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Petralex
Developer(s)IT4YOU Corporation
Initial releaseiOS: 16 February 2014; 10 years ago (2014-02-16) [1]
Android: 1 April 2014; 10 years ago (2014-04-01) [2]
Stable release
iOS: 2.9.5 (17 February 2020; 4 years ago (2020-02-17))[1]
Android: 3.4.18 (30 January 2020; 4 years ago (2020-01-30))[2]
RepositoryPetralex hearing aid for Android,
Petralex hearing aid for iOS
Written inJava and C++
Operating systemAndroid 5.0 and later
iOS 10.0 or later
Compatible with iPhone, iPad, and iPod touch
Size24 MB (Android)
68.4 MB (iOS)
Available in19 languages[1] [2]
List of languages
English, Arabic, French, German, Hindi, Indonesian, Italian, Japanese, Korean, Persian, Polish, Portuguese, Russian, Simplified Chinese, Singhalese, Spanish, Thai, Turkish, Vietnamese
TypeHealth, Hearing aid, Hearing aid application
LicenseDonationware
Websitepetralex.pro/en

"Petralex" is a hearing aid application for smartphones and tablets that implements a digital hearing aid with a built-in in situ-audiometry procedure.[3][4] This application takes into account the ambient sound environment and independently adjusts to the user's ear. [4] Petralex was developed by IT4YOU corporation for smartphones and tablets with Android and iOS operating systems [3] and is distributed free of charge through the Donationware system.

Development history

Petralex hearing aid application development was started in July 2012. It was originally planned to test the computational facilities of the iPhone 3G S platform based on iOS for the implementation of a signal processing system that performs a hearing correction scheme for sensorineural hearing loss.

In February 2014, at the time of publication of the first Petralex version in the AppStore for smartphones starting with iPhone 4 and later, the application included a binaural hearing correction system that performs audio signal processing separately for the left and right ears. This system is implemented using headphones or a headset that are compatible with the iPhone 4 with newer devices. Also in Petralex 1.0, a dynamic range compression system was implemented. This system has the option to customize the gain formula of the following:

After the successful implementation of Petralex on iPhone, on April 6, 2014, a version of the iPad application was released.

In application version 1.3.0, released on June 16, 2014, the possibility of using wireless bluetooth headphones and headsets has been dropped, the interface has been updated, and the option of acoustic feedback suppression has been added.[1]

From that time to the present, Petralex development team continues to improve the application by adding new features and improving algorithms. [2][1]

Basic principles of work

Petralex basic principles of work, like most of hearing aid applications, are similar to those of traditional hearing aids. [3][5]

Petralex implements two modes: setup mode and hearing correction mode.

Setup mode represents hearing test using in situ-audiometry procedure. This mode allows the user to measure his hearing thresholds for both ears separately using tone audio signals of different frequencies from 125 Hz to 8000 Hz. [5]

Hearing correction mode represents an audio signal processing system, which implements a broadband (without subband decomposition) signal processing scheme. This scheme uses broadband method for changing the correction of the spectral envelope of a signal using a filter with a finite impulse response. FIR filter frequency response is based on the user's hearing thresholds: amplification performed of those frequencies that the user hears worse. [9][10][5]

Figure 1 - Petralex hearing aid application general signal processing scheme

Petralex general signal processing scheme (figure 1) corresponds to the hearing aid application general scheme.

Input audio signal, acoustic feedback (echo) and background noise are captured by the microphone, summed and then divided into subbands using an analysis filter bank, which decomposes this signal into perceptually matched subband components. Then, subband signals passes threw the following blocks: noise reduction, acoustic feedback cancellation and hearing loss compensation. Noise reduction block implements noise reduction algorithm based on the psychoacoustically motivated spectral weighting rule. Acoustic feedback cancellation block implements the normalized adaptive least-mean-square algorithm. Hearing loss compensation block implements frequency dependent signal attuneation, based on the users hearing thresholds as a result of the in situ-audiometry. This block also performs dynamic range compression, which compensates non-linear amplification of the human cochlea. Output signal is synthesized from subbands using synthesis filter bank. [9][10][5]

