Demographic and functional characteristics of CBS patients according to PiB status.

There were no significant differences between PiB-positive and PiB-negative CBS patients, or controls in age, gender, mean education or symptom duration. Although PiB-negative CBS patients were cognitively and functionally impaired compared to controls, PiB-positive cases demonstrated greater impairment overall. All neuropsychological and behavioral data represented as median (minimum - maximum). aPiB-positive v PiB-negative, P<0.05. bPiB-negative v Controls, P<0.05. cPiB-positive v Controls, P<0.05.