title: Assessment of cognitive function while on low-dose propranolol: implications for usage by survivors in a disabled submarine.
abstract: While awaiting rescue from a disabled submarine (DISSUB), survivors will likely endure an atmosphere of rising CO2 which will eventually be lethal. Previously, it was determined that low-dose propranolol reduces resting metabolic carbon dioxide production and therefore may increase survival time in this scenario. The actions and decisions survivors would carry out in a DISSUB situation would require an unaltered cognition state. Therefore, we wanted to determine if low-dose propranolol impairs cognitive function. Eight healthy males completed a counterbalanced, randomized, placebo-controlled, double-blinded crossover study in which each subject received propranolol (40 mg twice daily) or placebo (lactose pill twice daily) over a 72-hour period. The alternate condition was separated by a minimum 96-hour washout period. Subjects performed a series of 6 tasks from the Automated Neuropsychological Assessment Metrics (ANAM) battery and answered a self-report sleepiness scale each morning and afternoon. Subjects exhibited increased accuracy in one of the ANAM tasks while on propranolol compared to placebo, but showed no difference between treatments on the other 5 tasks and sleepiness scale. These results suggest that 40 mg of propranolol taken twice daily does not significantly impair cognitive function and may be a viable option for use in a DISSUB scenario.
authors.affiliation: Naval Submarine Medical Research Laboratory, Building 156 Trout Avenue, Naval Submarine Base New London, Box 900, Groton, CT 06349-5900, USA.
authors.forename: Seth A
authors.initials: SA
authors.lastname: Reini
authors.forename: David M
authors.initials: DM
authors.lastname: Fothergill
authors.forename: Wayne G
authors.initials: WG
authors.lastname: Horn
mesh_terms: D000319:Adrenergic beta-Antagonists / Q000627:therapeutic use*; D000328:Adult; D000465:Algorithms; D002245:Carbon Dioxide / Q000378:metabolism*; D003071:Cognition / Q000187:drug effects*; D018592:Cross-Over Studies; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D006801:Humans; D008297:Male; D008887:Military Medicine; D008889:Military Personnel; D009483:Neuropsychological Tests; D011433:Propranolol / Q000627:therapeutic use*; D018570:Risk Assessment; D013366:Submarine Medicine; D017741:Survivors
chemical_list: D000319:Adrenergic beta-Antagonists; D002245:Carbon Dioxide; D011433:Propranolol