Ninety percent of hearing loss occurs due to loss of hair cells or auditory nerve cells. We now know that fish, amphibians and birds are able to grow new hair cells after insult. Birds are the only animals that show both hair cell regeneration and vocal learning, making them a unique model for aspects of human hearing impairment. While long-term hair cell regeneration in mammals appears to be feasible in the near future, questions remain as to the functionality of these regenerated hair cells beyond basic audiograms. There are devastating consequences of hearing loss on human speech and language both in children and adults. Here we investigate the effects of regenerated hair cells in an animal system whose complex vocal repertoire is learned and maintained through hearing.
In the proposed research, we ask whether auditory perception is fully restored following hair cell regeneration in birds. This proposal continues two threads of investigation from previous project periods. One area of research investigated the basic mechanisms and simple perceptual consequences of acquired hearing loss and recovery. We now probe for effects on higher-level perception. Past work on this grant shows that in addition to hair cell regeneration, birds also seem to regain much of their auditory capabilities including the discrimination, recognition and production of learned vocalizations (Dooling et al., 1997). However, the human clinical literature is replete with patients who have normal audiograms but poor speech recognition, especially in noisy environments (Kujawa & Liberman, 2009). The exact etiology of these perceptual deficits is still murky. Using avian models, we will hope to shed light on some of the causes that may lead to better clinica...
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...ration using three masking approaches: energetic, ’babble’, and informational. These experiments attempt to directly model aspects of the human clinical problem of hearing impaired and cochlear implant patients who have near-normal thresholds with amplification but still show poor speech understanding in noisy environments.
Specific Aim 3. Explore possible ameliorations of hair cell damage/hearing loss in birds with an inherited, developmental high frequency hearing loss and ongoing hair cell proliferation. BW canaries temporarily increase hair cell proliferation after noise exposure (Gleich et al., 1997) and show hearing improvement after ototoxic insult and recovery (Dooling et al., Submitted). Here we plan to further investigate how regenerative mechanisms play a role in hearing restoration and whether it is possible to completely “cure” BW canary hearing loss.
The next speaker, Dr. Gottlieb investigated the hearing aspect of our senses. He investigated the interaction between our heari...
One of the best-known and interesting findings in speech perception research is the “phonemic restoration phenomenon”. It is a beneficial and amazingly utilized human ability by which, “under certain conditions, sounds actually missing from a speech signal can be synthesized by the brain and clearly heard”(Kashino, 2006. P.318). This shows the brains sophisticated ability in comprehending speech in the everyday life noisy settings.
Cochlear Implants only restore very limited audibility. When described by formerly hearing Deaf people they compare it to hearing underwater, “fuzzy and timbre” yet still able to discern some
“Music is perpetual, and only the hearing is intermittent,” wrote the iconic American essayist, poet and philosopher Henry David Thoreau, a lofty proclamation that inspired my focus to help those with hearing loss through restoration. After a winding journey in search for an academic focus, I discovered that audiology is far more than just aiding deaf or hard of hearing individuals, but restoring balance, managing loss through therapy, and discovering new research techniques that may involve auditory neuropathy spectrum disorder. After arriving at my destination, I also learned that it is my responsibility as a future audiologist to be a leader, to work hard toward achieving a better future for myself, and a better world for humanity at large. This vision drives my aspiration to join the University of South Florida’s graduate audiology program this coming fall, and continue my examination of clinical audiology as a member of your community.
Sound is localised to the ear by the pinna, travelling down the auditory canal, vibrating the eardrum. The eardrums vibrations are then passed down through the ossicles, three small bones known as the hammer, anvil and stirrup that then transfer the vibrations to the oval window of the cochlea. The cochlea is filled with fluid that when exposed to these vibrations stimulate the sterocilia. This small hair cells "wiggle" along to certain frequencies transferring the vibrations into electrical impulses that are then sent to the brain. If the ear is exposed to noise levels of too high an intensity the sterocilia are overstimulated and many become permanently damaged . (Sliwinska-Kowalska et. All,
Losing a vital sense makes living life more difficult. Gene therapy, the process of replacing faulty genes with genes genetically engineered to replace them, can potentially cure deafness. Yashimo Raphael experimented with intentionally deafened guinea pigs and the gene Atoh 1, a gene said to replace lost hair cells in the inner ear. He found that hair cells grew, but were not fully functional. The slight aid in hearing the gene did give the guinea pigs almost completely disappeared after a few weeks time. Although the new hair cells did not function properly, the fact that they grew defied nature and was a successful start.
