Scientists are unsure why smell loss occurs in Parkinson’s, one popular theory is that the Parkinson’s process may start in the olfactory bulb, the part of the brain that controls the sense of smell, and the gut.
Some researchers believe clumps of the protein alpha-synuclein may form in these parts of the body first, before migrating to other parts of the brain.
Other symptoms of the disease include a cramped handwriting, tremors, uncontrollable movements during sleep, limb stiffness or slow movements, voice changes, and rigid facial expression or masking.