title: Does the chronotype classification need to be updated? Preliminary findings.
abstract: Traditionally, chronotype classification is based on the Morningness-Eveningness Questionnaire (MEQ). It is implicit in the classification that intermediate individuals get intermediate scores to most of the MEQ questions. However, a small group of individuals has a different pattern of answers. In some questions, they answer as "morning-types" and in some others they answer as "evening-types," resulting in an intermediate total score. "Evening-type" and "Morning-type" answers were set as A(1) and A(4), respectively. Intermediate answers were set as A(2) and A(3). The following algorithm was applied: Bimodality Index = (Sigma A(1) x Sigma A(4))(2) - (Sigma A(2) x Sigma A(3))(2). Neither-types that had positive bimodality scores were classified as bimodal. If our hypothesis is validated by objective data, an update of chronotype classification will be required.
authors.affiliation: Department of Pharmacology, Federal University of Paraná, Curitiba, Brazil. brunojm@ymail.com
authors.forename: Bruno Jacson
authors.initials: BJ
authors.lastname: Martynhak
authors.forename: Fernando Mazzilli
authors.initials: FM
authors.lastname: Louzada
authors.forename: Mário
authors.initials: M
authors.lastname: Pedrazzoli
authors.forename: John Fontenele
authors.initials: JF
authors.lastname: Araujo
mesh_terms: D000293:Adolescent; D000465:Algorithms; D000818:Animals; D001938:Brazil; D002940:Circadian Rhythm; D005260:Female; D006801:Humans; D008297:Male; D008954:Models, Biological; D015233:Models, Statistical; D017440:Photoperiod; D011795:Surveys and Questionnaires; D055815:Young Adult