The Effect of Orthonasal and Retronasal Odorant Delivery on Multitasking Stress DISSERTATION Presented in Partial Fulfillment of the Requirements for the Degree Doctor of Philosophy in the Graduate School of The Ohio State University By Alexandra M. Pierce-Feldmeyer, B. S. Graduate Program in Food Science and Technology The Ohio State University 2017 Dissertation Committee Christopher T. Simons, Ph.D., Co-Advisor Ken Lee, Ph.D., Co-Advisor Yael Vodovotz, Ph.D. Earl Harrison, Ph.D. 1 Copyrighted by Alexandra Marie Pierce-Feldmeyer 2017 2 Abstract On a daily basis Americans experience too much stress, often stemming from the multitude of tasks needed to be accomplished in the workplace. Drugs or psychotherapy is often prescribed for chronic stress, but acute stress, which is equally harmful has few effective relief mechanisms. Aromatherapy has been suggested to elicit stress reducing properties but previous work produces variable results, causing studies to lack reputability. Robust literature is lacking likely because study methodologies vary heavily. Often, delivery method, odorant flow rate, aroma composition and concentration, and exposure time all differ, making studies difficult to compare. One of the variables that has not been formally assessed is the potential for odorant pathway to affect aroma stress reduction. Odorants can be sensed and perceived orthonasally (nostrils) or retronasally (oral cavity). Prior research indicates route of delivery impacts odorant perception, pleasantness, and directed behaviors thus suggesting differential processing of olfactory information. Therefore, differences in aroma delivery may dictate aromatherapy effectiveness. This important concept has not been studied previously. Lavender has a history of use in aromatherapy and thus we studied its impact compound, linalool delivered orthonasally and retronasally. Identical procedures assessed a control condition (ambient air inhalation) and vanillin, a common component of vanilla flavored foods. Adaptation, or the diminution in sensitivity to a stimulus following prolonged and constant exposure was first characterized for both the orthonasal and retronasal pathways. Linalool (12%) or vanillin (25%) were delivered orthonasally (6 LPM) and retronasally (8 LPM) in air phase through ii a custom built olfactometer. Once the perception of aroma compounds was better understood, the same delivery took place when assessing aroma effects on stress. Thirty-one subjects underwent a baseline period (10 min) where they were instructed to "sit quietly and try to relax" followed by a multitasking computerized stressor (10 min) and finally a recovery period (10 min). For each condition (orthonasal or retronasal) 30 minutes of aroma (linalool or vanillin) or ambient air inhalation occurred. Objective measures (α -amylase, heart rate variability, and mean heart rate), and subjective measures (Bond-Lader Mood rating scale, Nasa Task Load Index and overall stress perception) were recorded during each condition. Linalool was found to have significant effects on physiological markers of stress, whereas air and vanillin showed less support for stress reduction. Retronasal linalool exhibited the highest effect when compared to orthonasal administration. This study suggests linalool reduces stress in physiological ways, and is more effective when delivered retronasally, likely due to the higher concentration in the bloodstream. Key words: olfaction, orthonasal, retronasal, stress, linalool, vanillin iii Dedication To Robert Frost who helped inspire me to take the path less traveled. To my mother who knows what I need before I do. To my father who taught me how to work hard. To my brother who isn’t afraid to say he likes Nickelback just as much as I do. To my husband whom without I would be certifiably insane. To my advisor because there won’t be a day in my professional life I won’t ask myself: What would Dr. Simons do? * clink * iv Acknowledgments I would like to acknowledge my advisor, Dr. Simons and my committee members for guiding me through this process. I also want to acknowledge past and current Simons lab members that kept me afloat and for always helping me kill the cockroaches in the basement of Howlett Hall. I also want to acknowledge the Ironman brand for teaching me that Anything is Possible. v Vita Educational Record: Ph.D candidate Food Science and Technology Ohio State University, January 2014-present Columbus, OH B.S. Food Science University of Illinois, August 2011-December 2013 Champaign-Urbana, IL Publications 1. Bangcuyo, R.G., Smith, K.J., Zumach, J.L., Pierce, A.M., Guttman, G.A., Simons, C.T. The use of immersive technologies to improve consumer testing: the role of ecological validity, context and engagement in evaluating coffee. Food Quality and Preference. 41: 84-95, 2015. Fields of Study Major Field: Food Science and Technology vi Table of Contents Abstract ...................................................................................................................................... ii Dedication ................................................................................................................................ iv Acknowledgments ................................................................................................................... v Vita .............................................................................................................................................. vi List of Tables ............................................................................................................................ ix List of Figures ............................................................................................................................ x Chapter 1. Introduction ........................................................................................................ 1 Chapter 2: Literature Review .............................................................................................. 6 Stress is a problem ............................................................................................................................ 6 Defining Stress ................................................................................................................................... 7 Measures of Stress ......................................................................................................................... 11 Aromatherapy for stress mitigation ........................................................................................ 15 Odorants with stress reduction properties ........................................................................... 16 Odor effect mechanisms .............................................................................................................. 20 Chiral odorant molecules support the pharmacological hypothesis ..................................... 21 Psychological theories: the role of expectation ................................................................... 22 Variables of aromatherapy studies .......................................................................................... 24 Odorant delivery route ............................................................................................................................... 24 Exposure time ................................................................................................................................................ 26 Adaptation ....................................................................................................................................................... 27 Compounds of Interest ................................................................................................................. 30 Lavender ........................................................................................................................................................... 30 Vanillin .............................................................................................................................................................. 40 Inducing cognitive stress ............................................................................................................. 40 Objective ............................................................................................................................................ 42 Chapter 3: Olfactory adaptation is dependent on route of delivery .................... 43 Chapter 4: Validation of an ecological laboratory induced stressor to assess amelioration techniques .................................................................................................... 59 Introduction ..................................................................................................................................... 59 Stress is a problem ....................................................................................................................................... 59 vii Types of Stress ............................................................................................................................................... 59 Laboratory measures .................................................................................................................................. 60 Materials and Methods ................................................................................................................. 63 Subjects ............................................................................................................................................................