Human monoamine oxidase. Lack of brain and platelet correlation.

Monoamine oxidase (MAO) exists in two forms, MAO A and MAO B. Both are present in human brain, but the human platelet contains only MAO B. We studied whether individual variations in the activity of human platelet MAO B reflect individual variations in cerebral cortical MAO activities. Optimal conditions were determined for the measurement of MAO activities in both the platelet and cerebral cortex, obtained from 14 patients with epilepsy during clinically indicated neurosurgery. There was no significant correlation between the activities of MAO B in the cerebral cortex and platelets of these patients. Platelet MAO B activities also failed to correlate significantly with cerebral cortical MAO A activities. However, there was a significant positive correlation between cerebral cortical MAO A and MAO B activities. Individual variations in platelet MAO B activities do not reflect individual variations in either cerebral cortical MAO B or MAO A activities in patients with epilepsy who undergo neurosurgery.

Carotid occlusive disease. Effect of bright light on visual evoked response.

Four patients had severe carotid artery occlusive disease associated with ipsilateral visual blurring and exposure to bright light. Attenuation of the visual evoked response was noted after patients were exposed to an artificial source of light for 30 s. No significant abnormality of the visual evoked response was seen in the asymptomatic eyes or in the 16 eyes of eight control subjects, some of whom had carotid artery occlusive disease associated with ipsilateral venous stasis retinopathy. We concluded that ischemia of the macular region is necessary to produce these visual symptoms and that local retinal blood flow has been reduced to the flow threshold of electrical failure. These findings provide objective documentation of an abnormality that may be associated with an important symptom indicative of severe carotid artery occlusive disease.

Chronic periodic lateralized epileptiform discharges.

Six patients with chronic epilepsy had persistent periodic lateralized epileptiform discharges (PLEDs) in their interictal electroencephalographic recordings. Three patients had complex partial seizures, two had infantile spasms, and one had multifocal seizures. Four patients had cerebral pathologic changes consisting of tuberous sclerosis (two patients), a porencephalic cyst (one patient), and a chronic brain abscess (one patient). Although PLEDs are usually seen in association with an acute or subacute disturbance of cerebral function, the findings in this group of patients show that chronic PLEDs also can occur in patients with long-standing seizure disorders or chronic brain lesions.

An electroencephalographic study of glossopharyngeal neuralgia with syncope.

In the case described, electroencephalography (EEG) proved valuable for determining the nature of spells of loss of consciousness with brief clonic jerks associated with ear and throat pain. A 70-year-old woman had a history of episodic brief attacks of pain below the right ear and deep in the neck that had started three years previously. The spells became more severe and progressed to loss of awareness associated with clonic jerks of the extremities. Because of a concern that the spells represented seizures, an EEG was performed, with electrocardiographic monitoring. Multiple spells were recorded; they began with profound bradycardia followed by generalized slow-wave activity and then by suppression of all EEG activity correlating with loss of consciousness and clonic jerking. The spells were thought to represent syncopal attacks associated with glossopharyngeal neuralgia.

Brainstem auditory evoked potentials in 20 patients with palatal myoclonus.

Brainstem auditory evoked potentials (BAEPs) were obtained in 20 patients with palatal myoclonus. The group included 14 men and six women whose ages ranged from 19 to 82 years. Six of the patients had abnormal BAEPs: two with severe head trauma and one each with a brainstem infarct, tumor, demyelination, and an indeterminate inflammatory process. The 14 patients with normal BAEPs had palatal myoclonus secondary to head trauma (five patients), brainstem infarcts (four patients), cerebellar tumors (two patients), degenerative processes (two patients), and an Arnold-Chiari malformation (one patient). Since the auditory pathways are separate from the structures associated with palatal myoclonus, it is possible to have discrete lesions producing palatal myoclonus with sparing of the auditory structures, whereas diffuse or multifocal lesions of the brainstem are more likely to be associated with abnormal BAEPs.

Alpha-coma. Electroencephalographic, clinical, pathologic, and etiologic correlations.

"Alpha-coma" denotes the conjunction of clinical coma with an electroencephalographic pattern resembling that of normal wakefulness and predominantly consisting of alpha activity. Clinical, EEG, and pathologic data from 13 patients with this syndrome were reviewed. The patients were divided into two groups, based on the pathogenesis of their conditions. The first group consisted of eight patients with brain stem strokes, and the second group consisted of five patients with diffuse hypoxic encephalopathy resulting from cardiac or pulmonary arrest. There were some differences between the EEGs of the two groups. In the first group, the alpha pattern was located more posteriorly, showed more variability and reactivity, and was more persistent in sequential recordings. In the second group, the alpha activity was transient and showed little reactivity. In both groups, this pattern indicated a poor prognosis for survival.

New-onset seizures in critically ill patients.

