Epilepsy surgery in tuberous sclerosis: The Dutch experience

SummaryIntroductionEpilepsy associated with tuberous sclerosis complex (TSC) is drug resistant in more than half of the patients. Epilepsy surgery may be an alternative treatment option, if the epileptogenic tuber can be identified reliably and if seizure reduction is not at the expense of cognitive or other functions. We report the pre-surgical identification of the epileptogenic tuber and post-surgical outcome of patients with TSC in The Netherlands.MethodsTwenty-five patients underwent the pre-surgical evaluation of the Dutch Comprehensive Epilepsy Surgery Programme, including a detailed seizure history, interictal and ictal video EEG registrations, 3D FLAIR MRI scans and neuropsychological testing. Suitability of the candidates was decided in consensus. Seizure outcome, scored with the Engel classification, and cognition were reassessed at fixed post-surgery intervals.ResultsEpilepsy surgery was performed in six patients. At follow-up, four patients had Engel classification 1, two had classification 4. Improved development and behaviour was perceived by the parents of two patients. Epilepsy surgery was not performed in 19 patients because seizures were not captured, ictal onset zones could not be localised or were multiple, interictal EEG, video EEG and MEG results were not concordant, or seizure burden had diminished during decision making. A higher cognition index was found in the surgical patients compared to the non-surgical candidates.ConclusionsEpilepsy surgery can be performed safely and successfully in patients in whom semiology, interictal EEG, ictal EEG, MEG and the location of tubers are concordant. In other cases the risk of surgery should be weighed against the chance of seizure relief and in case of children subsequent impact on neurodevelopment

The EEG in the diagnosis of subdural empyema

The EEG findings in 9 patients with a subdural empyema are reported. In all cases the EEG, recorded before the diagnosis had been established, contained focal zeta waves, extensive unilateral depression of cortical activity and, in all but one, a diffuse slowing of the background activity. This combination has not been reported before in the literature and it is concluded that in its presence the existence of a subdural empyema should be seriously considered. Comparison with CT scan findings in 3 cases indicated that sometimes EEG may be more sensitive than CT scanning in the diagnosis of subdural empyema. The value of EEG and CT scan in the diagnosis of patients with an acute or subacute bacterial meningo-encephalitis is briefly discussed

Changes in quantitative EEG and blood flow velocity due to standardized hyperventilation ; a model of transient ischaemia in young human subjects

A standardized hyperventilation (HV) procedure has been developed in which the end-tidal pCO2n was decreased to 2 kpa. In 24 young male subjects blood flow velocity and qEEG were studied before, during and after HV. This standardized hyperventilation procedure gave rise to a decrease in blood flow velocity to 40% of baseline value and highly significant qEEG changes in 3 derivations. Both relative and absolute band power estimates showed an increase in slow activity and a decrease in alpha and beta activity. The use of subtraction spectra led to a more precise and detailed presentation of these changes than the use of classical qEEG parameters. These changes were reproducible after 1 week. The effects found in the presented model of HV-induced ischaemia appeared to be twice as large as those found in a model of hypobaric hypoxia. The present model might be used to test the efficacy of anti-ischaemic drugs in young human subjects

Cerebrovascular reactivity in patients with a recent lacunar infarction.

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The EEG in the diagnosis of subdural empyema

The EEG findings in 9 patients with a subdural empyema are reported. In all cases the EEG, recorded before the diagnosis had been established, contained focal zeta waves, extensive unilateral depression of cortical activity and, in all but one, a diffuse slowing of the background activity. This combination has not been reported before in the literature and it is concluded that in its presence the existence of a subdural empyema should be seriously considered. Comparison with CT scan findings in 3 cases indicated that sometimes EEG may be more sensitive than CT scanning in the diagnosis of subdural empyema. The value of EEG and CT scan in the diagnosis of patients with an acute or subacute bacterial meningo-encephalitis is briefly discussed

Association between impaired carbon dioxide reactivity and ischemic lesions in arterial border zone territories in patients with unilateral internal carotid artery occlusion

Item does not contain fulltextCONTEXT: Ischemic lesions in patients with internal carotid artery (ICA) steno-occlusive disease can be categorized on the basis of their location and presumed cause: external border zone infarcts, internal border zone infarcts, cortical infarcts, lacunar infarcts, and periventricular lesions. OBJECTIVE: To evaluate the association between the prevalence and size of ischemic lesions and cerebral vasomotor reactivity in patients with unilateral occlusion of the ICA. DESIGN: Cross-sectional study. SETTING: Referral center. PATIENTS: Seventy consecutive patients were included in this study. All patients had a transient or minor disabling retinal or cerebral ischemia that was associated with unilateral occlusion of the ICA. Ischemic lesions on magnetic resonance imaging were identified on hard copies, and volume measurements were obtained by a magnetic resonance workstation. Vasomotor reactivity was assessed with transcranial Doppler ultrasonography with carbon dioxide challenge. MAIN OUTCOME MEASURES: Prevalence and size of ischemic lesions. RESULTS: In the hemisphere ipsilateral to the ICA occlusion, we found an increased prevalence of internal border zone infarcts (P =.01), external borders zone infarcts (P<.001), and territorial infarcts (P =.02) compared with the contralateral hemisphere. Hemispheres with a carbon dioxide reactivity less than or equal to 18% demonstrated a significant increase in prevalence (P =.007) and volume (P =.003) of internal border zone infarcts compared with hemispheres with a carbon dioxide reactivity greater than or equal to 19%. No association between carbon dioxide reactivity and any other type of ischemic lesion was found. CONCLUSION: In patients with an ICA occlusion, only internal border zone infarcts demonstrate a significant association with diminished cerebral hemodynamics

EEG evidence for shunt requirement during carotid endarterectomy: optimal EEG derivations with respect to frequency bands and anesthetic regimen.

Item does not contain fulltextCurrently there is no consensus on the derivations that should be used for EEG monitoring during carotid endarterectomy (CEA). The aim of this study was to determine which derivations distinguish the best between patients requiring a shunt and patients who do not need a shunt. Four predefined frequency bands and two regimens for general anesthesia (isoflurane versus propofol) were used. EEG data (16 channels) were obtained from 152 EEGs recorded during carotid endarterectomy. Analog EEG signals of preclamp and clamp periods of 100 seconds were digitized to compute power spectra. Changes in power during clamping were calculated for all possible derivations in four predefined frequency bands and were expressed as Z-scores. For each derivation, the area under the receiver operating characteristics curve was calculated. Derivations with the greatest area under the receiver operating characteristics curve were considered to distinguish the best between the shunt and the nonshunt groups formed in retrospect on the basis of consensus between three independent and experienced board-certified electroencephalographers. The two different anesthetic regimens resulted in different patterns of EEG changes because of clamping. The optimal derivations to differentiate between the shunt and the nonshunt groups also differed for the two anesthetic regimens, although for both conditions, anterior head regions were especially preferred. The optimal derivations are given for each anesthetic regimen