P300 auditory event-related potentials in nontraumatic coma. Association with Glasgow Coma Score and awakening.

Auditory event-related potentials (ERPs) were performed in 20 patients with nontraumatic coma to determine the presence of a P300 ERP in coma and its association with the Glasgow Coma Score and awakening (Glasgow Outcome Score, > or = 3). A standard "oddball" paradigm was used: frequent tone, 1 kHz; rare tone, 2 kHz and 4 Hz; probability, 20%. The Glasgow Coma Score was determined concurrently with the P300 ERP. Thirty percent (6/20) of the comatose patients had a P300 ERP. The mean Glasgow Coma Score was significantly higher for those with a P300 ERP. Eighty-three percent (5/6) of those with a P300 ERP awoke. Presence of a P300 ERP was associated significantly with awakening, but absence of a P300 ERP did not preclude it.

Outcomes of pregnancy associated with antiepileptic drugs.

OBJECTIVE: To determine whether exposure to antiepileptic drugs during pregnancy is associated with poor fetal outcomes (anomalies and death) and to assess the relative risks with phenobarbital, phenytoin sodium, and carbamazepine. DESIGN: The design was a prospective case-control cohort study of pregnant women with epilepsy and their offspring. Outcomes were compared with those of a control group of 355 healthy women and their offspring. SETTING: The obstetrics service at Los Angeles County/University of Southern California Medical Center, Los Angeles, a large, inner-city, teaching hospital. PATIENTS: Two hundred eleven subjects who were pregnant during the years 1987 through 1990, 174 of whom were delivered of infants, were available for analysis. A control group of 355 healthy women and their offspring from the same hospital were randomly selected from a computerized database. INTERVENTION: None. MAIN OUTCOME MEASURE: Anomalies and fetal death were the primary outcome measures. RESULTS: Offspring of women with epilepsy who were exposed to antiepileptic drugs had a higher rate of fetal death and anomalies than did the control population (P = .001). Abnormal outcomes were associated with the three major antiepileptic drugs (carbamazepine, phenytoin, and phenobarbital). In terms of abnormal outcome (death and anomalies), phenobarbital was associated with the highest relative risk, phenytoin with intermediate relative risk, and carbamazepine with the lowest relative risk (P = .019). Numbers were insufficient for assessment of risk associated with valproic acid. CONCLUSION: All three major antiepileptic drugs (phenobarbital, phenytoin, and carbamazepine) are associated with an increased risk of fetal death and anomalies. We found phenobarbital to be most associated with poor pregnancy outcome.

Agenesis of the corpus callosum: limits of functional compensation.

Two patients with radiologically confirmed total agenesis of the corpus callosum, and free of gross focal hemispheric pathology, received a battery of lateralized and free-field language and perceptual-motor tests. These tasks allowed a comparison of (1) agenic findings with previous results from surgical commissurotomy patients, and (2) the inter- and intrahemispheric performance for each agenic subject. In general, the results indicate that the two agenic patients do not demonstrate the marked deficits of cross-integration reported after commissurotomy. However, there was an upper limit to their integrative capacity for visual, and to an even greater extent, for fine motor and kinesthetically mediated performance. The tasks that proved particularly difficult appeared to have common factors which may be related to functional capabilities of the ipsilateral motor pathways and anterior commissure.

Abnormal visual evoked potentials in myotonic dystrophy.

Pattern-shift visual evoked potentials (VEPs) were recorded in 17 patients with myotonic dystrophy. Abnormalities of latency or amplitude were found in 10 patients (59%) with no obvious retinal or other significant ocular abnormality. All patients had a visual acuity of 20/30 or better. Since most patients had bilateral VEP abnormalities, localization of the disturbance was not certain.

Serum neuron-specific enolase in the major subtypes of status epilepticus.

