Neuroscience Clerkship

 
 

CLINICAL PRESENTATION OF PARKINSON'S DISEASE

Parkinson disease (PD) is one of the most common neurological disorders, affecting approximately 1% of individuals older than 60 years progressive. Pathologically, PD is a neurodegenerative disorder associated with a loss of dopaminergic nigrostriatal neurons. It is named after English physician, James Parkinson, who first described the "shaking palsy" in an essay in 1817.
 

Above: The major neuropathologic findings in PD are a loss of pigmented dopaminergic neurons in the substantia nigra (blue arrow: patient with PD; yellow arrow: normal).
 
Cardinal Features of Parkinson's Disease

 

• Tremor

Most prominent at rest and attenuates with action

About four to six cycles per second

Enhanced by emotional stress

Absent during sleep

Affects distal appendicular muscles (“pill rolling”)

Commonly confined to one limb or one side for months to years before becoming more generalized

Quick time movie of tremor in PD
(courtesy Department of Neurology, Queen Elizabeth Hospital
Birmingham, UK)
 

• Rigidity

Increased resistance to passive movement

Affects axial and proximal limb muscles

Affects agonist and antagonist muscles to a similar extent

Constant throughout range of movement

Causes characteristically flexed posture of patients

Can be detected early in the disease process

Cogwheel rigidity is characterized by superimposed tremor that can be seen and felt when passively moving the extremity

 

• Bradykinesia

Delay in initiation and execution of voluntary movements

Reduction in automatic movements, such as swinging arms while walking

Effective activity may be briefly regained during an emergency (i.e., patient may leap aside to avoid an oncoming motor vehicle)

 

• Postural instability

Forward displacement of the head

Forward or backward instability of the trunk

Small shuffling steps (“festinating” gait)

Unsteadiness on turning

Difficulty maintaining an erect posture when being slightly pushed

Tendency to fall

 

• Mild Decline in Intellectual Function

Impaired visual-spatial perception

Impaired attention

Impaired concentration

 

Additional Clinical Findings May Include:

Immobile face ("masked facies") with widened palpebral fissures, infrequent blinking

Myerson’s/glabellar sign – repetitive tapping over the bridge of the nose produces a sustained blink response

Soft and poorly modulated (monotonous) voice

Micrographia

Dystonia – sustained muscle contraction resulting in abnormal position; i.e. inversion of the foot with flexion or extension of the toes

No muscle weakness (given sufficient time for power to develop) or alteration in tendon or plantar reflexes

Sensory complaints (pain, aching, numbness, tingling, burning, or coldness)

Depression

Dementia

(Note: some of these additional clinical findings are sequelae of the cardinal features listed above).