Patient-administrated olfactory and gustatory test
Both olfaction and taste were assessed in all the patients. The olfactory threshold was determined using solutions with a decreasing concentration of denatured ethyl-alcohol. Ethyl-alcohol has an olfactory threshold 10 times lower than N-butyl-alcohol [8], therefore the patient was asked to prepare a 40% in 100 mL water solution (bottle 0) using a using a syringe or a graduated container. In the following bottles (from 1 to 8), the patients diluted a part of the previous solution with two parts of water, thus obtaining solutions with consequent 1:3 dilutions. Finally, a control bottle was filled with water only. The test was performed by asking the patient to smell the alcohol-containing bottle, starting with the less concentrated (bottle 8), reporting if he found any differences compared to the control bottle. In case of a negative answer, the examination continued with the consequent bottle.
The discriminative test was performed asking the patient to find some commonly used odorants [Table 1]. Therefore, the subject smelled an odorant for each of the 7 groups providing an assessment of the discriminative ability from 0 (no discrimination) to 10 (normal discrimination). The discriminatory score was obtained from the average of the ratings of the 7 odorants.
The threshold and identification test scores, after being analyzed separately, were finally converted into a composite score. The scoring system is shown in table 2 [Table 2].
For the evaluation of the gustatory function, the patient was asked to prepare four solutions, one for each primary taste [9-11]:
The patient was asked to put in mouth a tea spoon of each solution, reporting the quality of taste perception, scoring it from 0 (ageusia) to 10 (normal perception). The bitter solution comes always the last [9-10]. The overall test score was obtained by the average of the values ​​reported for each of the primary tastes. The scoring system is reported in table 3 [Table 3].