title: Classification of temporomandibular joint sounds based upon their reduced interference distribution.
abstract: Temporomandibular joint (TMJ) sounds were recorded in 98 orthodontic retention patients, mean age 19 +/- 8.6 (s.d.) years, by interview, auscultation and electronic recording. Sounds were found by auscultation in 41% and by interview in 32% of the subjects, more often in females than in males (P < 0.05). A new method for time-frequency analysis, the reduced interference distribution (RID), was used to classify the electronic sound recordings into five subclasses, RID types 1-5, based upon location and number of their energy peaks. RID types 1-3 had a few energy peaks close in time. RID types 4-5, typical of subjects with crepitation, had multiple energy peaks occurring close in time for a period of 20-300 ms. RID type 1, found in 45% of the subjects, typical of patients with clicking, had its dominant energy peak located in a frequency range < 600 Hz and was significantly more common in the female than in the male subjects (P < 0.01). RID type 2, found in 68% of the subjects, with the dominant peak in the range 600-1200 Hz, and RID type 3, found in 38% of the subjects, with the peak in the frequency range > 1200 Hz, were found to have a similar gender distribution. RID type 4, found in 49% of the subjects, had the energy peaks distributed in the frequency range < 600 Hz. RID type 5, found in 43% of the subjects, more often in females than in males (P < 0.05), had the peaks distributed over the whole frequency range from about 30 Hz up to about 3000 Hz. In conclusion, a more detailed classification could be made of the TMJ sounds by displaying the RIDs than by auscultation. This suggests that RID classification methods may provide a means for differentiating sounds indicating different types of pathology.
authors.affiliation: Department of Biologic & Materials Sciences, University of Michigan, Ann Arbor, USA.
authors.forename: S E
authors.initials: SE
authors.lastname: Widmalm
authors.forename: W J
authors.initials: WJ
authors.lastname: Williams
authors.forename: R L
authors.initials: RL
authors.lastname: Christiansen
authors.forename: S M
authors.initials: SM
authors.lastname: Gunn
authors.forename: D K
authors.initials: DK
authors.lastname: Park
mesh_terms: D000293:Adolescent; D000328:Adult; D001314:Auscultation; D002965:Classification; D003766:Dental Occlusion; D003769:Dental Occlusion, Traumatic / Q000503:physiopathology; D004582:Electronics, Medical; D005260:Female; D006801:Humans; D007407:Interviews as Topic; D008297:Male; D008310:Malocclusion / Q000503:physiopathology / Q000628:therapy; D012737:Sex Factors; D013016:Sound; D013704:Temporomandibular Joint / Q000502:physiology* / Q000503:physiopathology; D013705:Temporomandibular Joint Disorders / Q000503:physiopathology; D013706:Temporomandibular Joint Dysfunction Syndrome / Q000503:physiopathology