Stimulation of the human nasal passage with pungent vapor elicits motor res
ponses in a zone around the eye. This Investigation addressed whether quant
ification of such responses, particularly activity of the orbicularis oculi
muscle, could yield a sensitive index of nasal pungency. We placed an arra
y of small, high-contrast targets just beneath the lower eyelid and videota
ped their movement to capture deformation of the skin atop the orbicularis
oculi during 3 s stimulation with pungent concentrations of ethyl acetate.
Eleven subjects participated. Analysis of the movements served to determine
mechanical strain, which yielded a single index that we termed 'maximum st
rain'. This increased with concentration of the vapor and with time during
and just after stimulation. Comparison with psychophysical data showed that
the strain became evident at concentrations just detectable as pungent. Ma
ximum strain measured on the skin shows promise as an objective index of pu
ngency.