Introduction to Parkinson's Science/Q Page 90

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How does Parkinson's spread through the nervous system?Edit

What is the Braak model?Edit

It would be easier to address the issue of spreading if we knew exactly what the infective agent was! Reading most literature on the subject you might get the impression that the disease is all about a part of the brain called the sbstantia nigra, but, whatever the agency is that is at work, it leaves its footprints all over the place. These take the form of dead and dying neurons containing clumps of a protein called alpha synuclein, better known as Lewy bodies and neurites.

Professor Heiko Braak works at the Institute of Clinical Neuroanatomy, Johann Wolfgang Goethe-Universit, Frankfurt am Main, and he had the idea of following the trail of footprints back to its source.

He published the results in 2003/4 [1] and [2] and divided the pathway into a number of sequential stages:-


STAGE LOCATION(S) PD SYMPTOMS
I and II medulla oblongata pre-symptomatic
I and II pontine tegmentum pre-symptomatic
I and II olfactory bulb pre-symptomatic
I and II anterior olfactory nucleus pre-symptomatic
III and IV substantia nigra symptomatic
III and IV midbrain symptomatic
III and IV forebrain symptomatic
V and VI mature neocortex advanced stages

This, coupled with the observation that one of the earliest symptoms of the disease is a reduction in the sense of smell, would appear to imply that the infective agency is inhaled.

Hawkes et al (1997) [3] studied this aspect of the disease and concluded:-

Olfactory damage in Parkinson's disease is consistent and severe and may provide an important clue to the aetiology of the disease.

Further ReadingEdit

Images for Braak staging:- https://www.google.co.uk/search?num=10&hl=en&site=imghp&tbm=isch&source=hp&biw=1024&bih=512&q=braak+staging&oq=braak&gs_l=img.1.0.0l5j0i5j0i10i24j0i24l3.1814.9604.0.12530.7.6.1.0.0.0.160.607.5j1.6.0...0.0...1ac.1.Ev6nYfHdeWo

ReferencesEdit

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  1. Braak, H.; Ghebremedhin E.; Rüb, U.; Bratzke, H. and Del Tredici, K. (2004) Abstract Cell Tissue Res. 318 (1) 121 – 134. Stages in the development of Parkinson's disease-related pathology. http://www.ncbi.nlm.nih.gov/pubmed/15338272
  2. Braak, H.; Del Tredici, K.; Rüb, U.; de Vos, R. A.; Jansen Steur, EN. and Braak, E. (2003) Abstract Neurobiol. Aging 24 (2) 197 – 211Staging of brain pathology related to sporadic Parkinson’s disease http://www.ncbi.nlm.nih.gov/pubmed/12498954
  3. Hawkes, C.H.; Shephard, B.C. and Daniel, E. (1997) Abstract j. Neurol. Neurosurg. Psychiatry 62:436-446 Olfactory dysfunction in Parkinson's disease http://jnnp.bmj.com/content/62/5/436.abstract