P300 event-related brain potential as an index of recognition response to autobiographical and recently learned information in closed-head-injury patients

Fourteen patients who sustained a closed-head injury had their P300 (P3) measured in a visual recognition paradigm to test the use of P3 as an index of recognition in this population. Subjects participated in recognition tests for both autobiographical information (their birthday) and for a word list learned immediately before testing while event-related potentials were recorded. Within-subjects tests were used to determine that the P3 amplitude in response to oddball items (the subject's birthday and the studied word list) was larger than the P3 in response to non-oddball items for 9 of 11 subjects in the autobiographical condition, and 6 of 12 subjects in the word- list condition. Averaged P3s to oddball items were also larger than P3s to non-oddball items in standard group tests (p < .001), suggesting this difference can be used as an index of recognition in closed-head-injury patients.