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- Cochlear hair cell regeneration based on stem cells: A systematic reviewPublication . Costa, Vítor Bruno; Tomé, David; Çirtlik, Zeynep Yağmur; Öztürk, Yaren; Clemêncio, Filomena; Pitt-Byrne, Theresa; Tomé, David; Costa Clemêncio, Filomena MariaAccording to the World Health Organization (WHO), by 2050 at least 700 million people will need access to hearing care and hearing rehabilitation services. The search for cell or gene therapies has been intensifying, and stem cell therapy looks a promising candidate to support hearing regeneration and reduce these numbers. The aim of this study is to provide an overview of current advances in stem cellbased therapies for cochlear hair cell regeneration and the processes being developed for future applicability. Identification and review of all articles in the databases PubMed, Web of Science, and PLoS One using the terms stem cell, auditory hair cell regeneration, and mammalian during February 2023 and following the PRISMA guidelines. 50 articles were obtained, published between 2003 and 2022 and were systematically analyzed. The current research quantity is limited and further studies are needed, particularly in human tissue. The simultaneous use of cell therapy and gene therapy may lead to more promising results. Moreover, advances in cochlear hair cell regeneration with stem cells suggest there is a realistic potential to make the technique a useful future therapy.
- Perspetivas terapêuticas na Otosclerose: tratamento cirúrgico versus prótese auditiva um estudo retrospetivo observacionalPublication . Amorim, Miguel; Santos, Ana-Luísa; Neto, Ana; Tomé, David; Tomé, DavidA Otosclerose é uma das causas de perda auditiva de transmissão mais frequente no adulto, existindo dois tipos de reabilitação, cirurgia ou colocação de prótese auditiva. Avaliar os resultados de cirurgia e da adaptação protésica na otosclerose, confrontando as duas opções na redução do air-bone gap. Para este estudo, selecionaram-se 64 pacientes, 46 dos quais da lista de cirurgia do serviço de ORL do Hospital S. João de Deus, tendo os restantes 18 colocado prótese auditiva. A cirurgia foi realizada em 71,9% dos casos e a colocação de prótese auditiva em 28,1%, verificando-se resultados médios, na redução do air-bone gap melhores nos pacientes que foram submetidos a cirurgia. Concluiu-se que a cirurgia foi a técnica de reabilitação mais eficaz na redução ao air-bone gap.
- Hearing evaluation of Portuguese school communities: School-based Audiology versus Hearing ScreeningPublication . Lopes, Paula; Tomé, David; Sousa, Aida; Magalhães, António; Tomé, David; da Costa Lopes, Paula MariaObjective: The incidence of the hearing loss and of otological problems was studied in school communities in the north of the country with 2550 participants between 3 and 17 years old. Study Design: statistical data collected within the schools with a standard auditory hearing screening protocol. Material and Methods: All participants were evaluated with the same protocol, an audiological anamnesis, otoscopy and audiometric exam screening were fulfilled. Results: Different otological problems were identified and the audiometric screening exam counted auditory thresholds that outpointed uni and bilateral hearing loss in about 5,7% of the cases. Conclusions: The study has demonstrated that auditory school screening should take place as early as possible and be part of the primary health care to identify and direct children to appropriate education and attendance.
