Parkinsons

Parkinsonism: A Syndrome

• a clinical syndrome (a collection of symptoms) characterized by a specific set of motor signs. It is not a single disease

• Core motor signs

  • bradykinesia: slowness of movement

  • rigidity: stiffness or inflexibility of limbs and trunk

  • resting tremor: involuntary shaking, most prominent at rest

  • postural instability: impaired balance and coordination

The Causes

• Parkinson’s Disease (PD): the most common cause (idiopathic, meaning of unknown cause)

  • 80% of cases

• Drug-Induced Parkinsonism: second most common cause

  • certain medications block or reduce the effect of dopamine in the brain

  • symptoms can be severe but potentially reversable

• Vascular Parkinsonism: caused by small strokes that damage the basal ganglia

• there’s more

Parkinson’s Disease: The Specifics

• Parkinson’s disease: a specific neurodegenerative disorder

• the most common cause of parkinsonism

• a progressive, neurodegenerative disease

• cause: unknown; but believed to be a combination of genetic and environmental factors

  • family history is a significant risk factor

  • environmental factors: exposure to certain toxins, such as pesticides, and heavy metals

    • agent orange: herbicide used to kill foliage during Vietnam War

  • men are 50% more likely to be diagnosed than women

• primary pathology: the death of dopamine-producing neurons in the substantia nigra, a key structure within the basal ganglia

The Basal Ganglia’s Role in Motor Control

• basal ganglia: a cluster of nuclei found in the brain

• location: base of the forebrain and the top of the midbrain

• function: serves as a “gatekeeper” or “modulator” for movement, it helps select and initiate desired movements while inhibiting unwanted ones

  • has two pathways

• associated with: regulating voluntary motor movements, procedural learning, habit formation, conditional leaning, eye movements, cognition, and emotion