Notes on Parkinson's Plus Syndromes

Overview of Parkinsonism

• Definition: Parkinsonism refers to a group of neurological disorders that present with similar symptoms to Parkinson's disease (PD) but are not classified as idiopathic PD.
• Two Types of Parkinsonism:
  • Levodopa Responsive:
    • Example: Idiopathic PD
    • Symptoms include: bradykinesia, rigidity, postural instability, and often tremor
    • Responds to levodopa treatment.
  • Levodopa Non-Responsive:
    • Includes Parkinson's plus syndromes.

Common Parkinson's Plus Syndromes

1. Lewy Body Dementia

   • Key Features:
     • Early dementia within one year of parkinsonian symptoms.
     • Hallucinations are common.
     • Neuroleptic sensitivity; can lead to agitation and confusion.

2. Multiple System Atrophy (MSA)

   • Key Features:
   • Early autonomic dysfunction, including:
     • Orthostasis
     • Erectile dysfunction
     • Incontinence
   • Symptoms often appear early in the disease progression.

3. Progressive Supranuclear Palsy (PSP)

   • Key Features:
   • Early vertical gaze impairment (can't look down).
   • Frequent falls, which happen earlier than in typical PD.
   • Rigidity, particularly in axial muscles.
   • Possible brain stem symptoms: dysphagia, oral dyskinesias, dysphonia.

4. Corticobasal Degeneration (CBD)

   • Key Features:
   • Highly asymmetric symptoms at onset.
   • Symptoms include apraxia, alien limb phenomenon, and cognitive deficits.
   • Apraxia affects motor planning—patients cannot execute movements despite having the ability to move.
   • Alien limb syndrome—limbs may move without patient control.

Neuropathology of Parkinson's Plus Syndromes

• Idiopathic PD:
  • Degeneration begins in the caudal medulla leading to early REM behavior disorder.
  • Lewy body deposition occurs progressively from the brain stem to the cortex, ultimately leading to dementia.
• Progressive Supranuclear Palsy:
  • Tau protein deposition in the upper brain stem and diencephalon.
  • Symptoms include vertical gaze dysfunction and axial rigidity due to midbrain involvement.
• Multiple System Atrophy:
  • Characterized by abnormal protein build-up (alphasynucleinopathy) in various brain regions:
    • Cerebellum (MSA cerebellar type)
    • Subcortical structures (MSA striatonigral type)
    • Brain stem leading to autonomic dysfunction (MSA autonomic type).
• Corticobasal Degeneration:
  • Also involves Tau deposition with significant parietal lobe involvement, leading to higher-level cortical sensory issues.