Page "Dysgeusia" Paragraph 10

Suprathreshold tests, which provide intensities of taste stimuli above threshold levels, are used to assess the patient's ability to differentiate between different intensities of taste and to estimate the magnitude of suprathreshold loss of taste.

From these tests, ratings of pleasantness can be obtained using either the direct scaling or magnitude matching method and may be of value in the diagnosis of dysgeusia.

Direct scaling tests show the ability to discriminate among different intensities of stimuli and whether a stimulus of one quality ( sweet ) is stronger or weaker than a stimulus of another quality ( sour ).

Direct scaling cannot be used to determine if a taste stimulus is being perceived at abnormal levels.

In this case, magnitude matching is used, in which a patient is asked to rate the intensities of taste stimuli and stimuli of another sensory system, such as the loudness of a tone, on a similar scale.

For example, the Connecticut Chemosensory Clinical Research Center asks patients to rate the intensities of NaCl, sucrose, citric acid and quinine-HCl stimuli, and the loudness of 1000 Hz tones.

Assuming normal hearing, the results of this cross-sensory test show the relative strength of the sense of taste in relation to the loudness of the auditory stimulus.

Although many of the tests are based on ratings using the direct scaling method, some tests do use the magnitude-matching procedure.