Thank you @tarazkp for your continuous support & upvote and your well appreciated resteem & comment. :)

Yeah mate, these neurological conditions are pretty unknown and very uncommon indeed. As you probably have already confirmed along the documentary. If you find this topic of some interest and want to investigate a little bit more about the subject. I'd recommend you google about Vilayanur S. Ramachandran. One of the experts in the field and one of the most popular neurologist and communicator with thousands of videos, TED talks conferences and a good amount of documentaries about these matters.

In fact, the documentary I shared above is not exactly the one I saw many years ago. I'm under the impression that the one I saw also had to Ramachandran as one of the scientist featured and interviewed in there. I'm not totally sure of that though. Perhaps, the one that I saw was an older one from the golden age of the science documentaries on cable tv. Maybe one of the good chaps from Nova, Time Life Multimedia, The early Discovery or any other of the multiple and excellent BBC producer associates.