= degeneration of basal ganglia + other system Typically no good response to L-Dopa, faster progression.
Rare.

Multiple System Atrophy (MSA)
Etio: olivopontocerebellar degen, striatronigral degeneration, early autonomic failure
Presentation: ataxia; post. hypotension, impotence. Pyramidal signs: upgoing plantars; hyperreflexia
Signs:
Ix: MRI “hot cross bun sign”
Mx: supportive. Life expectancy: 6-9y from dx

Progressive Supranuclear Palsy (PSP)
Etio: pallidum, substantia nigra, periaqueductal grey matter, superior colliculi
Presentation: axial rigidity; vertical supranuclear gaze palsy (↓ voluntary saccades, preserved reflexive upward gaze); postural instability (classically fall backwards), axial rigidity, pseudobulbar palsy, FTD
Signs:
Ix: MRI midbrain atrophy = “hummingbird sign”
Mx: amantadine may improve gait. Life expectancy ~7

Lewy Body Dementia
Epid: M>F Pathophysiology: Lewy bodies (eosinophilic inclusion bodies) in brainstem + neocortex. Anatomy: Widespread
Presentation: Functional ↓, complex cognitive actions • Detailed visual hallucinations, Parkinsonism • REM sleep disorders (prodromal) • ∆ mood, behaviour, judgment • fluctuation
Progression: Death within 7 years after diagnosis • ! Sensitive to neuroleptics
Ix: +ve DAT scan
Management: Rivastigmine may help

ICD-10 criteria for dementia

↓ memory/cognitive function
clear consciousness
∆ social/emotional behaviour
≥ 6/12 duration