Cardinal Features of Parkinson's Disease

Primary Motor Symptoms

The American College of Radiology suggests that bradykinesia is characterized by slowness of movement and progressive reduction in speed and amplitude of repetitive actions, representing one of the most disabling features of PD 1, 3
The American College of Radiology indicates that postural instability is a loss of postural reflexes leading to impaired balance and increased risk of falls, typically appearing later in disease progression 1, 3

The American College of Radiology states that PD is the most common parkinsonian syndrome, with peak onset between 60-70 years of age 1, 3
The American College of Radiology notes that symptoms typically manifest after approximately 40-50% of dopaminergic neurons in the substantia nigra have been lost, with an estimated 5-year interval between initial neuronal loss and symptom appearance 1

Dysarthria and dysphagia are common symptoms, according to Clinical Nutrition 4, 5
Sialorrhea (excessive drooling) is also a symptom, as reported by Clinical Nutrition 4, 5

Autonomic dysfunction, including gastrointestinal dysmotility, gastroparesis, constipation, and urinary incontinence, is a common non-motor feature, as noted by Clinical Nutrition 4, 5
Cognitive impairment and dementia, especially in later stages, are important non-motor features, according to the American College of Radiology 1
Neuropsychiatric symptoms, such as depression, anxiety, apathy, and psychosis, are also common, as reported by Clinical Nutrition 4

The American College of Radiology suggests that other parkinsonian syndromes to consider include Progressive Supranuclear Palsy (PSP), Multiple System Atrophy (MSA), and Corticobasal Degeneration (CBD) 1, 3

Weight loss is common and associated with disease progression due to increased energy expenditure from dyskinesias and rigidity, as noted by Clinical Nutrition 4, 5