WO2024098100A1

WO2024098100A1 - Systems and methods for providing relief to a subject experiencing tinnitus

Info

Publication number: WO2024098100A1
Application number: PCT/AU2023/051124
Authority: WO
Inventors: Paul Davis
Original assignee: Tinnitus Telecare Pty Ltd
Current assignee: Tinnitus Telecare Pty Ltd
Priority date: 2022-11-09
Filing date: 2023-11-08
Publication date: 2024-05-16
Anticipated expiration: 2025-05-09
Also published as: AU2025204234A1

Abstract

A method and system have been developed for providing relief to individuals with tinnitus using an electronic device. The method involves determining the subject's hearing threshold profile, creating an audio filter based on this profile to reduce the dynamic range of the input audio signal, and generating a treatment audio signal. This treatment sound is then outputted to the subject through audio playback. The system includes a transceiver, digital storage media, electroacoustic transducers, and a processor that applies the method.

Description

SYSTEMS AND METHODS FOR PROVIDING RELIEF TO A SUBJECT EXPERIENCING TINNITUS

Field of the Invention

[1] The present invention relates to systems and methods for providing relief to a subject experiencing tinnitus and in particular those carried out on an electronic device.

[2] The invention has been developed primarily for use for subjects experiencing tinnitus and will be described hereinafter with reference to this application. However, it will be appreciated that the invention is not limited to this particular field of use.

Background of the Invention

[3] Tinnitus is commonly described as a persistent ringing in the ears. However, the perceived sound can include a range of noises like humming, buzzing, crickets, pulsing, whirring, droning, etc. Tinnitus is usually defined as the perception of a sound that has no external correlation i.e., it is internally generated in each patient. It can have a range of effects on the individual. Moderate to severe cases can find it extremely debilitating, particularly because of sleep deprivation, and severe cases can even have suicidal ideation.

[4] Numerous studies in the USA have indicated that around 10-15% of the general population have chronic tinnitus, with approximately 5% of the population being moderately affected, and 1-2 % severely affected (Henry, Dennis, & Schechter 2005). Australia & the UK typically have similar incidence rates for auditory pathologies.

[5] Historically, tinnitus was considered to be incurable, but recently it has been shown that the annoyance associated with tinnitus can be treated. It has also become measurable in live humans, especially with Positron Emission Tomography (PET) and Magnetoencephalography (MEG) scans. These studies have confirmed that tinnitus is our own normal internal noise floor (‘brain static’), which has been uncovered by hearing loss. In cases where it is annoying, there have been neuroplastic changes in the auditory pathways from the brain trying to compensate for the hearing loss. [6] In one notable MEG study at Macquarie University in Sydney it was found that targeted acoustic stimulation (via Neuromonics Tinnitus Treatment) can reverse the annoyance (McMahon, Ibrahim, & Mathur, 2016).

[7] Repeat MEG scans, compared to a no-treatment control group, directly measured changes in the strength and location of tinnitus-related electrical activity, and this correlated with improvements in the perception of tinnitus.

[8] T rad itional ly , treatments attempted to just mask tinnitus, which aimed to replace the unpleasant internal sound with a more pleasant external sound that was easier to ignore. This effect only worked while the acoustic stimuli was turned on.

[9] Most patients report that external sounds typically do not mask their tinnitus, unless they are turned up to a level that is uncomfortably loud, and that level can have the potential to aggravate their tinnitus. A level that gave enough relief was usually one that was too loud to use when going off to sleep, or to relax or concentrate.

[10] Many attempts to make tinnitus masking/treatment more effective try to measure the pitch of each patient’s tinnitus, then emphasize the matching frequency region in a modified stimulus.

[11] Many patients, however, find it difficult to match their tinnitus with an external sound, as tinnitus is now known to be a neurological event (not a sound), and as such doesn’t behave like an external sound.

[12] Some patients have resorted to using amplified external sound at a loudness level that only partly masks their tinnitus, as anything louder is not tolerable for them. However, this reduces the amount of relief experienced, as well as reduces the sense of control over the tinnitus. It also reduces the neural stimulation level for the hearing- impaired frequencies, so reducing the efficiency of any longer-term improvements in tinnitus intrusiveness.

[13] Many patients experience a pitch that is higher than the human speech range, which is higher that the output of conventional clinical audiometers, so they cannot be given a relevant comparison sound to compare with it, especially when octave confusion is occurring. Some patients are unable to conceptually grasp the notion of what pitch is, and so fixate on loudness, invalidating results. [14] Others experience multiple sounds, and some are too broad to have a specific frequency region. It is also common that the pitch of each patient’s tinnitus can vary considerably. Thus, tinnitus pitch measures can be a very precarious basis for modifying sound.

[15] A somewhat recent approach is to ‘notch out’ or greatly attenuate an octave of sounds in the frequency range of the tinnitus pitch, with the treatment still providing equal amounts of gain in the other frequencies above and below the pitch. However, a randomized controlled clinical trial found no significant improvement after three months of this therapy (Stein et al 2016). The treatment is also likely to be subject to the abovementioned performance limitations due to variance in tinnitus pitch measurements.

[16] There are now several other variations of this notch-out approach. One of the first studies which used the relevant pre/post measures was able to be included in a meta-analysis. This used calculations of Cohen’s d effect sizes of treatment, which represents how consistently effective a treatment is. Results found that the notch-out study produced markedly lower effect size results than intermittent masking by Neuromonics (Davis et al 2015).

[17] Another approach used a predetermined masking algorithm which provided intermittent masking of the tinnitus wherein, at a comfortable listening level, during peaks of the audio signal the tinnitus was completely obscured, whereas during troughs the perception of the tinnitus occasionally emerges. The aim of this treatment was to provides an immediate sense of relief, control and relaxation for the person, while enabling sufficient perception of the tinnitus for habituation and long-term treatment to occur.

[18] However, the uptake of this method has been limited and there are limitations of this method. For example, the underlying musical audio was distracting and not necessarily conducive to providing a relaxing effect. The user would then focus on hearing the tinnitus when it was intermittently perceived.

[19] Also, the volume of the audio often needs to be at a relatively higher level than 65 dB SPL to give enough relief. To elicit an otoacoustic emissions (OAE) suppression effect, the masker had to be of a presentation level lower than 65 dB SPL, as more than that can create a stapedius muscle reflex, and so ruin the desired effect. Elucidating a reflex could have limited the effectiveness of the neuroplasticity treatment effects.

[20] The present invention seeks to provide a solution, which will overcome or substantially ameliorate at least some of the deficiencies of the prior art, or to at least provide an alternative.

[21] It is to be understood that, if any prior art information is referred to herein, such reference does not constitute an admission that the information forms part of the common general knowledge in the art, in Australia or any other country.

