Clinical test of gustatory function including umami taste.

Area of Science:

• Sensory science
• Neuroscience
• Otorhinolaryngology

Background:

• Gustatory function assessment is crucial for diagnosing chemosensory disorders.
• The umami taste, described by Ikeda using monosodium glutamate, is a key taste quality.
• Existing gustatory tests can be enhanced to include umami.

Purpose of the Study:

• To extend a validated gustatory test by incorporating four concentrations of monosodium glutamate (umami).
• To evaluate the reliability and applicability of this extended gustatory test in both clinical and experimental settings.

Main Methods:

• Ninety-six subjects with normal taste and smell underwent an extended gustatory test with sweet, sour, salty, bitter, and umami tastes.
• Results were compared to a control group (n=139) not tested with umami.
• Test-retest reliability was assessed in a subgroup of 46 participants.

Main Results:

• No significant differences in taste sensitivity were found across the four taste qualities between groups (p > 0.3).
• The sum of correctly identified tastants showed no significant deviation (p = 0.81).
• The extended gustatory test demonstrated high test-retest reliability (r46 = 0.77; p < 0.001).

Conclusions:

• The extended gustatory test, including umami taste, is reliable and valid.
• This enhanced test is suitable for use in both experimental research and clinical diagnosis of gustatory dysfunction.