Mutation in mitochondrial DNA as a cause of presbyacusis

Much of the hearing loss that occurs in old age is likely to be due to the long-term deterioration of the mitochondria in the different structures of the cochlea. The current review surveys some of the basic information on mitochondria and mitochondrial DNA, as a background to their possible involvement in presbyacusis. It is likely that oxygen radicals damage mitochondrial DNA and other components of the mitochondria, such as their proteins and lipids. This further compromises both oxidative phosphorylation and the repair processes in mitochondria, setting up a vicious cycle of degradation. Evidence is presented from inherited point mutations on the possibly most critical sites for mutations in mitochondrial DNA associated with hearing loss. It is suggested that random sorting and clonal expansion of mutations both maintain the integrity of the pool of mitochondrial DNA molecules and give rise to the apoptosis that leads to loss of vulnerable cells, and hence to deafness. It is moreover suggested that apoptosis of the vulnerable cells of the inner ear may to some extent be preventable, or at least delayed. Copyright (C) 2004 S. Karger AG, Basel.

Theory-of-mind development in oral deaf children with cochlear implants or conventional hearing aids

Background: In the context of the established finding that theory-of-mind (ToM) growth is seriously delayed in late-signing deaf children, and some evidence of equivalent delays in those learning speech with conventional hearing aids, this study's novel contribution was to explore ToM development in deaf children with cochlear implants. Implants can substantially boost auditory acuity and rates of language growth. Despite the implant, there are often problems socialising with hearing peers and some language difficulties, lending special theoretical interest to the present comparative design. Methods: A total of 52 children aged 4 to 12 years took a battery of false belief tests of ToM. There were 26 oral deaf children, half with implants and half with hearing aids, evenly divided between oral-only versus sign-plus-oral schools. Comparison groups of age-matched high-functioning children with autism and younger hearing children were also included. Results: No significant ToM differences emerged between deaf children with implants and those with hearing aids, nor between those in oral-only versus sign-plus-oral schools. Nor did the deaf children perform any better on the ToM tasks than their age peers with autism. Hearing preschoolers scored significantly higher than all other groups. For the deaf and the autistic children, as well as the preschoolers, rate of language development and verbal maturity significantly predicted variability in ToM, over and above chronological age. Conclusions: The finding that deaf children with cochlear implants are as delayed in ToM development as children with autism and their deaf peers with hearing aids or late sign language highlights the likely significance of peer interaction and early fluent communication with peers and family, whether in sign or in speech, in order to optimally facilitate the growth of social cognition and language.

NASCIDOS NO SILÊNCIO: AS RELAÇÕES ENTRE FILHOS OUVINTES E PAIS SURDOS NA EDUCAÇÃO

Este trabalho busca apresentar as vivências de três pessoas ouvintes, além do próprio autor, filhas de pais surdos, discutindo as relações familiares entre pais e filhos, mostrando as diferenças em relação às famílias que não possuem pessoas surdas no seu âmago, desmistificando preconceitos e pré-conceitos. Devido as barreiras comunicacionais e pelo preconceito, muitos surdos acabavam sendo privados do direto de serem pais. Nos relatos apresentados nesta dissertação, houve momentos em que isso quase aconteceu na vida dos sujeitos entrevistados para esta pesquisa. Porém, com força e consciência dos direitos adquiridos, esses pais surdos não permitiram que tal coisa acontecesse. O texto inicia com a trajetória formativa e profissional do autor para, em seguida, trazer os autores que abordam temas como surdez (Wrigley, 1996; Lacerda, 1998; Perlin, 1998; Moura, 2000; Sá, 2002; Quadros, 2004; Sacks, 2007), antropologia (Hall, 1992; Gomes, 2008), relações familiares (Lacan, 1987) e autobiografia (Ferraroti, 1991; Pineau, 2006; demartini, 2008). A língua de sinais e a história educacional dos surdos também são discutidas neste trabalho. Por último, são apresentados os relatos de história de vida feitos na pesquisa de campo de forma literária, com as análises dos depoimentos colhidos pelos sujeitos entrevistados (filhos ouvintes e pais surdos) os quais evidenciam que ser filho de pais surdos pode ser tão normal quanto ser filho de pais ouvintes.

