Dr. Will Sedley Requesting YOUR Input — Predictive Brain Processing for Tinnitus

Discussion in 'Research News' started by Hazel, Feb 4, 2020.

    1. mrbrightside614

      mrbrightside614 Member Podcast Patron Benefactor Advocate

      Location:
      NE Ohio, USA
      Tinnitus Since:
      July 2019
      Cause of Tinnitus:
      Acoustic trauma
      Thanks for your time, Will.

      Is it still the prevailing consensus that tinnitus is primarily (save some outliers like auditory radiation) a function of hearing loss? If so...

      Since hearing loss can be present at many untested frequencies (e.g. 8437 Hz, 12897 Hz) would curing the hearing loss by restoring the hair cells and their synaptic connections corresponding with such frequencies likely reduce or cure the tinnitus? Upon hearing restoration, might tinnitus reduction then depend on brain plasticity/elasticity to recognize that since the function has been restored, there is no need to keep inputting/outputting this aberrant signal?
       
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    2. mrbrightside614

      mrbrightside614 Member Podcast Patron Benefactor Advocate

      Location:
      NE Ohio, USA
      Tinnitus Since:
      July 2019
      Cause of Tinnitus:
      Acoustic trauma
      I should mention that I realize this is not the focus of your research and that you may not be able to provide a picture of the opinion at large. I also should mention the theory that hearing losses below the regions of perceived tinnitus frequency might be the causative factor of increased central gain, and thus causative of perception of high frequency tinnitus even if there is no damage at the corresponding OHC's.
       
    3. UKBloke

      UKBloke Member Podcast Patron Benefactor

      Tinnitus Since:
      1991
      Cause of Tinnitus:
      Loud Music / family history
      Maybe you can do an interview for the Tinnitus Talk Podcast?
       
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    4. AUTHOR
      AUTHOR
      Hazel
      Dreaming

      Hazel Director Staff Podcast Patron Benefactor Hall of Fame Advocate

      Location:
      the Netherlands
      Tinnitus Since:
      10/2017
      Cause of Tinnitus:
      one-sided hearing loss (of unknown origin)
      We've already scheduled a date in June! We'll definitely use this thread as input for the interview :)
       
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    5. UKBloke

      UKBloke Member Podcast Patron Benefactor

      Tinnitus Since:
      1991
      Cause of Tinnitus:
      Loud Music / family history
      Brilliant!
       
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    6. bobvann
      Devilish

      bobvann Member

      Location:
      Inside the vortex
      Tinnitus Since:
      April 2017
      Cause of Tinnitus:
      E drums headphones
      Thanks for pointing out those who sell expensive hearing aids for the snake oilists they are.
       
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    7. AndrewW

      AndrewW Member

      Tinnitus Since:
      07/2019
      Cause of Tinnitus:
      Unknown
      Hi Will,

      As someone for whom neuromodulation sounds show some effect (reducing or eliminating tonal element of tinnitus), I am very excited about the direction of your research. Your theory seems compatible with my experience as my tinnitus is quite variable and when it's at a particular threshold (e.g., between hiss/crickets and tone) my expectations seem to have some (very minor) influence on what I hear.

      Have you any idea at this stage when the online sound trials might occur? I'd love to take part in those!
       
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    8. I am interested in your study proposal. Combining detailed modeling with clinical data has a lot of potential and it seems you try to be clear about what is supporting a theory and what is proving a theory. As you have mentioned, this seems helpful for other areas as well and I hope the next step is examining hyperacusis. I’ll be excited to see the results.

      I hope something below is useful.

      Research Testing Questions/Thoughts
      1. Given the exclusion criteria you seem to need for the experiment, I think it would be good to highlight that this experiment is studying a subtype of Tinnitus. Acknowledging heterogeneity and studying the subtypes of tinnitus is something that we all would like more emphasis on.
      2. Despite attempts to exclude more reactive cases, how will you handle people with pain from sounds you generate or whose tinnitus changes or increases as a result of the sound?
        1. If they are already inside an MEG, it would be interesting to see what this expensive machine picks up when their tinnitus gets worse or if they feel pain. I imagine you would need to instruct them to let you know.
      3. Comments about the fMRI that you may have already considered:
        1. MRI sounds will strongly overlap with your sounds even with hearing protection.
        2. MRI testing will likely activate global circuits including discomfort from confinement, visual processing alterations, and attention to MRI sounds in ways that the EEG and MEG will not.
        3. Hearing protection will change the frequency distribution of the sounds you are presenting, filtering high frequencies more than low frequencies.

