title: Cerebrovascular reactivity in young subjects with sleep apnea.
abstract: OBJECTIVE
  Regional brain alterations may be involved in the pathogenesis and adverse consequences of obstructive sleep apnea (OSA). The objectives for the current study were to (1) determine cerebrovascular reactivity in the motor areas that control upper airway musculature in patients with OSA, and (2) determine whether young patients with OSA have decreased cerebrovascular reactivity in response to breath holding.
  
  
  METHODS
  Case-control study.
  
  
  METHODS
  Academic center.
  
  
  METHODS
  Twelve subjects with OSA (age 24-42 y; apnea-hypopnea index 17; interquartile range [IQR] 9, 69 per hour) and control subjects (n = 10; age 29-44 y; AHI 2; IQR 1, 3 per hour).
  
  
  RESULTS
  Subjects underwent blood oxygen level-dependent functional magnetic resonance imaging (BOLD-fMRI) while awake, swallowing, and breath holding. In subjects with OSA, during swallowing, there was less activity in the brainstem than in controls (P = 0.03) that remained reduced after adjusting for cortical motor strip activity (P = 0.036). In OSA subjects, brain regions of increased cerebrovascular reactivity (38; IQR 17, 96 cm(3)) was smaller than that in controls (199; IQR 5, 423 cm(3); P = 0.01). In OSA subjects, brain regions of decreased cerebrovascular reactivity during breath hold was greater (P = 0.01), and the ratio of increased-to-decreased brain regions was lower than that of controls (P = 0.006). Adjustment for cerebral volumes, body mass index, and white matter lesions did not change these results substantively.
  
  
  CONCLUSIONS
  In patients with obstructive sleep apnea (OSA), diminished change in brainstem activity during swallowing and reduced cerebrovascular reactivity may contribute to the etiopathogenesis and adverse cerebrovascular consequences, respectively. We speculate that decreased cerebral auto-regulation may be causative of gray matter loss in OSA.
authors.affiliation: Southern Arizona Veterans Administration Health Care System, Tucson, AZ.
authors.forename: John
authors.initials: J
authors.lastname: Buterbaugh
authors.affiliation: Southern Arizona Veterans Administration Health Care System, Tucson, AZ.|Arizona Respiratory Center, Tucson, AZ.
authors.forename: Charles
authors.initials: C
authors.lastname: Wynstra
authors.affiliation: Southern Arizona Veterans Administration Health Care System, Tucson, AZ.|Arizona Respiratory Center, Tucson, AZ.
authors.forename: Natalie
authors.initials: N
authors.lastname: Provencio
authors.affiliation: Arizona Respiratory Center, Tucson, AZ.|Department of Medicine of University of Arizona, Tucson, AZ.
authors.forename: Daniel
authors.initials: D
authors.lastname: Combs
authors.affiliation: Southern Arizona Veterans Administration Health Care System, Tucson, AZ.
authors.forename: Michael
authors.initials: M
authors.lastname: Gilbert
authors.affiliation: Southern Arizona Veterans Administration Health Care System, Tucson, AZ.|Arizona Respiratory Center, Tucson, AZ.|Department of Medicine of University of Arizona, Tucson, AZ.
authors.forename: Sairam
authors.initials: S
authors.lastname: Parthasarathy
mesh_terms: D000328:Adult; D015992:Body Mass Index; D001933:Brain Stem / Q000503:physiopathology*; D062485:Breath Holding; D016022:Case-Control Studies; D003679:Deglutition / Q000502:physiology; D005260:Female; D066128:Gray Matter / Q000473:pathology; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D010100:Oxygen / Q000097:blood; D012137:Respiratory System / Q000098:blood supply* / Q000294:innervation* / Q000503:physiopathology; D020181:Sleep Apnea, Obstructive / Q000473:pathology / Q000503:physiopathology*; D014851:Wakefulness / Q000502:physiology; D055815:Young Adult
chemical_list: D010100:Oxygen
keywords: cerebral autoregulation; functional magnetic resonance imaging; obstructive sleep apnea; sleep apnea; stroke