We studied causes of new-onset seizures in 55 patients admitted to medical and surgical intensive care units between 1981 and 1991. In one-third of the patients, sudden withdrawal of narcotic agents was associated with tonic-clonic seizures. In another third, acute metabolic changes, predominantly severe hyponatremia (sodium < or = 125 mEq/l), accounted for new-onset seizures. In eight patients, drug toxicity (antibiotics and antiarrhythmic agents) predisposed to seizures. Only five patients had previously unrecognized structural CNS abnormalities that were manifested by focal or generalized tonic-clonic seizures. In six patients, the cause remained unknown. Twenty-four patients had recurrent seizures despite treatment with standard antiepileptic drugs. Status epilepticus occurred in four patients. Outcome was poor in only 34% of the patients, particularly in those with metabolic causes. Sudden withdrawal of narcotic drugs may be a significant cause of new-onset seizures in patients with life-threatening disorders.

Electroencephalographic evaluation in Sturge-Weber syndrome.

The most consistent electroencephalographic finding in 16 cases of Sturge-Weber syndrome was a unilateral reduction of background amplitude in the waking record. Comparable asymmetries were noted in those patients in whom sleep recording also was done. Physiologic responses (to hyperventilation and photic driving) usually were decreased on the involved side. These hemispheric electroencephalographic abnormalities are detectable in infancy even before the characteristic intracranial calification develops. Epileptiform activity, when focal, was limited to the involved hemisphere.

Psychologic and social adjustment to epilepsy in Rochester, Minnesota.

The psychologic and social aspects of epilepsy have rarely been assessed in community-based samples. We administered the Washington Psychosocial Seizure Inventory in 1985-1986 to 125 nonretarded adults, 18 to 59 years of age, who in 1980 had active epilepsy and resided in Rochester, Minnesota. Individuals having seizures or taking anticonvulsant medications within the past 12 months had somewhat poorer adjustment than those without recent seizures or medications, but even this more severely affected group appeared relatively well adjusted.

EEG in cough syncope.

In 17 patients with cough syncope, electroencephalograms showed normal interictal recordings in 12 patients, minimally abnormal recordings in 4, and a moderately abnormal recording in 1. Fourteen episodes of cough syncope (six patients) were recorded, with the EEGs showing diffuse theta and delta slowing during the episodes. These findings were similar to those seen during other types of syncope. Although eight patients had rhythmic or clonic-like movements during the episodes, no epileptiform activity was seen. The exact mechanism of cough syncope is not known, but the vigorous coughing probably increases CSF pressure enough to impair intracranial circulation, causing syncope due to cerebral ischemia.

A clinical and electrophysiological evaluation of myoclonus.

The records of 23 consecutive patients with myoclonus who were seen during a 16-month period were analyzed prospectively. The patients were divided into two groups: epileptic and nonepileptic. The epileptic patients had focal and stimulus-elicitable myoclonus with enlarged somatosensory evoked potentials and enhanced long-loop reflexes, and they responded well to anticonvulsants, especially clonazepam and valproic acid. The nonepileptic group had massive and spontaneous jerks with normal-sized somatosensory evoked potentials and long-loop reflexes, and they responded poorly to anticonvulsants. Evaluation of these clinical and electrophysiologic characteristics can help in the classification of obscure movement disorders and in predicting responses to therapy.

Movement-activated central fast rhythms: an EEG finding in action myoclonus.

Five patients with relatively mild but disabling action myoclonus displayed a subtle and heretofore unemphasized electroencephalographic manifestation of action myoclonus consisting of low-voltage, central fast activity somatotopically related to the extremity being used. The importance of recognizing this rhythm lies in its association with milder forms of action myoclonus which resemble other types of movement disorders, the difficulty in recognizing this rhythm unless special tests are carried out, and the beneficial response of anticonvulsant therapy if the nature of the movement is realized.

An acute syndrome with psychiatric symptoms and EEG abnormalities.

Four patients with abrupt onset of psychosis had prominent periodic EEG abnormalities with diffuse sharp waves. Other laboratory studies, including CSF and CT, were normal. The EEG abnormalities disappeared within 1 to 7 days. Clinical improvement was complete and commenced after the EEG showed improvement. The cause remains obscure, but it seems to be a transient organic disturbance of cerebral function that must be distinguished from primary psychiatric disorders.

Stimulus-induced EEG complexes and motor spasms in subacute sclerosing panencephalitis.

Patients with subacute sclerosing panencephalitis (SSPE) typically present with spontaneous periodic, stereotyped electroencephalographic (EEG) complexes and motor spasms, which are not usually affected by sensory stimuli. This report describes two patients with SSPE in whom the EEG complexes and the motor movements occurred mainly in response to afferent stimuli. Various forms of stimuli were effective in precipitating the movements and EEG complexes, particularly when the stimulus was unexpected or startled the patient. During sleep, the EEG complexes spontaneously occurred in a more periodic fashion, typical of SSPE, but afferent stimuli were still effective in evoking the EEG complexes and associated motor spasms.

Risk factors for generalized tonic-clonic seizures: a population-based case-control study in Rochester, Minnesota.