Summary of the Invention

[22] According to an aspect of the invention, there is provides a method of providing relief to a subject experiencing tinnitus, the method comprising: determining a hearing threshold profile of the subject across a predetermined frequency range; providing an electronic device, the electronic device configured, in use, to: receive an input audio signal; produce an audio filter based on the hearing threshold profile of the subject across the predetermined frequency range, the audio filter being adapted to reduce a dynamic range of the input audio signal and at least partially compensate for a hearing loss of the subject; and generate a treatment audio signal by applying the audio filter to the input audio signal; and outputting the treatment audio signal to the subject as a treatment sound via an audio playback thereby providing relief to the subject experiencing tinnitus.

[23] In an embodiment, the treatment sound can be a sound of water moving and/or falling in a natural setting.

[24] In an embodiment, the sound of water moving and/or falling in a natural setting can be selected from the group consisting of a sound of rainfall on a surface, a stream, a waterfall, and waves on a seabed surface.

[25] In an embodiment, the treatment audio signal can have a relatively high longer- term average of higher frequencies than music or other natural sounds.

[26] In an embodiment, the audio treatment signal can be substantially uninterrupted.

[27] In an embodiment, the audio treatment signal can provide substantially continuous masking of tinnitus experienced by the subject. [28] In an embodiment, the treatment audio signal can have a dynamic range of less than 37 dB.

[29] In an embodiment, the treatment audio signal can have a bandwidth having a minimum value of approximately 0.1 kHZ and a maximum value greater than 12kHz.

[30] In an embodiment, the hearing threshold profile of the subject can comprise an audiogram recording or recording of the lowest volume at which a sound is audible to the subject at discrete frequencies within the predetermined frequency range.

[31] In an embodiment, a minimum value of the predetermined frequency range can be 0.25kHz and a maximum value of the predetermined frequency range is within the range 8kHz to 20kHz.

[32] In an embodiment, the audio filter can be adapted to partially account for hearing loss of the subject up to a frequency within the range of 8kHz to 20kHz.

[33] In an embodiment, a maximum volume of the treatment sound can be less than a volume that causes discomfort to the subject.

[34] In an embodiment, the treatment sound can comprise a sound pressure level less than 75 dB (A).

[35] In an embodiment, the method of providing relief to a subject experiencing tinnitus further can comprise reducing one or more signal peak(s) within the predetermined frequency range to thereby reduce distortion of the audio input signal and improve comfort of the subject.

[36] In an embodiment, production of the audio filter can comprise measuring and recording a hearing threshold value across the predetermined frequency range for each ear of the subject.

[37] In an embodiment, production of the audio filter can comprise: determining a median value of the range of hearing threshold values; adding isometric loudness transforms values and hearing device frequency response compensation values to the hearing threshold values to provide compensated values; subtracting the median value from each of the compensated values and multiplying the resultant values by a gain constant value.

[38] In an embodiment, determining a median value of the range of hearing threshold values can comprise: determining a lowest hearing threshold value; determining a highest hearing threshold value, and calculating the median of lowest and highest hearing threshold values.

[39] In an embodiment, the method of providing relief to a subject experiencing tinnitus further can comprise, when hearing is tested in dB hearing level: converting the hearing threshold values from dB hearing level to dB sound pressure level.

[40] In an embodiment, the gain constant can be within the range of 0.2 to 0.55.

[41] In an embodiment, the treatment audio signal can be produced as 4D sound.

[42] According to another aspect of the invention, there is provided a tinnitus treatment system configured to provide relief to a subject experiencing tinnitus, the tinnitus treatment system comprising: a transceiver for receiving and/or transmitting data; a digital storage media configured for storing one or more selected from data and software instructions; one or more electroacoustic transducer(s); a processor operatively connected to the transceiver, digital storage media, and one or more electroacoustic transducer(s); wherein the processor is configured, in use, to be directed by software instructions to: receive an input audio signal; determine a hearing threshold profile of the subject across a predetermined frequency range; produce an audio filter based on the hearing threshold profile of the subject across the predetermined frequency range, the audio filter being adapted to reduce a dynamic range of the input audio signal and at least partially compensate for a hearing loss of the subject; generate a treatment audio signal by applying the audio filter to the input audio signal; and transmit the treatment audio signal to the one or more electroacoustic transducer(s) to generate a treatment sound via an audio playback thereby providing relief to the subject experiencing tinnitus.

[43] In an embodiment, the treatment sound can be a sound of water moving and/or falling in a natural setting.

[44] In an embodiment, the sound of water moving and/or falling in a natural setting can be selected from the group consisting of a sound of rainfall on a surface, a stream, a waterfall, and waves on a seabed surface.

[45] In an embodiment, the treatment audio signal can have a relatively high longer- term average of higher frequencies than music or other natural sounds. [46] In an embodiment, the audio treatment signal can be substantially uninterrupted.

[47] In an embodiment, the audio treatment signal can provide substantially continuous masking of tinnitus experienced by the subject.

[48] In an embodiment, the treatment audio signal can have a dynamic range of less than 37 dB.

[49] In an embodiment, the treatment audio signal can have a bandwidth having a minimum value of approximately 0.1 kHZ and a maximum value greater than 12kHz.

[50] In an embodiment, the hearing threshold profile of the subject can comprise an audiogram recording or recording of the lowest volume at which a sound is audible to the subject at discrete frequencies within the predetermined frequency range.

[51] In an embodiment, a minimum value of the predetermined frequency range can be 0.25kHz and a maximum value of the predetermined frequency range is within the range 8kHz to 20kHz.

[52] In an embodiment, the audio filter can be adapted to partially account for hearing loss of the subject up to a frequency within the range of 8kHz to 20 kHz.

[53] In an embodiment, a maximum volume of the treatment sound can be less than a volume that causes discomfort to the subject.

[54] In an embodiment, the treatment sound can comprise a sound pressure level less than 75 dB (A).

[55] In an embodiment, tinnitus treatment system configured to provide relief to a subject experiencing tinnitus can further comprise, in use, reducing one or more signal peak(s) within the predetermined frequency range to thereby reduce distortion of the audio input signal and improve comfort of the subject.

[56] In an embodiment, production of the audio filter can comprise measuring and recording a hearing threshold value across the predetermined frequency range for each ear of the subject.

[57] In an embodiment, production of the audio filter can comprise: determining a median value of the range of hearing threshold values; adding isometric loudness transforms values and hearing device frequency response compensation values to the hearing threshold values to provide compensated values; subtracting the median value from each of the compensated values; and multiplying the resultant values by a gain constant value.

[58] In an embodiment, determining a median value of the range of hearing threshold values can comprise: determining a lowest hearing threshold value; determining a highest hearing threshold value, and calculating the median of lowest and highest hearing threshold values.

