| Abnormalities of the septum pellucidum on MR scans in first-episode schizophrenic patients
G Degreef, G Lantos, B Bogerts, M Ashtari and J Lieberman Department of Psychiatry, Hillside Hospital Division of the Long Island Jewish Medical Center, Albert Einstein College of Medicine, Glen Oaks, NY 11004. PURPOSE AND METHODS: Cavities in the septum pellucidum have been widely regarded in clinical neurology or in autopsy series as incidental findings of little clinical importance; however, an association between this developmental anomaly and a diagnosis of psychosis has been reported. We compared MR brain scans of schizophrenic patients with normal control subjects to determine the prevalence of this finding in the two groups: RESULTS: A cavum septum pellucidum was found in 14 of 62 (23%) schizophrenic patients and only one of 46 control subjects (2%). Pronounced enlargement of the cavum septum and a cavum vergae were seen only in two schizophrenic subjects. A partial agenesis of the corpus callosum was also seen in one of the schizophrenic cases with the largest cavum septum pellucidum. CONCLUSIONS: The increased prevalence of a cavum septum pellucidum, the cavum vergae, and partial callosal agenesis in schizophrenics support the hypothesis that anomalous development of the brain is an important aspect of this disorder. The disturbed structures are closely linked developmentally to the limbic system which has been implicated etiologically in studies of schizophrenia. fifth ventricle --> cavity of septum pellucidum a slitlike, fluid-filled space of variable width between the left and right transparent septum, which occurs in less than 10% of human brains and may communicate with the third ventricle. Synonym: cavum septi pellucidi, duncans ventricle, fifth ventricle, pseudocele, pseudoventricle, sylvian ventricle, ventricle of sylvius, ventriculus quintus, vieussens ventricle, wenzels ventricle. The quest of cavum septi pellucidi: obscure chance event discovery or the result of some encoded disturbance? Developmental cerebral dysplasias, cavum septi pellucidi and epilepsy: clinical, MRI and electrophysiological study. V OBJECTIVES: Developmental cerebral dysplasias are frequent causes of epilepsy. The early stage of gestation, mainly the period of neural crest separation and neuroblast migration (disturbance of midline structures, heterotopias, cortical dysplasias and disturbance of the ventricular and vascular formation), may be considered as a cause of serious cerebral dysplasia. The aim of the study was focused on frequent simultaneous occurrences of epileptic seizures and the defect or abnormality of the ventricular system - cavum septi pellucidi (CSP). MATERIAL AND METHOD: In our study the clinical symptoms, EEG and somatosensory evoked potentials (SEP's) following median nerve stimulation and MRI pictures in the group of patients with CSP (n= 35), were analyzed. In the SEP analysis, a control group of normal, healthy volunteers (n = 40) and a group of age matched patients with epileptic seizures of different origin, without structural lesions evident on MRI (n=21), were used. RESULTS: Analysis of the patient population with CSP (CSP was confirmed by MRI) showed that approximately in 2/3 cases, different types of cranio-cerebral dysplasias were evident on MRI. More than 2/3 of the patients with CSP showed epilepsy and an abnormal EEG record, however, focal EEG changes were seen more frequently in the group of patients with epilepsy without CSP, than in patients with CSP. The SEP's in patients with CSP showed a statistically significant prolongation of latency of thalamic P15 waves, however these changes were not present in the group of patients with epilepsy of a different origin. CONCLUSIONS: In a group of patients with CSP, dysplastic MRI changes, together with the prolongation of thalamic wave latencies according SEP, were examined. These clinical symptoms may be considered the result of disturbances of early gestation and of lesions of midline structures. CSP became an interesting model opportunity for us, and allowed for the clinical, MRI and electrophysiological examination of developmental cerebral dysplasias. We believe that there is an important role for septal and diencephalic midline structures in cerebral electrogenesis, and possibly in the origin of epileptic seizures too. |