1. Use of memory and concentration evaluation in distinguishing progressive supranuclear palsy from Parkinson's disease

Progressive supranuclear palsy (PSP) and Parkinson's disease (PD) can be difficult to distinguish in the early stages. This study assessed the utility ofneuropsychological assessment in this differential diagnosis among 22 male patients, 15 of whom had PD and seven of whom had PSP. All patients had been diagnosed by clinical neurologic exam and SPECT scan. A battery of tests was administered to each patient. The PSP patients performed worse than the PD patients on Digit Span and the Selective Reminding Test (SRT). Sensitivity, specificity, and predictive value (positive and negative) tests showed SRT, Trail Making A, and Digit Span to be the most robust differentiators between the two groups. Digit Span forward and Trail Making A showed the strongest negative predictive values, suggesting that an attentional deficit may underlie the cognitive differences between the two groups.