[traspler]

I am currently participating in a study using tEAS (transcranial electrical and auditory stimulation) for tinnitus. Can‘t say much about if it works or not especially as the study was redesigned and will contain less treatment, so I‘m not too optimistic. (Background: 10y tinnitus without any known cause, was coping very will for the last 8y, had a terrible last 2y but I am starting to get over it again so in general I am hopeful about my future at least)

But as this is HN I wanted to share a technical detail: The device used for the stimulation is pretty new and, as all medical devices are, pricey. It is connected to a laptop through USB-C but not only for data, it‘s completely powered through it. Sounds neat, right. But what happens if either by accident or not knowing any better you unplug the cable? Then it dumps all the stored charge through the electrodes into whoever has them on their scalp at the moment. It‘s VERY uncomfortable and I am shocked (hahaha) that a device like this has such a failure mode and that this is even allowed.

[ajnin]

More importantly, what happens if there is a short somewhere and the USB port becomes connected to mains voltage ? Computers are not medical devices, and I'd say it is fairly common to feel a small tingle when touching ports so isolation is not that great. The actual medical device should use an isolation transformer or be powered by batteries.

[tomohawk]

Interesting side effect of making USB ubiquitous. There are even laws saying it must be used instead of proprietary connectors.

At this point, it is likely cost prohibitive to make a proprietary connector that is not USB.

Perhaps the relevant standards body should take these sorts of needs into account for things like USB which are meant to be used universally. The last thing we need is 'medical grade USB' that costs 100x normal USB.

[danuker]

Typical laptops are not grounded. You might want to try a desktop (but also check that the wall plugs are properly grounded).

But I agree that for an expensive medical device, shocking its users is unacceptable.

[traspler]

I‘m only a participant, not one of the organizers but even then, the laptop was provided with the device by the company to be used together, I would assume that simply for support and data integrity reasons they are not interested in using a different PC.