The yield of preoperative sequential routine scalp EEGs in patients who underwent anterior temporal lobectomy for mesial temporal sclerosis.

Mesial temporal lobe epilepsy syndrome (MTLES) is the most common surgically remediable epileptic syndrome in adults. Its diagnosis is easy when clinical history is supported by positive laboratory findings. However, routine EEG may not be informative in some patients, thus delaying accurate diagnosis. Therefore, we sought to determine how often routine EEGs displayed epileptiform discharges pre-operatively in a group of patients who underwent surgery for MTLES. Retrospectively, we reviewed the outpatient EEG records of MTLES patients who underwent surgery at our epilepsy center between 1997-2008 and had at least one routine pre-operative EEG recording in our outpatient laboratory. For each patient, serial EEGs were coded as normal, displaying nonspecific abnormalities or lateralized and localized interictal epileptiform discharges. Seventy patients were included in the study. We reviewed 230 EEGs. In almost half of the patients (47.1%) all EEGs were normal or revealed nonspecific findings. In patients who had >1 EEG, almost 3 EEGs had to be recorded to detect the epileptiform discharges for the first time and 6.23 years were needed to accomplish this. Sleep deprivation considerably increased the yield. In summary, patients who have a clinical history suggesting MTLES may need at least 3 routine scalp EEG recordings (with at least one of them after sleep deprivation) to detect epileptiform abnormalities and it may take much time. Therefore, a single prolonged outpatient video-EEG monitoring or an overnight inpatient monitoring might be reasonable alternatives to serial EEGs.

L-2-hydroxyglutaric aciduria: report of four Turkish adult patients.

BACKGROUND: l-2-Hydroxyglutaric aciduria is a rare progressive neurometabolic disorder of childhood inherited as an autosomal recessive trait. Urine organic-acid screening is necessary for its diagnosis. Although it is a disorder of childhood, recently adult cases have been reported. CASES: Here we report 4 adult patients in whom diagnoses were established in adulthood. These patients had some interesting features. First, their diagnoses were delayed until adulthood because of mild clinical symptoms. In such cases, the typical MRI findings are the best diagnostic clue for l-2-Hydroxyglutaric aciduria. Second, there was a correlation between the severity of the clinical course and the extent of MRI findings. The cerebral white-matter lesions were diffuse and confluent on the MRI of 3 of the 4 patients, who also experienced a rapidly progressive clinical decline. Third, there were different clinical presentations even within the same family. CONCLUSIONS: For the evaluation of patients with symptoms referable to cerebellar, pyramidal, extrapyramidal, or cognitive impairment as well as seizures associated with subcortical white-matter and symmetrical dentate nuclei and basal ganglia involvement on MRI, urine organic acid analysis should be included in the evaluation, regardless of patient's age.

Prognosis of patients with mesial temporal lobe epilepsy due to hippocampal sclerosis.

PURPOSE: Hippocampal sclerosis (HS) is the most common pathology in mesial temporal lobe epilepsy (MTLE). There are a few reports concerning prognosis in patients with MTLE-HS treated medically. The study was carried out to determine the clinical risk factors affecting prognosis. METHODS: We enrolled 287 patients with MTLE-HS treated medically. Gender, age at onset of epilepsy, history of trauma, infection, febrile convulsion, status epilepticus, mental retardation, handedness, consanguinity, side of hippocampal sclerosis, additional extrahippocampal temporal lesion, aura, seizures types, antiepileptic drugs, psychiatric disturbances and seizure frequency were noted. All patients were divided into three groups. Group I: patients seizure-free during follow up, Group II: patients with improved seizure control whose seizure frequency had decreased >50% after the treatment, and Group III: patients with poor seizure control whose seizure frequency had no change or increased. Each clinical feature was also compared among three subgroups statistically. RESULTS: Early age of seizure onset [Group II-III (p=0.000) and Group I-III (p=0.0004)], age of head trauma [Group II-III (p=0.04)], the presence of mental retardation (p=0.04) and female sex (p=0.03) were risk factors for poor prognosis. However, the other parameters did not affect prognosis. CONCLUSION: Recognizing bad prognostic features such as the presence of mental retardation, early age of seizure onset, age of head trauma and female gender may help physicians to identify risk groups with MTLE-HS and drug resistance seizures for epilepsy surgery.

Predictive factors for postoperative outcome in temporal lobe epilepsy according to two different classifications.

PURPOSE: The determination of prognostic factors is important for predicting outcome after epilepsy surgery. We investigated the factors related to surgical outcome within a homogeneous group of patients suffering from pathologically proven mesial temporal lobe epilepsy with hippocampal sclerosis (MTLE-HS), and compared Engel's outcome classification system with the latest one proposed by the ILAE. METHOD: We included 109 patients with MTLE-HS who were followed-up for at least 1 year after epilepsy surgery. A retrospective chart review was performed to extract patients' demographic details, and potential pre-postoperative risk factors. Outcome of surgery was defined by the Engel's and ILAE classifications. In addition, the course of prognosis was determined according to the changes in ILAE classifications on an annual basis. Univariate and multivariate logistic regression analyses were used for the latest available outcomes and two different courses of prognosis. RESULTS: The average duration of follow up was 4.78+/-2.55 years in the 109 patients with MTLE-HS. The univariate and multiple logistic regression analyses showed that the occurrence of seizures during the first month after surgery was a significant risk factor for a poor outcome. A history of trauma was also significant for patients with late recurrence of postsurgical seizures after at least 1-year seizure remission. CONCLUSION: The occurrence of seizures during the first month after surgery is a significant prognostic factor in patients with MTLE-HS. Ignoring early postoperative seizures in classification systems may result in difficulty in identifying the course of epilepsy after surgery.

Focal EEG findings in juvenile absence syndrome and the effect of antiepileptic drugs.

The presence of focal EEG abnormalities in juvenile absence syndrome (JAS) may cause it to be misdiagnosed as focal epilepsy. The purpose of our study was to determine the presence of focal EEG abnormalities in patients with JAS and to ascertain whether some clinical features or antiepileptic drugs (AEDs) have an effect on focality. Serial EEGs of 52 consecutive patients with JAS were retrospectively analyzed. The patients were divided into two groups according to whether they were treated with valproic acid and/or lamotrigine (VA-LTG) or not during the times of these EEG recordings. The relationship between the presence of EEG focality and the use of AEDs in addition to other risk factors was examined. Two or three consecutive EEGs (total 100) of the 52 patients were evaluated. Among these, the rates of focal EEG abnormalities were 18%, 36%, and 25% during the follow-up EEGs without AEDs (5/27) and first (16/45) and second EEGs (7/28) with AEDs, respectively. The last two EEGs showed a tendency towards a higher proportion of EEG focality in patients who received other AEDs (47%-45%) compared with those that received VA-LTG (13%-12%). The proportion of JAS patients with focal EEG findings in serial EEGs tended to decrease with an increasing rate of VA-LTG use. As a hypothetical explanation, changes in EEG focality may reflect the effect of AEDs other than VA and/or LTG, in addition to a developing hyperexcitable cortical area.

Investigation of HSV-1, HSV-2, CMV, HHV-6 and HHV-8 DNA by real-time PCR in surgical resection materials of epilepsy patients with mesial temporal lobe sclerosis.

OBJECTIVE: The objective of this study is to investigate the presence of viral DNAs of HSV-1, HSV-2, HHV-6, HHV-8, and CMV in hippocampus of the patients with mesial temporal lobe epilepsy (MTLE) syndrome. METHODS: Pathological specimens were obtained from 33 patients with MTLE undergone temporal lobectomy with amygdalo-hippocampectomy due to intractable seizures. Autopsy materials from the hippocampus of 7 patients without neurological disease were used as controls. The data was also correlated with the clinical history of patients including febrile convulsions, age, and history of CNS infections. Real-time polymerase chain reaction method was performed for detection of DNAs of these viruses. RESULTS: HHV-6, HSV-1 and HHV-8 were detected in the hippocampus of 3, 2 and 1 patients with MTLE respectively. None of the hippocampus of patients with MTLE was positive for DNA of HSV-2 and/or CMV. Three patients with positive HHV-6 DNAs had febrile convulsions and family history for epilepsy. None of our control specimens showed PCR positivity to any of the 5 tested viruses. CONCLUSIONS: Our study is the first to report the presence of HHV-8 viral genome in the brain tissue of patient with MTLE. Viral DNAs were detected in a total of 18% of the patients in this study; we can conclude that activity of the latent virus in patients with hippocampal sclerosis should be more extensively studied to establish its role in active infection.

Eye closure sensitivity and epileptic syndromes: A retrospective study of 26 adult cases.

