Table 1 Probabilsitic diagnostics worked example

From: Refining the diagnostic accuracy of Parkinsonian disorders using metaphenomic annotation of the clinicopathological literature

Contrast

Tremor

Orthostatic hypotension

Rapid eye movement sleep behaviour disorder

TOTAL LR

Pre-test probability

Post-test odds

Probability

Probability with elevated NFLC

PD vs MSA

2.23

1.25

0.85

92.49

0.32

29.19

0.97

0.83

PD vs PSP

3.32

2.23

4

PD vs DLB

2.32

1.3

0.44

MSA vs PD

0.45

0.8

1.18

3

0.45

1.36

0.58

0.89

MSA vs PSP

1.49

1.79

4.73

MSA vs DLB

1.04

1.05

0.52

PSP vs PD

0.3

0.45

0.25

0

0.14

0

0

0

PSP vs MSA

0.67

0.56

0.21

PSP vs DLB

0.7

0.58

0.11

DLB vs PD

0.43

0.77

2.29

30.34

0.09

2.76

0.73

0.31

DLB vs MSA

0.96

0.96

1.94

DLB vs PSP

1.43

1.71

9.17

  1. Worked example of a 50yo with Parkinsonism plus RBD, Orthostatic Hypotension and tremor. The most likely diagnosis with this combination is PD (0.97) or DLB (0.73), followed by MSA (0.58). However, if this individual has an elevated NFLC result, this flips, making a diagnosis of MSA more likely (0.89 vs 0.83). Ascertaining additional clinical signs enables one to refine this further – Building on the example above, if a rest tremor was present, PD would remain the most likely even with elevated NFLC (PD 0.99 vs MSA 0.78), however the additional presence of erectile dysfunction with the rest tremor then makes MSA far more likely (MSA 0.99 vs PD 0.88). CBD not shown as RBD has not been reported in this condition.
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