Unique Measurements of Intranasal Trigeminal Function

Introduction: Assessments of intranasal trigeminal function require specialized equipment or time intensive lateralization of trigeminal odorants. The goal of this study was to investigate novel methods of measuring intranasal trigeminal function and determine correlations to validated measures of trigeminal function.

Methods: Prospective cohort study of 41 healthy control patients without nasal congestion. Trigeminal temperature function of cool/warmth detection threshold and cold/heat pain threshold were measured with the Thermal Sensory Analyzer (TSAII) device, as previously validated at buccal mucosa and infraorbital skin. Identical temperature sensory function was then assessed at the anterior septum and inferior turbinate. Lateralization of trigeminal odorants eucalyptol, isothiocyanate, and acetic acid was conducted. Visual analog scales (VAS) of trigeminal function were collected.

Results: Extraoral cheek site and oral site TSAII measures were moderately correlated, suggesting consistent assessment of trigeminal function. Nearly all intranasal TSAII measures correlated between the septum and turbinate. Oral and extraoral cheek sites had modest correlations to intranasal cold and heat discomfort. Oral site had modest correlations of cold and heat detection to intranasal sites, with turbinate appearing to have the most correlations. Isothiocyanate lateralization was the most closely correlated to intranasal TSAII scores for cold and heat discomfort. Turbinate TSAII measures had weak correlations with subjective trigeminal VAS scores.

Conclusions: Intranasal trigeminal measures of thermal function detection and pain correlate to validated extraoral and intraoral thermal measures. The turbinate appears to have stronger correlations to the mouth and face than found in the septum. TSAII testing might provide a rapid, novel method of intranasal trigeminal function assessment.