Parkinson's Disease: Sensitivity and Specificity

Introduction: Specifically, idiopathic Parkinson's. The differential diagnosis would include Essential Tremor, Parkinson's-Plus syndromes (Multi-System Atrophy, Progressive Supranuclear Palsy, Dementia with Lewy Bodies), and secondary Parkinson's (toxic such as MPTP, traumatic such as dementia pugilistica).

[Edit Diagnosis] [Merge dx] [Add prevalence]

Tags: Neurologic Tag this Diagnosis.

The sensitivity and specificity of findings for Parkinson's Disease are listed below. See the left navigation bar to change the display.

Untagged

Finding	Sensitivity	Specificity	Comments, Study
Asymmetric Onset	72%	58%	i.e. 42% of movement disorders that are not PD begin asymmetrically Study: Arch Neurol. 1999 Jan;56(1):33-9. PMID: 9923759
Bradykinesia	Sensitivity = 77%		specificity not assessed Study: Arch Neurol. 1999 Jan;56(1):33-9. PMID: 9923759
Can Ride a Bicycle	96%	52%	i.e. patient can still ride a bicycle versus Parkinson's-Plus Study: The Lancet 377(9760):125 (2011). http://www.thelancet.com/journals/lancet/article/PIIS0140-6736(11)60018-4/fulltext
Cardinal Features	69%	75%	>=2 of tremor, rigidity, and bradykinesia. Confirmed by autopsy. Study: Arch Neurol. 1999 Jan;56(1):33-9. PMID: 9923759
Levodopa Challenge	71%	81%	250/50 mg of L-dopa-carbidopa for an improvement of 30% on UPDRS score. At 24 month follow-up, they were re-tested with 1 g for 1 month when required. At this point, clinical criteria of the U.K. Parkinson's Disease Society Brain Bank were applied and definitive clinical diagnosis of PD was made. Study: Mov Disord. 2002 Jul;17(4):795-8. PMID: 12210878
Levodopa Responsiveness	94%	30%	>94% of true PD patients will respond to levodopa in general (see the other entry for a specific study, albeit with lower responsiveness). However, many other disorders, e.g. MSA and DLB, have good initial responsiveness (my 30% was ballparking based on separate series with different diseases). Study: Arch Neurol. 1999 Jan;56(1):33-9. PMID: 9923759
Postural Instability	Sensitivity = 37%		within first 5 years of presentation. Specificity not assessed, however early postural instability is usually diagnostic of PSP. Study: Arch Neurol. 1999 Jan;56(1):33-9. PMID: 9923759
Resting Tremor	69%	66%	i.e. 34% of MSA patients have resting tremor. Study: Arch Neurol. 1999 Jan;56(1):33-9. PMID: 9923759
Rigidity	Sensitivity = 89%		specificity not assessed but believed to be poor Study: Arch Neurol. 1999 Jan;56(1):33-9. PMID: 9923759