OBJECTIVES: To determine the relative magnitudes of neuron-specific enolase (NSE) levels after complex partial status epilepticus (SE), absence SE, generalized convulsive SE, and subclinical generalized convulsive SE (frequently referred to as acute symptomatic myoclonic status epilepticus). BACKGROUND: NSE is a marker of acute brain injury and blood-brain barrier dysfunction, which is elevated in SE. METHODS: Serum NSE levels were drawn in 31 patients 1, 2, 3, and 7 days after SE. Patients were classified as acute symptomatic or remote symptomatic, and the duration and outcome of SE were determined and correlated with the peak NSE level. RESULTS: NSE was elevated significantly in all four subtypes of SE, but NSE levels were highest in complex partial and subclinical SE. The mean peak NSE level for the complex partial SE group was 23.88 ng/mL (n = 12), 21.5 ng/mL for absence SE (n = 1), 14.10 ng/mL for the generalized convulsive SE group (n = 12), and 37.83 ng/mL for the subclinical SE group (n = 6), all of which was significantly higher than normal control subjects (5.02 ng/mL). Outcome was significantly different between the three groups (p = 0.0007), and was significantly worse for subclinical SE (p = 0.0005, subclinical versus generalized convulsive SE). CONCLUSION: Serum NSE levels were highest in complex partial and subclinical generalized convulsive SE. The extremely high levels of NSE in subclinical SE reflect the severity of the acute neurologic insults and poor outcome common to subclinical SE. High NSE levels in complex partial SE reflects the long duration of SE in this subgroup, and potential for brain injury.

Serum neuron-specific enolase in human status epilepticus.

Neuron-specific enolase (NSE) is a sensitive marker of brain injury after stroke, global ischemia, and coma. We report changes in serum NSE (s-NSE) in 19 patients who sustained status epilepticus. s-NSE peaked within 24 to 48 hours after status epilepticus. The mean peak s-NSE level for the entire group was elevated compared with the levels for normal controls (24.87 ng/ml versus 5.36 ng/ml, p = 0.0001) and for epileptic controls (24.87 ng/ml versus 4.61 ng/ml, p = 0.0001). The mean peak s-NSE level for the 11 subjects without an acute neurologic insult (15.44 ng/ml) was also significantly increased compared with levels for normal and epileptic controls. Further, s-NSE was significantly correlated with outcome and duration. We conclude that s-NSE is a promising in vivo marker of brain injury in status epilepticus and warrants further study in larger populations.

Voluntary control of two lateralized conscious states: validation by electrical and behavioral studies.

A subject is described who can voluntarily select and hold either of two qualitatively different states of consciousness. Evidence is presented which confirmed differential left or right hemisphere dominance in each state. Asymmetries of EEG alpha and task performance scores indicated a state-dependent shift in functional lateralization. Evoked response studies showed directional changes in rate of interhemispheric transmission correlated with state-related hemisphere dominance. These findings demonstrated that capability for voluntary endogenous control of cerebral dominance under natural conditions.

Transcallosal, interfornicial approaches for lesions affecting the third ventricle: surgical considerations and consequences.

A group of 11 patients with a variety of lesions affecting the 3rd ventricle have been treated using a direct transcallosal interfornicial approach to the region. In 3 patients, no attendant hydrocephalus was present. In an effort to minimize potential cortical injury related to the approach, we studied the venous anatomy in the region of the coronal suture. Based on this study, appropriate flap placement and interhemispheric entry points were defined. Although no lasting, clinically apparent morbidity was observed in any of the 11 cases, we performed more sophisticated studies of the interhemispheric transfer of somesthetic and perceptual motor tasks, as well as psychometric testing related to parameters of intelligence and memory, 3 to 8 months postoperatively in 6 cases. The results and clinical material indicate that this surgical technique is a safe, feasible alternative in the management of a wide spectrum of pathological lesions within this region. A transcallosal, interfornicial approach offers excellent visualization of the entire 3rd ventricle without the dependence on hydrocephalus or an extensive extra-axial mass to enhance the exposure. With proper planning and technique, it may be accomplished with a minimum of physiological consequence.

