2.2.1Electrogustometry
We have evaluated taste acuity with electrogustometry (EGM). Electrical
stimuli were delivered using an electrogustometer (TR-06, Rion Co,
Tokio, Japan) with a single, flat, circular stainless steel stimulus
probe (5mm in diameter).
All subjects were instructed not to drink or eat for at least an hour
before the beginning of the testing session. A 500-ms electric stimulus
was applied, beginning at -6 dB and increasing up to +34 dB (3-400 μΑ)
in 2dB-steps [12,13,15]. Thresholds were measured randomly on both
sides of the tongue to avoid any possible bias. All six areas were
tested with the same stimulus duration before proceeding with the
application of a stimulus of different duration. The subject was kept
unaware of whether the current was applied (blind test) as previously
reported [11,12]. A two-alternative forced-choice initially
ascending single-staircase detection was employed using a two-down,
one-up rule [11,12].