Salt Taste Sensitivity and Stimulus Volume: Sips and Drops. Some Implications for the Henkin Taste Test

Various presentation procedures and stimulus volumes were compared in their effect on salt taste sensitivity. For sodium chloride (NaCl) stimuli pipetted onto the tongue, subjects had comparable measured sensitivity to 10 ml and 1 ml volumes but a reduced sensitivity to 0.1 ml volumes. The greatest sensitivity was achieved with 10 ml sipped volumes. Modification of the Henkin dropwise triangluar taste test, by increasing the stimulus volumes, increased subjects' sensitivity. Only the 1 ml pipette presentation increased the sensitivity of the Henkin procedure, albeit slightly, to the detection of changes in taste sensitivity, the purpose for which the procedure was actually designed. Such modification did not perturb salivary NaCl levels more than the regular Henkin procedure, so it would not be expected to introduce sensitivity drift.

Salt taste sensitivity and stimulus volume: effect of stimulus residuals

Sodium chloride (NaCl) stimulus residuals were seen to be greater after a large-volume NaCl rinse than after a small-volume rinse. Predicted changes in sensitivity dependent on adapting concentrations determined by residual levels were confirmed by signal detection R-index measures of sensitivity. R-index values were seen to be independent of the volume of the test water and NaCl stimuli used in their determination.