PERCEPÇÃO DE AUTO-ESTIMA E QUALIDADE DE VIDA DO JOVEM-ADULTO SURDO UNIVERSITÁRIO

O presente trabalho tem como tema central a opinião do surdo universitário sobre sua auto- estima e qualidade vida. Os objetivos foram conhecer o joven-adulto surdo universitário, segundo sua opinião, buscando especificamente identificar os fatores que contribuíram para o seu desenvolvimento psicológico e sua auto-estima; e identificar as características da qualidade de vida, considerando os aspectos físico, psicológico, relações sociais e meio ambiente. Participaram desta pesquisa 3 jovens-adultos surdos, universitários. O método utilizado foi o descritivo qualitativo, usando-se como fonte de coleta de dados a entrevista livre e o WHOQOL-bref. O método qualitativo na área da saúde visa investigar o significado que os fenômenos sentimentos, idéias, vivências, manifestações, dentre outros, tem para as pessoas e que dão molde às suas vidas incluindo os cuidados com a saúde. Percebemos que ao atingirem a fase adulta, os sujeitos pesquisados conseguem tomar decisões e escolher seus caminhos com maior liberdade em função das experiências e condições que lhes foram apresentadas. Verificamos que as situações vividas no ambiente escolar e o aprendizado da língua de sinais contribuíram para sua constituição como sujeito não limitado à condição da surdez. Foi possível identificar que possuem expectativas profissionais futuras e expressaram suas dificuldades, desejos, frustrações diante do mercado de trabalho, relações sociais e familiares como qualquer outro individuo, encontrando recursos internos para o enfrentamento das circunstâncias cotidianas. Os resultados da pesquisa também permitiram observar que os surdos reconhecem o grau de satisfação que têm com a vida, seu estado de saúde e cuidados com seu bem-estar físico, psicológico e social. Concluímos que ao recontar sua história de vida os surdos têm a possibilidade de se reconhecer como sujeitos e a oportunidade de dar continuidade às próprias vivências que contribuíram para seu bem-estar

Hearing protectors: a dilemma involving acoustics and personal safety

This thesis is concerned with the optimising of hearing protector selection. A computer model was used to estimate the reduction in noise exposure and risk of occupational deafness provided by the wearing of hearing protectors in industrial noise spectra. The model was used to show that low attenuation hearing protectors con provide greater protection than high attenuation protectors if the high attenuation protectors ore not worn for the total duration of noise exposure; or not used by a small proportion of the population. The model was also used to show that high attenuation protectors will not necessarily provide significantly greater reduction in risk than low attenuation protectors if the population has been exposed to the noise for many years prior to the provision of hearing protectors. The effects of earplugs and earmuffs on the localisation of sounds were studied to determine whether high attenuation earmuffs are likely to have greater potential than the lower attenuation earplugs for affecting personal safety. Laboratory studies and experiments at a foundry with normal-hearing office employees and noise-exposed foundrymen who had some experience of wearing hearing protectors showed that although earplugs reduced the ability of the wearer to determine the direction of warning sounds, earmuffs produced more total angular error and more confusions between left and right. !t is concluded from the research findings that the key to the selection of hearing protectors is to be found in the provision of hearing protectors that can be worn for a very high percentage of the exposure time by a high percentage of the exposed population with the minimum effect on the personal safety of the wearers - the attenuation provided by the protection should be adequate but not a maximum value.

