Epileptic manifestations, cognitive impairment and autism spectrum disorders in patients with agenesis of the corpus callosum: the results of neuropsychological testing

Abstract

Aim. To assess the epileptic, cognitive and autistic manifestations of agenesis of the corpus callosum (ACC) in children.Material and methods. Clinical characteristics of 31 patients (median age 6.6±0.9 years) with ACC were studied. Group I included patients with combined ACC and epilepsy manifestations (n=12); among them, patients with atypical children’s autism (n=3), genetically confirmed Aicardi syndrome (n=3), microdeletion of the 3X long shoulder (n=1), and Miller-Dieker syndrome (n=1). Group II included patients with combined ACC without epilepsy (n=12); among them: children with autism caused by an organic brain disorder (n=2), genetically confirmed Mowat-Wilson syndrome (n=1), and microcephaly (n=1). In Group III, there were patients with isolated ACC without epilepsy (n=7). All patients underwent a neurologic examination, an assessment of the mental status, and a neuropsychological testing that included diagnostic neuropsychological tests according to Skvortsov et al. (2000), a neuropsychological survey and calculation of the lateral preference according to Semenovich et al. (2002), a test for the dominant hemisphere according to Yassman et al. (1999), as well as brain EEG and MRI.Results. In 75% of patients in Group I, symptomatic focal epilepsy was diagnosed (frontal-temporal – 4, frontal – 3, temporal – 2). Among other findings: 58% – complex partial seizures, 41.6% – complex partial seizures with secondary generalization, 16.7% – generalized seizures and their combination. In 16.7% of patients, there were atypical febrile seizures at the epilepsy debut with further transformation into symptomatic focal epilepsy of temporal localization. In 25% of patients in Group I, the neurogenetic Aicardi syndrome manifested in infantile (tonic) seizures up 10-20 attacks a day (symptomatic West syndrome). In 3 patients of Group I, atypical infantile autism was associated with symptomatic focal epilepsy (frontal-temporal – 2 and frontal – 1); 2 patients of Group II had infantile autism caused by an organic brain disease. In patients from Group I, the minimum value of the highest mental functions (HMF) score ranged from 25 to 51 (on average, Me =26.5) indicating severe cognitive disorders. In patients of Group III, the total HMF score varied from 77.5 to 87 (on average, Me =81) indicating mild cognitive disorders. Upon an inter-group comparison, patients with ACC associated with cerebral defects showed moderate to severe HMF disturbances (p < 0.002). The focal/multifocal epileptiform activity was recorded in 8 (67%) patients of Group I. In brain MRI scans of all patients of Group I, ACC was combined with various congenital development defects; in 3 (25%) patients of Group II, the structural lesions were dominated by congenital (hemispheric, arachnoid) cysts.Conclusion. Patients in Groups I and II have combined cerebral pathology with a predominance of combined congenital malformations, mainly associated with abnormal neuronal migration that negatively impacts the prognosis. In 75% of patients with combined ACC associated with temporal or frontal epilepsy, a highly severe cognitive deficiency was found; in 72% of cases of isolated ACC, mild cognitive disorders with a rather favorable prognosis were noted.