User also can change the total loudness threw the applicatiob interface to adjust the most comfortable listening level. [3]

Comparison with traditional hearing aids

Comparison characteristics between Petralex hearing aid application and traditional hearing aids are presented on the following table: [5][11][12]

Petralex Traditional Hearing aids
Chanels 256 15-111
Sample rate Maximum 44 kHz Maximum 14 kHz
Programmable hearing aid Yes (done by user) Yes (done by specialist)
In-built hearing test Yes Yes (limited)
Hearing test time 2 minutes (by the user) 30 minutes - 60 minutes (several times)
Effects of anti stigmatization Yes Yes (limited)
Audio recorder + Speech recognition in text Yes No, expert for intra channels (CIS)
Remote microphone option without additional devices Yes No
Binaural correction of both ears Yes No
Gain formula, that takes into acount the upper threshold of perception Yes No
Adjustable noise supppression Yes No
Ecosystem of assistive applications (radio, music player, etc.) Yes No
Built into app course of adaptation to hearing aid Yes No
Online gain formula change Yes No
Amplification of quiet sounds (dynamic compression - WDRC) Yes No
Batteries Built-in, rechargeable Removable, require weekly replacement
Software flexibility Yes No
Various types of headphones Yes No
Noticeable Yes No

Features

Petralex application key fetures are: [13]

Ecosystem

Four mobile applications (Petralex, Video Volume Booster, Radio Volume Booster and Music Volume Booster) form a single ecosystem. Hearing profile from Petralex can be used to setup additional applications, which provide user for listening to music, radio and video with amplified sound, adapted to the users hearing. Basic principles of work of these applications are similar to Petralex: the sound is amplified at those frequencies at which the user hears worse. [13]

International cooperation

In 2019 Petralex hearing aid application was implemented for subscribers of a leading telecommunication services provider in Sri Lanka - Dialog Axiata. This will allow users to utilise their smartphones with headset as a hearing enhancement tool, thereby making it an affordable and accessible solution. [14]

Scientific value

Petralex hearing aid application often mentioned in different scienific publications:

  • 2016: Information technology and telecommunications. [15]
  • 2017:
    • Academy of doctors of audiology. [16]
    • Education and Information Technologies. [17]
    • Modern Fuzzy Control Systems and Its Applications. [18]
    • Signal Processing: Algorithms, Architectures, Arrangements, and Applications (SPA). [9]
  • 2018: American Journal of Audiology. [19]

Awards

Since the first release Petralex has been awarded several awards:

  • 2014 - the PC Magazine edited the Petralex application for the "Best Soft 2014" award, recognizing this application as the best hearing aid that implements on a smartphone. [20]
  • 2016 - The best learning Program – virtual learning for people with hearing impairs.[21]
  • 2017 - winner of the Microsoft Inspire P2P contest. [22]
  • 2018 - silver winner of the Microsoft Inspire P2P contest. [23]