[59] In an embodiment, the tinnitus treatment system configured to provide relief to a subject experiencing tinnitus can further comprise, when hearing is tested in dB hearing level: converting the hearing threshold values from dB hearing level to dB sound pressure level.

[60] In an embodiment, the gain constant can be within the range of 0.2 to 0.55.

[61] In an embodiment, the treatment audio signal can be produced as 4D sound.

[62] In an embodiment, the processor can be part of a user device.

[63] In an embodiment, the user device can be selected from the group consisting of a computer, a hearing aid, a mobile phone, a smart watch, and a tablet.

[64] In an embodiment, the user device can comprise a user interface configured for interacting with the user to obtain the hearing threshold profile.

[65] To those skilled in the art to which the invention relates, many changes in construction and widely differing embodiments and applications of the invention will suggest themselves without departing from the scope of the invention as defined in the appended claims. The disclosures and the descriptions herein are purely illustrative and are not intended to be in any sense limiting.

[66] Other aspects of the invention are also disclosed.

Brief Description of the Drawings

[67] Notwithstanding any other forms which may fall within the scope of the present invention, a preferred embodiment I preferred embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings in which: [68] Figure 1 shows a system in accordance with one embodiment of the present invention;

[69] Figure 2 shows a method to be carried out by the system in Figure 1 in accordance with one embodiment of the present invention;

[70] Figure 3 shows the frequency response of 6 recordings of waves on a beach and one recording of a waterfall;

[71] Figure 4 shows a spectrographic representation of waves on a beach and orchestral music;

[72] Figure 5 shows the frequency response of a typical high-quality wave recording and two high quality music recordings (one orchestral and one contemporary relaxation music);

[73] Figure 6 shows an example hearing threshold profile of a subject and frequency response of the sound of waves on a beach;

[74] Figure 7 shows the steps of an algorithm for producing a filter signal;

[75] Figure 8A shows the test patient’s hearing threshold profile indicating hearing loss, expressed in the dB HL units;

[76] Figure 8B illustrates the source recording of waves on a beach and effect of test subject’s Prescribed filter on the source recording;

[77] Figure 9 shows the test subject’s compensation contour from Figure 8B applied to the source recording to demonstrate how the frequency response of the treatment audio signal becomes modified per ear due to application of the algorithm;

[78] Figure 10 shows Table 1 setting out a relative dynamic range of water sounds compared with music;

[79] Figure 11 shows Table 2 setting out Apple AirPod 2 earphones additive correction values;

[80] Figure 12 shows Table 3 setting out Apple AirPod 3 earphones additive correction values;

[81] Figure 13 shows Table 4 setting out Apple AirPod Pro earphones additive correction values; [82] Figure 14 shows Table 5 setting out published Equal Loudness Transforms.

Description of Embodiments

[83] Figure 1 shows a system for providing relief to a subject experiencing tinnitus 100. The system 100 comprises a transceiver 12 for receiving and/or transmitting data. The system 100 comprises digital storage media 16 configured for storing one or more selected from data and software instructions. The system 100 further comprises a processor 14 operatively connected to the digital storage media 16 and the transceiver 12. The processor 14 is configured for being directed by software instructions for carrying out the following method 200 comprising the steps of: receiving an audio signal (step 210 of Figure 2); producing a filter based on the hearing threshold and loudness discomfort level profile of the subject across a predetermined frequency range, the filter being adapted to reduce a dynamic range of the audio signal and at least partially compensate for hearing loss of the subject (step 212 of Figure 2), and generating a treatment audio signal by applying the filter to the audio signal (step 214 of Figure 2).

[84] The method 200 further comprises playing back the treatment audio signal to a subject experiencing tinnitus e.g., through speakers in earphones 20.

[85] For example, the system can comprise an electronic device 10 such as a desktop computer or a mobile phone which includes a transceiver 16 and processor 14.

[86] The system 100 can further comprise a downloadable app which presents an interface on the screen of the electronic device 10 for the user to interact with. The method 200 can be executed by executing software instructions stored in the digital storage media 16 or memory of the system 100. The app can also be used to facilitate measuring an audiogram or hearing threshold profile on which the method 200 is based.

[87] Once the hearing threshold profile is generated and stored in the memory 16 or uploaded from another source, the method 200 can be executed to generate a treatment audio signal. Once the filter is generated it can be stored in the memory. The treatment audio signal can also be stored in the memory once it is generated.

[88] The system can further comprise an audio receiver device 20 such as inner-ear earphones which include speakers for audio playback of the treatment audio signal into the ears of a subject 5. Figure 1 shows wireless earphone in which the transmitter transmits data to earphones via a radiofrequency signal 15. As described below, audiogram measurements can also be taken using the system 100.

[89] In other embodiments, the system can be embodied within a medical device or a hearing aid. For example, the method could be embodied as a tinnitus program in a hearing aid.

[90] In other embodiments the speakers could be incorporated in other mediums e.g., pillow speakers or underwater speakers used in floatation tanks which would allow therapy to be delivered while the user is sleeping or experiencing floatation therapy.

Obtaining a hearing threshold profile

[91] The method comprises firstly determining a hearing threshold profile of the subject. This comprises measuring and recording hearing threshold values in each ear at discrete intervals across the predetermined frequency range. An audiometry test can be conducted by a licensed professional or by the user or subject themselves to determine an audiogram or hearing threshold profile of the subject. The test comprises the recording of the lowest volume at which a tone is audible at discrete frequencies within the predetermined frequency range.

[92] The test can begin by playing a tone at 0.25kHz and extending the frequency of the tone incrementally across the predetermined frequency range including the entire audible range of a subject’s hearing e.g., up till 8kHz, 10kHz, 12kHz, 14 kHz, 16 kHz, or 20kHz. A minimum value of the predetermined frequency range can be 0.25kHz, and a maximum value of the predetermined frequency range can be within the range 8kHz to 20 kHz.

[93] In an embodiment the app will allow the end user to test their thresholds of hearing through their earphones such as Apple AirPod earphones. For example, the user will push and hold a button on the app interface and a calibrated sound will be played at increasing loudness in one ear through one earphone. The sound volume will start to reduce and the user can release the button on the interface when the sound is no longer audible. The app will then record the volume at which the button was released and store this data to build the hearing threshold profile. This process can be repeated at discrete intervals across the predetermined frequency range. In an embodiment, the app will calculate and present a real time graphic representation of the audiogram. When the test for one ear is completed, the other ear can then be tested. This data is then stored in the digital storage media to be retrieved and used to produce the audio filter.

