Patterns of hippocampal abnormalities in malformations of cortical development.

OBJECTIVE: To assess whether different types of malformation of cortical development (MCD) are associated with specific patterns of hippocampal abnormalities. METHODS: A total of 122 consecutive patients with MRI diagnosis of MCD (53 males, age range 1-58 years) were included in the study. Hippocampal measurements were made on 1-3 mm coronal T1-weighted MRIs and compared with MRIs of normal controls. RESULTS: A total of 39 patients had focal cortical dysplasia, 5 had hemimegalencephaly, 5 had lissencephaly-agyria-pachygyria, 11 had SLH, 11 had PNH, 12 had bilateral contiguous PNH, 5 had schizencephaly, and 34 had polymicrogyria. The frequency of hippocampal abnormalities in these patients with MCD was 29.5%. A small hippocampus was present in all types of MCD. Only patients with lissencephaly and SLH had an enlarged hippocampus. Abnormalities in hippocampal rotation and shape were present in all types of MCD; however, these predominated in PNH. None of the patients with lissencephaly-agyria-pachygyria or SLH had hyperintense signal on T2 or FLAIR images or abnormal hippocampal internal architecture. CONCLUSION: A small hippocampus was present in all types of MCD; however, the classic MRI characteristics of hippocampal sclerosis were often lacking. Abnormal enlargement of the hippocampus was associated with only diffuse MCD due to abnormal neuronal migration (lissencephaly-agyria-pachygyria and SLH).

Analysis of shape and positioning of the hippocampal formation: an MRI study in patients with partial epilepsy and healthy controls.

The purpose of this study was to evaluate systematically shape and positioning of the hippocampal formation (HF) in patients with partial epilepsy related to malformations of cortical development (MCD) and those with temporal lobe epilepsy (TLE). We studied 76 patients with MCD, including focal cortical dysplasia (n = 29; lesions located outside the temporal lobe in all), heterotopia (lesions outside of the temporal lobe, n = 14; lesions extending into the temporal lobe, n = 16), polymicrogyria (bilateral perisylvian, n = 14; unilateral perisylvian, n = 3) and 30 patients with TLE (hippocampal atrophy, n = 15; normal hippocampal volumes, n = 15). Shape and positioning of the HF were evaluated using a set of eight predefined morphological characteristics. In addition, the degree of hippocampal vertical orientation and medial positioning were assessed quantitatively. Patients were compared with 50 healthy controls. At least three criteria describing abnormal HF shape and positioning were found in 5/50 (10%) healthy controls, 37/76 (49%) MCD and 13/30 (43%) TLE patients. An association with all criteria was found in MCD and TLE, but not in healthy controls. In MCD there was no association between the side of HF shape abnormalities and the side of the cortical malformation or the EEG focus. Likewise, in TLE, HF abnormalities were not related to the side of the EEG focus. In both MCD and TLE patients who had hippocampal atrophy, no association was found between the side of HF shape abnormalities and the side of atrophy. Abnormal HF shape and positioning are found in a similar proportion in MCD and TLE. In TLE, they may be a marker of a more extensive disorder of brain development and may participate in the development of this condition.

Neuromuscular consequences of prolonged hunger strike: an electrophysiological study.

OBJECTIVES: The purpose of this study was to determine the electrophysiological consequences of neuromuscular and central nervous system involvement in a group of patients presented with the neurological complications of a long-term hunger strike (HS). METHODS: Motor and sensory nerve conduction (NCV), F wave, somatosensory evoked potential (SEP) and motor evoked potential (MEP) studies were performed in 12 male and 3 female patients (mean age: 29.4) following HS. RESULTS: All patients whose weight loss was 11-31 (mean: 22.8) kg after 69-day HS, had neurological findings consistent with Wernicke's encephalopathy or Wernicke-Korsakoff syndrome. Abnormally prolonged latency and/or low amplitude sensory nerve action potentials were found in 7 patients. The amplitudes of compound muscle action potentials were significantly reduced in ulnar, median and tibial motor NCV studies as compared to the controls. F waves elicited by median nerve stimulation at wrist and muscle responses evoked by cervical and lumbar magnetic stimulation had significantly prolonged latencies. MEPs recorded from the lower extremities showed a slight prolongation in central conduction times. The cortical response latencies were prolonged in tibial SEPs. CONCLUSIONS: The most prominent finding in this patient group was the low amplitude of CMAPs elicited in motor NCV studies which was concluded to be resulted from the reversible muscular changes. The other electrophysiological findings suggested that peripheral nerves and long central nervous system pathways were also mildly involved.

Periodic lateralized epileptiform discharges: association with seizures.

The clinical features and EEGs of 45 consecutive patients (40 adults and 5 children) who had periodic lateralized epileptiform discharges (PLEDs) were reviewed to determine the relationship between seizures and PLEDs. Focal encephalitis and ischemic stroke were the most frequent underlying processes for adult patients. All of the children, but only six of the adults, had long-lasting cerebral disorders whereas the remaining adults had acute or subacute illness. There were 38 patients (84.4%) experiencing a seizure disorder. Twenty-six of them had their first seizure during their acute illness, as the pattern of PLED was encountered. Eight cases had status epilepticus, and seven of them had epilepsia partialis continua. Nineteen patients had a recent seizure in the day when PLEDs were observed but not during EEG recording; 12 patients had their seizures within 10 days before the observation of PLED. PLEDs were grouped into three categories with respect to their extensions: lateralized to one hemisphere (n = 22), localized in one region (n = 17) and being prominent over one side with contralateral spread (n = 6). The last group was found to be more closely associated with frequent seizures or status epilepticus than the other two groups. Our results showed that PLEDs were highly correlated with recent seizures in the majority of the patients. These EEG findings may be considered as a manifestation of an increased neuronal excitability caused by different etiologies; but not an ictal pattern.

Eye closure related spike and wave discharges: clinical and syndromic associations.

Precipitation of spike and wave (SW) discharges in some epileptic patients by eye closure (EC) has rarely been reported. To disclose the clinical characteristics and classification of syndromes of epileptic patients with SW discharges induced by EC, we investigated 10 patients (1 M, 9 F) showing this peculiar EEG feature. The patients aged between 9-39 years (mean 20.6 +/- 9.058), underwent short-term (1-3.5 hr) video-EEG investigations in order to document the appearance of the SW discharges within 3 seconds of the act of EC, in at least two occasions. Clinical analysis showed that 5 female patients who had the syndrome of juvenile myoclonic epilepsy (JME) had a later onset of epilepsy (13-15 years) than the 3 patients (3 girls) with eyelid myoclonia with absences (EMA) (3-8 years of age at onset). The remaining 2 patients who were diagnosed as childhood absence epilepsy (CAE) and juvenile absence epilepsy (JAE) according to the international classification, did not show photosensitivity on the video-EEG. All but one of the 5 JME patients had experienced myoclonic seizures in intermittent photic stimulation (IPS) at the time of EC, associated with multiple spike and wave discharges. Two of the 3 EMA patients exhibited typical absences with eyelid myoclonia during the act of EC. The high rate of family history of epilepsy in first degree relatives of our patients was an outstanding feature, which could have future implications in research of the genetic basis of epilepsy patients with ECS.