We investigated the sensitivity of the P300 event-related brain
potential (ERP) recorded during a memory-demanding task to memory
function in subjects with dementia of the Alzheimer's type (DAT),
those with mild cognitive impairment (MCI), and normal elderly
controls. We also explored the ability of neuropsychological (delayed
verbal memory), neuroanatomical (MRI-based hippocampal volume), and
electrophysiological (memory search P300 amplitude) memory measures to
distinguish between the three subject groups using discriminant
function analyses. Fourteen patients with DAT, 16 with MCI, and 15 age-
and education-matched controls were tested. P300 amplitude was reduced
in DAT subjects at all levels of memory load; however, it did not
differ between MCI and control subjects. Delayed verbal memory
performance best discriminated DAT from MCI and control subjects, while
delayed verbal memory and hippocampal volume best discriminated MCI
subjects from controls. These results support the utility of
neuropsychological and neuroanatomical measures in diagnosing dementia
and do not support the notion that P300 amplitude is sensitive to
mild memory dysfunction when measured using the current task.
(JINS, 2004, 10, 200–210.)