[94] In other embodiments the pitch of the tinnitus can be determined. For example, a relative measure of the main pitch of their most intrusive tinnitus sound can then be ascertained by use of multiple paired comparison sounds. The user will be asked to choose between two sounds a forced choice comparison style to determine which sound is closest to the pitch of their tinnitus. These comparison sounds (pure tone or narrow band noise etc) can be compiled based on answers already provided in the case history. Alternatively, subjects can also have the option to directly adjust a range of sounds to reference against their tinnitus. They can then fine-tune components such as pitch, bandwidth, and loudness until it is a match with their tinnitus. This data is helpful for counselling purposes, as well as for determining candidacy for various sound therapy options.

[95] In an embodiment, the app, in operation with the earphones can be configured to measure Loudness Discomfort Levels. Loudness discomfort measures can be measured at certain frequencies selected within the predetermined frequency range to determine the point that sounds are becoming uncomfortably loud. This data will help set an upper limit of compression to keep the treatment signal tolerable.

[96] In an embodiment, the app can be configured to determine Minimum Masking Level (MMLs). The test will then determine how loud a broad band sound is required to be to mask the subject’s tinnitus. It is a pre/mid/post therapy measure and also helpful for candidacy considerations.

[97] In another embodiment, the process can include delivering a short ‘sound massage’ of sea sounds that have been emphasized around the pitch of the subject’s worst hearing loss or tinnitus. This can help the subject relax if they are nervous about the possibility of the testing process making their tinnitus worse.

[98] Testing data can be stored in a cloud. Tests can be repeated after the subject has experienced therapy for a period of time to determine changes in tinnitus experience and hearing. [99] Advantageously, as the audiogram is recorded via the app using wireless earphones, the method is self-calibrated. This accounts for the individuals’ unique ear canal resonance, and its unique interaction with the earphone. Furthermore, the Apple AirPod 3 earphones and AirPod Pro earphones also self-calibrate to each user’s own ear canal resonance properties, further enhancing their suitability for delivering therapy via this method.

[100] The above-described method which includes testing at extra high frequencies (>8 kHz) could also be used to obtain data for programming of hearing aids, providing optimal customization across the full frequency range of wide-band aids. Many patients complain of problems hearing in background noise, but their hearing within the usual testing range is found to be normal. However, testing of the extra high frequencies can often find hearing loss in the relevant region, and that data can be used to optimally program wide-band hearing aids to improve speech discrimination, as well as increase the appreciation of music and environmental sounds.

[101] The extra high frequency hearing test described above can also be used for the monitoring of ototoxic medicines or chemical exposure, and early identification of noise induced hearing loss.

Audio signal

[102] As mentioned above, the filter is applied to the audio signal to generate a treatment audio signal. The audio signal may be a recording of a sound of water moving or falling in a natural setting. For example, the audio signal can be a recording of the sound of waves on a seabed surface or a rainfall or a waterfall.

[103] In an example, the audio signal is a high fidelity recording selected for relaxing wave intervals or other natural modulations which have a relaxing effect on the user.

[104] The use of water sounds as the source stimuli has a number of advantages. Firstly, water sounds have a relatively broad frequency response, and especially a relatively greater longer-term average of the very higher frequencies than music or other natural sounds. This is advantageous for compensating hearing loss at higher frequencies (as mentioned below) as the most frequent hearing loss configuration in tinnitus patients is relatively worse in the highest frequencies.

[105] Figure 3 shows the frequency response of six different high quality wave recordings and one high quality waterfall recording. It is displayed in the conventional dB FS (Full Scale) units, where 0 dB is maximal loudness, so the graph is expressed in negative dB. They all cover a relatively wide frequency range (i.e., 86 Hz to 17,140 Hz).

[106] Therefore, the audio signal can have a bandwidth having a minimum value of approximately 0.1 kHZ and a maximum value up to 20kHz.

[107] Psychophysical measurements of tinnitus patients by the Applicant over the past thirty years have shown that the tinnitus expression in patients with typical high to very high frequency tinnitus is able to be masked at a lower intensity level when the stimuli have sufficient strength in the same frequency region of the tinnitus. The applicant has also found that the long-term use of high-frequency stimuli can have much greater permanent improvements in tinnitus disturbance than use of sounds with a narrower bandwidth.

[108] Water sounds also have relaxation-inducing properties. This is beneficial as the experience of tinnitus is typically stressful. A water stimulus that can replace the unpleasant internal sound (tinnitus) with a more pleasant external sound that can be more readily ignored.

[109] Another advantage of water sounds over more complex stimuli like music is that patients are readily able to focus on it or not, while music tends to be more distracting when trying to focus on external sounds. Furthermore, repeated use of the same music can become annoying for some people.

[110] The audio signal can also be selected so that it has minimal audio gaps when played back and so, does provides substantially no intermittent masking of tinnitus. Comparatively, music tends to have a lot more intermittency than water sounds in terms of finer variations of contrasting sounds like between various musical instruments being played simultaneously.

[111] This is shown in the spectrographic representations of the waves on beach vs orchestral music of Figure 4. The first spectrographic representation is an audio file of the waves on a beach. The second spectrographic representation is of orchestral music.

[112] The high level of level intermittency in music lends itself very well to the notion of intermittent masking. In this approach, the patient is repeatedly exposed to their tinnitus very briefly in the troughs of the music spectrum. [113] Dynamic Range (DR) is equivalent to the difference from the softest to the loudest moments of a recording. When there is a wide dynamic range present, there are noticeable variations in level, which make recordings more engaging to the listener (which has pros/cons in the case of tinnitus treatment).

[114] Table 1 (Figure 10) displays the relative dynamic range of water sounds compared with music. Absolute measures were expressed in dB FS, whereby 0 dB is maximal loudness, so the more negative the values are, the softer the sounds are. These results showed that classical music (orchestral) had the widest DR, whilst the waterfall had the narrowest DR. The relaxation music and waves on a beach had a similar DR in this measurement series, but it is problematic to generalize too much about this, given the diversity of relaxation music and the diversity of wave sound recordings.

[115] Thus, in an embodiment, the audio signal can have a dynamic range of less than 30 dB, such as 25 dB or 27 dB, when there is no significant hearing loss present. When correcting for hearing loss, even in part, the dynamic range of the customized audio signal might be less than 40 dB. In other embodiments, the audio signal can have a dynamic range of 1 dB or 25 dB or between 1 dB and 25 dB.

[116] Figure 5 shows the relative frequency response of a typical high-quality wave recording and two high quality music recordings (one orchestral and one contemporary relaxation music).

[117] The wave recordings displayed more sound energy for high and extra high frequencies than the orchestral and contemporary relaxing music. The classic tinnitus patient hearing configuration shows little or no loss at the low frequencies, then slopes to a more substantial loss for high frequencies. Music produces much more energy in the good hearing bass area, and much less for the upper (treble) frequencies where hearing loss is more pronounced. This means that much less spectral modification is required for waves than music to overcome the hearing loss effect using the present method. This greatly reduces distortion as well as maximizes the available frequency range of spectral modification in the customization process.

