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Objective: To study the clinical features and genetics of idiopathic generalised epilepsy (IGE) beginning in adult life. Methods: Consecutive patients with IGE, defined as generalised seizures with spike or polyspike [...]

Further research is needed to determine causal factors for autosomal dominant nocturnal frontal-lobe epilepsy. While evidence suggests a second locus for the disorder at chromosome 15q24 in addition to 20q13.2 with a clinically homogeneous phenotype, a wide range of molecular defects that contribute to the disorder are complicating accurate causal determination.

When epilepsy is both severe and unresponsive to medication, the last resort for treatment may be the surgical removal of the focus, the part of the brain where the epileptic seizure originates. Of course, the success of the method requires a precise determination of the location of the focus. The preliminary evaluation of the patient invariably includes electroencephalography (EEG). In many cases, electrophysiological abnormalities found by the EEG indicate a spot likely to be an epileptic focus. In some cases, however, the EEG findings are not conclusive. It is often necessary, therefore, to surgically implant electrodes for more precise evaluation before the surgical treatment itself can be planned. Researchers have now shown that some patients may be spared the implantation of electrodes in the brain by using the SPECT imaging technique. SPECT, or single-photon emission tomography, creates images of the distribution of radioactive tracer molecules in the brain. Radioactive tracer molecules may be chosen which reflect the circulation of blood within the brain. Since the brain is constantly altering its own circulation to meet the changing needs of different parts, the location of an epileptic focus may be visualized by observing corresponding changes in blood flow. In 83 percent of the 78 epileptic patients studied, an specific increase in blood flow could be observed during or shortly after a seizure. In 80 percent of the patients, there was also a depression of blood flow in much of the temporal lobe outside of the actual focus itself. This may provide a trap for the unwary; a quick look at the SPECT image might suggest that the opposite side of the brain is experiencing an increase in blood flow, but this illusion is created by the depression of blood flow on the same side as the focus. SPECT data is, in itself, inadequate for the determination of the location of an epileptic focus. However, if the determination made by SPECT coincides with the determination made by EEG, it may be possible to spare the patient the implantation of electrodes. It is thought that as many as half of all temporal lobe epilepsy patients facing surgery may be spared the implantation of electrodes using this procedure. (Consumer Summary produced by Reliance Medical Information, Inc.)

MELAS, the syndrome of mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes, can be difficult to diagnose. The various symptoms of the syndrome are apparently all related to defects in some of the mitochondria, the tiny organelles within cells that provide critical steps in the cells' energy metabolism. The distribution of symptoms in the body is likely to be related to the distribution of defective mitochondria. Often, the disorder can be diagnosed by observing a particular pathology of muscle fibers in a small muscle biopsy specimen. However, these so-called ''ragged-red fibers'' are not always visible. Similarly, lactic acidosis, an excessive amount of lactic acid in the blood, is often but not always present. The mitochondrial abnormalities exacts their toll on brain function, but the brain abnormalities that can be visualized on computed tomography (CT) are somewhat general in appearance and cannot be used to make a specific diagnosis. On the other hand, magnetic resonance imaging (MRI) reveals alterations in the brains of patients with MELAS which may prove to be relatively specific. Three cases are presented in which MRI revealed a particular pattern. The areas on the MRI around the cerebral cortex and the cortex of the cerebellum in each case were very light, a finding referred to by MRI technicians as hyperintensity. Similar findings occur in strokes, but the areas affected by strokes are defined by the anatomical distribution of blood vessels in the brain. No obstruction of blood flow could produce the patterns of hyperintensity seen in the present patients. Some areas of affected white matter were observed, but these invariably lay immediately underneath areas of affected cortex. Although there is no cure for the MELAS syndrome, the proper diagnosis of the disorder may permit the prevention of the more serious symptoms. The avoidance of stress and exertion may help minimize the effects of this metabolic disorder. (Consumer Summary produced by Reliance Medical Information, Inc.)

When temporal lobe epilepsy is sufficiently severe, surgery becomes a viable option. This involves the separation of the area of the brain that is the starting point of the seizure from the rest of the brain. In most patients with intractable temporal lobe epilepsy, the seizures arise from mesial structures, particularly the hippocampus. The hippocampus is a small structure relative to other structures of the human brain, and initial attempts to use magnetic resonance imaging for the preoperative visualization of hippocampal damage have met with limited success. At least some of the difficulties may have arisen from the lack of experience with examining images of the hippocampus, rather than from the inadequacies of the imaging technique itself. Hippocampal sclerosis (hardening caused by excessive fibrous tissue growth) is the most frequent postoperative abnormality that is detected in these patients, affecting between 50 and 70 percent. To evaluate the potential of magnetic resonance imaging in evaluating hippocampal sclerosis, 41 surgically resected specimens of the hippocampus from patients with intractable epilepsy were compared with preoperative magnetic resonance images. Hippocampal sclerosis was definitively identified in 27 of the pathological specimens. Of the 27 cases in which hippocampal sclerosis could be identified pathologically, 25 were identified as hippocampal sclerosis by observers who were not given any background on the cases before examining the magnetic resonance images. Conversely, of the 14 cases in which hippocampal sclerosis was not present, only two were identified has having hippocampal sclerosis on the basis of the MRI. The results suggest that experience with viewing magnetic resonance images can result in satisfactory accuracy in the identification of hippocampal sclerosis. (Consumer Summary produced by Reliance Medical Information, Inc.)

J Neurol Neurosurg Psychiatry 2004;75:368-369. doi: 10.1136/jnnp.2003.021691 A proposal that an endogenous benzodiazepine-like agent named endozepine-4 might be responsible for presentations of recurrent stupor has gained wide acceptance. A case [...]

Absence status is a clouding of consciousness which may range from mild torpor to deep stupor. Although this type of seizure is usually associated with either subtle or overt myoclonic jerking, it may go unrecognized. Sometimes, absence status may be the sole symptom of generalized epilepsy, but usually it is associated with other seizure activity. Tonic-clonic seizures may begin an episode of absence, occur in the middle of absence status, or terminate absence. Absence status may last for periods of hours to days. Generally, an intravenous injection of benzodiazepine is sufficient to terminate absence status. However, many drugs used in the treatment of epilepsy fail to prevent absence status. Barbiturates, phenytoin, carbamazepine, trimethadione, and ethosuximide have all been found to be of little value. However, a review of 25 patients with absence status revealed that valproate is effective in preventing absence status in the majority of patients, and that it should be considered the drug of choice in these cases. Valproate was effective in controlling absence status in all 18 patients who were diagnosed with primary generalized epilepsy. Two patients with absence seizures and epilepsy coexisting with brain damage did not respond significantly to treatment. Among the five patients with focalization, that is, a degree of asymmetry in the seizure electrical activity thought to be outside the normal range of generalized epilepsy, a positive response was obtained which was not as favorable as that observed in the 18 patients with generalized epilepsy. (The authors emphasize that their use of the description 'focalization' should not be confused with focal, or partial, epilepsy; it is still a form of generalized epilepsy.) Although the present retrospective study did not include control groups or randomized treatment, the striking response obtained with valproate treatment suggests that it should be considered for all cases of absence status in patients with primary generalized epilepsy. (Consumer Summary produced by Reliance Medical Information, Inc.)

The paper published in this issue by Jutila et al (this issue, pp 486-94) adds to the literature regarding surgical treatment of temporal lobe epilepsy. (1) This paper presents results [...]