Significance of multimodality evoked potential abnormalities in sarcoidosis.

To assess central nervous system (CNS) involvement with normal CNS examination, multimodality evoked potentials were obtained in 25 patients with confirmed multisystem sarcoidosis. Twelve patients had abnormal evoked potentials: brainstem auditory evoked potentials (BAEP) were abnormal in 5, median nerve somatosensory evoked potentials (SEP) were abnormal in 4, and visual evoked potentials (VEP) were abnormal in 6 patients. Contrast-enhanced magnetic resonance imaging (MRI) of the brain in two patients with abnormal evoked potentials revealed no supportive structural lesions. Multimodality evoked potentials can detect subclinical neurosarcoidosis and are an important adjunct to neuroradiology in the diagnosis of neurosarcoidosis.

Unruptured intracranial aneurysms: seizures and antiepileptic drug treatment following surgery.

Twenty-one patients operated on for unruptured intracranial aneurysms were studied retrospectively in order to identify the incidence of postoperative seizures, factors predictive of seizures, and the response to discontinuation of antiepileptic drugs. The overall risk of postoperative seizures in initially seizure-free patients was 15.7%. Although seizures were not uncommon, antiepileptic drugs were successfully tapered in most of the patients before 12 months.

Visual evoked response correlates of cerebral specialization after human commissurotomy.

Visual evoked responses (VERS) were recorded from commissurotomy patients and normal subjects in order to investigate the electrophysiological correlates of cerebral lateralization and independent hemispheric processing. A verbal task consisted of detecting rhyming words and a spatial task consisted of comparing matching shapes. Stimuli were delivered, by means of a computer graphic display, into the right visual field, the left visual field, or both visual fields. Behavioral results and evoked response waveforms showed lateralization for verbal processing in the left hemisphere for the patient group. Analysis of variance of product moment correlation coefficients between VER waveforms indicated significant differences between unilateral and bilateral stimulation for both patients and normals. Commissurotomy and normal VERs showed similar patterns of correlation when verbal stimuli were delivered to the left hemisphere, but differed during right hemisphere stimulation. The results are discussed in terms of VER correlates of visual-verbal processing.

Frequency analysis of the EEG in children with sickle cell disease.

An automated technique for EEG frequency analysis was employed in the study of nine children with sickle cell disease. Quotients, Q(1) (delta+theta/alpha+beta) and Q(2) (theta/alpha+8), were calculated from the computed power in each frequency range. Recordings from occipital-parietal and temporal-frontal areas resulted in a higher Q(1) for sickle cell disease patients than for reported normals (p<.002 and p<.05 respectively). Q(2) value from the occipital-parietal sites were also higher for the sickle cell group (p<.05).The technique reported here lends itself to serial studies in appropriate patient groups and suggests the possibility of an organic basis for some of the results found.

Language after dominant hemispherectomy.

Linguistic and related cognitive abilities were investigated two years after dominant left hemispherectomy for cerebral malignancy in a 12 year old female. Auditory comprehension of speech was superior to other modes of language abilities with expressive speech being the least developed. Findings suggested an isolation or non-communication between the systems for speaking and for writing and visual perception. It was concluded that language mechanisms in the right hemisphere were not just at a low level of development of the functions found in the dominant hemisphere but were modified as a result of interference by preexistent spatioperceptual systems.

Short-latency somatosensory evoked potentials in myotonic dystrophy: evidence for a conduction disturbance.

Short-latency somatosensory evoked potentials were recorded in 13 patients with myotonic dystrophy (MyD). The MyD were compared with age-matched controls. The mean conduction latency between the brachial plexus and dorsal column nuclei (EP-N14) was significantly longer for the MyD. Results suggest an afferent conduction disturbance in MyD.

