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Sensory Overview


Although he is blind, David Jenne has not allowed his condition to prevent him from doing what he loves. He tells his story through song.
Reprinted from PN March 2011

The latest research and technological advancements to help people with hearing and seeing disabilities was presented at the Science Symposium.

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Walter Reed Army Medical Center (WRAMC), the University of Pittsburgh, the National Intrepid Center of Excellence (NICoE), and the VA Rehabilitation Research and Develop­ment Service collaborated to produce the latest State of the Science Symposium, on November 19, 2010.

Several times throughout the year, with the support of the Paralyzed Veterans of America (PVA); the University of Pittsburgh’s Departments of Rehabilitation Science and Technology, and Physical Medicine and Rehabilitation; and the VA Human Engineering Research Laboratories (HERL) partner with WRAMC and NICoE to educate healthcare professionals on a variety of topics presented by some of the most respected subject matter experts in the field.

Highlighting Success

The most recent symposium, “Sensory and Communication Impairments,” took place at the NICoE on the National Naval Medical Center campus in Bethesda, Md. This marked only the second time the venue was used for the State of the Science Symposium, and it was many of the participants’ first visit to the architectural masterpiece that looks more like a luxury hotel than a rehabilitation facility. The building’s magnificence is a true tribute to the sacrifices of the men and women who have served in the U.S. armed forces.

The talks included in the symposia typically have a personally driven message. Dr. John J. Rieser, a researcher on brain plasticity, exemplified the various conditions and assistive technologies through several personal connections, while Dr. Bärbel Rohrer, a researcher on degenerative eye conditions, related her research to helping advance the technologies that would benefit her funding source, Steve Wynn, the Las Vegas real estate mogul who has such a condition. Col. Vickie Tuten, due to her experiences as an audiologist and researcher in the U.S. Army, is driven to create assessments that will encourage soldiers and decisionmakers to implement preventive hearing devices. Technologies such as digital assistive hearing devices and cochlear implants are now driving the market to create better and more effective tools that are accessible to the masses.

On occasion, symposium directors highlight the successes of people who are individually affected by various conditions. David Jenne, a blind singer, described his story through song. An accomplished guitar player, Jenne is a self-taught musician who has not allowed his condition to prevent him from doing what he loves. Organizations such as Easter Seals have encouraged his dream and allowed him to buy a new guitar. 

Technology Growth

As opposed to a purely data-driven presentation, Rieser’s talk on “Theory and Issues in Research on Blindness and Brain Plasticity” focused on personal stories from the people who have inspired his successful career in vision research. He cited Emerson Foulke, a blind researcher on human perception, who used one of the first-generation screen readers, and his mother, who has macular degeneration, as two of his inspirations. Through these examples, Rieser suggested that though more and more technology is produced in terms of navigation aids such as GPS maps, the technology has a long way to go to truly replace normal vision.

Information provided by low-tech options such as long canes and guide dogs substitute well and assist people in their independent mobility. The audience was able to relate to Rieser’s presentation by his display of diagrams demonstrating what people with glaucoma and tunnel vision see while reading. The difficulty of recognizing faces was demonstrated by explaining that they are not bottom up, but based on one-by-one features—it is more holistic, compared with reading, which cortically, is a simpler process.  

Rohrer, of the Medical University of South Carolina, also used a personal example to show the effects of retinitis pigmentosa. Wynn, who owns the Wynn and Encore hotels and is nearly blind, created a foundation to fund vision research. Rohrer, a recipient of such funding, studies genetic eye conditions. People affected by this have night blindness and eventual extreme low vision, often leading to blindness. Rohrer’s research focuses on monitoring photoreceptors, which convert absorption of light into electrical signals that allow people to see. When photoreceptors degenerate, people can go completely blind. Future treatments may involve transplants, implants, gene therapy, stem cells, and drug therapies. However, many of these will involve stringent Food and Drug Administration (FDA) approval and reimbursement issues. Therefore, drug therapies are likely the most immediate solution.

Rohrer seeks to determine the commonalities in photoreceptor degeneration. By identifying a common function, she and her team will be able to assist in the development of a drug therapy to treat the masses with degenerative eye conditions. Rohrer said oxygen stress, measured as levels of ATP, impairs basal respiration and depletes mitochondrial respiratory capacity and is suspected to contribute to the degeneration of retinal function. Through a series of discussions related to cellular interactions, she described how ATP levels can be regulated and, thus, degeneration may be prevented. Through experiments with mice, Rohrer’s compounds have thus far proven they have the ability to prevent photoreceptor degeneration. Extreme light exposure, which lowered the vision of mice, was used to simulate photoreceptor degeneration over a period of time. However, when eye drops of the compounds were used to treat the mice, they were successful in increasing the number of photoreceptors.

Rohrer’s future work involves fishing out the target of the mitochondria in molecules. When researchers identify this, the specific area can be targeted and the compound can be used to treat it. The future is bright indeed; Rohrer and her colleagues believe they are close to creating a drug to treat retinal degeneration and associated conditions.

Do You Hear What I Hear?

Tuten reviewed topics in the preservation of another sense—hearing. Through active prevention, the prevalence of hearing loss can decrease, especially in soldiers, and new assessment tools can be used to disseminate information on where hearing loss is occurring and how to effectively prevent and treat it. About 25% of OEF/OIF (Operation Enduring Freedom/Operation Iraqi Freedom) servicemembers and veterans have auditory dysfunction due to blast exposure. Tuten suggests protecting vision is sexy and cool and perhaps fashionable, but questions whether hearing prevention, especially in an environment that is susceptible to mortar attacks and exposure to IEDs, is regarded the same way.

