Impairment of Visual Fixation and Preparatory Saccade Control in Borderline Personality Disorder with and without co-morbid Attention-Deficit/ Hyperactivity Disorder.

Abstract

Background: Borderline Personality Disorder (BPD) is associated with heightened impulsivity, evidenced by increased substance abuse, self-harm and suicide attempts. Addressing impulsivity in individuals with BPD is a therapeutic objective; but its underlying neural basis in this clinical population remains unclear, partly due to its frequent co-morbidity with attention-deficit/hyperactivity disorder (ADHD).

Methods: We employed a response inhibition paradigm - the interleaved pro-/anti-saccade task (IPAST) - among adolescents diagnosed with BPD with and without comorbid ADHD (N=25 and N=24, respectively) during concomitant video-based eye-tracking. We quantified various eye movement response parameters reflective of impulsive action during the task, including delay to fixation acquisition, fixation breaks, anticipatory saccades, and direction errors with express saccade (Saccade Reaction Time [SRT]: 90-140 ms) and regular saccade latencies (SRT > 140 ms).

Results: Individuals with BPD exhibited deficient response preparation, exampled by reduced visual fixation on task cues and greater variability of saccade responses (i.e., SRT and peak velocity). The ADHD/BPD group shared these traits, as well as produced an increased frequency of anticipatory responses and direction errors with express saccade latencies and reduced error correction.

Conclusions: Saccadic deficits in BPD and ADHD/BPD stem not from an inability to execute anti-saccades, but rather from an inadequate preparation for the upcoming task set. These distinctions may arise due to abnormal signaling in cortical areas like the frontal eye fields, posterior parietal cortex, and anterior cingulate cortex. Understanding these mechanisms could provide insights into targeted interventions focusing on task set preparation to manage response inhibition deficits in BPD and ADHD/BPD.