Studies on the relationship between electrogustometry and sour taste perception.

OBJECTIVE Electrogustometry is used as a measurement of taste perception. The prevailing theory is that the anodal current delivered to the tongue mucosa stimulates the sour taste receptors, but this is not universally accepted. Our aim was to evaluate to what extent electrogustometry relates to an ability to detect sour taste--rather than sweet, salt, or bitter. METHODS We compared automated electrogustometric thresholds with visual analogue scale (VAS) ratings of various tastant solutions in 114 subjects. The whole mouth, and each side of the tongue were tested separately. VAS scores from the strongest set of solutions, and the lowest electrogustometry thresholds for each location were used for statistics. RESULTS There was a significant correlation between electrogustometry threshold and the whole mouth perception of the salt taste solution. Electrogustometry correlated significantly but weakly for all taste qualities when testing was confined to left and right oral tongue. The positive predictive values of electrogustometry were no better in relation to sour taste perception than to the other taste qualities. CONCLUSIONS Our results do not support the theory that electrogustometry is mediated by sour taste receptors or even that it reflects the sour taste quality. We postulate that electrogustometry measures a function of taste perception, which is different from that induced by chemical stimuli.