This paper describes recommended methods for the use of event-related brain potentials (ERPs) in clinical research and reviews applications to a variety of psychiatric and neurological disorders. Techniques are presented for eliciting, recording, and quantifying three major cognitive components with confirmed clinical utility: mismatch negativity (MMN), P300, and N400. Also highlighted are applications of each of the components as methods of investigating central nervous system pathology. The guidelines are intended to assist investigators who use ERPs in clinical research, in an effort to provide clear and concise recommendations and thereby to standardize methodology and facilitate comparability of data across laboratories.

Background: While previous studies have shown an increased rate of suicidal behavior in the relatives of suicide victims, it is unclear if this is attributable merely to increased familial rates of psychiatric disorders. Therefore, we conducted a family study of adolescent suicide victims (suicide probands) and community control probands (controls) to determine if the rates of suicidal behavior were higher in the relatives of adolescent suicide probands even after adjusting for differences in the familial rates of psychiatric disorders. Method: The relatives of 58 adolescent suicide probands and 55 demographically similar controls underwent assessment for Axis I and II psychiatric disorders, lifetime history of aggression, and history of suicidal behavior (attempts and completions) using a combination of family study and family history approaches. Results: The rate of suicide attempts was increased in the first-degree relatives of suicide probands compared with the relatives of controls, even after adjusting for differences in rates of proband and familial Axis I and II disorders (odds ratio, 4.3; 95% confidence intervals, 1.1-16.6). On the other hand, the excess rate of suicidal ideation found in the relatives of suicide probands was explained by increased familial rates of psychiatric disorders. Among suicide probands, higher ratings of aggression were associated with higher familial loading for suicide attempts. Conclusions: Liability to suicidal behavior might be familially transmitted as a trait independent of Axis I and II disorders. The transmitted spectrum of suicidal behavior includes attempts and completions, but not ideation, and the transmission of suicidal behavior and aggression are related.

An event-related brain potential (ERP) reflecting the acoustic-phonetic process in the phonological stage of word processing was recorded to the terminal words of spoken sentences. The peak latency of this negative-going response occurred between 270 and 300 msec after the onset of the terminal word. The independence of this response (the phonological mismatch negativity, PMN) from the ERP component known to be sensitive to semantic violations (N400) was demonstrated by manipulating sentence endings so that phonemic and semantic violations occurred together or separately. Four conditions used sentences that ended with (1) the highest Cloze probability word (e.g., “The piano was out of tune.”), (2) a word having the same initial phoneme of the highest Cloze probability word but that was, in fact, semantically anomalous (e.g., “The gambler had a streak of bad luggage.”), (3) a word having an initial phoneme different from that of the highest Cloze probability word but that was, in fact, semantically appropriate (e.g., “Don caught the ball with his glove.”), or (4) a word that was semantically anomalous and, therefore, had an initial phoneme that was totally unexpected given the sentence's context (e.g., “The dog chased our cat up the queen”). Neither the PMN nor the N400 was found in the first condition. Only an N400 was observed in the second condition while only a PMN was seen in the third. Both responses were elicited in the last condition. Finally, a delayed N400 occurred to semantic violations in the second condition where the initial phoneme was identical to that of the highest Cloze probability ending. Results are discussed with regard to the Cohort model of word recognition.

The time course and cortical basis of reading comprehension were studied using magnetoencephalography. The cortical structures implicated most consistently with comprehension were located in the immediate vicinity of the left auditory cortex, where final words totally inappropriate to the overall sentence context evoked enduring activation starting approximately 250 ms and lasting up to 600 ms after word onset. Contextually appropriate but unexpected words produced weaker activation which terminated earlier. Highly anticipated words totally failed to activate this area, suggesting that the conceptual network became involved only if unexpected information was detected during the primary word identification process. We propose that the point in time (350 ms after word onset) where the response to appropriate but unexpected endings started to diverge from those to contextually inappropriate endings reflects the boundary between understanding a single word and the meaning of a whole sentence.