P 300 latency of the auditory evoked potential in dementia

A two-tone discrimination paradigm was employed to elicit the P 300 component of the event related brain potential from 10 demented patients. P 300 latency was found not to be prolonged in the dementia group compared to age normative predictions derived from a patient control group. This finding contrasts with a number of studies of demented patients that generally found P 300 latency to exceed normative data. It was concluded that the results of normal latency in dementia is obviously due to the control of medication and the exclusion of patients who were unable to perform the required counting task.