title: Neural responses during Valsalva maneuvers in obstructive sleep apnea syndrome.
abstract: The repetitive upper airway muscle atonic episodes and cardiovascular sequelae of obstructive sleep apnea (OSA) suggest dysfunction of specific neural sites that integrate afferent airway signals with autonomic and somatic outflow. We determined neural responses to the Valsalva maneuver by using functional magnetic resonance imaging. Images were collected during a baseline and three Valsalva maneuvers in 8 drug-free OSA patients and 15 controls. Multiple cortical, midbrain, pontine, and medullary regions in both groups showed intensity changes correlated to airway pressure. In OSA subjects, the left inferior parietal cortex, superior temporal gyrus, posterior insular cortex, cerebellar cortex, fastigial nucleus, and hippocampus showed attenuated signal changes compared with controls. Enhanced responses emerged in the left lateral precentral gyrus, left anterior cingulate, and superior frontal cortex of OSA patients. The anterior cingulate, cerebellar cortex, and posterior insula exhibited altered response timing patterns between control and OSA subjects. The response patterns in OSA subjects suggest deficits in particular neural pathways that normally mediate the Valsalva maneuver and compensatory actions in other structures.
authors.affiliation: Department of Neurobiology, School of Nursing, University of California, Los Angeles, Los Angeles, California 90095-1763, USA. rharper@ucla.edu
authors.forename: Luke A
authors.initials: LA
authors.lastname: Henderson
authors.forename: Mary A
authors.initials: MA
authors.lastname: Woo
authors.forename: Paul M
authors.initials: PM
authors.lastname: Macey
authors.forename: Katherine E
authors.initials: KE
authors.lastname: Macey
authors.forename: Robert C
authors.initials: RC
authors.lastname: Frysinger
authors.forename: Jeffry R
authors.initials: JR
authors.lastname: Alger
authors.forename: Frisca
authors.initials: F
authors.lastname: Yan-Go
authors.forename: Ronald M
authors.initials: RM
authors.lastname: Harper
mesh_terms: D000328:Adult; D000403:Airway Resistance / Q000502:physiology; D001341:Autonomic Nervous System / Q000503:physiopathology*; D001794:Blood Pressure / Q000502:physiology; D001921:Brain / Q000503:physiopathology; D016000:Cluster Analysis; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D015656:Respiratory Mechanics; D020181:Sleep Apnea, Obstructive / Q000503:physiopathology*; D014636:Valsalva Maneuver / Q000502:physiology*