Interexaminer reliability and clinical validity of the temporomandibular index: a new outcome measure for temporomandibular disorders.
OBJECTIVE
The operational definitions for the Craniomandibular Index (CMI) were redesigned to conform precisely to those of the Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD), resulting in a single examination protocol, the Temporomandibular Index (TMI). The objectives were to evaluate interexaminer reliability of the TMI as well as its criteria and construct validity for measurement of TMD severity.


METHODS
Interexaminer reliability of the TMI was assessed on 12 subjects. Criterion validity of the TMI was evaluated relative to the CMI, the latter having established validity. Construct validity of the TMI was evaluated for its capacity to differentiate TMD patients (n = 79) from normal subjects (n = 20) and to detect changes in severity over time.


RESULTS
The examiner's average TMI scores were 0.27 +/- 0.19 (SD) and 0.26 +/- 0.20. Agreement was excellent, with an intraclass correlation coefficient (ICC) of 0.93. The scores for the TMI and the CMI correlated highly, with an ICC of 0.97. Statistical contrasts between the symptomatic groups and the normal subjects were highly significant (P < .001). In 20 TMD patients who underwent treatment for their disorder, their mean change of 0.12 from their pretreatment TMI scores was highly significant (P < .001).


CONCLUSIONS
This study has provided statistical evidence for the clinical reliability and validity of the TMI, which indicates that the RDC examination protocol is appropriate for determining TMD severity by the TMI algorithm, and diagnosis of TMD subtypes by the RDC algorithm.
Pehling
Jason
J
TMJ and Orofacial Disorders Center, Seattle, Washington, USA.
Schiffman
Eric
E
Look
John
J
Shaefer
J
J
Lenton
Pat
P
Fricton
James
J
D000293:Adolescent; D000328:Adult; D000465:Algorithms; D018771:Arthralgia / Q000175:diagnosis; D005157:Facial Pain / Q000175:diagnosis; D005260:Female; D006801:Humans; D008297:Male; D008410:Masticatory Muscles / Q000503:physiopathology; D015588:Observer Variation; D017063:Outcome Assessment, Health Care / Q000379:methods*; D010147:Pain Measurement; D011594:Psychometrics; D016059:Range of Motion, Articular; D015203:Reproducibility of Results; D012720:Severity of Illness Index; D013705:Temporomandibular Joint Disorders / Q000145:classification* / Q000175:diagnosis*