SIMPLIFIED NEUROPATHOLOGICAL DIAGNOSIS OF DEMENTIA WITH LEWY BODIES

Pathological criteria have recently been developed to differentiate th ose cases where Lewy bodies contribute to the dementing process. We ap plied consensus criteria to 20 cases with a pathological diagnosis of Alzheimer's disease (all demented) and/or Parkinson's disease (three w ithout dementia) and eight controls. In addition, we applied the crite ria to the different cortical layers to determine whether the site of the semiquantification affected the diagnosis. In the parietal lobe, f ew Lewy bodies were observed, and this region could be excluded. Rare Lewy bodies present in the frontal association cortex in a number of P arkinson's disease cases resulted in their classification as limbic or transitional cases with Lewy bodies. Exclusion of this non-limbic ass ociation cortex resulted in many of these cases with rare cortical Lew y bodies being re-classified as having brain stem predominant Lewy bod ies, thus improving the diagnostic accuracy of the criteria. Most of t hese cases were nondemented. No other case was re-classified by exclud ing these cortical regions from the analysis, Few Lewy bodies were pre sent in cortical layers I and II, and these layers could be excluded f rom the semiquantitative procedure without change to the overall class ification of cases. The occasional presence of possible Lewy bodies in cases with Alzheimer's disease and controls incorrectly classified th ese cases as having brain stem predominant Lewy body disease, although these cases had no brain stem Lewy bodies. These modifications to the consensus criteria for assessing Lewy body disease (i.e, exclude pari etal and frontal lobe, cortical layers I and II, and cases without bra in stem Lewy bodies), provide significant time and cost savings for ne uropathologists and researchers using this criteria to diagnose and st udy dementia with Lewy bodies.