PURPOSE: The transient, mainly generalized, together with brief changes in EEG baseline immediately after eye closure, is called 'eye closure sensitivity' (ECS) which was first reported by Robinson in 1930 and there have been limited number of studies investigating ECS and epilepsy syndromes. Therefore, we aimed to reveal the possible relationship between ECS and the epilepsy syndromes in our adult patients. PATIENTS AND METHODS: Adult patients monitored in Hacettepe University Hospitals EEG Laboratory, from January 1995 to December 2005, were screened retrospectively for the presence of ECS. During EEG recording, all patients were asked to open their eyes for at least for 10s and close their eyes at the end of this period in six different montages. Hyperventilation and photic stimulation were performed according to the standard protocol of IPS. RESULTS: Twenty-six patients have had ECS during EEG recording. Nineteen (73%) were women, and mean age of the patients was 24 years. The mean ages were 12.3+/-5.4 years for seizure onset and 18.5+/-4.9 years for initial detection of ECS. Eleven had a history of febrile seizures. There was a family history for epilepsy in five patients. Photosensitivity in their EEG was noticed in 11 patients. ECS was established in five epilepsy syndromes: eyelid myoclonia with absences (EMA); (n: 6), juvenile myoclonic epilepsy (JME); (n: 6), idiopathic generalized epilepsy (IGE with tonic clonic seizure); (n: 4), juvenile absence epilepsy (JAE); (n: 1) and idiopathic occipital lobe epilepsy (IOE) (n: 9). All patients were seizure free with or without anti-epileptic medication during follow up. CONCLUSION: ECS is more common in females. It may overlap with photosensitivity but be independent from photosensitivity. It may be seen in different epilepsy syndromes including IOE which was not reported previously.

Structural lesions in periodic lateralized epileptiform discharges (PLEDs).

In this study we investigated the structural lesions of patients with periodic lateralized epileptiform discharges (PLEDs) to determine the possible relationship of lesions to PLEDs' localization on EEG and to metabolic abnormality. Clinical findings and electroencephalography (EEG), computerized tomography (CT) and magnetic resonance imaging (MRI) of the 71 adult patients with PLEDs were evaluated. Stroke, herpes encephalitis and intracranial tumor or abscess were the most common etiological factors. Cortical gray matter and adjacent subcortical white matter lesions were detected in 64.7%, cortical gray matter lesions in 11.3% and subcortical white matter lesions in 4.2% of the patients. Although it is thought that PLEDs occur mostly with acute lesions, chronic lesions causing PLEDs were found in 35.2% of the patients. Bilateral lesions were detected in 19.7% and 33.8% of the patients had metabolic abnormality. PLEDs localized the region of the lesion in 63.4% of the patients. PLEDs are usually self-limited features, but chronic PLEDs were detected in 5 patients in this study. Acute structural lesions involving cortical gray matter with adjacent subcortical white matter were found in most of the patients with PLEDs, but the lesion localization and age, acute or chronic, varied.

Generalised periodic epileptiform discharges: clinical features, neuroradiological evaluation and prognosis in 37 adult patients.

Generalised periodic epileptiform discharges (GPEDs) are very rare patterns and are classified as periodic short-interval diffuse discharges (PSIDDs), periodic long-interval diffuse discharges (PLIDDs) and suppression-burst patterns according to the interval between the discharges. In this study we analysed the demographics, history of the seizures during the current illness, mental status, diagnosis, metabolic abnormalities, neuroimaging studies and prognosis of 37 adult patients who had GPEDs in their EEGs. Ages ranged from 17 to 82 years (mean 45 years). There were 19 males and 18 females. The most common aetiology of GPEDs was metabolic and/or infectious disease which was established in 22 patients (59.5%). Other aetiologies included subacute sclerosing panencephalitis (SSPE) in 11 patients (29.7%) and Creutzfeld-Jakob disease (CJD) in 4 patients (10.8%). We showed that structural lesions were found in most of the patients with GPEDs, but concurrent metabolic abnormalities and/or infectious diseases were also detected. Consciousness was impaired and clinical conditions were poor in various degrees in all of the patients when GPEDs were seen. Relatively little is known regarding the mechanism of GPEDs. When GPEDs are seen in EEG, the patient should carefully be checked for metabolic abnormalities and/or infectious diseases and intracranial lesions. GPEDs may be helpful in the determination of prognosis, showing the poor prognosis especially in cases when suppression-burst pattern is seen.