# Numerical Study of Tympanosclerosis Including Its Effect on Human Hearing
## 4 Discussion and Conclusions  
Biomechanical studies of tympanosclerosis can be of great aid to improve our understanding of the mechanisms of tympanosclerosis plaque formation and its biomechanical behavior. The finite element method can be a very powerful tool to simulate the tympanosclerosis effects.  
Histologically, tympanosclerosis is a change in the subepithelial connective tissue of the eardrum and middle ear. Tympanosclerosis plaques (calcium phosphate concentration) occur due to the fact of a degenerative process of collagen fibers, causing calcification of the tissues. Several factors contribute to the formation of these calcium plaques, such as the eardrum healing after the removal of ventilation tubes that were previously placed for the drainage of fluid from the middle ear; otitis of the middle ear; infections that become chronic; and traumas of the eardrum. Clinically, myringosclerosis is usually asymptomatic without causing hearing loss. Tympanosclerosis, according to the area and affected ossicles, can cause hearing loss. It is very important to have a correct approach to treatment. The goal is auditory preservation without recourse to solutions that can leave sequelae.  
Figure 11: Phase angles for the stages footplate, comparing different situations.  
Figure 12: Stages footplate displacements, comparing the different sound pressure applied.  
The results have shown that the localization and dimension of the plaques are very important. When larger plaques were present, the mobility of the stapes decreased, as well as when the tympanic annulus and the area of the malleus handle were involved.  
This work presents a comparative (and quantitative) study between the different affected parts of the tympanic cavity with tympanosclerosis. Three different cases of tympanosclerosis were considered: (1) myringosclerosis; (2) tympanosclerosis affecting the eardrum and the malleus; (3) tympanosclerosis affecting the eardrum and the three ossicles. A computational approach was applied to assess the importance of the tympanosclerosis effects and their correlation with hearing loss.  
The 3D middle ear model used was validated by comparing the displacements of the umbo and the stapes with other data available in the literature. A sound pressure level of 80, 90 and 100 dB SPL was applied to the external auditory canal. The onset of tympanosclerosis can be symptomatic of acute middle ear infection and related to its structural change. The findings from this study are corroborated by clinical practice.  
Improving the study of tympanosclerosis behavior can be of extreme importance, particularly in people who have had recurrent middle ear infections in the past, resulting in hearing loss or other complicated pathologies with unhealthier effects.  
Conceptualization, F.G., C.S. and R.N.J.; methodology, M.P., C.S. and B.A.; software, M.P. and B.A.; validation, F.G., M.P., C.S. and B.A.; formal analysis, C.S. and B.A.; investigation, R.N.J., F.G. and C.S.; resources, F.G. and C.S.; data curation, M.P. and B.A.; writing--original draft preparation, F.G.; writing--review and editing, M.P. and R.N.J.; visualization, F.G. and C.S.; supervision, R.N.J. All authors have read and agreed to the published version of the manuscript. Funding provided by Ministerio da Ciencia, Tecnologia e Ensino Superior-Fundacao para a Ciencia e a Tecnologia (Portugal). This research was also supported by the Portuguese Foundation of Science and Technology, through LAETA, project UIDB/50022/2020. Institutional Review Board Statement: Not applicable. Informed Consent Statement: Not applicable. Data Availability Statement: Not applicable. Conflicts of Interest: The authors declare no conflict of interest.