Event-Related Potential Measures of Attention Capture in Adolescent Inpatients With Acute Suicidal Behavior

Abstract

Impaired executive functions, modulated by the frontal lobes, have been suggested to be associated with suicidal behavior. The present study examines one of these executive functions, attentional control, maintaining attention to the task-at-hand. A group of inpatient adolescents with acute suicidal behavior and healthy controls were studied using a passively presented auditory optimal paradigm. This “optimal” paradigm consisted of a series of frequently presented homogenous pure tone “standards” and different “deviants,” constructed by changing one or more features of the standard. The optimal paradigm has been shown to be a more time-efficient replacement to the traditional oddball paradigm, which makes it suitable for use in clinical populations. The extent of processing of these “to-be-ignored” auditory stimuli was measured by recording event-related potentials (ERPs). The P3a ERP component is thought to reflect processes associated with the capturing of attention. Rare and novel stimuli may result in an executive decision to switch attention away from the current cognitive task and toward a probe of the potentially more relevant “interrupting” auditory input. On the other hand, stimuli that are quite similar to the standard should not elicit P3a. The P3a has been shown to be larger in immature brains in early compared to later adolescence. An overall enhanced P3a was observed in the suicidal group. The P3a was larger in this group for both the environmental sound and white noise deviants, although only the environmental sound P3a attained significance. Other deviants representing only a small change from the standard did not elicit a P3a in healthy controls. They did elicit a small P3a in the suicidal group. These findings suggest a lowered threshold for the triggering of the involuntary switch of attention in these patients, which may play a role in their reported distractibility. The enhanced P3a is also suggestive of an immature frontal central executive and may provide a promising marker for early identification of some of the risk factors for some of the cognitive difficulties linked to suicidality.

Delta Event-Related Oscillations Are Related to a History of Extreme Binge Drinking in Adolescence and Lifetime Suicide Risk

“…They found participants with a history of suicide attempts exhibited deficits in detecting “the need for inhibitory control,” as indexed by a more positive change in the N2 response of the ERP. Larger P3a components in a passively-presented auditory ERP paradigm were found in another sample of adolescent inpatients with suicidal behavior [ 142 ]. Activated dorsolateral prefrontal cortex has been demonstrated in fMRI studies of youth that attempted to regulate their emotional responses to negative pictures [ 143 ] as well.…”

Active and Passive Attentional Processing in Adolescent Suicide Attempters: An Event-Related Potential Study

“…This could result in a larger target-N2 but reduced target-P3b in this group. Tavakoli et al 27 observed that passive attention capture was enhanced in their suicidal group. It is therefore possible that the while the target-P3b may be reduced, the novel-P3 may be enhanced in the suicidal group.…”

“…The sample size was deemed to be appropriate based on a power analysis of effect size, using group means and SDs observed in our previous study. 27 With this effect size, a sample of 10 participants per group was found to be adequate. When the effect size was reduced to approximate mean group differences found in other studies, a sample size of 14 was found to be adequate.…”

“…Differences were not apparent between those with less violent methods and healthy controls. Tavakoli et al 27 examined P3a amplitudes, suggestive of attention capture, in adolescents with acute suicidal behavior and healthy controls while participants watched a silent video and thus ignored a multi-feature auditory sequence. They reported an enhanced P3a to the novel sound deviants in the suicidal group suggesting that the suicidal patients may exhibit hypersensitivity to potentially relevant but to-be-ignored stimuli.…”

“…In the present study, adolescent inpatients with acute suicidal behavior and healthy controls were compared. The same novel sounds used by Tavakoli et al 27 were presented but within an active 3-stimulus oddball paradigm, consisting of frequently occurring standard stimuli, rarely occurring targets, and novel sounds. The participant's task was to respond to the occurrence of only the target stimulus.…”