Faculty Bibliography

Callosotomy has played a unique role in the treatment of epilepsy and in the understanding of human brain function. The pioneering work of Dejerine and Liepmann presenting the first findings of callosal lesion pathology at the turn of the 20th century was accepted but then quickly forgotten. Two schools resurrected the phoenix of callosal syndromes: Roger Sperry and Michael Gazzaniga leading in experimental neuroscience, and Norman Geschwind leading in clinical neurology. Callosotomy remains an effective technique to treat atonic, tonic, and tonic-clonic seizures, especially in patients with symptomatic generalized epilepsies such as Lennox-Gastaut syndrome. Neurologic, cognitive, and behavioral complications limit its use given that precise characterization of these complications as well as their frequency is difficult. The high frequencies of developmental delays, severe seizures, head injuries, antiepileptic drug burden, and other factors limit the ability to attribute a specific change to surgical intervention, since surgery can change multiple factors. For example, subtle behavioral changes in executive function and personality are difficult to delineate in a population with preexisting neurologic and psychiatric disorders. Despite this, a clearer picture of the effects of callosotomy, as defined by clinical neurology and neuropsychology as well as cognitive neuroscience, is emerging

Studies in the general population demonstrate that anxiety disorders are associated with impaired quality of life and function. Available evidence suggests that comorbid anxiety disorders are frequent among patients with epilepsy but that neither the interrelationships between them nor the impact of anxiety disorders on functional outcome is well studied. The study and management of anxiety disorders are further complicated by the occurrence of seizures, the temporal relationship between seizures and anxiety symptoms/syndromes, and the influence of antiepileptic drugs. Increased recognition of anxiety disorders among patients with epilepsy and evaluation of the potential impact of these disorders on functional outcome and the beneficial and detrimental effects of antiepileptic drugs in clinical practice are needed

A 38-year-old woman with a right posterior temporo-occipital brain tumor developed partial seizures with illusory motion perception of environmental objects going from the center to the periphery within her left visual field. Subdural EEG recordings during visual seizures revealed onsets in the right temporo-parieto-occipital junction. Her ictal visual distortion was probably caused by activation of V5, an area involved in motion perception. Given that the tumor location corresponds with the ictal onset in the V5 area, and the semiology of her seizures, this case supports that epileptic dysfunction in V5 can cause illusions of visual motion

A 23-year-old right-handed woman developed isolated transient prosopagnosia following surgical resection of a right posterior temporal seizure focus. At 18 years of age she had developed secondarily generalized tonic-clonic seizures. Preoperative neuropsychological evaluation was normal, and neurological examination revealed only a left superior quadrant achromatopsia. MRI revealed a circumscribed lesion in the right inferolateral temporo-occipital junction. Following surgery she was agitated for 36 hours, and afterward, when her attention and orientation improved, she was unable to recognize familiar faces. She could, however, recognize familiar voices. Her prosopagnosia resolved over the next 6-7 days. This case demonstrates that isolated prosopagnosia can occur in patients with lesions restricted to the right inferior posterior temporal-anterior occipital region. The temporary nature of the prosopagnosia may result from postsurgical tissue injury, including focal cerebral edema, with compensation by ipsilateral or contralateral areas

Behavioral changes, such as mood disorders, anxiety, psychosis, and nonepileptic seizures often occur after temporal lobectomy. We report a man who selectively lost emotional attachments to family members after right temporal lobectomy. However, emotional responsiveness to strangers was normal or increased

In patients with mesiotemporal sclerosis, posterior hippocampal involvement at the ictal onset is not associated with an excellent outcome. A study confirmed that ictal onset in the posterior parahippocampal gyrus is associated with a less favorable outcome compared with ictal onset in the anterior parahippocampal gyrus in patients with mesiobasal temporal lobe epilepsy who are undergoing foramen ovale recording. The authors hypothesized that involvement of the two medial contact points of posterior basal temporal subdural (SD) strip at the ictal onset, representing ictal onset in the posterior parahippocampal gyrus, may also adversely influence the surgical outcome. With this objective, the authors assessed the incidence of posterior basal temporal SD strip (the two medial contact points) involvement at the ictal onset in patients with mesiotemporal sclerosis and determined whether presence of this finding influenced surgical outcome. Thirty-six patients with mesiotemporal sclerosis underwent a single SD grid (lateral frontotemporal) and strips (three basal temporal and one orbitosubfrontal) monitoring. Based on the earliest involvement of basal temporal strips (the two medial contact points) during the seizure, patients were classified into (1) anterior and/or middle basal temporal, or (2) posterior basal temporal (with or without involvement of anterior and/or middle basal temporal) ictal onset groups. A temporal lobectomy with adequate resection of the ictal onset zone was performed in all patients. Surgical outcome was based on Engel's classification. Six of 36 (17%) patients were classified into the posterior basal temporal ictal onset group. Only two patients from the posterior basal temporal ictal onset group experienced a good outcome compared with 26 of 30 patients from anterior and/or middle basal temporal ictal onset group (P = 0.01). In patients with mesiotemporal sclerosis who were monitored with SD electrodes, involvement of the two medial contact points of posterior basal temporal strip at the ictal onset (representing ictal onset in the posterior parahippocampal gyrus) occurred in 17% of the patients. These patients might not experience an excellent surgical outcome despite including the ictal onset zone in resection. These findings may be useful in presurgical counseling of patients with mesiotemporal sclerosis who undergo intracranial SD monitoring