- Phonological and articulation treatment approaches in Portuguese children with speech and language impairments: a randomized controlled intervention studyPublication . Lousada, M.; Jesus, Luís M. T.; Capelas, S.; Margaça, C.; Tomé, David; Valente, A.; Hall, A.; Joffe, V. L.In Portugal, the routine clinical practice of speech and language therapists (SLTs) in treating children with all types of speech sound disorder (SSD) continues to be articulation therapy (AT). There is limited use of phonological therapy (PT) or phonological awareness training in Portugal. Additionally, at an international level there is a focus on collecting information on and differentiating between the effectiveness of PT and AT for children with different types of phonologically based SSD, as well as on the role of phonological awareness in remediating SSD. It is important to collect more evidence for the most effective and efficient type of intervention approach for different SSDs and for these data to be collected from diverse linguistic and cultural perspectives. To evaluate the effectiveness of a PT and AT approach for treatment of 14 Portuguese children, aged 4.0–6.7 years, with a phonologically based SSD. The children were randomly assigned to one of the two treatment approaches (seven children in each group). All children were treated by the same SLT, blind to the aims of the study, over three blocks of a total of 25 weekly sessions of intervention. Outcome measures of phonological ability (percentage of consonants correct (PCC), percentage occurrence of different phonological processes and phonetic inventory) were taken before and after intervention. A qualitative assessment of intervention effectiveness from the perspective of the parents of participants was included. Both treatments were effective in improving the participants’ speech, with the children receiving PT showing a more significant improvement in PCC score than those receiving the AT. Children in the PT group also showed greater generalization to untreated words than those receiving AT. Parents reported both intervention approaches to be as effective in improving their children's speech. The PT (combination of expressive phonological tasks, phonological awareness, listening and discrimination activities) proved to be an effective integrated method of improving phonological SSD in children. These findings provide some evidence for Portuguese SLTs to employ PT with children with phonologically based SSD.
- Influence of the basilar membrane shape and mechanical properties in the cochlear response: A numerical studyPublication . Areias, Bruno; Parente, Marco; Gentil, Fernanda; Jorge, Renato NatalHearing impairment is one of the most common health disorders, affecting individuals of all ages, reducing considerably their quality of life. At present, it is known that during an acoustic stimulation a travelling wave is developed inside the cochlea. Existing mathematical and numerical models available in the literature try to describe the shape of this travelling wave, the majority of them present a set of approaches based on some limitations either or both of the mechanical properties used and the geometrical description of the realistic representation. The present numerical study highlights the distinctions of using a spiral model of the cochlea, by comparing the obtained results with a straight, or simplified model. The influence of the implantation of transversely isotropic mechanical models was also studied, by comparing the basilar membrane with isotropic and transversely isotropic mechanical properties. Values of the root mean square error calculated for all models show a greater proximity of the cochlear mapping to the Greenwood function when the basilar membrane is assumed with transversely isotropic mechanical properties for both straight and spiral model. The rootmean square errors calculated were: 2.05, 1.70, 2.72, 2.08 mm, for the straight-isotropic, straight-transversely isotropic, spiral-isotropic and spiral-transversely isotropic model, respectively.
- Cupula response to otoconia debris in the semicircular canalPublication . Santos, Carla F.; Belinha, J.; Gentil, Fernanda; Parente, Marco; Jorge, Renato NatalThe vertigo symptoms are commonly related with inner ear diseases and it affects 20%-30% of the world population, and its prevalence increases with age. In this work, a three-dimensional computational model of the semicircular canal of the vestibular system, containing the fluids which promote the body balance, was used. The smoothed-particle hydrodynamics method was the computational process used to simulate the fluid behaviour, in which the elements are represented by particles and have constant mass. The other vestibular components were discretized using the finite element method. The movement performed to endolymph/cupula interaction analysis was reproduced in the simulation through the acquisition of the displacement field based on image analysis. The results obtained with the frames of the video recorded during the process is the appropriate method to simulate the real moves, due to the analysis of the region of interest located near the inner ear. The data obtained from the video acquisition were the input in the simulation with the semicircular model. The principal stress cupular response allowed to understand the interaction of the vestibular structures during a vertigo episode, and the influence of the otoconia in the cupula displacement. This model is the first step to improve the vestibular rehabilitation and the quality of life of patients suffering from vertigo.
- On the hearing effects of a cholesteatoma growing: A biomechanical studyPublication . Mendonça, Leonor ; Santos, Carla F.; Gentil, Fernanda; Parente, Marco ; Areias, Bruno ; Jorge, Renato NatalChronic otitis media enables the appearance of a benign middle ear tumor, known as a cholesteatoma, that may compromise hearing. To evaluate the influence of a cholesteatoma growth on the hearing function, a computational middle ear model based on the finite element method was used and three different size of cholesteatoma were modeled. The cholesteatoma solidification and the consequent degradation of the ossicles were also simulated as two condition that commonly occurs during cholesteatoma evolution. A sound pressure level of 80 dB SPL was applied in the tympanic membrane and a steady state analysis was performed for frequencies from 100 Hz to 10 kHz. The displacements of both the tympanic membrane and the stapes footplate were measured. The results were compared with a healthy case and it was shown that the cholesteatoma development leads to a decrease in the umbo and stapes displacements. The ossicles degradation simulation showed the higher difference comparing with the cholesteatoma in an initial stage, with lower displacements in the stapes footplate mainly for high frequencies. The observed displacement differences are directly connected to hearing loss, being possible to conclude that cholesteatoma evolution in the middle ear will lead to hearing problems, mainly in an advanced stage.
