No abstract

Suicidality is a life-threatening symptom in patients with bipolar disorder (BD). Impulsivity and mood instability are associated with suicidality in mood disorders. Evidence suggests that gray and white matter abnormalities are linked with impulsivity in mood disorders, but little is known about the association between corpus callosum (CC) and impulsivity in BD. We examined the relationship between CC areas, impulsivity and suicidality in BD patients. We studied 10 female BD patients with a history of suicide attempt (mean±sd age 36.2±10.1y), 10 female BD patients without suicide attempt history (44.2±12.5y) and 27 female healthy subjects (36.9±13.8y). Impulsivity was evaluated by the Barratt Impulsivity Scale (BIS). We traced MR images to measure the areas of the CC genu, anterior body, posterior body, isthmus and splenium. The genu was divided into anterior, middle and posterior regions. The suicidal and non-suicidal BD patients had significantly higher BIS total, attention and non-planning scores than the healthy subjects (Ps<0.01), and the suicidal BD patients had significantly higher BIS motor scores than the non-suicidal BD and healthy subjects (Ps<0.01). There were no significant differences among the three groups on any regional CC areas, although the suicidal BD patients had the smallest areas. The suicidal BD patients showed a significant inverse correlation between anterior genu area and the BIS total (r=−0.75, p=0.04), motor (r=−0.79, p=0.02) and non-planning scores (r=−0.79, p=0.02). These correlations were not found in the non-suicidal BD patients or healthy subjects. The results suggest that the anterior medial frontal region may be involved in the pathophysiology of impulsive and suicidal behaviors in BD.

Rapid automatic naming tasks are clinical tools for probing brain functions that underlie normal cognition. To compare performance for various stimuli in normal subjects and assess the effect of aging, we administered six single-dimension stimuli (color, form, number, letter, animal, and object) and five dual-dimension stimuli (color-form, color-number, color-letter, color-animal, and color-object) to 144 normal volunteers who ranged in age from 15 to 85 years. Rapid automatic naming times for letters and numbers were significantly less than for forms, animals, and objects. Rapid automatic naming times for color-number and color-letter stimuli were significantly less than for color-form, color-animal, or color-object stimuli. Age correlated significantly with rapid automatic naming time for each single-dimension stimulus and for color-form, color-number, color-animal, and color-object stimuli. Linear regression showed that rapid automatic naming times increased with age for aggregated color stimuli, aggregated single-dimension stimuli, and aggregated dual-dimension stimuli. This age effect persisted in subgroups less than 60 years of age and greater than 60 years of age. We conclude that normal performance time is dependent on the task, with letter and number stimuli eliciting most rapid responses, and that most rapid automatic naming times increase with age.

No abstract