Tinnitus can be a common symptom of hearing a sound, either intermittent or constant, and it often only subjective in nature. A meta-analysis of 22 articles was conducted, in which tinnitus and TMD or CSDs were investigated as primary or secondary outcome measures.
Since it is often speculated that jaw and neck function can impact symptoms of tinnitus, the aim of this study was to determine if there was a correlation between tinnitus and TMD or CSDs. If an association is found, then addressing TMD or CSD could possibly help in reducing tinnitus.
TMD and tinnitus
All of the studies that examined tinnitus and TMD found a correlation between tinnitus symptoms and TMD. Of the 11 studies that investigated tinnitus and TMD of arthrogenous origin, 8 studies found a correlation in symptoms: the more prevalent the TMD arthrogenous symptoms, the more prevalent the tinnitus. Of the 7 studies that looked at TMD with myofascial symptoms, all found a positive correlation with tinnitus.
Cervical spine and tinnitus
With regards to the correlation with CSDs, the information did not show a linear correlation. It was noted that those with tinnitus did report more CSD symptoms. However, just because a subject expressed having CSD symptoms, this did not mean it was more likely to have tinnitus as noted by the authors of this review.
While this literature review shows that there can be a link between tinnitus and TMD in particular, why would this be? The authors highlight the structural links between the jaw joint and the inner ear.
It is speculated that the muscles associated with mastication may influence the inner ear canal through the tensor veli palatini, the eustachian tube, or several of the inner ear ligaments. It is hypothesised that these imbalances in muscle tension or TMJ mechanics can contribute to auditory symptoms.
While this study has several limitations such as a rather broad and subjective classification of TMD and CSDs, it does shed light on the mechanical link for addressing tinnitus. This is critical for further developing potential treatments for treating those who suffer from tinnitus.
> From: Bousema et al., Trends Hear 22 (2018) 2331216518800640 . All rights reserved to The Author(s). Click here for the online summary.
Expert opinion
The function of the TMJ is often overlooked in the orthopaedic (and neurological) communities. While the joints in the cervical spine are able to produce a host of mechanical and neurological symptoms, the proximity of the TMJ to the auditory structures should also be strongly considered with any auditory or potential cranial neurological symptoms.
By better understanding how physiotherapy can address the TMJ and associated symptoms (not just pain, but headaches, tension, disrupted sleep and ofcourse tinnitus) enables physiotherapists to cross over between neurological and orthopaedic treatment as required to address several specific issues.
