Continuous intraoperative monitoring of middle cerebral artery blood flow velocities and electroencephalography during carotid endarterectomy. A comparison of the two methods to detect cerebral ischemia.

BACKGROUND AND PURPOSE: Intraoperative monitoring of brain function may influence the outcome of carotid endarterectomy (CEA). METHODS: We performed transcranial Doppler (TCD) monitoring of middle cerebral artery blood flow velocities (VMCAs) and eight-channel electroencephalographic (EEG) recording simultaneously in 82 patients undergoing CEA. Thiopental narcosis limited EEG interpretation in 11 patients, thus allowing direct comparison of both methods in 71 patients. RESULTS: There was a significant correlation between VMCA decrease and the frequency of EEG changes after carotid clamping (P < .001). Eight patients (11%) showed a VMCA decrease exceeding 60%, accompanied by EEG changes in 7 patients. Altogether, 16 patients (22%) showed severe or moderate EEG changes. Stenosis or occlusion of the contralateral carotid artery led to an increase of abnormal findings with both monitoring methods, which was, however, significant only for TCD (P < .05). Four patients (4.8%) suffered intraoperative transient ischemic attacks. In 3 of these patients, there were no abnormal findings with either of the methods. The events were thus unpredictable and probably of embolic origin. The fourth patient showed VMCA decrease to 0 and severe EEG changes. Nine patients had severe or moderate EEG changes without significant VMCA decrease and without complications. EEG monitoring alone in these would have led to unnecessary use of a shunt with the increased risk of embolism. CONCLUSION: EEG and TCD monitoring are complementary techniques. Their results showed a good overall correlation but with marked differences in the individual patient. TCD monitoring alone was sensitive enough to prevent ischemic intraoperative complications. EEG findings are of limited value when barbiturates are used.

Quantitative comparison of language deficits produced by extraoperative electrical stimulation of Broca's, Wernicke's, and basal temporal language areas.

Subdural electrodes were implanted over the language-dominant left lateral convexity in 45 patients undergoing evaluation for epilepsy surgery. In 29 patients, additional electrodes were placed over the left basal temporal cortex. We identified language areas by using intermittent electrical stimuli applied while patients read aloud. Aphasia was classified as expressive or receptive based on additional testing performed when electrical stimulation elicited reading arrest in the absence of direct excitatory or inhibitory motor effects. Using correlated logistic regression, we noted no statistically significant differences among Broca's, and Wernicke's areas and the basal temporal language area (BTLA) regarding the frequency with which electrical stimulation interfered with language. Speech production deficits, however, occurred significantly more frequently in Broca's than in Wernicke's area (p = 0.012). In contrast, language comprehension deficits occurred with equal frequency when Broca's and Wernicke's areas were stimulated. These results suggest that both Broca's and Wernicke's areas play important roles in language comprehension and that the primarily expressive aphasia of patients with lesions of Broca's area results mainly from the predominant participation of Broca's area in language production.

Prolonged epileptic apneas in a newborn: a case report with ictal EEG recording.

We report a case of repetitive and prolonged apneas, correlating with EEG-focal epileptiform discharges over the right temporal region, in a full-term newborn. After administration of phenobarbital the apneas completely ceased. The neurological examination, the psychomotor development, and the EEG at the age of 12 months were normal. The prolonged duration of the epileptic apneas, the ictal rhythmic delta wave activity, and the favorable outcome distinguish our patient from the majority of previously reported cases.

Anatomic distribution of cortical language sites in the basal temporal language area in patients with left temporal lobe epilepsy.

In evaluation for surgical treatment of intractable psychomotor seizures originating in the language-dominant left mesiotemporal region, subdural grid electrodes were placed in 29 patients over the temporoparietal cortex and over the basotemporal region. In 13 patients, cortical stimulation of the basotemporal region showed interference with language processing. The most anterior border of the basotemporal language area began 1.1 cm posterior to the anterotemporal tip, and the most posterior margin of the language region was located 6.1 cm posterior to the temporal tip. The most lateral and the most mesial border were located 1.4 and 5.9 cm, respectively, from the lateral edge of the temporal lobe. The region in which language disturbance could be elicited included the inferior temporal gyrus, the fusiform (lateral and medial occipitotemporal) gyrus, and the parahippocampal gyrus. The basotemporal area most consistently involved with language function was the fusiform gyrus (60% of affected electrodes), followed by the inferotemporal (30%), and the parahippocampal (10%) gyri.

Rapid reversibility of autoinduction of carbamazepine metabolism after temporary discontinuation.

