Do you know if leech therapy can restore any hearing loss which has been a hereditary condition (nerve deafness) ?

Scam: Leeches have been used experimentally for skin ulcers, but the crazy stuff that's being endorsed by celebrities nowadays (putting them on acupuncture points, using them with castor oil massages, and so forth) is just silly. They'll target hereditary hearing loss because you may be desperate, real science has little to offer, and wishful thinking makes people say it seems to be working. Good luck.

Not likely: While there are many "experimental" treatments for nerve deafness, there are no scientifically proven ones. If the nerve loss occurred a long time ago, then many of these "experimental" treatments probably won't work. Buyer beware! talk to your local ENT for some sound proven advice!