We appreciate Dr Jellinger's report on 16 additional patients, confirming our finding that neuronal loss and gliosis in the SNC and SNR determine the severity of the hypokinetic components of dysarthria in PSP.1 In both reports, symptom intensity was correlated with neuronal loss and gliosis rather than with the density of neurofibrillary tangles, which is the pathologic hallmark of this disease. While it is not surprising that neuronal loss correlates with symptom intensity, neurofibrillary tangles also might have been expected to be critical. The results of both studies suggest that, at least in some brain regions, the density of neurofibrillary tangles is an inadequate measure of disease severity. Perhaps this is because these intracellular inclusions are less frequent when there is more neuronal loss. Nevertheless, these studies demonstrate that drawing inferences from the distribution of neurofibrillary tangles is no substitute for careful clinicopathologic studies.
Kluin KJ, Gilman S, Foster NL, D'Amato CJ, Bluemlein L, Little R, Sima AAF, Bruch LA, Johanns JR. In reply. Arch Neurol. 2001;58(9):1499-1500. doi: