From the Guidelines
Parkinson's disease is characterized by several physical examination signs, including resting tremor, rigidity, bradykinesia, and postural instability, which are essential for its diagnosis, as stated in the ACR Appropriateness Criteria for movement disorders and neurodegenerative diseases 1. The physical exam signs of Parkinson's disease include:
- Resting tremor, typically asymmetric and occurring at 4-6 Hz
- Rigidity, felt as resistance throughout passive movement of limbs
- Bradykinesia, manifesting as slowness of movement
- Postural instability, which usually appears later in the disease course
- Masked facial expression (hypomimia)
- Reduced blinking
- Stooped posture
- Shuffling gait with reduced arm swing
- Micrographia (small handwriting)
- Hypophonia (soft speech) The diagnostic criteria for Parkinson's disease primarily rely on clinical assessment, as there is no definitive laboratory or imaging test, and a diagnosis requires the presence of bradykinesia plus either resting tremor or rigidity, as supported by the study 1. Key features that support the diagnosis of Parkinson's disease include:
- Asymmetric onset
- Good response to levodopa therapy
- A slowly progressive course Red flags that suggest alternative diagnoses, such as multiple system atrophy (MSA), progressive supranuclear palsy (PSP), and corticobasal degeneration (CBD), include:
- Early falls
- Symmetric symptoms
- Rapid progression
- Poor levodopa response
- Early autonomic dysfunction Neuroimaging may be used to exclude other conditions but doesn't confirm Parkinson's disease, and DaTscan (dopamine transporter imaging) can help differentiate Parkinson's from essential tremor but isn't routinely required, as mentioned in the study 1.
From the Research
Physical Exam Signs of Parkinson's Disease
- Rest tremor, bradykinesia, rigidity, and loss of postural reflexes are generally considered the cardinal signs of Parkinson's disease 2
- Other clinical features include secondary motor symptoms such as hypomimia, dysarthria, dysphagia, sialorrhoea, micrographia, shuffling gait, festination, freezing, dystonia, and glabellar reflexes 2
- Non-motor symptoms include autonomic dysfunction, cognitive/neurobehavioral abnormalities, sleep disorders, and sensory abnormalities such as anosmia, paresthesias, and pain 2
Diagnostic Criteria
- The presence and specific presentation of the cardinal signs are used to differentiate Parkinson's disease from related parkinsonian disorders 2
- Absence of rest tremor, early occurrence of gait difficulty, postural instability, dementia, hallucinations, and the presence of dysautonomia, ophthalmoparesis, ataxia, and other atypical features, coupled with poor or no response to levodopa, suggest diagnoses other than Parkinson's disease 2
- A thorough understanding of the broad spectrum of clinical manifestations of Parkinson's disease is essential to the proper diagnosis of the disease 2
Motor Features
- The most characteristic motor feature of Parkinson's disease is bradykinesia, with other cardinal motor features including tremor (particularly rest tremor), rigidity, and postural instability/gait changes 3
- Additional motor features common to the disease include dystonia, postural abnormalities, speech and swallowing dysfunction, and levodopa-related dyskinesias 3
- Motor symptoms in Parkinson's disease include akinesia and bradykinesia, tremor and rigidity, gait disturbance, impaired handwriting, grip force and speech deficits, among others 4
Clinical Characteristics
- Parkinson's disease is characterized by a range of motor symptoms, with some symptoms having similar clinical profiles, neural substrates, and responding similarly to dopaminergic medication and deep brain stimulation (DBS) 4
- Typical symptoms of Parkinson's disease include bradykinesia/akinesia, rigidity, rest tremor, and postural instability, along with dissymmetry, shuffling gait, and camptocormia, micrographia, aphasia, hypophonia, dysphagia, and hypomimia 5
- Early symptoms of Parkinson's disease include akathisia/restlessness, insomnia, somnolence, hyposmia, and neck pain 5