From the Guidelines
The four cardinal features of Parkinson's disease (PD) are resting tremor, bradykinesia, rigidity, and postural instability, as characterized by the progressive degeneration of dopaminergic neurons in the substantia nigra/striatum 1. These features are the primary clinical manifestations of PD, a neurodegenerative disease and movement disorder.
- Resting tremor is a rhythmic, involuntary shaking that occurs when the affected body part is relaxed and supported against gravity, typically presenting as a "pill-rolling" motion between the thumb and forefinger at 4-6 Hz, which characteristically diminishes with purposeful movement.
- Bradykinesia refers to slowness of movement and is considered the most disabling symptom, manifesting as difficulty initiating movements, reduced amplitude of movements, and problems with sequential or repetitive tasks like buttoning clothes or brushing teeth.
- Rigidity is increased muscle tone or stiffness that can present as either "lead-pipe" (uniform resistance throughout range of motion) or "cogwheel" (ratchet-like resistance) when the examiner moves the patient's limbs.
- Postural instability is the impairment of balance reflexes that typically appears later in the disease course, causing patients to have difficulty recovering from perturbations and increasing their risk of falls, as noted in the clinical presentation of PD 1. These symptoms result from the progressive loss of dopaminergic neurons in the substantia nigra pars compacta, leading to dopamine deficiency in the basal ganglia and disruption of motor control pathways, ultimately affecting the patient's quality of life and increasing morbidity and mortality 1.
From the FDA Drug Label
Its characteristic features include resting tremor, rigidity, and bradykinetic movements. It is designed to assess the severity of the cardinal motor findings in patients with Parkinson's disease (e.g., tremor, rigidity, bradykinesia, postural instability, etc.),
The 4 cardinal features of Parkinson's disease (PD) are:
- Tremor: resting tremor
- Rigidity: increased muscle tone
- Bradykinesia: slow movement
- Postural instability: impaired balance and posture 2
From the Research
Cardinal Features of Parkinson's Disease
The 4 cardinal features of Parkinson's disease (PD) are:
- Bradykinesia: slowness of movement 3, 4, 5, 6
- Rigidity: stiffness of the muscles 3, 4, 5
- Tremor: typically a resting tremor 3, 4, 5, 6
- Postural instability: impaired balance and coordination 3, 4, 5
Descriptions of Cardinal Features
These cardinal features are the primary motor symptoms of PD and are used to diagnose the disease 7, 3, 4, 5, 6. They can be ameliorated by levodopa treatment in most patients 4. The presence and severity of these symptoms can vary between patients and can progress over time 3, 6.