A computer-controlled electrogustometer for the estimation of evoked taste thresholds

A comparison of two electric taste stimulation devices

Electrical stimulation of the tongue, commonly used in clinical evaluations of taste dysfunction, can produce a variety of sensations including reports of metallic taste. Two studies compared responses to a fabricated electrical stimulator (a 1.6 V battery, anode side exposed) and a clinical electrogustometer (Rion TR-06). Batteries placed on the anterior dorsal tongue surface produced sensations similar in intensity and quality to those produced by the clinical electrogustometer, with equal intensity on the tongue tip for the 1.6 V battery in the range of 33-56 microA from the electrogustometer. A second study examined responses on three areas of the tongue on each side. Responses declined for areas lower in fungiform papillae for both devices, but at different rates. Higher current levels were required to match the battery in lower density areas, indicating spatial summation for the larger battery surface area. A consistent pattern of lateral differences was seen in only one subject. Quality descriptions were similar in frequency whether or not a word list was provided, with metallic, sour, pain and bitter being the most frequently mentioned words for both electric stimuli. Similarities in response to the battery device and electrogustometer were evident in intensity, qualities evoked, lack of a laterality effect and decreasing response in areas with lower fungiform papillae density. The battery device may provide an inexpensive portable alternative to an electrogustometer for use in clinical testing of taste.

Reliability of electrogustometry for the estimation of taste thresholds

Electrogustometry has been used as a clinical tool for diagnosis and assessment of a variety of conditions. Several studies which have estimated electrogustometric taste threshold have reported good test-retest reliability but there is some evidence that thresholds measured this way may decrease with practice. In this study, repeated testing of the right and left sides of the tongue of two subjects over 80 sessions resulted in considerable session-to-session variability for both subjects, and three of the four sets of threshold estimates decreased systematically with continued testing. Two of the four data sets continued to show systematic decreases when the first 10 sessions were omitted from analysis to allow for any initial unfamiliarity with the testing procedure. This suggests that estimates based on few tests should be interpreted with caution, particularly when used for evaluation or monitoring of interventions.

Automated electrogustometry: a new paradigm for the estimation of taste detection thresholds

Electrogustometery, first introduced in the 1950s for the clinical assessment of taste function, has returned to favour in recent years. This is due, in part, to the credence given to the procedure by an increased understanding of the mechanisms of taste transduction. The reliability and validity of electrogustometric assessments of taste function should increase with the use of automated testing. An automated computer-controlled testing paradigm was used to obtain threshold estimates simultaneously from the left and right sides of the tongue in 97 volunteers aged between 17 and 63 years. A small but statistically significant advantage was found for thresholds from the right side of the tongue (P<0.01). The range of thresholds, and of interside differences obtained with this procedure, are reported, and practical issues related to testing are discussed.