Serial position effects in patients with mild cognitive impairment and early and moderate Alzheimer's disease compared with healthy comparison subjects

This study aimed to investigate whether the serial position effects in memory can differentiate patients with different subtypes of mild cognitive impairment (MCI) from healthy controls and patients with different stages of Alzheimer's disease (AD).

The serial position effects was tested with the CERAD word list task in 184 persons (39 healthy control subjects, 15 amnestic MCI single domain subjects, 23 amnestic MCI multiple domain subjects, 31 nonamnestic MCI subjects, 45 early or mild AD patients, and 31 moderate AD patients).

With progression of dementia, memory deficits increased and the impairment in the primacy effect during the learning trials advanced, whereas the recall of recent items was less impaired. The serial position profile of nonamnestic MCI patients resembled that of healthy control subjects, whereas amnestic MCI patients showed poorer performance in all 3 positions but no significant difference as a function of serial word position.

Analyses of the serial position effect may be a useful complement to clinical neuropsychological measures for distinguishing amnestic MCI patients from normal aging and patients with different stages of dementia.