[118] Figure 6 shows an example hearing threshold profile of a subject and frequency response of the sound of waves on a beach. [119] The average frequency response of example wave recordings are shown when it is converted into dB HL units and inverted to be displayed adjacent the average hearing thresholds of tinnitus patients. Figure 6 also shows hearing loss is more severe at higher frequencies. The wave sounds, without modification give too much power for the better hearing low frequencies and not enough power to overcome the greater hearing loss in the higher frequencies. There is considerable gain compensation required to at least partially mask the tinnitus and provide the most efficient longer-term treatment effect.

[120] In other embodiments, the audio signal could be other sounds which have similar characteristics to the wave or waterfall sounds as described above. For example, the audio signal could be wind noise, water fountains, rain on the roof, whale/dolphin sounds, music, recordings of cats purring, deep breaths, guided relaxation exercises etc, or it could be mixed with other such sounds. In other embodiments, the audio signal could be a live sound source and not necessarily a recording.

Pre-treatment of audio signal

[121] The method comprises the step of pre-treating the audio signal by reducing the peaks of the signal across the predetermined frequency range of the audio signal. This is done to reduce distortion and improve comfort.

[122] Using audio editing software, the loudest intensity peaks of the audio signal are softly compressed during pre-treatment of the audio signal. The most intense peaks of the acoustic stimulation can be further soft limited by the application of a programmable compression effect at certain frequencies across the frequency range of the audio signal. Based on the hearing test and/or loudness discomfort level measurement results, the algorithm prescribes (and applies) a compression threshold to keep the signal comfortable for the user, at each frequency. This is approximately equivalent to the measured or estimated loudness discomfort level minus 2 dB. Alternatively, proprietary software can be produced to automate the testing and the prescriptive calculations. It can then produce custom audio gain filtering and compression characteristics and then output stimuli that are treatment-ready and able to be dispensed in a telehealth setting. Algorithm to produce a filter signal

[123] Figure 7 shows the steps of an algorithm for producing a filter signal.

[124] Step 310 comprises determining a median value of the range of hearing threshold values.

[125] To minimize distortion in the final recording, and to maximize the available range of customization, the algorithms ensure that there is equal amounts of amplification and attenuation in the processing of the source recording for each patient’s prescription.

[126] Determining a median value of the range of hearing threshold values comprises: determining the lowest hearing threshold value; determining the highest hearing threshold value, and calculating the median of lowest and highest hearing threshold values.

[127] In other words, the median value is obtained by calculating the median between the lowest hearing threshold value in their lowest hearing ear, and the highest hearing threshold at their highest hearing ear.

[128] From this median, the desired compensation contour will be calculated in terms of how much sound must be either attenuated or amplified at each frequency. To prevent very isolated portions of particularly good or bad hearing from skewing the results, in an embodiment, the algorithm averages three adjacent highest hearing threshold values at adjacent frequencies and the three adjacent lowest hearing threshold values at adjacent frequencies before calculating the median.

Calibration

[129] Hearing thresholds are measured using the standard acoustical calibration units of dB SPL (Sound Pressure Level). They are also prescribed and processed in dB SPL. When the hearing threshold data is obtained through Apple Airpod2, AirPod 3, AirPod Pro, or other well-known earphones, conversion of hearing threshold values from dB HL to dB SPL is not required when the same earphones are used to replay the treatment.

[130] It is not clinically viable to measure every minor hearing threshold frequency, only the major (key) frequencies. In Step 310, the measured hearing threshold values are then supplemented by the prediction of the frequencies in between them. They are predicted by linear extrapolation, which constitutes the mean of the two surrounding (measured) frequencies.

[131] In step 312, the hearing threshold values are then added to the isometric loudness curve compensation values.

[132] For counselling purposes, we can later convert the hearing test results in dB SPL to dB HL (Hearing Level) if it needs to be compared with conventional audiometric testing protocols. To compensate for the frequency response of conventional audiometric headphones relative to the above use of AirPods, additive correction values are added to the measured hearing threshold values. The earphone additive correction values are dependent on the make and model of the earphone. The values for Apple AirPod 2, 3 and AirPod Pro are presented in Figures 11 , 12, and 13, respectively, as examples across a frequency range of 0.07 to 16 kHz. These figures also display the correction factors used to convert the results of testing in dB SPL into the HL units required for counselling purposes.

[133] Users will need to specify the type of earphone used so the output can be optimally calibrated. These AirPods 2 and 3 models are ‘open ear’ style earphones while the Pro models are more occluding and protrude deeper into the ear canal. They all have a relatively high sound quality and tend to disconnect from the audio source less readily than more generic earphones. They also are manufactured with high engineering tolerances, leading to low batch variation, so their frequency response tends to be quite consistent/predictable in the manner that medical devices require.

[134] The Apple AirPod Pro type that typically seals off the ear canals could be relatively obtrusive, and hot and itchy with extended use. However, the applicant has found they can be effective for tinnitus treatment and hearing testing if the smallest ear tip sizes are used so they are not sealing off the ear canal. Other well-known high- fidelity transducers can also be used if their frequency response is well documented, and the sizing can be configured to be a relatively open ear effect.

[135] Isometric loudness transform values are used to relatively ‘flatten out’ the frequency response of the environmental stimuli in the preparation stage of the production process. These additive values summate the normative loudness perception data of a full range of pure tones, which is then corrected for the unique acoustic properties of the ear as it interfaces with the earphones. [136] In an example, Isometric Loudness Transforms from Takeshima et al (2001) can be used as they account for higher frequencies (Table 5 as shown in Figure 14). The 40 Phon curve was chosen as it closest to the typical listening level of the algorithm modified stimuli for tinnitus patients using it at quieter times (for reference, human speech tends to be in the 60 Phon range).

[137] These isometric loudness transform values are added to the hearing threshold values at the respective frequency across the frequency range. To provide a value for all audiogram data, the ILT values can be linearly extrapolated to determine ILT values in between subsequent values.

[138] At step 314, the median value is then subtracted from each corrected value. This median is derived as described above from averaging the hearing threshold values at the patient’s worst ears’ worst hearing frequencies with the best ear’s best hearing frequencies. This means that the source stimuli are either attenuated or amplified by an equivalent maximal degree.

[139] At step 316, the resultant values at each frequency are then multiplied a gain constant. The gain constant can be a number between 0.25 to 0.60. In an example, the gain constant is 0.37. For example, patients with extremely sloping hearing loss (from very good low frequency hearing down to very severe hearing loss in the high frequencies) might benefit from an increase in the gain constant. Those with very decreased sound tolerance (hyperacusis) can also be prescribed a higher gain constant to enable a greater masking at lower volume.

