(I should clarify: I know some of the State Department staff in Havana; I don't know any of the injured people.)
My understanding is that nobody is entirely clear whether this is permanent or not. Some people have recovered quickly and others are still having lingering effects. Several suffered a concussion, which just doesn't work -- I work for an audio simulation company (think jets and helicopters) and there's just no way audible sound or even infrasound can do this.
OTOH, there is a theory that guided infrasound can do serious tissue damage, which was possibly the cause of Dyatlov Pass[1].
My understanding is that nobody is entirely clear whether this is permanent or not. Some people have recovered quickly and others are still having lingering effects. Several suffered a concussion, which just doesn't work -- I work for an audio simulation company (think jets and helicopters) and there's just no way audible sound or even infrasound can do this.
OTOH, there is a theory that guided infrasound can do serious tissue damage, which was possibly the cause of Dyatlov Pass[1].
[1] https://en.wikipedia.org/wiki/Dyatlov_Pass_incident