Evaluation of tests of central nervous system performance after hypoxemia for a model for cognitive impairment.
The sensitivity of several neurophysiological and cognitive tests to different levels of hypoxia was investigated. Cerebral hypoxia in healthy volunteers may be a disease model for dementia or other forms of brain dysfunction. Twelve healthy subjects were included in a randomized, single-blind, placebo-controlled, three-period cross-over trial. They received three air/N2 gas mixtures via mask breathing [aimed at peripheral oxygen saturation (SPO2) values of > 97% (placebo), 90% and 80%, with normal end-tidal CO2]. Central nervous system effects were tested regularly for 130 min by saccadic and smooth pursuit eye movements, electro-encephalogram, visual analogue scales and cognitive tests. Treatments were well tolerated. Compared to SPO2 90%, SPO2 80% reduced saccadic peak velocity by 16.4 degrees/s [confidence interval (CI) -26.3, -6.4], increased occipital delta power by 14.3% (CI 3.6, 25.1), and significantly increased most cognitive reaction times. SPO2 80% also decreased correct responses for the binary choice task and serial word recognition [-1.3 (-2.2, -0.3) and -3.5 (-6.2, -0.8), respectively] compared to SPO2 90%. Cognitive performance was decreased by SPO2 80% and increased by SPO2 90% compared to placebo. Sensitive effect measurements can be identified for these interventions. The applicability as a model for cognitive impairment should be investigated further.
van der Post
J
J
Centre for Human Drug Research, Leiden University Medical Center, Leiden, The Netherlands. jvdp@chdr.nl
Noordzij
L A W
LA
de Kam
M L
ML
Blauw
G J
GJ
Cohen
A F
AF
van Gerven
J M A
JM
D000328:Adult; D000339:Affect / Q000502:physiology; D001288:Attention / Q000502:physiology; D002245:Carbon Dioxide / Q000097:blood; D002755:Choice Behavior / Q000502:physiology; D003072:Cognition Disorders / Q000523:psychology*; D018592:Cross-Over Studies; D004311:Double-Blind Method; D004569:Electroencephalography; D005260:Female; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D000860:Hypoxia / Q000150:complications / Q000523:psychology*; D008297:Male; D008568:Memory / Q000502:physiology; D011939:Mental Recall / Q000502:physiology; D008954:Models, Biological; D009483:Neuropsychological Tests; D010100:Oxygen / Q000097:blood; D011597:Psychomotor Performance / Q000502:physiology*; D011930:Reaction Time / Q000502:physiology; D011932:Reading; D012438:Saccades / Q000502:physiology; D014796:Visual Perception / Q000502:physiology
D002245:Carbon Dioxide; D010100:Oxygen