- Numerical study of tympanosclerosis including its effect on human hearingPublication . Gentil, Fernanda; Parente, Marco; Santos, Carla; Areias, Bruno; Jorge, Renato NatalTympanosclerosis is an abnormal disorder of the middle ear or only the eardrum (i.e., myringosclerosis) in which there are calcium deposits. Normally, it is caused by recurrent middle ear infections. In this work, a 3D finite element model of the ear was developed, simulating different cases of tympanosclerosis. Through this model, the magnitude and the phase angle of the umbo and stapes displacement were obtained. The middle ear sound transfer function was determined for a stimulus of 80, 90 and 100 dB SPL, in a frequency range between 100 Hz and 10 kHz, applied on the outer surface of the eardrum in the external auditory canal. Depending on the tympanosclerosis affected area, the main conclusion is that worse results (leading to hearing loss) occur when all of the ossicular chain is affected.
- Influence of middle ear tumours on the biomechanical behaviour of the chorda tympaniPublication . Mendonça, Leonor; Santos, Carla F.; Gentil, Fernanda; Parente, Marco; Areias, Bruno; Jorge, Renato NatalChronic otitis media may lead to the development of a cholesteatoma, a benign middle ear tumour. If this occurs, the chorda tympani nerve, a facial nerve branch that crosses the middle ear, may be compromised. The influence of cholesteatoma development near chorda tympani nerve was studied, in order to assess the consequences of this mass in terms of possible facial paralysis. To do so, an ear model based on the finite element method was used. The chorda tympani nerve was originally discretized and assembled in the model. Two different sized tumours were created so cholesteatoma growth could be simulated. The pressure in this nerve were assessed in two moments - when the tumour first interacts with it, pushing it down, and when the tumour compresses it against the incus. Moreover, the effect of applying pressure directly on the nerve was also evaluated, so tumour geometry did not interfere in the analysis. The obtained stress allowed to infer on the consequences regarding taste disturbance and facial paralysis, although some studies report that when pressure fades away, it is possible to fully recover. The von Mises stress was higher when the chorda tympani nerve was pushed against the incus by the large tumour, in the contact area between the nerve and the ossicle.
- Finite element modelling of the surgical procedure for placement of a straight electrode array: Mechanical and clinical consequencesPublication . Areias, Bruno; Parente, Marco P. L.; Gentil, Fernanda; Jorge, Renato M. NatalA cochlear implant is an electronic device implanted into the cochlea to directly stimulate the auditory nerve. Such device is used in patients with severe-to-profound hearing loss. The cochlear implant surgery is safe, but involves some risks, such as infections, device malfunction or damage of the facial nerve and it can result on a poor hearing outcome, due to the destruction of any present residual hearing. Future improvements in cochlear implant surgery will necessarily involve the decrease of the intra-cochlear damage. Several implant related variables, such as materials, geometrical design, processor and surgical techniques can be optimized in order for the patients to partially recover their hearing capacities The straight electrode is a type of cochlear implant that many authors indicate as being the less traumatic. From the finite element analysis conducted in this work, the influence of the insertion speed, the friction coefficient between the cochlear wall and the electrode array, and several configurations of the cochlear implant tip were studied. The numerical simulations of the implantation showed the same pattern of the insertion force against insertion depth, thus indicating the different phases of the insertion. Results demonstrated that lower insertion speeds, friction coefficients and tip stiffness, led to a reduction on the contact pressures and insertion force. It is expected that these improved configurations will allow to preserve the residual hearing while reducing surgical complications.