Operator-administered olfactory and gustatory test
The Connecticut Chemosensorial Clinical Research Center (CCCRC)
orthonasal olfaction test [12-16] was used to evaluate the olfactory
function. As required by the test protocol, olfactory threshold was
determined by means of 60 mL deionized waters solutions, with increasing
concentration of N-butyl-alcohol. The most concentrated bottle (bottle
0) presented 4% dilution. The other 8 bottles (bottles 1-8) contained
decreasing concentrations with consequent 1:3 dilutions. For each
threshold step, two identical squeezable bottles were presented to the
patient: one containing the N-butanol solution, from the major to the
minor dilution, and the other filled with deionized water. The test was
conducted as previously described for both nostrils, and the average
value determined the overall score [17].
Ten well-known Italian odorants were used to assess the olfactory
discriminative function: chocolate (Nutella, Ferrero, Italy), coffee,
Baby powder (Manetti & Roberts, Florence, Italy), Vicks-VapoRub
(Proctor & Gamble, Cincinnati, OH, USA), ammonia, fruit-flavored
chewing gum (Perfetti Van Melle Italia S.r.l, Lainate, Italy), ketchup
(Heinz, Pittsburgh, PA, USA), orange, soap (Ivory, Proctor & Gamble,
Cincinnati, OH, USA) and black pepper. The odorants were presented one
at a time, in identical and opaque 180 mL containers covered by gauze.
Therefore, the patient had to identify the odorant on a 20 items list
containing the 10 test samples and 10 distractors.
The threshold and discriminative test scores were finally converted into
the CCCRC composite score. The scoring system is shown in Table 2
[Table 2].
As regards the gustatory function assessment, the primary taste
solutions were identical to those used in the telephone test and already
proposed by other authors [9,10]. As the only variation, at the
hospital, deionized water was used as solvent and control instead of
normal drinking water. One at a time, approximately 1 ml of each basic
flavor was put on the patient’s tongue with a cotton swab, taking care
to test the bitter last. Therefore, the patient had to indicate the
perceived taste: salty, acid, sweet, bitter or neutral. Depending on the
number of primary tastes perceived, the score could vary between 0 and
4. The scoring system is reported in table 3 [Table 3].