title: Asymmetry in parkinsonism, spreading pathogens and the nose.
abstract: Parkinson's disease, as well as many other parkinsonisms, including most toxic, neurodegenerative and familial types are typically asymmetric. No explanation for this phenomenon exists. A summary of the frequency of asymmetry in a spectrum of parkinsonian disorders is provided. Evidence against asymmetry being the result of normal asymmetries of the substantia nigrais reviewed. Asymmetry either results from a greater susceptibility on one side or a spreading pathology entering or starting on one side of the CNS. With the increasing evidence for spreading pathologies (toxins, viruses, α-synuclein), knowledge of neuroanatomical connections, and literature implicating spreading pathogens from the enteric and olfactory nerves, potential explanations can be theorized and explored, including the possibility of a pathogen preferentially entering or originating in the olfactory bulb on one side, with subsequent involvement of the other side.
authors.affiliation: Department of Medicine, University of Manitoba, Deer Lodge Centre, 200 Woodlawn St., Winnipeg, MB R3J 2H7, Canada. dhobson@cc.umanitoba.ca
authors.forename: Douglas E
authors.initials: DE
authors.lastname: Hobson
mesh_terms: D000818:Animals; D006801:Humans; D009296:Nasal Cavity / Q000382:microbiology / Q000473:pathology* / Q000821:virology; D009830:Olfactory Bulb / Q000382:microbiology / Q000473:pathology* / Q000821:virology; D020734:Parkinsonian Disorders / Q000382:microbiology / Q000473:pathology* / Q000821:virology