VALIDITY AND RELIABILITY OF THE PRELIMINARY NINDS NEUROPATHOLOGIC CRITERIA FOR PROGRESSIVE SUPRANUCLEAR PALSY AND RELATED DISORDERS

We investigated the validity and reliability of diagnoses made by eigh t neuropathologists who used the preliminary NINDS neuropathologic dia gnostic criteria for progressive supranuclear palsy (PSP) and related disorders. The specific disorders were typical, atypical, and combined PSP, postencephalitic parkinsonism, corticobasal ganglionic degenerat ion, and Pick's disease. These disorders were chosen because of the di fficulties in their neuropathologic differentiation. We assessed valid ity by measuring sensitivity and positive predictive value. Reliabilit y was evaluated by measuring pairwise and group agreement. From a tota l of 62 histologic cases, each neuropathologist independently classifi ed 16 to 19 cases for the pairwise analysis and 5 to 6 cases for the g roup analysis. The neuropathologists were unaware of the study design, unfamiliar with the assigned cases, and initially had no clinical inf ormation about the cases. Our results showed that with routine samplin g and staining methods, neuropathologic examination alone was not full y adequate for differentiating the disorders. The main difficulties we re discriminating the subtypes of PSP and separating postencephalitic parkinsonism from PSP. Corticobasal ganglionic degeneration and Pick's disease were less difficult to distinguish from PSP. The addition of minimal clinical information contributed to the accuracy of the diagno sis. On the basis of results obtained, we propose clinicopathologic di agnostic criteria to improve on the NINDS criteria.