Diagnostic Approach

Parkinson’s disease (PD) diagnosis is primarily clinical, based on a combination of motor and non-motor symptoms. However, differentiating PD from similar conditions can be challenging due to overlapping symptoms with other neurodegenerative disorders. Here’s a detailed look at the diagnostic approach for PD:

Clinical Diagnosis

• Motor Symptoms: The cardinal motor symptoms include bradykinesia, resting tremor, rigidity, and postural instability.
• Non-motor Symptoms: These may include sleep disturbances, mood disorders, autonomic dysfunction, and cognitive changes.

Diagnostic Criteria

• UK Parkinson’s Disease Society Brain Bank Criteria: This is widely used for clinical diagnosis and includes bradykinesia and at least one of resting tremor or rigidity.
• Movement Disorder Society Clinical Diagnostic Criteria for Parkinson’s Disease: Offers a more comprehensive approach, including non-motor symptoms and biomarkers.

Neuroimaging

• Dopamine Transporter (DAT) SPECT Imaging: Helps in differentiating PD from other causes of tremor as it shows reduced striatal dopamine transporter uptake.
• MRI: Can rule out other causes of parkinsonism but is typically normal in idiopathic PD.

Response to Medication

• Levodopa Challenge Test: A significant and sustained response to levodopa is supportive of a PD diagnosis.

Exclusion Criteria

• Presence of atypical features or rapid progression may indicate other parkinsonian syndromes.

Differential Diagnosis

• Essential to differentiate PD from multiple system atrophy, progressive supranuclear palsy, corticobasal degeneration, and drug-induced parkinsonism.

Genetic Testing

• While not routinely done, it can be helpful in familial cases or when genetic counseling is considered.

Biomarkers

• Research is ongoing for biomarkers in blood, CSF, or neuroimaging to aid in early diagnosis.