Validity of diagnostic and monitoring tests used for temporomandibular disorders.

Currently, diagnosis of temporomandibular disorders (TMD) depends on a comprehensive history and physical examination, supplemented, when indicated, by images of hard and soft tissues. However, there are electronic diagnostic devices being marketed to acquire other measures described as relevant to TMD and to use these for diagnosis of TMD and for monitoring the effects of treatment. This paper reviews the capacity of several devices to measure these variables accurately and reliably and to assess the theoretical basis of each of these tests. Diagnostic ability was established, when possible, according to the commonly accepted measures of sensitivity, specificity, and positive predictive values. It was found that many tests lack theoretical validity, that measurement validity tends to be poor, and that diagnostic ability can be even worse than chance, because of a high percentage of false-positive diagnoses. Based on these findings, the use of these instruments in clinical practice is inappropriate at this time and may lead to the treatment of large numbers of subjects who have no disorder.