Many psychiatric patients have difficulties in executive function, often marked by impaired ability to inhibit immediate reactions and effectively control responses to the external environment. Behavioral measures can be a useful tool to measure inhibition and response control by requiring the patient to respond to target information while inhibiting responses to non-target information. Electrophysiological methods such as P300 also provide useful information involving discrimination between target and non-target auditory and visual stimuli. Patients who have similar abilities to process information effectively in both auditory and visual modalities may be more effective in discriminating between target information and responding effectively. This study examined auditory and visual response control in a group of neuropsychiatric patients by comparing behavioral performance on the Integrated Visual and Auditory Continuous Performance Task (IVA+Plus) with visual and auditory P300.

Hypothesis: Patients with similar amplitudes in auditory and visual P300 will have better scores on IVA+Plus measures of response control.

Methods: Archival auditory and visual P300 and IVA+Plus data were collected from a community-based neuropsychiatric outpatient clinic. Patients were self-referred for a broad range of psychiatric presentations, including mood deregulation, anxiety, difficulties with attention and behavioral control, and memory impairment. The remaining sample included 72 patients (n=72), after removing patients with invalid IVA+Plus scores on multiple domains (n=3) or without clearly identifiable P300 amplitude peaks (n=17). Patients were categorized into three groups (Auditory Dominance, Visual Dominance, and No Dominance) based on differences between auditory and visual P300 amplitudes at Cz, Pz, or both electrode sites. Patients with >25% difference between auditory and visual P300 amplitudes were grouped based on the modality with higher amplitude (Auditory Dominance or Visual Dominance). Patients with <25% difference were categorized as No Dominance. One-way between-subject ANOVAs were utilized to compare mean IVA+Plus scores in measures of response control.

Results: Patients in Auditory Dominance (n=31), Visual Dominance (n=10), and No Dominance (n=31) groups were similar in gender, handedness and age distribution. ANOVA analyses identified statistically significant differences between the three groups on IVA+Plus measures of response control, including Full Scale Response Control (FSRC), F(2,69)=3.846, p=.026, Auditory Response Control (ARC), F(2, 69)=4.188, p=.019, and Auditory Prudence (AP), F(2,69)=3.561, p=.034. Scores were significantly higher in each of these domains for patients with No Dominance in P300 amplitudes, while scores were reduced for patients with either an Auditory Dominance or Visual Dominance in P300 amplitude.

Conclusions: Data supports the hypothesis that patients who demonstrate similar electrophysiological processing of both auditory and visual stimuli have better response control. Findings suggest that shared resources across auditory and visual modalities enhance the ability to discriminate between target and non-target information, which appears associated with improved effectiveness in choosing behavioral responses and managing impulses. This study is the first of its kind to directly link P300 to response control with the IVA+Plus Continuous Performance Task, and the results provide insight into brain-to-behavior relationships based on differences in auditory and visual processing. Additionally, findings support a multimodality approach to assessment and intervention incorporating measures of both behavior and electrophysiology.