Patients in whom carbamazepine (CBZ) monotherapy is discontinued for preoperative EEG/video monitoring often display toxicity if their previous maintenance dosage is resumed, even after a few days without CBZ. To determine whether this is due to rapid reversibility of autoinduction of CBZ metabolism, single-dose studies of CBZ pharmacokinetics were performed before and after discontinuation for monitoring in 6 adults receiving CBZ monotherapy. The CBZ-free period was 5.7 +/- 1.1 days (mean +/- SD). The pharmacokinetic parameters of CBZ before and after discontinuation were volume of distribution (Vd) 1.28 +/- 0.29 versus 1.22 +/- 0.331/kg (NS), elimination half-life (t1/2) 13.7 +/- 1.67 versus 22.2 +/- 2.36 h (p < 0.001), and clearance (Cl) 1.54 +/- 0.39 versus 0.92 +/- 0.32 L/kg/day (p = 0.012). Assuming that deinduction is a first-order process, a deinduction t1/2 of 3.84 days was obtained by log linear regression analysis. We showed that after CBZ discontinuation half of the enzymatic autoinduction is already lost after 3.84 days, indicating very rapid deinduction. Our results also provide the necessary information to predict clearance and appropriate dosage reduction for CBZ at time of reintroduction.

Comprehension deficits elicited by electrical stimulation of Broca's area.

We report on three patients with intractable focal seizures arising from the language-dominant left hemisphere. In the work-up prior to surgical treatment, arrays of subdural electrodes were placed over the left temporal lobe and adjacent supra-Sylvian region. Electrical stimulation of the inferior frontal cortex language region ('Broca's area') produced marked interference with language output functions including speech arrest, slowing of oral reading, paraphasia and anomia. At some cortical language sites in this region cortical stimulation also produced language comprehension deficits, particularly in response to more complex auditory verbal instructions and visual semantic material. The severe impairment of comprehension verbal information was in clear contrast with ability to process non-verbal material, which was not affected.

Arousal responses to added inspiratory resistance during REM and non-REM sleep in normal subjects.

BACKGROUND: Arousal in response to increased airflow resistance during sleep, especially rapid eye movement sleep (REM), could be an important protective mechanism against asphyxia. METHODS: The arousal response to the application of an external inspiratory resistance of 25 cm H2O/l/s was determined during REM and non-REM sleep in ten healthy men. RESULTS: The number of arousals occurring within two minutes of the load application was significantly higher during REM sleep than during either of the non-REM sleep stages 2 and 3/4, and was similar to that during stage 1. The proportion of arousals to non-arousals decreased significantly from stage 1 to stage 4. The mean time to arousal in REM was significantly shorter than in non-REM stages 1, 2 or 3/4 and increased significantly from stage 1 to stage 3/4. The duration of sleep (comparing the results of the first with the second half of the sleep period time) did not modify the arousal response in stages 2 and 3/4. CONCLUSIONS: The results show a significantly increased arousal response to an added inspiratory resistive load in REM sleep compared with non-REM sleep stages 2, 3 or 4 in normal men. In the context of previous studies these data could add support to the hypothesis that the decreased arousal response during REM sleep in patients with sleep apnoea might be due to an impairment of the normal "central processing" of this stimulus.

[Epilepsy and pregnancy]. / Epilepsie und Schwangerschaft.

Epilepsy affects almost 1% of all pregnant women. The effect of pregnancy upon epilepsy is unpredictable for the individual patient. In one third to one half of the patients epilepsy had no effect on seizure frequency, in one fourth to one third of the patients seizure frequency increased, and in one third to one fourth it improved. Several reasons are discussed for a frequently observed tendency to a drop in plasma concentration of antiepileptic drugs during pregnancy where the daily dose was kept unchanged. For unknown reasons, perinatal lethality is up to twice as high as in controls. The risk of bearing children with malformations is approximately 1.5-3 times higher for mothers with epilepsy than in non-epileptic mothers. Apart from antiepileptic drugs the role of genetic factors, the type and severity of epilepsy and the possible influence of grand-mal seizures during pregnancy must be considered to be involved in congenital anomalies. Polypharmacy produces more frequent anomalies than monotherapy. Valproate should be avoided in the pregnant women due to the increased incidence of neural tube defects. At this time there is no reason to discourage a mother on antiepileptic drug therapy from breast feeding.

[Results in microsurgical carotid artery endarterectomy]. / Ergebnisse der mikrochirurgischen Karotisendarteriektomie.

