Obstructive Sleep Apnea and Age

Abstract

Rationale: Healthy aging is associated with cognitive deficits similar to those found in obstructive sleep apnea (OSA). As in OSA, older adults show compensatory cerebral activation during cognitive demands in the face of neurocognitive decline. Objectives: The current study examines whether the combination of increasing age and sleep apnea will lead to a stronger compensatory response than either factor alone, or overwhelm the brain's capacity to compensate. Methods: A total of 14 treatment-naive patients with sleep apnea (aged 25-59 yr) and 14 age-matched healthy control subjects were each divided into two age groups of young (,45 yr) and middleaged (> 45 yr). All underwent a sleep study, followed the next morning by a functional magnetic resonance imaging session that included a sustained attention and a verbal encoding task. A priori contrast analyses compared middle-aged patients with OSA to young patients, young control subjects, and middle-aged control subjects. Measurements and Main Results: Middle-aged patients with OSA showed reduced performance for immediate word recall and slower reaction time during sustained attention compared with the other three groups (middle-aged control, young sleep apnea, and young control). For both tasks, decreased activation was detected for middle-aged sleep apnea relative to the other groups in task-related brain regions. Conclusions: These results suggest that the presence of both sleep apnea and increasing age overwhelmed the brain's capacity to respond to cognitive challenges with compensatory recruitment and to maintain performance. The findings that sleep apnea impairs performance and brain function at a younger age than what might ordinarily be expected underscore the importance of early diagnosis and treatment of sleep apnea.

The impact of ageing and sex on the association between sleepiness and sleep disordered breathing

“…The study by Ayalon et al ., 2010 has recently shown that the combined effects of SDB and aging produced significant impairments in cognitive function and neural activation, greater than either variable acting independently [17]. These data are also in accordance with the findings obtained from an aging animal model of OSA, where exposure to chronic intermittent hypoxia produced impaired special learning and increased neural apoptosis in older rats [18].…”

Sleep-Disordered Breathing and Cognition in Older Adults

“…It is possible that the older adult with lifelong subclinical untreated SDB has developed a compensatory tolerance for its effects, or “pre-conditioning” and therefore does not exhibit associated cognitive disturbance[56]. It is also possible that the older adult with lifelong subclinical untreated SDB has reached a threshold whereby normal age-associated neurodegenerative processes render them no longer able to withstand the impact of SDB on cognition, resulting in significant cognitive impairment and decline in ability to care for self [9, 52]. Neither of these hypothetical scenarios considers the impact of new onset SDB in the older adult, which the epidemiological literature suggests is highly widespread [1].…”

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Double Insult Hypothesis . Case-controlled prospective studies should examine the “double insult” hypothesis [52] of SDB-associated cognitive dysfunction in older adults. Alchanatis and colleagues [28] and Mathieu and colleagues [27] reported somewhat contradictory findings using optimal study designs to address the question of whether the cognitive deficits observed in older adults with SDB are of similar or greater magnitude than those observed in middle and younger aged adults with SDB and normal control subjects.

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Sleep Apnea Syndrome and Cognition

“…Ayalon et al (2010) demonstrate that the presence of OSA accelerates the age-related decline in cognitive performances in middle-aged patients (>45 years) showing a decreased activation of the frontal gyrus, hippocampus, and parietal lobe during a sustained attention and a verbal encoding task. These results are supported by a morphological study (Torelli et al, 2011) showing a correlation between age and volumes of the total and left hippocampus, amygdale, and brain parenchyma in OSA patients.…”