Here:
And here is the oral defense of her PhD, which I haven't yet watched with English subtitles:
Six patients were planned, but only 
four completed the implantation and one-year follow-up.  
After one year:  
- 1 patient ("super-responder") showed major improvement  
- 2 had mild, non-significant improvements  
- 1 had no benefit  
No serious adverse events occurred, and hearing remained stable.  
The most important part of the thesis, chapter 7, is still 
under embargo, as the corresponding paper is 
under peer review (in 
Neurotherapeutics).  
For now, only the detailed single case of the super-responder has been published.  
It's somewhat disappointing in terms of results, although there remains some cautious optimism. DBS can be remarkably effective in desperate cases, far more than any other treatment, but only for a limited and still poorly identified group of patients.  
Ideally, researchers need to determine in advance who can truly benefit from it, which will require more studies.  
In short, before this procedure becomes available for severe cases, we'll probably have to wait another ten years or so, though I could be wrong.
Let's not forget the other DBS studies, including those in France, which target different areas of the brain. Together, they could lead to a faster and broader understanding of the full potential of DBS.