[140] Certain environmental water sound recordings with low dynamics (not much variation from the softest to the loudest sounds), can be optimized by a relatively lower gain constant. A recording with higher than usual dynamics could also be processed by a relatively higher gain constant.

[141] The gain multiplier can be varied over several stages of treatment to further improve the effect of the treatment. For example, a starting level of gain multiplier of the order of 0.46 could maximize the engrossing nature of the recording to maximize the relaxation inducing effect. Therefore, the degree of tinnitus suppression effect is enhanced and the treatment signal provides the greatest perception of tinnitus relief and control whilst using the recording. [142] When there are indications that the habituation process is underway, the second stage could revert to a level close to the 0.37, for example, with the intention of a medium term ‘breaking down’ of tinnitus perception compared with all the other neural activity within the auditory pathways, and so facilitating a more permanent reduction in the intrusiveness of the tinnitus.

[143] During the third stage the gain constant could be reduced to a level around 0.30 for maintenance of the subject’s improvements once tinnitus is no longer significantly disturbing. The clinician may further fine tune the gain at each stage.

Providing the treatment audio signal

[144] The resultant profile is the modified audiogram data. Directed via the app, the processor processes the source recordings accordingly to make a new recording that is customized for that patient. That is, the modified audiogram data is combined with the audio file to provide the treatment audio signal. This can be either a one-time permanent change to the treatment data file or by a filter bank that provides the modification ‘on the fly’ while the replay of the source file is in process.

Customising output for Loudness discomfort level

[145] In an embodiment, the maximum volume of the treatment sound across the entire frequency range of the treatment sound is less than a volume that causes discomfort to the subject.

[146] The treatment signal can also be further customised by direct measurements of each patient’s Loudness Discomfort Level (LDL), by setting the compression threshold 2 dB or so lower than their LDL threshold. Other clinical measures of aberrant loudness growth can also be utilized to ascertain a compression threshold that is low enough to be comfortable.

[147] As loudness tolerance tends to improve over the course of treatment, repeat measures of the improved tolerance of loudness at certain frequencies can be used to modify their treatment stimuli to provide less compression to the audio signal. This increases the ‘headroom’ of the stimuli, giving an even more natural acoustic experience, as well as increasing the efficiency of the treatment over the longer term.

[148] The maximum volume of the treatment audio signal can be varied based on the patient’s individual LDL. In an example, the maximum volume of the treatment sound can be less than 70 dB SPL or less than or more than 75 dB SPL. Example

[149] An example of a test subject’s hearing, prescription of treatment audio signal and functional result is provided.

[150] The subject is a 50-year-old male with 21 years noise exposure in the building industry. He reports very intrusive tinnitus, mainly in the left ear. The pitch of the tinnitus is centred around 4000Hz. His hearing is considerably worse on the left side, and a ‘noise notch’ is evident for the high frequencies.

[151] Figure 8A shows the test patient’s hearing threshold profile indicating hearing loss, expressed in the dB HL units. As it is the ‘loss’ of hearing that is the key consideration, it is displayed in this audiogram format whereby the y axis shows increasing severity of loss going down the page. Any values higher than 20 dB are considered hearing losses. Figure 8B shows the corresponding prescription of the required filter, which has been determined using the algorithm above. This graph expresses its results in dB SPL units, and the y axis now shows increasing gain as it goes up the page.

[152] Figure 9 illustrates the source recording of waves on a beach and effect of the test subject’s prescribed filter on the source recording i.e., the treatment audio signal. The source recording is one of the Tinnitus TeleCare recordings that has been preprepared with compression and channel separation modifications. As the left and right channels responses are functionally equivalent in terms of long-term spectral averages, Figure 9 nominally shows just the right channel.

[153] In Figure 9, the test subject’s compensation contour from Figure 8B has been applied to the source recording to demonstrate how the frequency response becomes modified in each ear due to the application of the algorithm. The graph is expressed in dB SPL, and the y axis shows increasing gain ascending the page.

[154] As shown in Figure 9, the frequency response of the source recording of waves has been modified in a way that partly compensates for the patient’s hearing loss in each ear. Notably the filter is adapted to partially account for hearing loss across the predetermined frequency range such as between 0 kHz to 16 kHz and even up till 20 kHz

[155] Notably, the present algorithm does not prescribe absolute gain targets, only relative frequency response, and then the patient is able to regulate their volume control, guided by clinical protocol. For example, if a patient reports that they are able to mask their tinnitus at a relaxingly low level and it was a great help in going off to sleep, then the customized wave stimuli should be optimized for the most efficient permanent treatment effect after a few months of use at those times when the tinnitus is intrusive.

[156] A minimum of three hours a day of therapy by listening to the treatment audio signal is recommended, usually at the times when the tinnitus tends to be most annoying, such as the quiet times and for sleeping. In this example, the patient reported that he was now able to mask his tinnitus at a relaxingly low level and it was a great help in going off to sleep.

4D sound

[157] In an embodiment, 4D sound can be produced in a multi-step process to treat auditory disorders and maximize relaxation effects. For example, it begins with use of a special 24-bit/48 kHz mid-side microphone recording technique of environmental water sounds, to provide a surround-sound type effect (3D).

[158] 3D sound aims to mimic real-life audio listening. It uses various microphones and speakers and specific post-hoc processing to place acoustic objects in a three- dimensional space. This is more than just sounds from the left & the right. It includes sounds below, above, or even behind the listener. Further post-hoc intra-channel and inter-channel time and phase manipulation of the water sounds are used to make the audio more engrossing and more relaxing.

[159] Aspects of the water recordings are then custom-made to move dynamically in time, and so, 4D sound is produced. In an embodiment, this can include enhancing the perception of water coming closer to the listener, and then away to each ear. It can also make the dynamics of the waves more closely emulate the time course of a deep breath by a relaxed person. The production of the 4D effect is the last step in the mastering process.

[160] The algorithm is then applied to the recordings, producing a filter based on the hearing threshold profile of the subject across a predetermined frequency range, the filter being adapted to reduce a dynamic range of the audio signal and at least partially compensate for hearing loss of the subject and generating a treatment audio signal by applying the filter to the audio signal. [161] Another audio dimension is then introduced using static binaural panner software plugins to replicate the effect of binaural recordings, whereby an acoustic mannequin is used with microphones on the inside of a pair of artificial ear canals. This gives an even more life-like sound through earphones.