100 consecutive carotid endarterectomies were performed by a microscopic technique with monitoring of cerebral perfusion by transcranial Doppler sonography and EEG. No additional cerebral deficits occurred in this series. Perioperative mortality due to medical complications occurred in 2 instances. During the average follow-up period of 15 months, 1 patient suffered a lethal cerebral infarction ipsilateral to the operated carotid artery and 1 patient a contralateral minor stroke. 2 patients died from unrelated causes during follow-up.

[Epileptic seizures in patients with a cerebrovascular infarction]. / Epileptische Anfälle bei Patienten mit zerebrovaskulären Insulten.

In view of the possible occurrence of epileptic manifestations and possible factors predisposing to them, the clinical course of 90 cerebral infarct patients was studied retrospectively and prospectively in a medical rehabilitation department for an average of 29 1/2 months. The following results were obtained: "prodromal" seizures (i.e. those preceding a cerebral insult) were not detectable in any of the study patients. 25 patients (27.7%) suffered epileptic seizures, 1 (1.1%) in the acute insult phase only, 2 (2.2%) in this as well as in the later phase, and 22 (24.4%) in the late phase only. All seizures in the acute insult phase were focal-motor or secondary generalized. Among all 24 patients (26.6%), the latency of late epileptic manifestations ranged from 2 1/2 months to 3 3/4 years and averaged about 12 months. Patients with cortical or cortical-subcortical brain lesions suffered epileptic seizures-as reported in the literature-significantly more frequently than those with exclusively subcortical insults. Based on the features of the focal (motor or psychomotor) seizures and/or interictal focal EEG spikes, there was clear evidence of a focus giving rise to epileptic discharges in the insulted hemisphere in 75% of the patients with late seizures. Under antiepileptic therapy (chiefly with phenytoin), the seizure frequency was slight (not exceeding 2 per year in 3/4 of the patients).

Results of microsurgical carotid endarterectomy. A prospective study with transcranial Doppler and EEG monitoring, and elective shunting.

100 consecutive carotid endarterectomies in a total of 93 patients were performed using the operative microscope. Cerebral perfusion and activity were monitored with simultaneous transcranial Doppler (TCD) and EEG. Thiopentone for cerebral protection was given prior to carotid clamping in 11 cases when an insufficient collateral circulation was suspected on the basis of the pre-operative TCD or angiography and if temporary intraluminal shunting was to be avoided because of a high bifurcation, long stenosis or associated carotid artery kinking. A temporary intraluminal shunt was inserted electively if the mean middle cerebral artery flow velocity fell after cross-clamping below 30-40%. Direct closure of the arteriotomy was preferred over a patch graft, which was performed only in cases with concomitant stricture of the arterial wall. No peri-operative strokes occurred in the present series. Two patients died due to medical complications in the post-operative period. During the mean follow-up of 15 months, 1 patient suffered a lethal stroke ipsilateral to the treated carotid artery and another patient had a minor contralateral stroke. Two patients died of unrelated causes during follow-up. Two patients suffered a single reversible neurologic deficit corresponding to the treated carotid territory. Four other patients had a single contralateral hemispheric or retinal reversible ischaemic attack during follow-up.

[Epileptic activity of the occipital lobe. Clinico-electroencephalographic contribution]. / Zur Frage der epileptischen Aktivität des Okzipitallappens. Klinisch-elektroenzephalographischer Beitrag.

Our analysis of the course of illness in 14 patients, whose common electroencephalographic characteristic was epileptogenic activity in the occipital area, showed very different clinical symptoms. The first group comprised patients who presented bilateral amaurosis. In four of these cases, the occipital hypersynchronous EEG activity was merely a secondary symptom of either ischaemic hypoxia or of a degenerative process in the occipital visual cortex and was not responsible for the genesis of the actual blindness. In two further cases of monosymptomatic temporary loss of vision, it was difficult to make a differential diagnosis between ictal blindness, respectively status epilepticus amauroticus occurring in a occipital lobe epilepsy and a migraine attack involving the basilar territory. The second group comprised five patients with paroxysmal visual hallucinations respectively illusions. Three of them suffered from hallucinations of the elementary type, respectively flickering fits in the hemianopic field, symptoms which are based on discharges in the visual cortex of the occipital lobe. In a case of one patient with complex visual hallucinations as well as in a further case with visual illusions, it was not possible to find out with certainty their place of origin. A study of these cases shows that the cortical or sub-cortical functional disturbance within the visual system causing the various optical deformations and visual hallucinations, form an inhomogeneous group with different etiology. In the only patient belonging to the third group, whose seizures were i.a. characterized through motor phenomena in the field of the ocular organs and the tonic lateral turning movement of the bulbi of the eyes and of the head, an occipital epileptic crisis with spread of discharges from the occipital pole to the frontomesial surface should be assumed. The occurrence of complex partial seizures, respectively generalized tonic-clonic attacks in two patients of the fourth group who have definite epileptogenic EEG-activity in the occipital area, can be explained by a propagation of paroxysmal activity to the temporal lobe or to the motor cortex. Because of the marked tendency to propagation of the hypersynchronous activity originating in the occipital lobe, many combinations of sensory and/or motor symptoms can occur within the frame-work of occipital epileptic seizures. On the basis of one scalp EEG finding, no final localizing conclusions may be drawn here.

