0.03), parapharyngeal fat pad diameter (older 1.7 (1.4-2.2) cm, younger 1.2 (1.0-1.8) cm; p=0.03) and cross-sectional area of the fat pads (older 13.8 (9.1-17.1) cm(2); younger 7.4 (5.9-13.0) cm(2); p=0.02) as measured by MRI. Using acoustic reflection, pharyngeal calibre (older 4.8 (3.8-6.6) cm(2), younger 3.4 (2.8-4.6) cm(2); p=0.03), pharyngeal volume (older 35.1 (30.9-55.4) cm(3), younger 27.2 (22.7-44.2) cm(3); p=0.04) and glottis area (older 2.7 (2.1-3.9) cm(2), younger 1.3 (1.1-1.9) cm(2); p=0.003) were also larger in older participants compared with younger participants. There was no difference in craniofacial measures between groups, including volumetric data and hyoid bone position. The larger pharyngeal calibre observed in older males may be compensating for an age-related enlargement in pharyngeal soft tissue that predisposes to OSA.

Hippocampal hypertrophy and sleep apnea: a role for the ischemic preconditioning?

The full impact of multisystem disease such as obstructive sleep apnoea (OSA) on regions of the central nervous system is debated, as the subsequent neurocognitive sequelae are unclear. Several preclinical studies suggest that its purported major culprits, intermittent hypoxia and sleep fragmentation, can differentially affect adult hippocampal neurogenesis. Although the prospective biphasic nature of chronic intermittent hypoxia in animal models of OSA has been acknowledged, so far the evidence for increased 'compensatory' neurogenesis in humans is uncertain. In a cross-sectional study of 32 patients with mixed severity OSA and 32 non-apnoeic matched controls inferential analysis showed bilateral enlargement of hippocampi in the OSA group. Conversely, a trend for smaller thalami in the OSA group was noted. Furthermore, aberrant connectivity between the hippocampus and the cerebellum in the OSA group was also suggested by the correlation analysis. The role for the ischemia/hypoxia preconditioning in the neuropathology of OSA is herein indicated, with possible further reaching clinical implications.

The history of managed care and the role of the child and adolescent psychiatrist.

The child and adolescent psychiatrist cannot practice in today's world without interacting with the world of insurance and managed care. This article reviews the history of the development of the managed care industry. It also examines the variety of roles clinicians play, whether as members of physician networks, as a peer or utilization reviewers, or as medical directors. The skills required of the physician employee and the contractual and ethical concerns are discussed.