title: Neckties and cerebrovascular reactivity in young healthy males: a pilot randomised crossover trial.
abstract: Background. A necktie may elevate intracranial pressure through compression of venous return. We hypothesised that a tight necktie would deleteriously alter cerebrovascular reactivity. Materials and Methods. A necktie was simulated using bespoke apparatus comprising pneumatic inner-tube with aneroid pressure-gauge. Using a randomised crossover design, cerebrovascular reactivity was measured with the "pseudo-tie" worn inflated or deflated for 5 minutes (simulating tight/loose necktie resp.). Reactivity was calculated using breath hold index (BHI) and paired "t" testing used for comparative analysis. Results. We enrolled 40 healthy male volunteers. There was a reduction in cerebrovascular reactivity of 0.23 units with "tight" pseudotie (BHI loose 1.44 (SD 0.48); BHI tight 1.21 (SD 0.38) P < .001). Conclusion. Impairment in cerebrovascular reactivity was found with inflated pseudo-tie. However, mean BHI is still within a range of considered normal. The situation may differ in patients with vascular risk factors, and confirmatory work is recommended.
authors.affiliation: Institute of Cardiovascular and Medical Sciences, College of Medical and Life Sciences, University of Glasgow, Glasgow G11 6NT, UK.
authors.forename: Mark
authors.initials: M
authors.lastname: Rafferty
authors.forename: Terence J
authors.initials: TJ
authors.lastname: Quinn
authors.forename: Jesse
authors.initials: J
authors.lastname: Dawson
authors.forename: Matthew
authors.initials: M
authors.lastname: Walters