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. Author manuscript; available in PMC: 2013 Jan 1.
Published in final edited form as: J Parkinsons Dis. 2012 Jan 1;2(1):57–65. doi: 10.3233/JPD-2012-11073

Figure 2.

Figure 2

Diagram of how sensitivity and specificity were determined. Sensitivities were calculated by dividing the number of cases containing a positive test (i.e. specified plaque measure) and patients with the disease (i.e. AD or dementia) - a in the figure above) by the total number of cases having the disease diagnosis regardless of test outcome (a + c). Specificities were calculated by dividing the number of cases having a negative test (i.e. lacking the specified plaque measure) and without the disease (i.e. no AD or dementia) - d in the figure above and by the total number of cases lacking the disease regardless of test outcome (b + d).