The relationship between masticatory muscles activity and tinnitus – preliminary study

Background
Structures of temporomandibular joints and ear have a common phylogenetic origin. Muscular imbalance in the area of masticatory muscles may lead to tinnitus.

Objectives
A comparison of muscular tension and masticatory muscles asymmetry between women with tinnitus and without tinnitus.

Material and methods
From a group of 96 examined responders, we found 32 women (aged 22 ± 2 years) who exhibited no temporomandibular joint disorders and who had not been treated otolaryngologically. The examined women were then placed within two groups: with tinnitus (16 people) and without tinnitus (16 people). Next, we examined the muscular activity in the temporomandibular muscles by way of sEMG at rest, when the teeth were clenched and when the mouth is opened maximally. To assess muscular asymmetry, the asymmetry index was used.

Results
Despite the lower bioelectrical muscular tension of masticatory muscles at rest and during the examined functions in people with tinnitus, the results were not important statistically (p > 0.05). However, we observed crucial statistical differences in masseter muscle asymmetry in people with tinnitus when clenching teeth (p = 0.042), and in the number of people with muscle asymmetry in the area of the masticatory muscles at rest (p = 0.012) and when teeth are clenched (p = 0.013), in comparison to a healthy group.

Conclusions
There is a relationship between changes in the asymmetry index of the masticatory muscles and the occurrence of tinnitus. In order to confirm the results, we recommend further examination in this area and longer observation time.