[162] The human ear canal tends to amplify sounds in the range of the human voice. The sound can end up sounding different for each person because of their unique head shape. Most recordings assume the frequency-modifying characteristics of the average ear canal. In the Apple AirPods 3 and Pro, for example, there are microphones inside the ear that automatically measure how sound is being transmitted to the subject’s eardrum. The earphones then dynamically equalise the low and mid frequencies to ‘normalise’ the frequency response so it is closer to the variations due to ear canal shapes that deviate from the average. The additional use of Apple AirPods thus enables the use of ‘Adaptive EQ’ to provide an automatic in-situ ear-canal calibration for each patient to further customise the experience. In an example, the resulting audio is finally mastered in the Dolby Atmos format or other lossless/near- lossless file compression formats.

[163] Apple’s Dynamic head tracking is built into spatial audio technology using gyroscopes and sensors inside the earphones that keep the sound image appearing to continue to come from the direction of the sound source (most often an iPhone), despite movement of the head away from it. This makes the recorded sound seem more natural. However, this dynamic head tracking feature should be turned off for therapy as it interferes with a measured dose to each ear when the subject's head is on one side of a pillow.

[164] The invention’s manner of producing 4D sound from 3D sound recordings can make nature or music sound more engrossing, so has applicability to help with facilitating relaxation states. It can also be applicable in non-healthcare settings, such as consumer entertainment or an aid to meditation etc.

[165] There are several differences between the described method and intermittent masking. For example, the water sounds have a very different long-term average frequency response and relatively lower dynamics, so the gain multipliers, compression characteristics, and calibration constants need to be quite different to those required for music. [166] Intermittent masking aims to correct for hearing loss to produce an equal sensation level of loudness across all frequencies, while the present method only partly corrects for hearing loss, and compensates also for decreased sound tolerance. The novel algorithm described above aims to provide an unequal sensation level and a high level of relief at a comfortable listening level and maximize the neural stimulation needed to train down the annoyance experienced with tinnitus. The described method allows for a full or alternate interaction with the tinnitus which helps to train down the intrusive/disturbing effects. It is also configured to maximize the relief from tinnitus at a comfortable listening level at the time of use.

[167] The above algorithm relies on hearing threshold measurements and loudness discomfort level measurements as the most reliable data to individually program each patient’s treatment stimuli.

[168] Advantageously the user only requires a generic electronic device such as an of a computer, a hearing aid, a mobile phone, a smart watch, or a tablet and earphones to receive therapy using the described methods via an app, and/or a web-based service. It could also be embedded within a hearing aid or other ear-level devices.

[169] The method and system described above can also be used to treat the auditory condition of Hyperacusis or any other form of Decreased Sound Tolerance, including what can experienced in Neurodivergent conditions like Autism Spectrum Disorder, Attention Deficit Hyperactivity Disorder, Obsessive Compulsive Disorder, Tourette’s Syndrome etc. Some of the effects of Post-Traumatic Stress Disorder can also be treated with the invention.

Comprising and Including

[170] In the claims which follow and in the preceding description of the invention, except where the context requires otherwise due to express language or necessary implication, the word “comprise” or variations such as “comprises” or “comprising” are used in an inclusive sense, i.e., to specify the presence of the stated features but not to preclude the presence or addition of further features in various embodiments of the invention.

[171] Any one of the terms: including orwhich includes or that includes as used herein is also an open term that also means including at least the elements/features that follow the term, but not excluding others. Thus, including is synonymous with and means comprising.

Scope of Invention

[172] Thus, while there has been described what are believed to be the preferred embodiments of the invention, those skilled in the art will recognize that other and further modifications may be made thereto without departing from the spirit of the invention, and it is intended to claim all such changes and modifications as fall within the scope of the invention. For example, any formulas given above are merely representative of procedures that may be used. Functionality may be added or deleted from the block diagrams and operations may be interchanged among functional blocks. Steps may be added or deleted to methods described within the scope of the present invention.

[173] Although the invention has been described with reference to specific examples, it will be appreciated by those skilled in the art that the invention may be embodied in many other forms.

Industrial Applicability

[174] It is apparent from the above, that the arrangements described are applicable to the healthcare industries.

Claims

Claims The claims defining the invention are as follows:

1. A method of providing relief to a subject experiencing tinnitus, the method comprising: determining a hearing threshold profile of the subject across a predetermined frequency range; providing an electronic device, the electronic device configured, in use, to: receive an input audio signal; produce an audio filter based on the hearing threshold profile of the subject across the predetermined frequency range, the audio filter being adapted to reduce a dynamic range of the input audio signal and at least partially compensate for a hearing loss of the subject; and generate a treatment audio signal by applying the audio filter to the input audio signal; and outputting the treatment audio signal to the subject as a treatment sound via an audio playback thereby providing relief to the subject experiencing tinnitus.

2. The method of providing relief to a subject experiencing tinnitus according to claim 1 , wherein the treatment sound is a sound of water moving and/or falling in a natural setting.

3. The method of providing relief to a subject experiencing tinnitus according to claim 2, wherein the sound of water moving and/or falling in a natural setting is selected from the group consisting of a sound of rainfall on a surface, a stream, a waterfall, and waves on a seabed surface.

