Part of reply from neuroscientist involved in tinnitus research, I summarised the bits I understood in a post above.
Its a independent 2nd opinion, from someone not involved in HIFU directly, but its positive about using HIFU so look forward to trial results, and wonder why this subject isnt being picked up more widely. HIFU for neuroscience is a new field, but HIFU has FDA approval and looks promising. Any questions about this I will try to answer
REPLY :
> I have no personal involvement in the field of therapeutic brain
> stimulation or lesioning for tinnitus relief, so I can only respond
> based on my slightly outsider knowledge (coming from a neighbouring
> but different part of tinnitus research).
> I personally like the idea of both brain stimulation and targeted
> lesioning for relief of neurological conditions, including tinnitus,
> in principle. I also consider it a major benefit if the intervention
> does not require a craniotomy, as this is likely to make it much more
> widely deliverable as a treatment. Of course we will need to see how
> the large-scale long-term studies pan out to decide whether each given
> intervention is worth making into a part of the routine care
> structure.
>
> The issue of heterogeneity certainly seems to exist for cortical
> correlates of tinnitus (at least cortical areas besides the auditory
> cortex itself, and possible within auditory cortex also), though I do
> not have a clear sense of how much heterogeneity there is in
> subcortical tinnitus correlates. From first principles, one might
> argue that because tinnitus has a peripheral origin, that the auditory
> periphery would show the most consistent abnormalities, which might
> become more heterogeneous in higher auditory or non-auditory centres.
> From my own results, and literature of which I am aware, there is
> nothing to suggest major heterogeneity of thalamic involvement in
> tinnitus.
>
> In terms of what the relevant functional correlate of tinnitus is,
> this becomes more than just academic if that correlate is going to be
> used to target treatment. Oscillatory correlates, such as those I work
> with, cannot be used to image the thalamus (it does not project out to
> the surface), so are probably not applicable to HIFU (in theory fMRI
> could be used to identify tinnitus correlates in the auditory
> thalamus). Oscillations could be used, in theory, to target cortical
> interventions (both invasive and non-invasive). As a general rule, the
> higher the frequency of an oscillation the harder it is to detect, and
> the less accurate and precise the localisation of its origin is.
> Auditory gamma oscillations are extremely difficult to detect, and
> tend to localise poorly, especially at an individual subject/patient
> level. Delta/theta oscillations are much stronger and localise better
> and more easily.
>
> An additional advantage to using delta/theta oscillations to target
> intervention is that they seem to represent a more low-level and
> fundamental part of the tinnitus generation pathway (the
> thalamocortical input), and are thus a more concrete measure. In my
> data there is nothing to suggest heterogeneity of the relationship of
> delta/theta oscillations in auditory cortex with tinnitus. Gamma, on
> the other hand, is probably a downstream response to the incoming
> tinnitus signal, which is more fickle and more influenced by other
> factors including attention.