New opportunities for the hearing impaired in the digital world - an overview of the Petralex Hearing Aid program

The beginning of any review of new applications for gadgets or software for applications is always pretty trite. I saw something new, got interested, tried it. In this review, the situation is similar, but there is a significant difference: the author has long been successfully cooperating with a team of developers for whom this application is only one product from a large portfolio.

Nevertheless, this particular application is special. It is not for entertainment and not to "kill time" on the way to work and back. No matter how pathetic it sounds, but this is what makes the world a little better.

In the world, according to the World Health Organization (WHO), about 10% of people experience some kind of hearing difficulty. This can create discomfort in communication, work, looking for friends and even in personal life. Many, especially young people, are embarrassed to use hearing aids, and given the cost of modern advanced models, they may simply not be affordable.

What can help smartphones? With the advent of telephones, many people with impaired hearing began to actively use them for communication through short text messages. But a smartphone is a full-fledged powerful computer. A year and a half ago, curious information appeared that the current model of the iPhone in terms of computing power is comparable to the total computing power of computer systems, which in the 70s provided the landing of a man on the moon.
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So, all the more so a smartphone and especially a modern desktop or laptop computer have sufficient computational resources to handle the audio signal. Any sound is air vibrations with a certain frequency. When the sound signal is transmitted in electronic devices, it is converted into electrical oscillations. So, it can be processed programmatically.

The IT4YOU company team developed audio signal conversion algorithms in accordance with the user's individual hearing characteristics and created the Petralex Hearing Aid application based on this algorithm.

As they say in another very banal phrase: "It is not easy to use it, but very simple." An ordinary user does not need to know anything about how smartphones work, nor about algorithms with complex transformations.

Download the application from the Apple Store for your smartphone or directly from the developer's site for home Windows - a computer or laptop.



After downloading the application will offer to pass a frequency test of hearing. To do this, the user simply press the button as soon as he hears the signal of a certain frequency. On the basis of such a “scan” of hearing, the application constitutes a kind of frequency map, based on which it later performs the conversion and individual adjustment of audio signals.



The user can save the setting as a “profile”. This is a useful function, because you can create several “profiles” of your own hearing, for example, for different environmental conditions or different uses. For example, one profile is better suited for watching movies in a cozy and quiet home environment, and another for classroom studies at the institute. And of course, a separate profile will be required for the smartphone to work as a hearing aid in a noisy street. It is also recommended to create your own profile for each of the output devices used: use new headphones - create a profile for them.



When you run the application on your smartphone or computer, the last profile used is automatically included. At any time, you can create a new profile. To do this, on the main screen, press the "Create a new" button.

After starting the application and selecting a profile, no further action is required from the user. From this point on, all audio signals coming through the device’s microphone or audio system are processed and adjusted to its individual hearing characteristics as well as the environmental conditions in accordance with the profile settings.

Along with the advantages of the application, there are drawbacks, namely:

• The microphone is not located directly in the ear and therefore does not use the functional advantages of the auricle and the natural acoustics of the outer ear;
• There are no clinical trial data, although the developers indicate that the application they created cannot be used as a hearing aid as prescribed by the doctor and the in situ audiometry procedure built into the application is used only to configure the application and cannot serve as a basis for making a diagnosis;
• The presence of signal processing delay on smartphones and tablets running the Android OS.

Basic principles of work

The Petralex Hearing Aid application provides two modes of operation: in-situ audiometry mode and correction mode.

In the in-situ audiometry mode, the user independently measures hearing thresholds using tonal signals generated with increasing amplitude from the lowest possible value to the maximum for 15 seconds. The signals are synthesized in the following sequence, 125, 250, 500, 1000, 2000, 4000, 6000, 8000 Hz.

In correction mode, a wideband (without subband decomposition) signal processing circuit is performed. The scheme uses a broadband method of changing the correction of the spectrum envelope using a filter with a finite impulse response. The frequency response of the digital filter is formed on the basis of the audiogram (previously obtained thresholds) of the user in such a way as to perform amplification of frequencies to which attenuation is observed.

Summary

As a result, the user can freely communicate with friends and colleagues, engage in classrooms with any number of students, listen to music, watch movies and clips. And he / she does not need a hearing aid, on the contrary, a modern fashionable gadget will fulfill its role completely unnoticed by others.

In 2014, the PC Magazine editors awarded the Petralex Hearing Aid application the Best Soft 2014 award, thereby recognizing it as the best hearing aid on the basis of a smartphone. (The Best Soft Award is an annual PC Magazine review on the selection of the most relevant, interesting, useful programs available to the Russian consumer. The Best Soft rating has been held for more than 12 years and managed to establish itself as an authoritative, expert council in the field of software) .

IPhone Version
Program for Windows 7,8 (32 & 64 bit)