Theory of brain disease faces challenge, most PD patients have additional, non-motor symptoms, and is coming to be understood as a much broader disease.
Current theorys see Parkinson’s as degeneration of the substantia nigra .The hypothesis Braak and colleagues research pathology would indicate that it advances from the peripheral nervous system to the brain stem in a staging system first described by Braak in 2003
Chronic constipation, loss of smell, and REM sleep disorders often occur before the motor symptoms
One of the attractive features of Braak’s staging scheme is that the areas of the nervous system littered with Lewy bodies at the earliest stages of disease could account for these non-motor symptoms.
The staging system, draws attention to the damage in other transmitter systems—in other words, apart from and before the nigrostriatal system. In addition, it can serve as a framework for relating the pathology in other parts of the nervous system (gastrointestinal tract, spinal cord, and so on) to that in the brain.
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