Clinically unclassifiable parkinsonism

Neurodegenerative diseases are legion and their classification just as protean. A useful approach is to divide them according to underlying pathological process, although even using this schema, there is much overlap and thus resulting confusion.

• neurodegenerative MRI brain (an approach)
  • measurements and ratios
    • midbrain to pons area ratio (for PSP)
    • Magnetic Resonance Parkinsonism Index (MRPI) (for PSP)
    • frontal horn width to intercaudate distance ratio (FH/CC) (for Huntington disease)
    • intercaudate distance to inner table width ratio (CC/IT) (for Huntington disease)
  • signs
    • hummingbird sign (of PSP)
    • Mickey Mouse sign (of PSP)
    • morning glory sign (of PSP)
    • hot cross bun sign (of MSA-C)
    • hockey stick sign (of Creutzfeldt-Jakob disease)
    • pulvinar sign (of Creutzfeldt-Jakob disease)
  • scoring systems
    • Fazekas scale for white matter lesions
    • posterior atrophy score of parietal atrophy (PA/PCA) (Koedam score)
    • medial temporal lobe atrophy score (MTA score)
    • global cortical atrophy scale (GCA scale)
• neurodegenerative diseases
  • synucleinopathies
    • diseases with Lewy bodies
      • Parkinson disease
        • Parkinson-plus syndrome
      • Lewy body disease
    • multiple systemic atrophy (MSA)
      • MSA-P (striatonigral degeneration)
        • putaminal rim sign
      • MSA-C (olivopontocerebellar degeneration)
        • hot cross bun sign
        • middle cerebellar peduncle sign
      • Shy-Drager syndrome
  • tauopathies
    • Alzheimer disease
      • typical/classical Alzheimer disease
      • variant (e.g. posterior cortical atrophy)
    • chronic traumatic encephalopathy (CTE)
    • corticobasal degeneration
    • frontotemporal lobar degeneration (FTLD) (not all are tauopathies) 
      • behavioral variant frontotemporal dementia (bvFTLD)
      • language variant frontotemporal dementia (lvFTLD) (primary progressive aphasia (PPA))
        • progressive non-fluent aphasia (PNFA)
        • semantic dementia
        • logopenic dementia
      • right temporal variant frontotemporal dementia
    • Pick disease
    • progressive supranuclear palsy (PSP)
  • amyloidoses
    • cerebral amyloid angiopathy (CAA)
      • Boston criteria for cerebral amyloid angiopathy
      • modified Boston criteria for cerebral amyloid angiopathy
      • Boston criteria 2.0 for cerebral amyloid angiopathy
      • Edinburgh criteria for lobar intracerebral hemorrhage associated with cerebral amyloid angiopathy
    • transthyretine-associated cerebral amyloidosis
    • neuronal intranuclear hyaline inclusion disease (NIHID)
  • TDP-43 proteinopathies
    • amyotrophic lateral sclerosis (ALS)
    • frontotemporal lobar degeneration (FTLD) (not all are TDP-43)
    • limbic-predominant age-related TDP-43 encephalopathy
    • Perry syndrome
  • spinocerebellar ataxias
  • Huntington disease
  • hereditary spastic paraplegia
  • clinically unclassifiable parkinsonism (CUP)
  • Unverricht-Lundborg disease
  • prion diseases (not always included as neurodegenerative)
    • Creutzfeldt-Jakob disease (sporadic, variant, familial, and iatrogenic)
      • Brownell-Oppenheimer variant of sporadic Creutzfeldt-Jakob disease
      • Heidenhain variant of sporadic Creutzfeldt-Jakob disease
      • Stern-Garcin variant of sporadic Creutzfeldt-Jakob disease
    • fatal familial insomnia
    • Gerstmann-Straussler-Scheinker disease
    • kuru
    • variably protease-sensitive prionopathy