Hearing is as integral as our learning and social sense, one of the first senses completed in the fetus, and is our 360° warning sense, as opposed to our 180° vision. Hearing makes soldiers lethal and survivors; soldiers hear before they see the enemy. Through a series of sound clips, Tuten demonstrated point on patrol, call for fire, and urban warfare and the effects of this complex auditory environment on servicemembers. Monitoring hearing annually, effectively providing and fitting hearing protective devices, and instructing and educating people on their use, can improve the status of hearing prevention. Additionally, clinicians should disseminate the effectiveness of these devices throughout the medical community.

Studies conducted by VA audiologists have shown that most OEF/OIF veterans have hearing difficulties; the need for central testing and effective rehabilitation is strongly suggested, but there is no standard of care. High-level functions occur in the auditory system, and damage to any of these areas can lead to substantial impairments even if peripheral function is unimpaired. Blast exposure causes issues in central auditory processing, including reduced sensitivity to location of sound and impairments in picking out a speech signal in competing speech.

Researchers from Tuten’s team and the Center for Rehabilitative Auditory Research are determining a test that could be used to detect central damage. Nearly a dozen tests have been identified that can be used synchronously to decide central damage, half of which were determined to be particularly effective. The two most effective (most information provided in the least amount of time) were the Staggered Spondaic Words and the Gaps in Noise tests. Future directions include continued data collection and analysis with the goal of developing an efficient test protocol for clinicians.


U.S. Army Col. Vickie Tuten is driven to create assessments that will encourage soldiers and decisionmakers to implement preventive hearing devices.

Based on these results, Tuten aims to develop new tests that can be used to diagnose and track progress on the types of auditory dysfunction most often experienced by blast-exposed veterans. This topic should also be of interest to the civilian sector in terms of sports or vehicular injuries.

Increasing Independence

Dr. Harry Levitt from the City University of New York spoke of the major technological advances in hearing science. Alexander Graham Bell, most known for inventing the telephone, also was integral in creating the foundation of many hearing technologies. Hearing aids have evolved over the years technologically and cosmetically and are acknowledged as important assistive devices; however, they are not a cure. New market forces are taking shape as advanced methods of signal processing have been introduced. There was a discrepancy in hearing technology between the expectations and realities of the devices, resulting in aids that were minimally useful.

Since the digital processing of audio signals came about in the 1960s, computerized audiological instruments have played a key role in sensory aids. Visual displays and speech-recognition tools have evolved since the development of single-channel cochlear prostheses, resulting in multichannel cochlear implants that have proven much more effective. Visible and tactile phonetic displays have also been attempted to increase the independence of people who are deaf/blind, but much training is required to make this technology useful. Directional inputs for hearing aids and cochlear prostheses, signal processing to enhance sound quality, automatic recognition and adjustment to acoustic environment, computer-based fitting techniques, and Internet-based rehabilitation strategies are future developments.

A new problem that deserves attention is that of electromagnetic pollution. Levitt commented that millions of radio waves were going through the auditorium, and new hearing technologies are so sensitive they pick up all sounds. Digital signals that come out of cell phones generate major interference, which disrupts the utility of new devices.

Implanted Devices

In her “Cochlear Implants” talk, the University of Maryland’s Dr. Monita Chaterjee described how the human auditory system performs analysis of sound and state-of-the-art technologies. Sound flows as information through the peripheral auditory system, which determines perception. In certain hearing loss, integral hair cells have mostly degenerated, but some neurons in the auditory nerve bundle are still functional. Cochlear implants (CIs) have tiny electrodes that send out electrical signals to the auditory nerves in the cochlea. The idea is to try to mimic the function of the hair cells; through an external and internal system, radio-frequency transmission coils simulate the hearing process.

Children, some younger than 1 year of age, now receive implants, and many of them can be mainstreamed quickly. However, limitations remain in functionality. The audience had a demonstration of sound processed at various channels. Somewhere between four and eight channels is the current state of the art, which results in a very blurred sound. Music at four channels is alarmingly inaudible. The average cochlear-implant patient is unable to enjoy music.

Chatterjee reminded the audience that cochlear implants do not restore normal hearing, that overall their functionality needs to improve because even music remains inaccessible, and they are prohibitively expensive. Evidence suggests earlier implantation helps patients take advantage of the greater plasticity or adaptability of the brain in the earliest stages of development.

Chatterjee suggests that to improve pitch/music perception and listening in noise, we must find ways to improve spectral resolution in the transmitted auditory image. The success of CIs is largely attributable to top-down processes by the brain as people have auditory and linguistic expectations of what comes after each word. Training must be emphasized more in the future, for children and adults, to compensate for some of what is lacking in technology. 

 Additional Presentations

Other technologies were presented by Dr. Corinne Vinopol, Institute for Disabilities Research and Training president and CEO, and assistive technology specialists Amanda Reinsfelder and Mark Lindholm, who discussed a variety of equipment demonstrations for the audience. Attendees interacted with the Ubiduo, a keyboard with a screen that functions as an auditory device designed to help people communicate in an office setting without an interpreter; it can be used up to 500 feet away.

Other technologies demonstrated included a large-print keyboard, a Victorreader (ability to make notes while reading), Zoomtext (designed for attention deficit for reading), and a mounting arm equipped with multiple switch gadgets. Reinsfelder also described the future of assistive technology (AT). What will be the future of AT when iPhones can do all of the above? Reinsfelder suggested many of the current technologies could be used in tandem with a smart phone and would thus be more accessible for the user, only needing to invest in and carry one device.

Information about this and future State of the Science workshops is at www.herlpitt.org or by contacting Shelly Brown at 412-954-5287. If you want to receive e-mails announcing future workshops, join HERL’s mailing list at http://listserv.herlpitt.org.

 

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