See also

References

  1. ^ a b c d e "‎Petralex hearing aid for iOS". App Store.
  2. ^ a b c d "Petralex hearing aid for Android". Google Play.
  3. ^ a b c d "Technology". PETRALEX Hearing Aid. Retrieved 2020-02-18.
  4. ^ a b Maidment David W.; Ferguson Melanie (2018-11-19). "An Application of the Medical Research Council's Guidelines for Evaluating Complex Interventions: A Usability Study Assessing Smartphone-Connected Listening Devices in Adults With Hearing Loss". American Journal of Audiology. 27 (3S): 474–481. doi:10.1044/2018_AJA-IMIA3-18-0019. PMC 6437711. PMID 30452751.
  5. ^ a b c d e f E.S. Azarov, M.I. Vashkevich, S.V. Kozlova, A.A. Petrovsky (2014). "Hearing correction system based on mobile computing platform (in Russian)". Informatika. Informatics, Vol. 2 (42): 5–24. ISSN 1816-0301.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  6. ^ D. Byrne, H. Dillon (1986). The national acoustic laboratories (NAL) new procedure for selecting the gain and frequency response of a hearing aid. Ear and Hearing, Vol. 7. pp. 257–265. PMID 3743918.
  7. ^ K.W. Berger, E.N. Hagberg, R.L. Rane (1980). Determining hearing aid gain. Hearing Instruments, Vol. 30. pp. 26–44.{{cite book}}: CS1 maint: multiple names: authors list (link)
  8. ^ G.A. McCandless, P.E. Lyregaard (1983). Prescription of gain/output (POGO) for hearing aids. Hearing Instruments, Vol. 34. pp. 16–21.
  9. ^ a b c Vashkevich, Maxim; Azarov, Elias; Petrovsky, Nick; Petrovsky, Alexander (2017). "Petralex: A smartphone-based real-time digital hearing aid with combined noise reduction and acoustic feedback suppression". 2017 Signal Processing: Algorithms, Architectures, Arrangements, and Applications (SPA): 249–254. doi:10.23919/SPA.2017.8166873. ISBN 978-83-62065-30-1.
  10. ^ a b Vashkevich, Maxim; Azarov, Elias; Petrovsky, Alexander (2012). "Low-delay hearing aid based on cochlear model with nonuniform subband acoustic feedback cancellation". 2012 Proceedings of the 20th European Signal Processing Conference (EUSIPCO): 514–518.
  11. ^ "PETRALEX Hearing Aid". PETRALEX Hearing Aid. Retrieved 2020-02-18.
  12. ^ Moore, Charles. "Petralex By IT ForYou Named #1 Hearing Aid App". www.macprices.net. Retrieved 2020-02-18.
  13. ^ a b "Free apps help better hearing!". PETRALEX Hearing Aid. Retrieved 2020-02-18.
  14. ^ PETRALEX Hearing Enhancement App Launch, retrieved 2020-02-20
  15. ^ "Overview of medical applications, devices and communication technologies the internet of things" (PDF). Information Technology and Telecommunications (in Russian). 4: 67–80.
  16. ^ "Smartphone Applications for Private Practice Audiologists. Abram Bailey and Brian Taylor - PDF Free Download". docplayer.net. Retrieved 2020-02-20.
  17. ^ "Mobile learning as alternative to assistive technology devices for special needs students". springerprofessional.de. Retrieved 2020-02-20.
  18. ^ Dintsis, Danil (2017-08-30). "Implementing Complex Fuzzy Analysis for Business Planning Systems". Modern Fuzzy Control Systems and Its Applications. doi:10.5772/67974. ISBN 978-953-51-3389-6.
  19. ^ Maidment David W.; Ferguson Melanie (2018-11-19). "An Application of the Medical Research Council's Guidelines for Evaluating Complex Interventions: A Usability Study Assessing Smartphone-Connected Listening Devices in Adults With Hearing Loss". American Journal of Audiology. 27 (3S): 474–481. doi:10.1044/2018_AJA-IMIA3-18-0019. PMC 6437711. PMID 30452751.
  20. ^ "Best soft 2014" (PDF). PC Magazine: Russian Edition (in Russian). Vol. 11 (281): p. 66. 2014. {{cite journal}}: |pages= has extra text (help); |volume= has extra text (help)
  21. ^ Lynch-Morin, Kathryn. "Get a closer look at the 2016 LERN International Award Winners". blog.lern.org. Retrieved 2020-02-17.
  22. ^ d_dintsis (2017-07-14). "Congratulations to the Partner P2P projects winners". IAMCP mentoring framework. Retrieved 2020-02-17.
  23. ^ "IAMCP Congratulates All Winners in the 2018 IAMCP Member Awards Program - Announced at MS Inspire, Tue., 7/17!". IAMCP @ Microsoft Inspire. 2018-07-18. Retrieved 2020-02-19.