This investigation is, to our knowledge, the first population-based case-control study of prenatal, perinatal, and postnatal risk factors for generalized tonic-clonic seizures (GTCS). The clinical diagnosis of GTCS was confirmed through the independent review of the complete medical history of potential cases by three neurologists. All subjects with onset of GTCS before age 30 who were residents of Rochester, Minnesota at time of diagnosis between 1935 and 1979, and who were born in this community, were included (N = 53). Two controls were matched to each patient, and for both patients and controls, the unique records-linkage system for residents of Rochester was used to obtain information about possible risk factors. A history of convulsions in the mother, febrile seizures, and head trauma were significantly more common in cases than in controls. However, factors previously suggested such as: advanced age of the mother, previous miscarriages, gestational toxemia or eclampsia, bleeding during the index pregnancy, low birth weight, asphyxia, or postmaturity were not confirmed. Based on the present and previous studies, we suggest that different types of seizures have different risk factors and should, therefore, be investigated separately.

Gadolinium-DTPA-enhanced magnetic resonance imaging in intractable partial epilepsy.

We performed magnetic resonance imaging (MRI), before and after the administration of gadolinium-DTPA (Gd-DTPA), in 23 patients with medically refractory partial epilepsy who subsequently had surgical treatment for their seizure disorder. In most patients, 61%, unenhanced and enhanced MRI studies were negative. In 26% the unenhanced image was positive, and the abnormality enhanced with Gd-DTPA. In 13% the unenhanced MR image was positive, but the abnormality did not enhance with Gd-DTPA. Gd-DTPA does not appear to increase the diagnostic yield of MRI in the presurgical evaluation of patients with partial epilepsy if the unenhanced MRIs are normal.

Long-term follow-up of temporal lobectomy in children.

Temporal lobectomy is an effective treatment for medically intractable seizures. The change in seizure status with prolonged postoperative follow-up is unclear. The authors followed 37 patients who underwent first time temporal lobectomy during childhood for at least 15 years. This study is the longest follow-up of children who have had a temporal lobectomy for intractable seizures. It demonstrates that seizure recurrence can increase with longer duration of follow-up.

Risk factors for absence seizures: a population-based case-control study in Rochester, Minnesota.

To our knowledge, this is the first population-based case-control study of risk factors for absence seizures (AS). Diagnosis of AS was based on clinical criteria. The complete medical history of potential cases, available through the records-linkage system for residents of Rochester, MN, was independently reviewed by three neurologists who agreed upon the diagnosis. All AS patients who were residents of Rochester at time of diagnosis between 1935 and 1979, and who were born in this community, were included (N = 30). Two population controls (born in Rochester) were matched to each patient, and for both patients and controls, the records-linkage system was used to obtain information about possible risk factors. The only factor significantly more common in cases than in controls was a history of febrile seizures (odds ratio = 12; p less than 0.01). We suggest that these febrile seizures represent either an early manifestation of the convulsive diathesis or the symptom of a preexisting brain dysfunction. None of the other factors investigated reached statistical significance, including those that have been previously suggested such as twin pregnancy, breech presentation at delivery, being first-born, and perinatal asphyxia. Sample size limitations should be considered in interpreting these findings.

Surgery for focal epilepsy in the older patient.

Eight of the 237 patients who received a surgical procedure for intractable partial epilepsy at the Mayo Clinic during a 3-year period were 50 years of age or older. All patients had disabling partial seizures of several years in duration that were refractory to antiepileptic drug medication. A neuroimaging-identified epileptogenic lesion prompted referral for surgical treatment in three patients. The only clinically significant morbidity associated with surgery in the eight patients was a transient exacerbation of an aphasia in a patient who underwent a left frontal corticectomy. All eight patients had a favorable seizure outcome, and three patients postoperatively are seizure free. Epilepsy surgery may be an appropriate alternate therapy for select patients in the sixth decade of life or older with medically refractory partial seizures.

MRI assessments of hippocampal pathology in extratemporal lesional epilepsy.

We performed a prospective study in 18 patients to determine the extent of MRI-identified hippocampal pathology in patients with intractable partial epilepsy of extratemporal origin. A mesial temporal signal-intensity alteration or hippocampal formation (HF) atrophy, or both, have been shown to be reliable markers of the temporal lobe of seizure origin in patients with mesial temporal sclerosis. All patients subsequently received surgical ablative therapy between 1988 and 1992. During shortterm follow-up, 14 of the 18 patients experienced a significant reduction in seizure tendency, and 12 patients were rendered seizure-free. Qualitative and quantitative (HF volumetry) assessments of HF pathology were performed retrospectively by a blinded investigator. No hippocampal imaging alteration was present in 17 patients. Left HF atrophy was confirmed in one patient with post-traumatic epilepsy who underwent a successful right frontal lobectomy. Morphometric MRI studies rarely identify hippocampal pathology in patients with extratemporal epilepsy.