Acufene somato-sensoriale e disturbi dell’articolazione temporo-mandibolare: sviluppo di test diagnostici e di terapie riabilitative per la valutazione ed il trattamento neuromuscolare

Tinnitus is the perception of sound in absence of a corresponding external acoustic stimulus. Somatosensory Tinnitus”, differently, is a tinnitus evoked or modulated by inputs from somatosensory, somatomotor e visual motor systems in some individuals. Inputs from these system seems to activate auditory patterns, leading to a “modulation” of tinnitus. Modulation can occur after a forceful muscle contractions of the temporomandibular joint (TMJ), head and neck, and limbs, pressure application on myofascial trigger points, head rotation and orofacial movements. Numerous studies have assessed that there are connections between auditory pathways and the dorsal column of the trigeminal system, where dorsal root and trigeminal cells send neural projection to the cochlear nucleus (CN). Aim of study The aim of this study is to investigate the effect of a conservative TMJ treatment on somatic tinnitus. The other aim of this study is to validate the routinely use of Teethan to measure somatic tinnitus. We aim to improve the quality of care for patients with somatic tinnitus attributed to TMJ or oral parafunctions. Methods Patients with stable somatosensory tinnitus occurring within the past 3 months were enrolled. Patients were excluded in case of clear otological or neurological causes of the tinnitus, progressive middle ear pathology, intracranial pathology, traumatic cervical spine or temporomandibular injury in the past 6 months, severe depression, tumours, previous surgery in the orofacial area. All patients will be assessed by means of medical history, ear-nose-throat examination with micro-otoscopy, brain magnetic resonance imaging, audiometry and Teethan exam. During anamnesis, patients are questioned about the presence of bruxism and clenching. Patients have been randomised into the treated group A or into the untreated group B. Group A received a Myofunctional rehabilitation cycle (one session per week for 10 consecutive weeks). Results The sample size calculation showed the need to enroll 22 patients to have a power of 95%. The Shapiro-Wilk test showed that the analyzed data did not respect the normal distribution therefore non-parametric tests such as the Wilcoxon test were used. The descriptive analysis has been reported in Table 1 where for each value analyzed the mean, standard deviation, standard error and coefficient of variation have been reported. The results of the Wilcoxon analysis highlighted how there is a statistically significant difference between the values before and after the treatment of POC-TA (72% vs. 81%, p<0.01), POC-MM (71% vs. 85%, p<0.001, TORS (82% vs 88%, p<0.01), THI (39% vs 20%, p<0.001), OMES (83% vs 92%, p<0.001) and JFLS-20 (27% vs 19%, p<0.01). Logistic regression analysis with the degree of tinnitus severity showed a correlation with the THI before treatment (Chi-squared 20.86; Cox & Snell R2= 0.61; P < 0.0001) (Figure 3). Logistic regression analysis with recovery from tinnitus showed a correlation with pre-treatment BAR, TORS and POC-TA values (Chi-squared 7.752 ; Cox & Snell R2=0.484; P < 0.01). However, regarding the logistic regression analysis of the position of the tinnitus (right or left) no statistically significant correlations were found ROC curve analysis confirmed this finding by showing an Area Under the Curve (AUC) of 100% (95%CI: 85%-100%) with a Youden index >56 and a sensitivity and specificity of 100% . (Figure 5) However, the analysis of the ROC curve did not confirm statically significant correlations between recovery from tinnitus and showed a correlation with BAR, TORS and POC-TA values prior to treatment. Conclusion In our study, a significant association between somatosensory tinnitus and TMJ pathology was identified. As highlighted by the results of the statistical analysis, the parameters of POC-TA, POC-MM and TORS improve after rehabilitation treatment, also associated with an attenuation of the intensity of tinnitus assessed via the THI questionnaire. This data demonstrates how the temporalis and masseter muscles are involved in the modulation of summative-sensory tinnitus. The correlation between THI and TORS highlights how stomatognathic balance is of fundamental importance; the presence of any cross bite, pre-contacts or the lack of dental elements can be considered risk factors for the development of somato-sensory tinnitus. To date, electromyographic examination has been used in clinical practice to study TMJ dysfunction. This test can become an excellent screening test to identify those patients suffering from tinnitus, without TMJ symptoms and without hearing deficits, who could still benefit from a myofunctional treatment.