Undiagnosed sleep‐related breathing disorders are associated with focal brainstem atrophy in the elderly

Abstract

This gray matter volume decrease in brain regions involved in breathing/autonomic functions, as well as their correlation with the severity of the disorder, suggests a pathophysiological link between structural changes and SRBDs.

Dysfunctional Nucleus Tractus Solitarius: Its Crucial Role in Promoting Neuropathogentic Cascade of Alzheimer’s Dementia—A Novel Hypothesis

“…Furthermore, their whole brain Gray matter volume (GMV) scans obtained using voxel-based MRI morphometry did not differ significantly between subjects with and without SRBD. However, bilaterally, a significant inverse relationship was found between AHI and GMV in the pontomedullary zone-involving (1) NTS, (2) NA, and (3) the DMNV [279]. The symmetrical atrophy of these key brainstem nuclei was interpreted as a function of episodic hypoxic and sleep-disordered conditions.…”

“…Applying strict exclusion criteria, 152 ''healthy older adults without any disease'', (mean age = 66), except for ''undiagnosed sleep-related breathing disorders (SRBD)'', and an AHI of 21 (±15) for males, and 16.7 (±12.9) for females, were studied [279]. The absence of subjective daytime sleepiness and a lack of involvement of any cortical or subcortical structures in these elderly underscored their overall health.…”

The Effect of Aging on Pulmonary Function

“…Loss of central control is potentially attributable to a reduction in the number of medullary ventral respiratory neurons. 35 In addition, the ability of peripheral mechanoreceptors and chemoreceptors in the chest wall and lung parenchyma to perceive methacholine-provoked bronchoconstriction and associated reduction in lung function significantly decreases with age. 4,14…”

Dysfunctional Sensory Modalities, Locus Coeruleus, and Basal Forebrain: Early Determinants that Promote Neuropathogenesis of Cognitive and Memory Decline and Alzheimer’s Disease

“…(A) Decrease in thalamocortical function decreases cholinergic activity and CBF, (B) repeated hypoxic events affect respiratory cholinergic mechanism and respiratory regulation. Consequently, the hypotrophy/atrophy of nucleus solitarius and nucleus ambiguus in pontomedullary junction affect hypoglossal nucleus, genioglossus function, upper airway patency, hypoxia, and cerebral oxygenation (Celle et al 2009;Daulatzai 2011Daulatzai , 2012bDaulatzai , 2015b.…”

“…This supports the view that the integrity of the sensory (involving trigeminal here) system is critically important, and that the sensory afferents regulate motor control (tongue), patent upper airway, and synchronize upper airway respiratory behavior-and hence the inspiratory event. Older individuals suffering from snoring, OSA, and pharyngeal sensory decline (owing to snoring that disrupts upper airway sensory receptor function) have a dysfunctional sensory mechanism that would have an adverse impact on pontomedullary nuclei (Celle et al 2009;Daulatzai 2013bDaulatzai , 2015b and upper airway patency. It is compelling to consider, therefore, that the ensuing attenuation of brainstem stimuli could represent an additional source of BFB dysfunction, since inputs from brainstem regulate BFB excitability (Schwaber et al 1982;McGinty and Szymusiak 1988;Steriade et al 1990;Rasmusson et al 1994).…”