Abstracts

RATIONALE: Anterior callosal sections (ACS) have been associated with very low surgical morbidity. ACS have been carried out while approaching lesions in the third or lateral ventricle regions or for the treatment of refractory generalized epilepsy. Difficulties in defining the neuropsychological morbidity in these patients included lesion resection-related neuropsychological deficits and epilepsy-induced neurologic plasticity. This paper reports on the neuropsychological effects of ACS performed as treatment for refractory generalized epilepsy.
METHODS: Eleven normal controls, 11 matched non-operated patients with refractory generalized epilepsy and 6 patients submitted to callosal sections restricted to its anterior half were studied. All were submitted to extensive neuropsychological and interhemispheric transfer testing including: WAIS, laterality questionnaire, unimanual motor tasks (associated fingers, stick transfer, tapping, copy, drawing, writing), sensorimotor tests (sequential gestures, reproduction, kinestesic interhemispheric transfer, praxis), bimanual coordination, simultaneous movements tasks (hands, fingers, tapping), alternating movements (hands, finger, palms), cooperative movement tasks (necklace, buttoning lacing, stick transfer), somesthesic tests (intra- and inter-hemispheric localization and object, geometric figures and texture comparison), stereognosis and dichotic listening test. Univariate parametric analysis, Tuckey testing, ANOVAS and T-student were employed whenever indicated.
RESULTS: ACS disrupted the performance in alternating and cooperative bimanual movements while simultaneous bimanual movements remained unaltered. ACS also caused a disruption in unimanual tasks with either hand in non-verbal command related paradigms. Despite being able to perform the tests and being quantitatively within the lower normal range, most patients with ACS were considerably slower then normals or matched controls while performing them.
CONCLUSIONS: Contrary to some previous studies, ACS was found not to be free of neuropsychological effects in this study and our data suggest that the anterior corpus callosum is involved in motor control. This might involve relays such as the premotor cortex, supplementary motor area and the motor rolandic cortex itself; all these cortical areas are trans-hemispherically connected through the anterior corpus callosum.