Alterations in the locus coeruleus in dementias of Alzheimer's and Parkinson's disease.

For diagnostic purposes, a differentiation can be made between the locus coeruleus (LC) in normal brain and the LC, in senile dementia of the Alzheimer's type (SDAT) and Parkinson's disease (PD). The differentiation is based on findings concerning the morphological alterations of the TH-immunoreactive; neurons, on the topographical distribution of neuron loss within the length of the LC, and on the total reduction in cell number.