Electroencephalographic findings in children treated with cytotoxic agents.

106 EEG investigations were carried out in 17 children with various types of neoplastic disease without cerebral involvement during one or more courses of treatment with cytotoxic agents. EEGs were recorded before and 24 h after administration of the drugs. A transient slowing of the dominant frequency in the alpha-band by about 1 c/s and a decrease in the relative power of alpha-activity by 20-30% was observed in only 4 patients. These children did not receive the same antineoplastic treatment. 1 patient received very high dose methotrexate, 2 patients received vincristine combined with other cytotoxic agents, and the other patient received L-asparaginase. It is suggested that EEG changes in patients receiving intravenous cytotoxic treatment usually occur only where there is a preexisting impairment of the blood-cerebrospinal fluid barrier or the blood-brain barrier.

[Long-term EEG course study in patients with Creutzfeldt-Jacob disease]. / Langzeitige EEG-Verlaufsuntersuchung bei einem Patienten mit Creutzfeldt-Jakobscher Erkrankung.

In a patient with Creutzfeldt-Jakob disease subsequently confirmed by autopsy, 34 EEGs were carried out in a 14 months period. 6 weeks after the beginning of the prodromal stage of the disease a triphasic, periodic activity was recorded for the first time. This activity was maximally in evidence at 15th week. A synchrony occurring between repetitive complexes and myoclonic jerks could between repetitive complexes and myoclonic jerks could only be observed during one recording. From the 5th month onwards the intensity of the periodic EEG pattern, seen longitudinally, gradually decreased. In the time-span from the 10th to the 13th month considerable fluctuations of periodic activity were found, this during the course of one as well as between different EEG recordings. These could reach from a pronounced typical pattern to complete disappearance of periodic triphasic complexes. As possible causes for these fluctuations, we discussed a variable driving by the subcortical pacemaker as well as a decreased capability of cerebral cortex--gradually loosing so many neurons--to react to subcortical stimuli. From the 14th month onwards the periodic activity no longer could be put in evidence. In the last EEG recorded 3 days before death isoelectric periods alternated with paroxysmal delta waves respectively sharp and slow wave complexes.

Conventional and spectral EEG analysis in children treated with cytotoxic agents.

One hundred and six EEG investigations were carried out in 17 children with various types of neoplastic disease without cerebral involvement during one or more courses of treatment with cytotoxic agents EEGs were recorded before and 24 hr after administration of the drugs. The EEGs were evaluated visually and by spectral analysis. A transient slowing of the dominant frequency in the alpha band by about 1 Hz and a decrease in the relative power of alpha activity by 20-30% was observed in only 4 patients. These children did not show any clinical or biochemical signs of neurotoxicity. The children did not receive the same antineoplastic treatment. One patient received very high dose methotrexate, 2 patients received vincristine combined with other cytotoxic agents and the other patient received L-asparaginase. It is suggested that EEG changes in patients receiving intravenous cytotoxic treatment usually occur only where there is pre-existing impairment of the blood--cerebrospinal fluid barrier or blood-brain barrier. No clinical signs of epilepsy, new epileptiform waves in the EEG or long-term changes in the background activity of the EEG were observed in this pilot study.

[Recurring paroxysmal abdominal pains of cerebral origin]. / Rezidivierende paroxysmale abdominale Schmerzen zerebraler Genese.

Cerebral origin of relapsing paroxysmal abdominal pains is discussed in the light of six case histories, other personal observations and the literature. The pains are assumed to be due to locally limited epileptic discharges in areas of the cortex where the digestive tract is represented. When the neuronal discharges reach other brain formations, multisymptomatic, partial or generalized epileptic seizures occur. In such cases, therefore, the abdominal symptomatology is either a first stage or a rudiment of a more complex course of attack, and should not be considered as the expression of a particular form of epilepsy that might be termed abdominal epilepsy. Difficulties regarding differential diagnosis ensue in the case of migraine with abdominal symptomatology. The latter should be taken into account when relapsing attacks of abdominal pain, which cannot be explained gastroenterologically, persist for hours and alternate with headache. In case of doubt, a family history of migraine confirms the diagnosis.