4. The method of providing relief to a subject experiencing tinnitus according to claim 1, wherein the treatment audio signal has a relatively high longer-term average of higher frequencies than music or other natural sounds. The method of providing relief to a subject experiencing tinnitus according to claim 1 , wherein the audio treatment signal is substantially uninterrupted. The method of providing relief to a subject experiencing tinnitus according to claim 1 , wherein the audio treatment signal provides substantially continuous masking of tinnitus experienced by the subject. The method of providing relief to a subject experiencing tinnitus according to claim 1 , wherein the treatment audio signal has a dynamic range of less than 37 dB. The method of providing relief to a subject experiencing tinnitus according to claim 1 , wherein the treatment audio signal has a bandwidth having a minimum value of approximately 0.1 kHZ and a maximum value greater than 12kHz. The method of providing relief to a subject experiencing tinnitus according to claim 1 , wherein the hearing threshold profile of the subject comprises an audiogram recording or recording of the lowest volume at which a sound is audible to the subject at discrete frequencies within the predetermined frequency range. The method of providing relief to a subject experiencing tinnitus according to claim 1 , wherein a minimum value of the predetermined frequency range is 0.25kHz and a maximum value of the predetermined frequency range is within the range 8kHz to 20kHz. The method of providing relief to a subject experiencing tinnitus according to claim 1 , wherein the audio filter is adapted to partially account for hearing loss of the subject up to a frequency within the range of 8kHz to 20 kHz. The method of providing relief to a subject experiencing tinnitus according to claim 1 , wherein a maximum volume of the treatment sound is less than a volume that causes discomfort to the subject. The method of providing relief to a subject experiencing tinnitus according to claim 12, wherein the treatment sound comprises a sound pressure level less than 75 dB (A). The method of providing relief to a subject experiencing tinnitus according to claim 1 , further comprising reducing one or more signal peak(s) within the predetermined frequency range to thereby reduce distortion of the audio input signal and improve comfort of the subject. The method of providing relief to a subject experiencing tinnitus according to claim 1 , wherein production of the audio filter comprises measuring and recording a hearing threshold value across the predetermined frequency range for each ear of the subject. The method of providing relief to a subject experiencing tinnitus according to claim 1 , wherein production of the audio filter comprises: determining a median value of the range of hearing threshold values; adding isometric loudness transforms values and hearing device frequency response compensation values to the hearing threshold values to provide compensated values; subtracting the median value from each of the compensated values and multiplying the resultant values by a gain constant value. The method of providing relief to a subject experiencing tinnitus according to claim 16, wherein determining a median value of the range of hearing threshold values comprises: determining a lowest hearing threshold value; determining a highest hearing threshold value, and calculating the median of lowest and highest hearing threshold values. The method of providing relief to a subject experiencing tinnitus according to claim 16, further comprising, when hearing is tested in dB hearing level: converting the hearing threshold values from dB hearing level to dB sound pressure level. The method of providing relief to a subject experiencing tinnitus according to claim 16, wherein the gain constant is within the range of 0.2 to 0.55. The method of providing relief to a subject experiencing tinnitus according to claim 1 , wherein the treatment audio signal is produced as 4D sound. A tinnitus treatment system configured to provide relief to a subject experiencing tinnitus, the tinnitus treatment system comprising: a transceiver for receiving and/or transmitting data; a digital storage media configured for storing one or more selected from data and software instructions; one or more electroacoustic transducer(s); a processor operatively connected to the transceiver, digital storage media, and one or more electroacoustic transducer(s); wherein the processor is configured, in use, to be directed by software instructions to: receive an input audio signal; determine a hearing threshold profile of the subject across a predetermined frequency range; produce an audio filter based on the hearing threshold profile of the subject across the predetermined frequency range, the audio filter being adapted to reduce a dynamic range of the input audio signal and at least partially compensate for a hearing loss of the subject; generate a treatment audio signal by applying the audio filter to the input audio signal; and transmit the treatment audio signal to the one or more electroacoustic transducer(s) to generate a treatment sound via an audio playback thereby providing relief to the subject experiencing tinnitus. The tinnitus treatment system configured to provide relief to a subject experiencing tinnitus according to claim 21 , wherein the treatment sound is a sound of water moving and/or falling in a natural setting. The tinnitus treatment system configured to provide relief to a subject experiencing tinnitus according to claim 22, wherein the sound of water moving and/or falling in a natural setting is selected from the group consisting of a sound of rainfall on a surface, a stream, a waterfall, and waves on a seabed surface. The tinnitus treatment system configured to provide relief to a subject experiencing tinnitus according to claim 21 , wherein the treatment audio signal has a relatively high longer-term average of higher frequencies than music or other natural sounds. The tinnitus treatment system configured to provide relief to a subject experiencing tinnitus according to claim 21 , wherein the audio treatment signal is substantially uninterrupted. The tinnitus treatment system configured to provide relief to a subject experiencing tinnitus according to claim 25, wherein the audio treatment signal provides substantially continuous masking of tinnitus experienced by the subject. The tinnitus treatment system configured to provide relief to a subject experiencing tinnitus according to claim 21 , wherein the treatment audio signal has a dynamic range of less than 37 dB. The tinnitus treatment system configured to provide relief to a subject experiencing tinnitus according to claim 21 , wherein the treatment audio signal has a bandwidth having a minimum value of approximately 0.1 kHZ and a maximum value greater than 12kHz. The tinnitus treatment system configured to provide relief to a subject experiencing tinnitus according to claim 21 , wherein the hearing threshold profile of the subject comprises an audiogram recording or recording of the lowest volume at which a sound is audible to the subject at discrete frequencies within the predetermined frequency range. The tinnitus treatment system configured to provide relief to a subject experiencing tinnitus according to claim 21 , wherein a minimum value of the predetermined frequency range is 0.25kHz and a maximum value of the predetermined frequency range is within the range 8kHz to 20kHz. The tinnitus treatment system configured to provide relief to a subject experiencing tinnitus according to claim 21 , wherein the audio filter is adapted to partially account for hearing loss of the subject up to a frequency within the range of 8kHz to 20 kHz. The tinnitus treatment system configured to provide relief to a subject experiencing tinnitus according to claim 21 , wherein a maximum volume of the treatment sound is less than a volume that causes discomfort to the subject. The tinnitus treatment system configured to provide relief to a subject experiencing tinnitus according to claim 21 , wherein the treatment sound comprises a sound pressure level less than 75 dB (A). The tinnitus treatment system configured to provide relief to a subject experiencing tinnitus according to claim 21 , further comprising, in use, reducing one or more signal peak(s) within the predetermined frequency range to thereby reduce distortion of the audio input signal and improve comfort of the subject. The tinnitus treatment system configured to provide relief to a subject experiencing tinnitus according to claim 21 , wherein production of the audio filter comprises measuring and recording a hearing threshold value across the predetermined frequency range for each ear of the subject. The tinnitus treatment system configured to provide relief to a subject experiencing tinnitus according to claim 21 , wherein production of the audio filter comprises: determining a median value of the range of hearing threshold values; adding isometric loudness transforms values and hearing device frequency response compensation values to the hearing threshold values to provide compensated values; subtracting the median value from each of the compensated values; and multiplying the resultant values by a gain constant value. The tinnitus treatment system configured to provide relief to a subject experiencing tinnitus according to claim 36, wherein determining a median value of the range of hearing threshold values comprises: determining a lowest hearing threshold value; determining a highest hearing threshold value, and calculating the median of lowest and highest hearing threshold values. The tinnitus treatment system configured to provide relief to a subject experiencing tinnitus according to claim 36, further comprising, when hearing is tested in dB hearing level: converting the hearing threshold values from dB hearing level to dB sound pressure level. The tinnitus treatment system configured to provide relief to a subject experiencing tinnitus according to claim 36, wherein the gain constant is within the range of 0.2 to 0.55. The tinnitus treatment system configured to provide relief to a subject experiencing tinnitus according to claim 21 , wherein the treatment audio signal is produced as 4D sound. The tinnitus treatment system configured to provide relief to a subject experiencing tinnitus according to claim 21 , wherein the processor is part of a user device. The tinnitus treatment system configured to provide relief to a subject experiencing tinnitus according to claim 41 , wherein the user device is selected from the group consisting of a computer, a hearing aid, a mobile phone, a smart watch, and a tablet. The tinnitus treatment system configured to provide relief to a subject experiencing tinnitus according to claim 41 , wherein the user device comprises a user interface configured for interacting with the user to obtain the hearing threshold profile.