ARRA IMPACT REPORT:
Assistive Technologies – Using Technology to Improve and Restore Communication Abilities
Public Health Burden
one in six Americans will experience a communication disorder in his or her
lifetime, which can impact emotional, social, recreational, educational, and
vocational pursuits. The prevalence of communication disorders is expected to
increase as the population ages and as medical care improves survival rates for
medically fragile infants and people affected by traumatic injuries and
diseases. The NIDCD conducts and supports
research to develop interventions and devices that improve or restore
communication abilities, including hearing aids, cochlear and brain stem
implants, and computer programs that help individuals with voice, speech, and
Although hearing aid technology has advanced rapidly over the past few decades, users still report that hearing aids are not particularly effective in certain listening environments, such as when multiple people are speaking or amidst loud background noise. To address these challenges, the NIDCD awarded American Recovery and Reinvestment Act (ARRA) funds supported scientists working on directional hearing aids, processing software, and other hearing aid technologies to help users understand speech when background noise is present.
- Development of Hearing Aid Microphone that Zeros in on Speech in a Noisy Environment: NIH-supported scientists developed a miniature diaphragm for microphones in hearing aids that mimicked the biology of an insect using its acute sound-localization ability to detect prey. The miniscule diaphragm zeroes in on the source of a sound and vibrates in response to it. The diaphragm is more sensitive at the frequency range for detecting speech. The scientists used ARRA funding to develop an electronic interface for the microphone diaphragm, so that it can convert the diaphragm motion into an electronic signal.1 The resulting microphone (the diaphragm plus the electronic interface) is small enough to be used in a tiny hearing aid that will provide users with improved ability to zero in on speech in a noisy environment.
- A New Algorithm to Sharpen the Contrast in Hearing Aid Speech Signals: Through an ARRA Challenge Grant program, NIDCD supported researchers developed and refined a new signal processing strategy, called a Contrast Enhancement (CE) algorithm, to sharpen the contrast in hearing aid speech signals. This strategy will be used to improve hearing aid performance and increase speech understanding in individuals with various types and severity levels of hearing loss. 2
- Development and Testing of a New Photonic Hearing Aid: A phase II Small Business Innovation Research (SBIR) project developed and tested a new photonic hearing aid that offers improved performance in noisy situations. The new design takes advantage of the natural acoustic advantages offered by the outer ear and ear canal; it also operates over a wider frequency range and generates less feedback than existing hearing aids. ARRA supplement funds were used to hire additional scientists and to purchase equipment to accelerate the pace of this research. 3
A cochlear implant (CI) is a small, complex electronic device that can restore the perception of sound to a person who is profoundly deaf or severely hard-of-hearing. A cochlear implant is very different from a hearing aid. Hearing aids amplify sounds so that they may be detected by damaged ears. CIs bypass damaged portions of the ear and directly stimulate the auditory nerve. Hearing through a CI is different from normal hearing and takes time to learn or relearn. CIs allow many people to recognize warning signals, understand other sounds in the environment, and enjoy a conversation in person or by telephone. In spite of these advances, many CI users still experience difficulty understanding speech in noisy environments, and users require significant auditory training following implantation. Scientists are working to address both of these barriers.
- Improved Sound Localization and Speech Perception: One ARRA-supported project improved sensitivity to interaural time differences (ITDs) in individuals who have a CI in each ear. An ITD measures the time between a sound reaching the closer ear and then the more distant ear. The development improved sound localization and speech reception in noise in the CI users. The scientists introduced “jittered” CI signals (electrical pulse trains with random interpulse intervals instead of consistent interpulse intervals), which caused sound-detecting neurons to fire more frequently, and improved ITD in both ears.4 The ARRA supplement supported an additional postdoctoral fellow to characterize the effects of jitter on ITD sensitivity.
- Telehealth Technologies to Obtain CI Performance Data from Users: ARRA funds enabled another NIH-supported investigator to determine that telehealth technologies (collecting data electronically from a remote location) can be used to obtain accurate CI performance data from users. The investigator determined that data collected remotely was statistically indistinguishable from data obtained from in-person testing, which can be more expensive and burdensome to the patient. 5
- Adapting User Auditory Training to an Internet Platform: Auditory training can improve CI users’ speech and music perception, even after many years of experience with their device. ARRA funds enabled an NIH-supported investigator to adapt a computer-based auditory training program to an Internet platform. As a result, CI users were able to train at home and improve their ability to identify vowels and consonants, sentences, the gender of a voice, and emotion.6
A brain-computer interface (BCI) allows individuals with movement disorders to interact more easily with the environment and the people around them. A BCI restores communication by reading the user’s “imagined arm movements” through recording of electrical brain activity. It then decodes the activity to control an external device, such as a computer or prosthetic limb.
Amyotrophic lateral sclerosis (ALS) and Locked-in Syndrome (LIS) rob individuals of voluntary movements even though they can still think and feel. In earlier tests, individuals implanted with BCIs were able to control a computer cursor, demonstrating that a BCI can activate nerve pathways in the brain even years after stroke or disease has eliminated voluntary control. Implanted devices sometimes stimulate tissue damage, however, making the long-term usefulness of a BCI uncertain. In an NIDCD ARRA Signature Project, NIH-supported scientists demonstrated that an individual with a BCI implant was able to control a computer cursor with a BCI even 1000 days after receiving the implant. 7
Contributing NIH Institutes & Centers
- National Institute on Deafness and Other Communication Disorders (NIDCD)