title: Effect of continuous positive airway pressure on regional cerebral blood flow in patients with severe obstructive sleep apnea syndrome.
abstract: OBJECTIVE
  Obstructive sleep apnea (OSA) is commonly associated with neural and cognitive deficits induced by recurrent hypoxemia and sleep fragment. The aims of this study were to use statistical parametric mapping (SPM) to analyze changes in regional cerebral blood flow (rCBF) in untreated patients with severe OSA before and after nasal continuous positive airway pressure (CPAP) treatment, examine the impact of OSA-related variables on rCBF, and assess the therapeutic effect of nasal CPAP treatment.
  
  
  METHODS
  Thirty male patients with severe OSA underwent brain single photon emission computed tomography (SPECT) scans twice before and after nasal CPAP treatment for ≥6 months, whereas 26 healthy controls underwent a single SPECT scan. The rCBF differences were compared between two OSA sub-groups (untreated and treated) and the control group, and correlations between rCBF differences and clinical parameters were analyzed.
  
  
  RESULTS
  Compared with the controls, the untreated OSA patients showed a significantly lower rCBF in multiple brain areas. After the treatment, partial reversal of the rCBF decreases was observed in the limbic and prefrontal areas. Moreover, complete reversal of the rCBF decreases was observed in the medial orbitofrontal, angular and cerebellar areas. Significant improvements in some clinical and polysomnographic variables (Epworth Sleepiness Scale, apnea-hypopnea index, CPAP duration, and arousal index) paralleled the rCBF changes after the treatment.
  
  
  CONCLUSIONS
  Decreased rCBF in severe OSA was significantly reversible by CPAP treatment and correlated with the improvements in the apnea-hypopnea index, arousal index, CPAP duration and Epworth Sleepiness Scale. These results suggest that long-term CPAP treatment improves rCBF in areas responsible for executive, affective, and memory function.
authors.affiliation: Department of Neurology, Neuroscience Center, Samsung Medical Center and Samsung Advanced Institute for Health Sciences & Technology (SAIHST), Sungkyunkwan University School of Medicine, Seoul, South Korea; Samsung Biomedical Research Institute (SBRI), Seoul, South Korea.
authors.forename: Jeong Sik
authors.initials: JS
authors.lastname: Kim
authors.affiliation: Department of Neurology, Daegu Health College Hospital, Daegu, South Korea.
authors.forename: Ji Hye
authors.initials: JH
authors.lastname: Seo
authors.affiliation: Department of Neurology, Neuroscience Center, Samsung Medical Center and Samsung Advanced Institute for Health Sciences & Technology (SAIHST), Sungkyunkwan University School of Medicine, Seoul, South Korea.
authors.forename: Mi-Ri
authors.initials: MR
authors.lastname: Kang
authors.affiliation: Department of Neurology, Neuroscience Center, Samsung Medical Center and Samsung Advanced Institute for Health Sciences & Technology (SAIHST), Sungkyunkwan University School of Medicine, Seoul, South Korea.
authors.forename: Min Jae
authors.initials: MJ
authors.lastname: Seong
authors.affiliation: Department of Neurology, Neuroscience Center, Samsung Medical Center and Samsung Advanced Institute for Health Sciences & Technology (SAIHST), Sungkyunkwan University School of Medicine, Seoul, South Korea.
authors.forename: Won Gu
authors.initials: WG
authors.lastname: Lee
authors.affiliation: Department of Neurology, Neuroscience Center, Samsung Medical Center and Samsung Advanced Institute for Health Sciences & Technology (SAIHST), Sungkyunkwan University School of Medicine, Seoul, South Korea; Samsung Biomedical Research Institute (SBRI), Seoul, South Korea.
authors.forename: Eun Yeon
authors.initials: EY
authors.lastname: Joo
authors.affiliation: Department of Neurology, Neuroscience Center, Samsung Medical Center and Samsung Advanced Institute for Health Sciences & Technology (SAIHST), Sungkyunkwan University School of Medicine, Seoul, South Korea; Samsung Biomedical Research Institute (SBRI), Seoul, South Korea. Electronic address: sbhong@skku.edu.
authors.forename: Seung Bong
authors.initials: SB
authors.lastname: Hong
mesh_terms: D000328:Adult; D001921:Brain / Q000098:blood supply*; D002560:Cerebrovascular Circulation / Q000502:physiology*; D045422:Continuous Positive Airway Pressure / Q000379:methods*; D006801:Humans; D008297:Male; D008875:Middle Aged; D020181:Sleep Apnea, Obstructive / Q000503:physiopathology / Q000628:therapy*
keywords: Cerebral blood flow (CBF); Continuous positive airway pressure (CPAP); Obstructive sleep apnea (OSA); Single photon emission computed tomography (SPECT)