• EDS is one of the most common symptoms of obstructive sleep apnea (OSA)
  • Animal and human studies suggest that the recurring cycle of intermittent hypoxia and sleep fragmentation associated with OSA may result in changes to the brain
  • The subsequent disruption in neurologic function may manifest as excessive sleepiness during the day 
  • While brain alterations have been linked to sleepiness, persistent EDS may be due to other factors such as chronic sleep loss and comorbid disorders

In an animal model of severe sleep apnea, chronic intermittent hypoxia led to significant neuronal injury

Long-term hypoxia significantly increased oxidative injury to wake-promoting dopaminergic and noradrenergic neurons compared with the control group (P<0.01) 
LC=locus coeruleus; vPAG=ventral periaqueductal gray matter. Image adapted from Zhu Y et al. J Neurosci. 2007;27(37):10060-10071. *Hypoxia/reoxygenation in adult mice for 6 months, modeling severe sleep apnea. Other wake-promoting neuronal groups (eg, other monoaminergic, cholinergic, orexinergic) were generally not affected.2
The loss of medial dendrites shown here represents irreversible and functionally significant injury to wake-promoting regions of the brain

At 6 months, a 40% loss of select wake-promoting dopaminergic and noradrenergic neurons was associated with irreversible wake impairments

In a separate animal model of OSA, chronic sleep fragmentation led to a significant loss of wake-promoting neurons

Exposure to sleep disruptions over 14 weeks caused a significant reduction of wake-promoting noradrenergic neurons compared with the control group (P<0.001), even after 4 weeks of recovery[/et_pb_text][et_pb_image src="https://stimcoremd.com/wp-content/uploads/2021/12/columns.png" _builder_version="4.14.2" _module_preset="default" theme_builder_area="post_content" title_text="columns" hover_enabled="0" sticky_enabled="0"][/et_pb_image][et_pb_text _builder_version="4.14.2" _module_preset="default" theme_builder_area="post_content" hover_enabled="0" sticky_enabled="0" text_orientation="center"]Image reprinted from Zhu Y et al. Front Neurol. 2015;6:109.[/et_pb_text][et_pb_text _builder_version="4.14.2" _module_preset="default" theme_builder_area="post_content" hover_enabled="0" sticky_enabled="0"]

50% loss of wake-promoting noradrenergic neurons