Quantitative Sensory Testing

A method for the quantitative assessment of a patient's sensory function by measuring the detection threshold of precisely calibrated sensory stimuli. Vibration, thermal, or pain stimuli are often chosen; these do not allow individual receptor types to be tested in isolation, but rather activate various combinations of them. While the sensory stimulus is an objective physical event, the patient's response to it is subjective. In case of deviation from normal, the lesion may be localized in the receptor portion, in the conducting pathways, or in the primary sensory cortex of the brain. In addition, psychoemotional factors can also influence the perception of the stimulus. The method has two approaches — the "stimulus limit" method and the "stimulus level" determination method. In the "limit" method, the subject determines when a decreasing stimulus is no longer detected. In the level method, stimuli of varying intensity levels are tested, and the subject's task is to determine that level. The advantage of the latter is that it does not depend on the patient's reaction speed.

Thus, the method can provide evidence of the involvement of small-diameter sensory nerve fibers; however, due to its degree of subjectivity, the method cannot be used in isolation and must be interpreted in a clinical context in combination with other data.

Text author: Dr. Sc. (Med.) Druzhinin D.S.