Regional dopamine transporter concentration in the caudate and the anterior cingulate related to cognitive function. In the DLB group, but not in the PD or HCS groups, loss of caudate dopamine transporter (DAT) concentration was associated with greater impairment in (A) CDR-SB scores (R
2=0.84 and P<0.0001 for overall model; P=0.0008 for interaction between diagnosis and caudate DAT concentration) and (B) visuospatial skills scores (R
2=0.45 and P=0.0006 for overall model; P=0.008 for interaction between diagnosis and caudate DAT concentration). (C) In the DLB group alone, higher anterior cingulate (AC) DAT concentration was associated with greater impairment in semantic memory and language performance (R
2=0.69 and P<0.0001 for overall model; P=0.0003 for interaction between diagnosis and AC DAT concentration). Symbols indicate actual values; lines are predicted values from the general linear model. CDR-SB, Clinical Dementia Rating Scale - sum of boxes; DLB, dementia with Lewy bodies; HCS, healthy control subjects; PD, Parkinson disease without dementia.