Eyeblink conditioning discriminates Alzheimer's patients from non-demented aged.

Classical conditioning of the eyeblink response in rabbits is a model system useful in research on the neurobiology of learning, memory and aging, and it has implications for Alzheimer's disease (AD). The hippocampus and cerebellum are brain structures of demonstrated involvement in eyeblink conditioning. AD profoundly impairs the septo-hippocampal cholinergic system; thus, AD patients should show greater impairment of eyeblink conditioning than non-demented, age-matched subjects. Twenty probable AD patients and 20 non-demented age-matched subjects were classically conditioned in the delay paradigm. While control subjects showed clear evidence of acquisition (31.54% conditioned responses [CRs]), probable AD patients showed significant impairment (10.77% CRs). Eyeblink classical conditioning may be useful for AD research and assessment.