Misdiagnosis of epileptic and non-epileptic seizures in a neurological intensive care unit.

OBJECTIVE: The etiological misinterpretation of paroxysmal neurological symptoms frequently causes a delayed treatment or an inappropriate utilization of ICU-capacities. METHODS: In this study, the data of 208 patients admitted to a neurological ICU because of acute transient neurological deficits, loss of consciousness or unclear motor phenomena were retrospectively analyzed. The initial emergency room diagnosis was compared to the final diagnosis and the rate of misdiagnosis was related to the patients' history and diagnostic data. RESULTS: In 13.9%, the emergency room diagnosis of epileptic seizures turned out to be incorrect, whereas in 15.6%, the final diagnosis of epileptic seizures was missed in the emergency room. Factors that were significantly correlated to missing the seizure diagnosis were (i) no prior history of epilepsy, (ii) old age, (iii) multi-morbidity, (iv) pathologic CT-scans demonstrating cerebrovascular lesions, (v) seizure description by non-professionals, (vi) predominantly negative seizure phenomena (aphasia, loss of consciousness, paresis), (vii) lack of tongue-bite lesions.

The Wada test in Austrian, Dutch, German, and Swiss epilepsy centers from 2000 to 2005: a review of 1421 procedures.

Twenty-six Austrian, Dutch, German, and Swiss epilepsy centers were asked to report on use of the Wada test (intracarotid amobarbital procedure, IAP) from 2000 to 2005 and to give their opinion regarding its role in the presurgical diagnosis of epilepsy. Sixteen of the 23 centers providing information had performed 1421 Wada tests, predominantly the classic bilateral procedure (73%). A slight nonsignificant decrease over time in Wada test frequency, despite slightly increasing numbers of resective procedures, could be observed. Complication rates were relatively low (1.09%; 0.36% with permanent deficit). Test protocols were similar even though no universal standard protocol exists. Clinicians rated the Wada test as having good reliability and validity for language determination, whereas they questioned its reliability and validity for memory lateralization. Several noninvasive functional imaging techniques are already in use. However, clinicians currently do not want to rely solely on noninvasive functional imaging in all patients.

Frequency of seizures and epilepsy in neurological HIV-infected patients.

BACKGROUND: Infection with the human immunodeficiency virus (HIV) is associated both with infections of the central nervous system and with neurological deficits due to direct effects of the neurotropic virus. Seizures and epilepsy are not rare among HIV-infected patients. We investigated the frequency of acute seizures and epilepsy of patients in different stages of HIV infection. In addition, we compared the characteristics of patients who experienced provoked seizures only with those of patients who developed epilepsy. METHODS: The database of the Department of Neurology, University of Münster, was searched for patients with HIV infection admitted between 1992 and 2004. Their charts were reviewed regarding all available sociodemographic, clinical, neurophysiological, imaging and laboratory data, therapy and outcome. Stage of infection according to the CDC classification and the epileptogenic zone were determined. RESULTS: Of 831 HIV-infected patients treated in our department, 51 (6.1%) had seizures or epilepsy. Three of the 51 patients (6%) were diagnosed with epilepsy before the onset of the HIV infection. Fourteen patients (27%) only had single or few provoked seizures in the setting of acute cerebral disorders (eight patients), drug withdrawal or sleep withdrawal (two patients), or of unknown cause (four patients). Thirty-four patients (67%) developed epilepsy in the course of their HIV infection. Toxoplasmosis (seven patients), progressive multifocal leukencephalopathy (seven patients) and other acute or subacute cerebral infections (five patients) were the most frequent causes of seizures. EEG data of 38 patients were available. EEG showed generalized and diffuse slowing only in 9 patients, regional slowing in 14 patients and regional slowing and epileptiform discharges in 1 patient. Only 14 of the patients had normal EEG. At the last contact, the majority of the patients (46 patients=90%) were on highly active antiretroviral therapy (HAART). Twenty-seven patients (53%) were on anticonvulsant therapy (gabapentin: 14 patients, carbamazepine: 9 patients, valproate: 2 patients, phenytoin: 1 patient, lamotrigine: 1 patient). Patients with only provoked seizures had no epilepsy risk factors except HIV infection, and were less likely to be infected via intravenous drug abuse. CONCLUSIONS: Seizures are a relevant neurological symptom during the course of HIV infection. Although in some patients seizures only occur provoked by acute disease processes, the majority of patients with new onset seizures eventually develops epilepsy and require anticonvulsant therapy. Intravenous drug abuse and the presence of non-HIV-associated risk factors for epilepsy seem to be associated with the development of chronic seizures in this patient group.

Presurgical seizure frequency and tumoral etiology predict the outcome after extratemporal epilepsy surgery.

