Hearing problems are among the most common complications which affect the quality of life of the elderly based on several epidemiological studies. Hearing aids and assistive listening devices do help to improve the listening experience; however, most individuals with hearing impairment do not like wearing hearing aids as hearing aids are deemed to be uncomfortable for prolonged usage, for example when watching TV. Hence, individual with hearing impairment tend to increase the TV volume which can cause normal hearing listeners to feel uncomfortable. This may discourage the participation and interaction between normal hearing listeners and individual with hearing impairment whilst watching TV. To encourage more family bonding time through watching TV and overcome these problems, we proposed a non-wearable assistive hearing device which we called the Parametric Assistive Hearing Devices (PAHD) that can improve auditory experiences for hearing impaired listener without disturbing normal hearing listeners within close proximity.
PAHD is developed using a unique and novel combination of parametric loudspeaker and conventional electro-dynamic loudspeakers developed by the NTU team. By using the combined sound projection of the parametric and conventional loudspeakers, higher sound clarity at predefined frequencies (especially in speech recognition) can be heard by hearing impaired listeners. By associating these predefined frequencies with the hearing impairment profile of a hearing-impaired listener, our system can be used to compensate the lower sensitivity at various frequencies and improve the auditory experience of the hearing-impaired listener. PAHD is built using the patented method and apparatus of generating highly directional and sound enhancement for ultrasonic loudspeaker system as well as algorithms for hearing level compensation.
PAHD have the potential to be incorporated into commercial TVs or sound system units that work both in enhancing the sound as well as confining the sound to specific areas. These are unique features for users to choose. For sound enhancement, the parametric loudspeaker will couple with conventional electro-dynamic loudspeakers. It will provide a good sound enhancement to specific areas for hearing impaired individuals in communal TV viewing while the rest can enjoy TV at a comfortable level. For sound confinement, simply turn on the parametric loudspeaker without conventional electro-dynamic loudspeakers. It will provide sound only to a specific location where it is useful for a location like B class hospital wards where everyone can turn their TV to their favourite channel without competing in volume and disturbing those that need to rest.
More than 360 million people in the world experience hearing loss, according to the report from the World Health Organisation (WHO). The report states that one in three persons over the age of 65 years (a total of 119 million people worldwide) live with hearing loss. As mean life expectancy increases globally, it is a trend that more people than ever are facing hearing loss. In Singapore itself, the percentage of hearing loss for persons over the age of 60 years is about 64.2% based on the Singapore National Survey 2010. Hearing loss is also associated with manyillnesses, such as dementia, where studies have shown that individuals with hearing loss have a risk of dementia that is as high as 20 times more than those who are not. Hearing loss is also associated with a higher likelihood of depression as hearing loss will lead to avoidance or withdrawal from social activities. Thus, through encouraging communal TV watching, the withdrawal behaviour caused by hearing loss will be reduced. Although there are numerous hearing aids and assistive hearing devices available in the market, they are normally costly and require users to wear a hearing device to assist their listening, which may not desire by users some of the time. Most of the assistive hearing devices for TV watching available in the market are through headphones. This mode of viewing also blocks the interactions between the user and someone next to them. PAHD is the solution to the problem that they face; it is a one-of-a-kind assistive device that cannot be currently found in the market.