The Changes of Olfactory and Trigeminal Pungency Thresholds in n-Aliphatic Alcohols with Different Carbon Chain in Normal Adults / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: Using n-aliphatic alcohols whose physical properties change gradually as their length increases, we investigated the changes of olfactory threshold and trigeminal pungency threshold with the increase of carbon chain length. MATERIALS AND METHOD: Olfactory and trigeminal pungency thresholds were measured in ethanol (C2), 1-butanol (C4), 1-hexanol (C6) and 1-octanol (C8) in 40 normal adults using a two-alternative forced-choice modified by the ascending method of limit (CCCRC) test. Plastic bottles with 30 ml of four n-aliphatic alcohols were diluted threefold successively by mineral oil. Plastic bottles containing only mineral oil were used as controls. RESULTS: The olfactory and trigeminal pungency thresholds decreased and the ratio of olfactory threshold/trigeminal pungency threshold increased with the length of carbon chain in n-aliphatic alcohols. The correlation coefficients among olfactory thresholds in each alcohol were higher than those among trigeminal pungency thresholds. CONCLUSION: Alcohol with long carbon chains showed low olfactory and trigeminal pungency thresholds, indicating that high lipid solubility is an important factor in olfaction and trigeminal chemosensitivity.

Measurement of Nasal Trigeminal Pungency Threshold: Comparison between Normals and Patients with Decreased Sense of Smell

BACKGROUND AND OBJECTIVES: In order to measure the level of nasal trigeminal pungency threshold and to evaluate the interaction between olfactory and trigeminal nerves, we measured olfactory thresholds and trigeminal pungency thresholds using 1-butanol in 40 normal people and in 46 patients with decreased sense of smell by non-sinonasal origin. MATERIALS AND METHODS: Two-alternative forced-choice modified ascending method of limit (CCCRC test) was used for the measurement of olfactory and pungency thresholds, using 1-butanol plastic squeezable bottles successively threefold diluted by distilled water as stimulus, while distilled water as blank. RESULTS: There was a statistically significant difference in pungency threshold between normals (2.18+/-1.5 dilution step) and patients (1.11+/-1.0 dilution step)(p<0.001). CONCLUSION: The pungency thresholds of hyposmics and anosmics are higher than those of normals, which suggests that a loss or decrease of olfactory sensation is accompanied by a simultaneous decrease of trigeminal chemosensitivity.