Effect of noise masking on the brain-stem and middle-latency auditory evoked potentials: central and peripheral components.

Brain-stem (BAEP) and middle-latency (MLAEP) auditory evoked potentials were recorded in zero noise and in 3 levels of continuous ipsilateral broadband noise. New information is presented on the effects of noise on BAEP wave I. Latency of wave I was not changed by increasing noise, but wave V latency linearly increased. Amplitude of waves I and V decreased non-linearly. The amplitude decrease was equivalent for both waves and occurred only at the higher noise levels. The dissociation of latency effects for waves I and V indicates a central component for the effect of noise on latency. The parallel amplitude change for waves I and V suggests a largely peripheral component. The MLAEP Pa latency also increased with increasing noise further supporting a central mechanism.

Interhemispheric transmission: assessment with vibratory somatosensory evoked potentials.

Interhemispheric transmission time (ITT) was derived from vibratory somatosensory evoked potentials (VSEP) arising in homologous cortical sensory--association areas of normals. Two different vibratory sources, an audiometer bone oscillator or an Optacon, were used to stimulate each index finger independently. ITT was calculated by subtracting the latency of the first major peak over the contralateral cortex (CL) from the latency of the corresponding peak over the ipsilateral area (IL-CL = ITT). Readily identified aberrant values were observed and rejected from the series of measurements leaving clear normal ranges. In addition to providing normal ITT data, clinical correlations were illustrated in two different disorders. Results suggested that important information relating to diagnosis and therapy of brain pathologies affecting interhemispheric transmission can now be made available in both experimental and clinical situations.

Assessment of median nerve somatosensory evoked potentials in cerebral ischemia.

Seventy patients with cerebral ischemia (21 with transient ischemic attack and 49 with stroke) were studied with short-latency median nerve somatosensory evoked potentials to characterize the evoked potentials in all ischemic patients and to investigate their efficacy for prognosis in stroke. Within 72 hours of symptom onset, all 70 patients received a scaled neurologic function score, with a maximum of 50 points. Somatosensory evoked potential abnormalities were found in 10% (2/19), 42% (15/36), and 93% (14/15) of all patients with initial neurologic examinations who had normal (50 points), mild-moderate (30-49 points), and severe deficits (less than or equal to 29 points), respectively. Thirty-seven of the 49 stroke patients were available for a follow-up neurologic assessment. Eight-nine percent (8/9) of the stroke patients with poor outcome had somatosensory evoked potential abnormalities; 82% (9/11) of the stroke patients with severe neurologic deficits at onset had poor outcome. Results demonstrate that somatosensory evoked potential abnormalities are common in patients with cerebral ischemia but that somatosensory evoked potential findings are not significantly better than a detailed neurologic examination in predicting outcome from stroke.

Noradrenergic cerebral stimulation of sensorineural impaired subjects: yohimbine effects on speech intelligibility and the auditory brain response.

Norepinephrine has been shown to improve signal-to-noise ratios of sensory systems, including that of the auditory system. Yohimbine has been observed to cause a selective increase of cerebral norepinephrine. It was administered in one dose to sensorineurally impaired subjects with the object of improving their speech hearing in noise. Speech intelligibility was measured by the adaptive procedure. Mild, significant improvement was noted in one of the hearing components, "attenuation," and an adverse effect was shown on "distortion," owing to noise. Auditory brainstem response was improved significantly. The objective of temporarily improving intelligibility in noise was not attained.

Migraine: a diagnostic test for etiology of food sensitivity by a nutritionally supported fast and confirmed by long-term report.

A diagnostic procedure during a nutritionally supported fast week followed by conventional food sensitivity management achieved major improvement for 80% of a migraine panel. This procedure gave a reliable (0.8 correlation coefficient) prognosis on the substantial value of this approach for selection of the treatment of migraine. The study gave two lines of evidence which indicate that migraine has an etiology of food sensitivity.