Affective aggression in patients with temporal lobe epilepsy - A quantitative MRI study of the amygdala

Recurrent episodes with interictal affective aggression are a rare but well -recognized problem in patients with temporal lobe epilepsy. They are refer red to as episodic dyscontrol or, more precisely, as intermittent explosive disorder (IED), The amygdala play a crucial role in the affective evaluati on of multimodal sensory input and the neurobiological mediation of aggress ive behaviour. With hippocampal sclerosis, in the context of mesial tempora l lobe sclerosis, being the most common cause of temporal lobe epilepsy, me hypothesized that the amygdala might be affected by the same pathogenic pr ocess in aggressive patients. We investigated 50 patients with temporal lob e epilepsy: 25 with and 25 without a history of IED, Data from clinical, el ectrophysiological, neuropsychological and psychometric investigations were obtained, as well as MRI scans for the quantitative assessment of possible amygdala pathology. We found no evidence of a higher prevalence of amygdal a sclerosis In the aggressive patients, Hippocampal sclerosis was significa ntly less common in patients with temporal lobe epilepsy and IED, However, a significant subgroup of patients (20%) with temporal lobe epilepsy and ag gressive behaviour had severe amygdala atrophy in the context of a history of encephalitis, Another subgroup of aggressive patients (28%) had differen t left temporal lesions affecting either the amygdala or periamygdaloid str uctures, IED was associated with left-sided or bilateral EEG and MRI abnorm alities, low IQ and high scores in depression and anxiety.