A Gizmodo news report explores the prion disease fatal familial insomnia, which includes symptoms such as personality changes and a lack of controlled movement.
The first prion disease to be identified was in the 1730s when sheep and goats in Great Britain started to come down with a mysterious illness that caused them to be irritable, lose weight, and become uncoordinated. The illness, which became known as “Scrapie,” could kill off whole flocks at a time. Scrapie was only found in Western Europe for the first two hundred years of its known existence, but in the mid-20th century, a Michigan farmer imported sheep from England and his entire flock was killed off by the disease. Today, only Australia and New Zealand are known to be free from scrapie.
Like all prion diseases, Fatal Familial Insomnia (FFI) is caused by a change or mutation of the PRNP gene, which allows it to clump together in the thalamus region of the brain, eventually destroying the cells there. The thalamus region controls sensory and motor skills, as well as regulation of consciousness and sleep. The mutated PRNP gene “eats” holes in the brain, giving it a “sponge-like” appearance. This can lead to the inability to sleep (progressively getting worse overtime) and when sleep is achieved, very vivid dreams. It has been observed from EEG readings taken while the victim is awake show signs associated with REM sleep. Essentially, they are so sleep deprived, they enter a dream-like state when awake.