April 14, 2021

Parkinson’s Disease Symptoms – 4 Cardinal Signs

The article Parkinson’s disease early symptoms described a variety of signs that might be indicative of oncoming or early Parkinson’s. Given that many of the signs could be due to a variety of completely unrelated conditions, a more structured and formal classification is required to differentiate Parkinson’s from other diseases. This can be achieved by grouping the symptoms into primary motor related symptoms (4 Cardinal Signs), associated symptoms and neuropsychiatric dysfunction.

This article explains the 4 primary/major motor symptoms for Parkinson’s disease diagnosis, which includes:


  • Caused by impaired conduction of signals/impulses from the brain to the muscles.
  • Affect about 70% of patients at start of disease. Not everyone will experience tremors although most go on to develop them at the later stages.
  • Typically starts on 1 side (unilateral) i.e. asymmetric, and progresses to both sides (bilateral) after several years.
  • Can possibly affect eyelids, jaw, tongue, lips, chin, arm, forearm, hand, fingers, leg, feet and some people experience a sensation as though their internals are ‘trembling’. However, people who experience head/torso or voice tremors tend not to have Parkinson’s (any apparent tremor is usually caused by the upper extremities shaking violently). Head tremor is a typical feature of the condition Essential Tremor (ET).
  • A useful diagnostic tool:
    Parkinson’s disease tremors: Resting tremors – Increase when the person is resting and decrease when the person begins to move.
    Non-Parkinson’s tremors: Active tremors – Increase when trying to use or move the part of the body and decrease on resting.
  • Characteristic ‘Pill Rolling’ action between the thumb and 1st finger.


Muscle Rigidity

  • Caused by increased and excessive muscle contractions and muscle tone.
  • Stiffness, lack of movement and associated pain in certain parts of body including face, neck, arms can be an early sign of the disease.
  • Abnormal muscle tone resulting in muscular spasm /cramps and abnormal posture (Dystonia) is associated with a lack of normal movement and rigidity.
  • 2 types of muscle rigidity that can attack at random:
    ‘Cogwheel Rigidity’: Non-uniform and ratchety.
    ‘Leadpipe Rigidity’: Uniform.
  • Unable to swing arms when walking. One side is usually more affected during early stages i.e. asymmetric.


Slow Movement (Bradykinesia)

  • Caused by impaired conduction of signals/impulses from the brain to the muscles.
  • Brady=Slow Kinesia= Movement
  • Freezing Episodes : Problem initiating voluntary movement. This can progress to freezing mid-action e.g. whilst walking (later stages of disease).
  • Walking characterized by small steps or shuffling action.
  • Issues of safety arise e.g. crossing a road becomes increasingly problematic.
  • Difficulty in rolling over in bed or standing up and getting out of a chair.
  • Associated with clinical evidence of asymmetry.


Postural Instability/Balance Disturbances

  • Caused by loss of reflexes.
  • Becomes more noticeable as the disease progresses and usually present at later stages. If it occurs early in the disease, it is normally an atypical Parkinson’s syndrome.
  • Stooped posture and gait disturbance.
  • Problem turning around and navigating stairways.
  • Issues of safety arise e.g.
    40% of patients have experienced a fall.
    10% of patients experience weekly falls.


Next, we will consider  Parkinson’s disease symptoms – Associated Symptoms