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Localization of TMJ sounds to side
S E Widmalm1, W J Williams, B K Ang
1Department of Biologic and Materials Sciences, School of, Dentistry, University of Michigan, USA. sew@umich.edu
Journal of Oral Rehabilitation
|November 8, 2002
Summary
Accurate diagnosis of temporomandibular joint (TMJ) clicking requires identifying the sound source. Bilateral electronic recordings can differentiate unilateral TMJ sounds, aiding differential diagnosis and preventing misdiagnosis of silent joints.
Area of Science:
- Biomedical Engineering
- Otolaryngology
- Dental Diagnostics
Background:
- Accurate identification of the temporomandibular joint (TMJ) sound source is crucial for differential diagnosis of disk displacement.
- Misdiagnosis can occur when TMJ clicking is perceived bilaterally, leading to uncertainty about the affected side.
Purpose of the Study:
- To investigate the effect of head tissues on the spectral characteristics of TMJ sounds.
- To determine if differences in sensor positioning can aid in localizing the TMJ sound source.
- To compare bilateral electronic recordings of unilateral TMJ sounds, analyzing attenuation, phase shift, and time delay.
Main Methods:
- Bilateral electronic recordings of unilateral TMJ sounds were obtained from 12 subjects with clicking.
- Small electret condenser microphones (40-20,000 Hz bandwidth) were placed at auditory canal openings.
- Sounds were recorded at a sampling rate of 48,000 Hz.
Main Results:
- Head tissues function as a filter, introducing frequency-dependent attenuation and phase shift to TMJ sounds.
- A time delay was consistently observed between ipsilateral and contralateral recordings, with contralateral recordings showing longer delays (0.2-1.2 ms).
- The group mean delay time was 0.68 ms (s.d. 0.292 ms).
Conclusions:
- Spectral analysis of bilateral TMJ sound recordings offers diagnostic value for cases with perceived bilateral clicking.
- This method can help clinicians avoid misdiagnosing a silent joint as one with clicking, improving diagnostic accuracy.