An investigation of how foreign language departments at American colleges and universities view American Sign Language

Corwin and Wilcox (1985) sent surveys to more than 100 American colleges and universities to determine the policies on the matter of accepting American Sign Language (ASL) as a foreign language. Their results indicated that 81% of those surveyed rejected ASL as a foreign/modern language equivalent. The most frequently stated opposition to ASL was that it lacked a culture. Some of the other objections to ASL were: ASL is not foreign; there is no written form and therefore no original body of literature; it is a derivative of English; and it is indigenous to the United States and hence not foreign. Based on the work of Corwin and Wilcox this study sent surveys to 222 American colleges and universities. Noting an expanding cognizance and social awareness of ASL and deafness (as seen in the increasing number of movies, plays, television programs, the Americans with Disabilities Act, and related news stories), this study sought to find out if ASL was now considered an acceptable foreign language equivalent. The hypothesis of this study was that change has occurred since the 1985 study: that a significant percent of post secondary schools accepting ASL as a foreign/modern language equivalent has increased. The 165 colleges and universities that responded to this author's survey confirmed there has been a significant shift towards the acceptance of ASL. Only 50% of the respondents objected to ASL as a foreign language equivalent, a significant decrease from the 1985 findings. Of those who objected to granting ASL foreign language credit, the reasons were similar to those of the Corwin and Wilcox study, except that the belief in an absence of a Deaf culture dropped from the top reason listed, to the fifth. That ASL is not foreign was listed as the most frequent objection in this study. One important change which may account for increased acceptance of ASL, is that 16 states (compared to 10 in 1985) now have policies stating that ASL is acceptable as a foreign language equivalent. Two-year colleges, in this study, were more likely to accept ASL than were four-year colleges and universities. Neither two- nor four-year colleges and universities are likely to include ASL in their foreign language departments, and most schools that have foreign language entrance requirements are unlikely to accept ASL. In colleges and universities where ASL was already offered in some department within the system, there was a significantly higher likelihood that foreign language credit was given for ASL. Respondents from states with laws governing the inclusion of ASL did not usually know their state had a policy. Most respondents, 84%, indicated their knowledge on the topic of ASL was fair to poor. ^

The effects of bilingual and monolingual reading videos on story recall with students who are deaf and hard of hearing

The purpose of this study is to investigate the effects of bilingual and monolingual videos on the reading comprehension of students with significant hearing impairments and/or deafness. Children with and without hearing losses need reading programs in which comprehension of meaning is the primary goal. This can occur only when print is represented in meaningful context, allowing children to create meaning from their own experience, background, and knowledge of language.^ Investigated in this study was whether students with significant hearing losses comprehended more information in a bilingual or monolingual instructional video format. There were three instructional videos produced: (a) the bilingual video which incorporated American Sign Language (ASL) with standard English captions, (b) a monolingual English video with standard English captions only, and (c) a monolingual ASL-only video. It was hypothesized that the effects of English captioning with ASL might serve as a bridge during instruction, increasing reading comprehension and written English for students. It was further hypothesized that this would allow students to integrate their own ASL knowledge to the printed text to construct meaning.^ Four separate analyses were conducted to see if the hypothesis was supported by the findings. However, all results indicated that there were no significant differences in students' written measures of reading comprehension recall across any of the three presentations of information (two monolingual and one bilingual condition). There were seven variables (word identification, word recall, sentence recall, story recall, written passage theme, written passage word count, and number of mature words) used to evaluate reading comprehension recall. No variable, either individually or grouped, demonstrated a significant difference between monolingual or bilingual instruction. ^

A curricular analysis of the servicing of students who are hearing impaired in Dade County, Florida

Deafness is an invisible handicap which makes education difficult due to its effect on language acquisition and development, speech acquisition, and ability to communicate with others. Teachers of students who are hearing impaired have been at odds for more than a century as to the best method of communication to use in teaching students who are hearing impaired, and in providing these students with communication systems that will enable them to be effective communicators. This dissertation utilized qualitative research methods to analyze whether the Dade County Public Schools Procedures for Providing Special Education for Exceptional Students-Hearing Impaired (DCPS), (1976-77; 1992-93) show evidence of an appropriate curriculum and instructional program that is responsive to the conditions facing exceptional education students identified as hearing impaired. Results indicate that many of the curriculum and instructional program requirements are not identified nor described when analyzed by Tyler's "Rationale" for Curriculum and Stufflebeam's Improvement-Oriented Evaluation Model, better known as Stufflebeam's CIPP Model. Recommendations to improve and enhance programs for students who are hearing impaired are offered based on this analysis. ^

