Analyzing the Construct Validity and Reproducibility of the Chemical Odor Sensitivity Scale (COSS) in a Migraine Sample

• Grant number: 25/22139-8
• Support Opportunities: Scholarships abroad - Research Internship - Master's degree
• Start date: February 16, 2026
• End date: August 15, 2026
• Field of knowledge: Health Sciences - Physiotherapy and Occupational Therapy
• Principal Investigator: Débora Bevilaqua Grossi
• Grantee: Vitória Carolina Leonel
• Supervisor: Melissa Cortez
• Host Institution: Faculdade de Medicina de Ribeirão Preto (FMRP). Universidade de São Paulo (USP). Ribeirão Preto , SP, Brazil
• Institution abroad: University of Utah (U), United States
• Associated to the scholarship: 24/13121-5 - Cross -cultural adaptation and analysis of the psychometric properties of visual and olfactory assessment instruments in patients with migraine, BP.MS

Abstract

Migraine is a complex neurological disorder marked by altered central sensory processing and persistent hypersensitivity, including symptoms such as osmophobia. This central sensory amplification is believed to contribute to the chronification of migraine. Osmophobia can be evaluated using self-report instruments such as the Chemical Odor Sensitivity Scale (COSS), which offer practical and accessible assessment options. However, despite the clinical relevance of osmophobia in migraine and the need for validated instruments to measure it, the psychometric properties of the COSS, specifically its validity and reliability, have yet to be established for individuals with migraine. To address this gap, the present project proposes to evaluate the construct validity and reliability of the COSS in a sample of the United States (U.S.) of individuals with migraine. Construct validity will be examined through hypothesis testing using self-report instruments (Headache Impact Test, Generalized Anxiety Disorder, Allodynia Symptom Checklist-12, Migraine-Specific Quality of Life Questionnaire version 2.1) and psychophysical assessments of olfactory performance (Sniffin' Sticks Test and the NHANES Pocket Smell Test). Reliability will be assessed through analyses of internal consistency, test-retest reproducibility, and standard error of measurement. During the internship at the University of Utah, the master's student will actively engage in data collection, statistical analyses, and scientific discussions with the host research team, while also receiving training in the laboratory's experimental protocols. This immersive experience will enrich the student's methodological competencies and foster a deeper understanding of the integration between subjective and objective markers in the evaluation of sensory alterations in migraine. Furthermore, the international collaboration will enhance the scientific rigor and analytical scope of the master's research project conducted in Brazil and strengthen the institutional partnership between research centers, promoting global alignment in the study of sensory biomarkers in migraine. (AU)