ALZHEIMERS-DISEASE AND EYEBLINK CONDITIONING - 750 MS TRACE VS 400 MSDELAY PARADIGM

Patients with probable Alzheimer's disease (AD) and hippocampal disrup tion are severely impaired in eyeblink classical conditioning (EBCC) i n the 400 ms delay paradigm. Hippocampectomized rabbits are not impair ed in the delay paradigm but perform poorly in the trace paradigm. It was anticipated that probable AD patients would be severely impaired i n the 750 ms trace paradigm. In Study 1, probable AD patients were sig nificantly impaired in the trace EBCC paradigm, but the sensitivity of the test was poorer than for the delay paradigm. In Study 2, probable AD patients tested in trace were tested in the delay paradigm 4 month s later. Sensitivity for AD was also better for the delay paradigm. Ra bbits and humans show behavioral parallels in the 400 ms delay paradig m but not in the 750 ms trace paradigm. The 400 ms delay EBCC paradigm was superior to the 750 ms trace paradigm for the detection of AD.