Enhancement of wireless networks with heterogeneous antennas

In recent years, wireless communication infrastructures have been widely deployed for both personal and business applications. IEEE 802.11 series Wireless Local Area Network (WLAN) standards attract lots of attention due to their low cost and high data rate. Wireless ad hoc networks which use IEEE 802.11 standards are one of hot spots of recent network research. Designing appropriate Media Access Control (MAC) layer protocols is one of the key issues for wireless ad hoc networks. ^ Existing wireless applications typically use omni-directional antennas. When using an omni-directional antenna, the gain of the antenna in all directions is the same. Due to the nature of the Distributed Coordination Function (DCF) mechanism of IEEE 802.11 standards, only one of the one-hop neighbors can send data at one time. Nodes other than the sender and the receiver must be either in idle or listening state, otherwise collisions could occur. The downside of the omni-directionality of antennas is that the spatial reuse ratio is low and the capacity of the network is considerably limited. ^ It is therefore obvious that the directional antenna has been introduced to improve spatial reutilization. As we know, a directional antenna has the following benefits. It can improve transport capacity by decreasing interference of a directional main lobe. It can increase coverage range due to a higher SINR (Signal Interference to Noise Ratio), i.e., with the same power consumption, better connectivity can be achieved. And the usage of power can be reduced, i.e., for the same coverage, a transmitter can reduce its power consumption. ^ To utilizing the advantages of directional antennas, we propose a relay-enabled MAC protocol. Two relay nodes are chosen to forward data when the channel condition of direct link from the sender to the receiver is poor. The two relay nodes can transfer data at the same time and a pipelined data transmission can be achieved by using directional antennas. The throughput can be improved significant when introducing the relay-enabled MAC protocol. ^ Besides the strong points, directional antennas also have some explicit drawbacks, such as the hidden terminal and deafness problems and the requirements of retaining location information for each node. Therefore, an omni-directional antenna should be used in some situations. The combination use of omni-directional and directional antennas leads to the problem of configuring heterogeneous antennas, i e., given a network topology and a traffic pattern, we need to find a tradeoff between using omni-directional and using directional antennas to obtain a better network performance over this configuration. ^ Directly and mathematically establishing the relationship between the network performance and the antenna configurations is extremely difficult, if not intractable. Therefore, in this research, we proposed several clustering-based methods to obtain approximate solutions for heterogeneous antennas configuration problem, which can improve network performance significantly. ^ Our proposed methods consist of two steps. The first step (i.e., clustering links) is to cluster the links into different groups based on the matrix-based system model. After being clustered, the links in the same group have similar neighborhood nodes and will use the same type of antenna. The second step (i.e., labeling links) is to decide the type of antenna for each group. For heterogeneous antennas, some groups of links will use directional antenna and others will adopt omni-directional antenna. Experiments are conducted to compare the proposed methods with existing methods. Experimental results demonstrate that our clustering-based methods can improve the network performance significantly. ^

Inducible Overexpression of Endothelin-3 in a Transgenic Mouse Leads to Hyperpigmentation That Decreases Over Time

Endothelin-3 (Edn3) has been shown to be an essential environmental cue in melanocyte development. Edn3 and its receptor, EdnrB, are allelic to mouse mutations occurring at the lethal spotting and piebald loci, respectively; these mutations result in hypopigmentation phenotypes. Mutations in the genes for both Edn3 and EdnrB are implicated in human pigmentation disorders such as Waardenburg-Shah syndrome, which is characterized by pigmentation defects, deafness, and megacolon. In this study, a tetracycline-inducible transgenic mouse model that overexpresses Edn3 under the control of the Keratin 5 promoter was shown to produce a hyperpigmentation phenotype that decreases over time. The expression pattern of transgenic Edn3 and its effects on the melanocyte population were examined in transgenic embryos, postnatal skin, and the skin of adult mice that exhibit faded hyperpigmentation. These studies suggest that overexpression of Edn3 in this model is restricted primarily to the roof plate of the neural tube and surface ectoderm in the developing embryo and to keratinocytes in the epidermis of postnatal mice. A decline in transgenic expression and a reduction in the dermal melanocytes and free melanin that characterize the phenotype in juvenile mice were shown to correlate with the fading of the hyperpigmentation phenotype. Transgenic mice in which transgenic expression was repressed (resulting in the disappearance of the hyperpigmentation phenotype) also exhibited a decrease in the dermal melanocyte population. The Edn3-overexpressing mice used in this study might be helpful m understanding human skin conditions characterized by dermal melanocytosis.

