I discovered this United Kingdom report recently; report is dated March 2017

NATIONAL INSTITUTE FOR HEALTH AND CARE EXCELLENCE
https://www.nice.org.uk/guidance/ipg...nts/overview-2

". . . It should not be regarded as a definitive assessment of the procedure . . ."

Perhaps it was recently posted to the web . . . I have not completely read the report and are in the process of doing so. It address the Onders studies, the DiPALS (UK) study, the RespiStimALS (France) study and studies in Turkey, and possibly others.