OBJECTIVE: To examine the predictive value of demographic data for the seizure outcome after extratemporal epilepsy surgery. METHODS: Eightyone patients who underwent resective extratemporal epilepsy surgery were retrospectively studied concerning (a) age at surgery, (b) onset of epilepsy, (c) duration of epilepsy, (d) number of seizures at the time of presurgical evaluation, (d) number of presurgically tested antiepileptic substances and (f) number of seizure types. The data were correlated to the postoperative seizure outcome after two years. RESULTS: 33 patients (40.7%) were seizure free two years after surgery. Univariate and multivariate analysis revealed that both tumor etiology and low presurgical seizure frequency were independently associated with seizure freedom after epilepsy surgery. The recurrence rate in patients with one or more seizures per day was more than two-fold if compared with patients with fewer seizures. The remaining demographic factors did not show a significant association with seizure outcome in our 81 patients. CONCLUSIONS: Fewer than daily seizures prior to surgery and a tumoral etiology independently increase the likelihood of remaining seizure free two years after extratemporal epilepsy surgery.

[Suggestion for a new, patient-oriented epilepsy classification]. / Vorschlag für eine neue patientenorientierte Epilepsieklassifikation.

The recent proposal by the ILAE Task Force for Epilepsy Classification is a multiaxial, syndrome-oriented approach. Epilepsy syndromes--at least as defined by the ILAE Task Force--group patients according to multiple, usually poorly defined parameters. As a result, these syndromes frequently show significant overlap and may change with patient age. We propose a five-dimensional and patient-oriented approach to epilepsy classification. This approach shifts away from syndrome orientation, using independent criteria in each of the five dimensions similarly to the diagnostic process in general neurology. The main dimensions of this new classification consist of (1) localizing the epileptogenic zone, (2) semiology of the seizure, (3) etiology, (4) seizure frequency, and (5) related medical conditions. These dimensions characterize all information necessary for patient management, are independent parameters, and include information more pertinent than the ILAE axes with regard to patient management. All cases can be classified according to this five-dimensional system, even at initial encounter when no detailed test results are available. Information from clinical tests such as MRI and EEG are translated into the best possible working hypothesis at the time of classification, allowing increased precision of the classification as additional information becomes available.

Cognitive changes after epilepsy surgery in the posterior cortex.

OBJECTIVE: The relationship between the posterior cortex and cognitive functions is still a relatively open field. There are no studies on populations in which functions of posterior structures were examined by a standardised neuropsychological examination before and after posterior resections. Changes in cognitive performance are regularly observed after epilepsy surgery in the temporal lobe. However, information about neuropsychological impairments after resections in the posterior cortex is poor, owing to the relatively low proportion of cortical resections in this area. METHODS: We retrospectively studied changes in cognition in the neuropsychological data of 28 patients prior to and 6 months after posterior cortical resections. RESULTS: Cognition significantly showed differences in performance intelligence quotient compared with verbal intelligence quotient. Post-operative verbal intelligence consistently increased, whereas performance intelligence decreased. There was no effect regarding the lesion side, continuation of seizures, or reduction of visual field after surgery. Epilepsy surgery in this area did not lead to significant differences in general intelligence after surgery. CONCLUSION: Functions of posterior areas could be described by standardised neuropsychological measures. Posterior regions contribute to explicit attentional and visuoconstructional abilities. Epilepsy surgery in the posterior cortex bears no risk for substantial decline in general cognition although some discrete impairment in performance intelligence may occur.

Lateralizing semiology predicts the seizure outcome after epilepsy surgery in the posterior cortex.

Compared with temporal or frontal resections, epilepsy surgery in the posterior cortex is rarely performed, and the literature concerning clinical predictors for the postoperative seizure outcome in this particular subgroup is sparse. The data of 42 patients with lesional focal epilepsies of the parieto-occipital lobe and the occipital border of the temporal lobe were evaluated retrospectively and related to the seizure outcome 2 years after epilepsy surgery. The investigated parameters included ictal semiology, pre- and postoperative EEG and neuroimaging, histological findings and demographic data. Postoperatively, seizure-free outcome was seen in: (i) 69% of patients with lateralizing auras, but only in 28% of patients without lateralizing auras (P = 0.01); and (ii) 57% of the patients with lateralizing seizures, but only in 17% of patients without lateralizing ictal semiology (P = 0.02). None of the patients with neither lateralizing auras nor lateralizing seizures achieved freedom from seizures (P < 0.01). The proportion of lateralizing seizures (P < 0.01) and auras (P = 0.02) in the total number of recorded seizures and auras was significantly related to the probability of a favourable surgical outcome. No patient with clinical lateralizing signs to the non-lesional hemisphere but 58% without such "false" lateralization achieved freedom from seizures (P = 0.02). The following parameters also proved to be predictive for a favourable seizure outcome: (i) tumoural aetiology; and (ii) absence of epileptiform discharges in the postoperative EEG. The presence and frequency of ictal semiology lateralizing to the lesional hemisphere and the absence of lateralizing signs to the non-lesional hemisphere are highly predictive of a favourable outcome after surgical treatment of epilepsy in the posterior cortex.