Amygdala in stroke/transient ischemic attack patients and its relationship to cognitive impairment and psychopathology: The Sydney Stroke Study

Objective: To examine the structural abnormalities in the amygdala in stroke patients and see what contribution the amygdala may make to psychopathology and cognitive dysfunction related to stroke, because the amygdala has important roles in the processing of emotions, cognitive function, and psychiatric disorders. Methods: The authors assessed 47 stroke/ transient ischemic attack (TIA) patients 3 - 6 months after the event and 54 comparison healthy subjects, using neuropsychological tests, medical and psychiatric examination and magnetic resonance imaging (MRI) brain scans. Volumetric T1-weighted MRI was used to obtain amygdala volumes by manual tracing. Results: Stroke/TIA patients had smaller right amygdalar volume, more white matter hyperintensities (WMHs), and larger lateral ventricles. The amygdala was smaller in stroke/ TIA patients with cognitive impairment compared to those without impairment. The right amygdala volume was negatively correlated with visual new learning and not related to depression, anxiety, irritability, agitation or apathy at baseline or 12-month follow-up. However, baseline amygdala volume was negatively correlated with Hamilton depression scores at 12 months in healthy comparison subjects. Hypertension and atrial fibrillation, and to a lesser extent WMHs, were predictors of amygdala volume. Conclusion: The amygdala is smaller in stroke/ TIA patients, especially in those with cognitive impairment. This may partly be accounted for by hypertension, white matter lesions, and atrial fibrillation. It is not related to psychopathology except that small amygdalae may increase vulnerability to depression.