Música e surdez: o ensino de música numa perspectiva bilíngue na escola regular

The present study focuses on the development of pedagogical activities in Music Teaching, aiming to enhance the accessibility of musical knowledge for both deaf and hearing students, using a bilingual approach in regular schools. Few studies address Music and Deafness, and those that do focus exclusively on the context of special education, and specifically the deaf student, which signals the urgent need for conducting research on this issue in the context of inclusion – empirically and carried out on school grounds. Therefore, we developed our study at a Natal City Public Elementary school, in a class of 6th graders, comprised of 37 students, 3 of whom were deaf. The objective of the study was to develop a proposal for a pedagogical intervention in Music Teaching, using a bilingual approach, with deaf and hearing students, in the context of regular school classes. The research is based on the theoretical framework presented in Penna (2010), Brito (2001) and Fonterrada (2008), with reference to music education, and Haguiara-Cervellini (2003), Finck (2009) and Louro (2006), with reference to inclusion in teaching music. To achieve this objective, we developed a proposal for intervention based on the methodological dictates of intervention research, presented in studies by Jobim and Souza (2011) in light of the theoretical concepts posited by Mikhail Bakhtin, which assert that knowledge is produced through interaction between subjects, dialogically and through alterity. This methodology was carried out in pedagogical workshops, conceived as spaces for the construction of knowledge, mobilizing participants to engage in ludic activities of musical experimentation. Content covered in these workshops focused on Pulse and Rhythm – basic elements in music education – demonstrating that awareness about and sensitivity to these elements is not limited to the auditory sensory perception of the student, once the entire body is used as an agent of acquisition and expression. Thus, we began the trajectory of our research from the starting point of the identification and perception of „Pulse‟, using one‟s own body and the body of classmates, representing it through physical expressions and movement. Subsequently, this Pulse was extended from the body to a percussion instrument, and was then represented graphically as lines of rhythm, constituting a process of reading and writing; ultimately the intervention culminated in the class presentation with the musical group De Pau e Lata (Stick and Can). In our analysis, faced with the challenges and possibilities presented in our study, findings showed satisfactory results with regard to the participation of all of the students: completing the activities proposed in the class, asking questions when they did not understand, positioning themselves when they thought it necessary, expressing opinions about the work completed, evaluating the workshops given, interacting, helping in the activities, constructing knowledge collaterally, experimenting and experiencing musical elements through the body in activities that applied to both groups (deaf and hearing) in the one class. These indications elucidate the viability of teaching music to deaf and hearing students, using a bilingual approach, and based on experiences with the body and communicative and cultural specificities involved, confirming, as well, the role of Sign Language as a mediator in the teaching/learning process.

Mechatronic solutions for measuring disturbance levels within a cochlea

Hearing implants are an important devices for combating deafness over the next 15 years. In this paper, we focus on the means to determine the sensitivity of the hearing organ to disturbances produced by implants and other interventions, and those induced by implantation. The preservation of residual hearing is an important aspect to be considered, however, the sensitivity of this to the process of implantation, device location and power levels is not well understood. Within this paper, a new experimental set-up to contrast the merits of different implantation techniques, implant location and power transmission are discussed and the initial results regarding disturbance levels using different surgical techniques are described.

O texto literário para a infância na educação de crianças surdas do 1.ª Ciclo

Dissertação apresentada à Escola Superior de Educação de Paula Frassinetti para obtenção do grau de Mestre em Ciências da Educação – Especialização em Educação Especial