Improved decision-making and psychophysiological responses in mesial temporal lobe epilepsy after anterior temporal lobectomy.

The somatic marker hypothesis is an influential model of human decision-making postulating that somatic feedback to the brain enhances decision-making in ambiguous circumstances, i.e. when the probabilities of various outcomes are unknown. The somatic feedback can be measured as autonomic responses, which are regulated by the amygdala. The failure to evoke this somatic feedback, which occurs in patients with amygdala lesions, impairs decision-making. The purpose of this study was to investigate the decision-making behaviour of mesial temporal lobe epilepsy patients with pre- and post-epilepsy surgery to ascertain whether the decision-making abilities of groups can be explained by means of the generation of somatic feedback responses. The preoperative group comprised 32 patients with mesial temporal lobe epilepsy due to hippocampal sclerosis, while the postoperative group comprised 23 patients who had undergone anterior temporal lobectomy. The age and gender-matched control group consisted of 30 healthy participants. Decision-making performances were assessed and skin resistance responses were measured simultaneously. The findings of this study reveal that the decision-making performance of preoperative patients with unilateral mesial temporal lobe epilepsy was impaired under conditions of ambiguity, i.e. they did not generate somatic feedback responses before making decisions around ambiguous outcomes, and produced significantly poor scores overall based on a decision-making task. In addition, the resection of epileptogenic limbic structures positively affected the generation of somatic feedback responses, as demonstrated by the significant difference between the magnitudes of autonomic responses of the pre- and post-operative groups. The findings of the study validate the contribution of mesial temporal lobe structures to decision-making behaviour, and also point to the importance of examining the connectivity patterns between the neural structures involved in the decision-making network.

Unilateral thalamic Vim and GPi stimulation for the treatment of Holmes' tremor caused by midbrain cavernoma: case report and review of the literature.

A 30-year-old man with brainstem cavernoma experienced hemorrhage and was operated in 2008. Six months after the operation, the patient presented with new complaints of left arm tremor namely Holmes' tremor. Neurological examination also revealed left-sided internuclear ophthalmoplegia, left-sided mild paresis, and increased deep tendon reflexes of the left upper extremity, truncal ataxia, and dysarthria. Brain magnetic resonance imaging showed a postoperative cavity and gliosis at the level of the superior and inferior colliculus in the right tegmentum and right red nucleus with extension to the substantia nigra. Fahn-Tolosa-Marin tremor rating scale (TRS) for his left upper extremity (Part A, score 6) was 11 for the proximal and the distal arm. After the failure of medical treatment, the patient underwent right globus pallidum internus and ventral intermediate thalamic nucleus deep brain stimulation. There were no side effects related to the stimulation. Final TRS months after operation was 3 for the proximal and 4 for the distal arm.

Treatment of homocystinuria-related dystonia with deep brain stimulation: a case report.

A 23-year-old woman with the medical history of homocystinuria that had been diagnosed at the age of 14 has been non-responsive to treatment. The patient presented with the symptoms of dysphonia, dysarthria and severe dystonia of the neck and left extremities. Blood and urine biochemistry revealed high levels of homocystine. Brain magnetic resonance imaging was normal with no detectable pathologies. Medical treatment strategies were used and repeated injections of botulinum toxin A were administered, but the symptoms showed no significant improvement. The patient was then operated, and deep brain stimulators targeting the bilateral globus pallidus internus were implanted. After the activation of the electrodes, dystonia symptoms showed a remarkable improvement. Good outcome was documented during the follow-up period of 7 months. To our best knowledge, this is the first reported case of homocystinuria-related dystonia symptoms that were successfully treated with deep brain stimulation.