      Questions/Thoughts about the theory

      1. Cochlear implants are an interesting case for studying time constants for reprogramming predictors I would imagine. People initially hear very harsh, robotic sounds and then adapt, presumably from changing the auditory predictors. Also cochlear implants have been shown to reduce tinnitus and hyperacusis after SSHL [Macias 2015, Mertens 2015].
      2. SBUTTs (Sudden Brief Unilateral Tapering Tinnitus) last about 30 seconds and then fade away to nothing. It would be interesting if a subject experiences this during testing and you observe using the MEG. A side note, SBUTTs seem to be more frequent in tinnitus and hyperacusis patients [Oron 2011].
      3. Why does playing a sound through headphones that resembles tinnitus not fade away? (Why is it not deemed imprecise relative to predicted sounds?). This seems like it may show limitations or barriers that need to be overcome. Especially if sound is used as the injection point to influence these feedback networks.
      4. Cause and effect for brain waves. I wonder if it is easy to jump to conclusions about what is actually causing these waves (global or local influences) although i’m out of my depth here.

      Works Cited

      Macias, Angel Ramos, et al. “Cochlear Implants as a Treatment Option for Unilateral Hearing Loss, Severe Tinnitus and Hyperacusis.” Audiology and Neurotology, vol. 20, no. 1, 2015, pp. 60–66., doi:10.1159/000380750.

      Mertens, Griet, et al. “Cochlear Implantation as a Long-Term Treatment for Ipsilateral Incapacitating Tinnitus in Subjects with Unilateral Hearing Loss up to 10 Years.” Hearing Research, vol. 331, 2016, pp. 1–6., doi:10.1016/j.heares.2015.09.016.

      Oron, Yahav, et al. “Sudden Brief Unilateral Tapering Tinnitus.” Otology & Neurotology, vol. 32, no. 9, 2011, pp. 1409–1414., doi:10.1097/mao.0b013e3182355626.
       
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    9. Frédéric

      Frédéric Member Podcast Patron Benefactor Advocate

      Location:
      Marseille, France
      Tinnitus Since:
      11/19/2012
      Cause of Tinnitus:
      acoustic trauma
      Exposing Pathological Sensory Predictions in Tinnitus Using Auditory Intensity Deviant Evoked Responses (see attached file) is the recently published study, which aimed to establish a biomarker of tinnitus.
       

      Attached Files:

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    10. Gabriel5050
      Depressed

      Gabriel5050 Member Podcast Patron Benefactor

      Tinnitus Since:
      2018
      Cause of Tinnitus:
      Noise exposure (most likely)
      I would gladly do the online sound part of the study. Scanning the brain seems like a good idea. We could certainly use a way to prove the presence of tinnitus. Just stop shoving TRT down our throats. Use animals, as long as it's ethical and good luck. I'll let other people do the smart talk.
       
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    11. Jaka
      Wishful

      Jaka Member

      Tinnitus Since:
      11/2019
      Cause of Tinnitus:
      Unknown
      It would be interesting to know if the reverse also applies. That listening to certain sounds can influence the default prediction of silence to tinnitus.

      I am way out of my league with this material here, but there are a lot of people who have expected hearing loss for their age, no other identifiable cause and they just suddenly noticed tinnitus without any obvious triggers.

      Also by the way I would be willing to participate in any possible test as long as it is feasible to do it remotely
       
    12. Will Sedley

      Will Sedley Member

      Tinnitus Since:
      2008
      Cause of Tinnitus:
      Repeated jaw contractions on background of mild noise traum
      Thanks again everybody for further comments and questions. As previously, please find a list of replies to specific points and questions below:

      Sudden vs. gradual onset hearing loss and risk of tinnitus development: I think it is likely that, even if these are of the same amount, sudden hearing loss poses a higher risk of tinnitus. Possibly because of how sudden the change in neural activity in the hearing pathway is, and also likely the physical and psychological stress and the altered attention (for instance, blast injuries in soldiers are such a common cause of tinnitus, combining sudden hearing trauma with physical injury and massive psychological distress).