There is no denying that hearing loss can have significant psychosocial impacts on those who experience it. The most negatively impacted group, however, is young children, for whom hearing loss can impede early learning and development (Connor et al., 2006). One viable solution to this problem takes the form of cochlear implants. An artificial cochlear unit is surgically implanted in the ear and functions by translating sounds directly into electrical impulses and sending them to the brain (Roland & Tobey, 2013, p. 1175). Despite the high success rates that they have produced, critics contend that cochlear implants should not be carried out on very young children. They cite certain physiological concerns as well as doubts about long-term effectiveness (Hehar et al., 2002, p. 11). Some have even expressed worries that cochlear implants will negatively impact young children’s social development by making them feel different or out of place (Ketelaar, 2012, pp. 518-519). Certainly, not every child with hearing loss is a viable candidate for an implant procedure. However, when a candidate has been positively identified, the procedure should take place as early as possible, in order to guarantee maximum educational and developmental benefits.
Hearing loss can affect a child dramatically in their early development. It is important to be aware and cautious of noticing signs towards possible hearing loss, because language and communication skills deve...
According to Chapman et al., (2000), the loss of hearing appears to be a chronic issue through...
Hearing loss is a major global public health issue. Hearnet (2017) defines hearing loss as “a disability that occurs when one or more parts of the ear and/or the parts of the brain that make up the hearing pathway do not function normally” (para. 1). There are many different types of hearing loss, which can have multiple causes, giving each individual experiencing the issue a unique hearing loss case. These types include Auditory Processing Disorders, when the brain has problems processing sound information; Conductive Hearing Loss, a problem with the outer or middle ear which prevents sound making its way to the inner ear; and Sensorineural Hearing Loss, when the Cochlea or auditory nerve is damaged and cannot
Helfer (1998) recognized the slowing of our temporal perceptual processes with increasing age. He suggested that this leads to auditory deformity, especially in the instance of time compressed speech. Speech comprehension requires rapid processing of stimuli that is not always completed in time-compressed speech because of the shortening of phonemes and a decrease in pauses. Helfer went a step further by taking into account that hearing is not just auditory but it is also visual, in that we use cues like looking at the person's mouth or facial expression while having a conversation.
Living in a world with no sound whatsoever is a reality to millions of people worldwide, regardless of age, race, gender, and socioeconomic status. Approximately 5% or 360 million people of the world’s population have deafness or hearing loss, according to the World Health Organization. Deafness can be either acquired or congenital depending on several factors, including genetics and health of the individual. Congenital deafness is the loss of hearing present at birth. Being born deaf has many consequences, both positive and negative. According to the American Speech-Language Hearing Association, over 50% of congenital deafness is due to hereditary and genetic issues. However, non-genetic factors can cause deafness in an individual at birth as well. Disease and illness while in utero of either the mother or child can cause the child to become deaf...
Then, when I was three years old, I had surgery to get a cochlear implant at the University of Minnesota. A cochlear implant is a small device which bypasses the damaged parts of the ear and directly stimulates the auditory nerve. Signals generated by the implant are sent by the auditory nerve to the brain, which recognizes t...
...nsations are then interpreted and we hear. The range of our hearing abilities is amazing. Most of this can be attributed to the sensitivity of our hair cells which can detect the smallest audible sounds yet withstand a trillion-fold increase in power (Martini, 2009). Our hair cells are constantly changing in order to adapt to our environment. We can have a conversation with our friends, listen to music, and distinguish which direction a car alarm is coming from without any awareness of the detailed process that is necessary for hearing. Overall, the process of turning sound waves into auditory sensations is quite remarkable.
...orm from which to carry out further research, it is clear that it cannot be accepted as a fully working model of speech perception. Alternative theories have since been proposed, such as the Massaro’s fuzzy logic model, which suggests that speech sounds are considered in terms of how likely they are to belong to a specific category. Thus the final decision of how a sound is perceived can take into account multiple features or sources of information, including visual information. While each theory has its own strengths and weaknesses, they differ fundamentally in whether or not they believe speech to have a “special” module in the brain. As of yet, the body of evidence is not sufficient to conclusively prove or disprove either, and the answer as to how exactly listeners extract the linguistic features of speech sounds from the acoustic signal has yet to be found.