title: Measuring and Characterizing the Human Nasal Cycle.
abstract: Nasal airflow is greater in one nostril than in the other because of transient asymmetric nasal passage obstruction by erectile tissue. The extent of obstruction alternates across nostrils with periodicity referred to as the nasal cycle. The nasal cycle is related to autonomic arousal and is indicative of asymmetry in brain function. Moreover, alterations in nasal cycle periodicity have been linked to various diseases. There is therefore need for a tool allowing continuous accurate measurement and recording of airflow in each nostril separately. Here we provide detailed instructions for constructing such a tool at minimal cost and effort. We demonstrate application of the tool in 33 right-handed healthy subjects, and derive several statistical measures for nasal cycle characterization. Using these measures applied to 24-hour recordings we observed that: 1: subjects spent slightly longer in left over right nostril dominance (left = 2.63 ± 0.89 hours, right = 2.17 ± 0.89 hours, t(32) = 2.07, p < 0.05), 2: cycle duration was shorter in wake than in sleep (wake = 2.02 ± 1.7 hours, sleep = 4.5 ± 1.7 hours, (t(30) = 5.73, p < 0.0001). 3: slower breathing was associated with a more powerful cycle (the extent of difference across nostrils) (r = 0.4, p < 0.0001), and 4: the cycle was influenced by body posture such that lying on one side was associated with greater flow in the contralateral nostril (p < 0.002). Finally, we provide evidence for an airflow cycle in each nostril alone. These results provide characterization of an easily obtained measure that may have diagnostic implications for neurological disease and cognitive state.
authors.affiliation: Department of Neurobiology, The Weizmann Institute of Science, Rehovot, 76100, Israel.
authors.forename: Roni
authors.initials: R
authors.lastname: Kahana-Zweig
authors.affiliation: Department of Neurobiology, The Weizmann Institute of Science, Rehovot, 76100, Israel.
authors.forename: Maya
authors.initials: M
authors.lastname: Geva-Sagiv
authors.affiliation: Department of Neurobiology, The Weizmann Institute of Science, Rehovot, 76100, Israel.
authors.forename: Aharon
authors.initials: A
authors.lastname: Weissbrod
authors.affiliation: Department of Neurobiology, The Weizmann Institute of Science, Rehovot, 76100, Israel.
authors.forename: Lavi
authors.initials: L
authors.lastname: Secundo
authors.affiliation: Loewenstein Rehabilitation Hospital, Ra'anana, 43100, Israel.|Sackler Faculty of Medicine, Tel Aviv University, Ramat Aviv, 69978, Israel.
authors.forename: Nachum
authors.initials: N
authors.lastname: Soroker
authors.affiliation: Department of Neurobiology, The Weizmann Institute of Science, Rehovot, 76100, Israel.
authors.forename: Noam
authors.initials: N
authors.lastname: Sobel
mesh_terms: D000328:Adult; D000388:Air; D016477:Artifacts; D005260:Female; D006801:Humans; D008297:Male; D008991:Monitoring, Physiologic / Q000379:methods*; D015508:Nasal Obstruction / Q000175:diagnosis / Q000503:physiopathology; D009666:Nose; D010507:Periodicity; D011187:Posture; D012119:Respiration; D012890:Sleep / Q000502:physiology; D014851:Wakefulness / Q000502:physiology