      The potential for different structures in the cochlea to be damages in some cases of tinnitus than in others: Absolutely I agree. I think all that is needed is some sort of damage that causes hearing loss. There is a lot of ongoing research interest looking at inner hair cell loss versus damage to the ribbon synapse, or to the different types of nerve fibres (high and low activation thresholds). Of course, a few cases of tinnitus may not require hearing loss at all, though this is an ongoing area of debate.

      Resolution of modern brain imaging methods being the limiting factor in being able to record the brain activity responsible for tinnitus: This is a good question, and is a plausible explanation for why we cannot 'see' tinnitus. The resolution of recordings possible in animals is essentially unlimited, so might be able to settle this issue, but the limiting factor in animals is knowing which ones actually have tinnitus, which is still controversial. Better biomarkers in animals (perhaps derived from better biomarkers in humans, as I am working on) might significantly help in this regard.

      Whether tinnitus is "a function of hearing loss": Tinnitus is clearly strongly related to hearing loss, but there are other factors at play here, and it is common to have hearing loss (of any severity) with no tinnitus.

      Would restoring hearing cure tinnitus: There is reason to think it might (and very strong reason to think it would at least quieten the tinnitus significantly). Restoring hearing should reduce spontaneous brain cell activity in the hearing pathway back down to normal levels (which are still above zero). The question is whether some tinnitus will remain because the brain has "learned" to find that sound pattern in the spontaneous cell firing. But, I still think this offers perhaps the best hope of a full tinnitus cure of all presently identified approaches.

      The upcoming study of sound therapy to try and treat tinnitus: There are no specific dates for commencement yet, and a few logistics still to be worked out. We will aim to post details on Tinnitus Hub when this is ready to run.

      In terms of the planned studies, the exclusion of certain subtypes: My plan is to be broad as possible in terms of who to recruit and include. The only restrictions really are looking to be profound hearing loss (because the investigative/treatment sounds would not get into the brain), tinnitus that is exacerbated by sound exposure (because it would be unsafe), or pulsatile tinnitus that is likely to be due to audible blood flow (and is therefore a different condition entirely). While there is an ongoing scientific debate about whether there are distinct tinnitus subtypes, or just a spectrum across various factors, I am aiming to target brain processes that I believe are likely to be common to all tinnitus subtypes if subtypes do exist.

      Sound protection: For fMRI, the issue of how scanner noise and sound protection affects hearing is one that applies to all auditory research and has well-established workarounds, which include using ear plugs with a flat frequency spectrum (like used by many musicians). In terms of the risks of sounds to hearing, there are known safe sound exposure limits, which will be followed. The less predictable issue is people who might find sounds unpleasant due to hyperacusis, or find their tinnitus exacerbated by the sounds. To mitigate this, we first pre-screen by asking whether people's tinnitus is made worse by moderate or loud sounds and advise non-participation to people in whom that applies. Then, the sounds to be used in the experiments are tested in a pre-experiment session where the frequency and volume of the sounds is adjusted to the ideal value, with one of the main focuses being ensuring the sounds are not uncomfortable.

      Short bursts of transient tinnitus: It would be great to study this, but to make anything of brain imaging studies we would have to capture literally hundreds of these in the same individual, so it is probably unfeasible.

      Why we do not tune out (and stop hearing) a constant persistent sound presented through headphones: We actually might, and I am not sure that anyone has ever tested this (it would require listening to the sound constantly without any breaks, day or night, for perhaps weeks on end). Although, the closer analogy to tinnitus would be wearing the headphones for a long period anyway, and following that to very gradually introduce a constant sound, starting from inaudibly quiet and slowly building up. I had previously applied for funding to try this, but did not get funded.

      Best wishes,
      Will
       
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