Differential correlation between neurochemical deficits, neuropathology, and cognitive status in Alzheimer's disease

The relationships between neurofibrillary tangles (NFT), senile plaques (SP), and the deficits in somatostatin (SRIH) and choline acetyltransferase (ChAT) levels were determined in Brodmann area 9, 40, 22, and 17/18 in 12 women whose Blessed test score (BTS) ranged from 27 to 1. NFT density correlated with the cognitive decline in areas 9, 40, and 22 and with SP number in area 22 and 17/18. ChAT levels were linked to the BTS in area 9, 40, and 22 and SRIH levels in area 9 only. ChAT, but not SRIH, did correlate with SP (area 22) and NFT (area 40 and 22). Decreases in ChAT and SRIH were correlated in areas 9 and 22. These results indicate that the somatostatinergic deficit in Alzheimer's disease is more regionally restricted than the cholinergic one. The correlation between SRIH and ChAT as observed in area 9 and 22 may indicate that somatostatin- and acetylcholine-containing elements in the frontal and temporal lobes are particularly relevant to the cognitive decline as observed in Alzheimer's disease.