Endovascular stroke therapy in Austria: a nationwide 1-year experience.

BACKGROUND AND PURPOSE: Based on a tight network of stroke units (SUs) and interventional centres, endovascular treatment of acute major intracranial vessel occlusion has been widely implemented in Austria. Documentation of all patients in the nationwide SU registry has thereby become mandatory. METHODS: Demographic, clinical and interventional characteristics of patients who underwent endovascular treatment for acute ischaemic stroke in 11 Austrian interventional centres between 1 October 2013 and 30 September 2014 were analysed. RESULTS: In total, 301 patients (50.5% women; median age 70.5 years; median National Institutes of Health Stroke Scale score 17) were identified.193 patients (64.1%) additionally received intravenous thrombolysis. The most frequent vessel occlusion sites were the M1 segment of the middle cerebral artery (n = 161, 53.5%), the intracranial internal carotid artery (n = 60, 19.9%) and the basilar artery (n = 40, 13.3%). Stent retrievers were used in 235 patients (78.1%) and adequate reperfusion (modified Thrombolysis in Cerebral Infarction scores 2b and 3, median onset to reperfusion time 254 min) was achieved in 242 patients (81.4%). Symptomatic intracranial haemorrhage occurred in 7%. 43.8% of patients (n = 132) had good functional outcome (modified Rankin Scale score 0-2) and the mortality rate was 20.9% (n = 63) after 3 months. Compared to the anterior circulation, vertebrobasilar stroke patients had higher mortality. Patients with secondary hospital transportation had better outcomes after 3 months than in-house treated patients. CONCLUSION: Our results document nationwide favourable outcome and safety rates of endovascular stroke treatment comparable to recent randomized trials. The ability to provide such data and the need to further optimize such an approach also underscore the contribution of respective registries.

Metabolic changes in the normal ageing brain: consistent findings from short and long echo time proton spectroscopy.

OBJECTIVES: Sixty three healthy subjects were measured to assess dependence of brain metabolites on age using short- and long echo time spectroscopy in different brain regions. MATERIAL AND METHODS: Younger and elderly humans were measured with long echo time (TE=135ms) 3D-MR-spectroscopic imaging (MRSI) (10 subjects) and with ultra-short echo (TE=11ms) time 2D-MRSI (7 subjects). In addition, results from single voxel (1)H-spectroscopy (TE=20ms) of two cohorts of 46 healthy subjects were retrospectively correlated with age. RESULTS: 3D-MR SI revealed reduced NAA/Cr in the older group in the frontal lobe (-22%; p<0.01), parietal lobe (-28%; p<0.01) and semiovale (-9%; p<0.01) compared to the younger group. Cho/Cr was elevated in the semiovale (+35%; p<0.01) and in the n. lentiformis (+42%; p<0.01) in the older group. NAA/Cho was reduced in all regions measured, except the thalamus, in the older group compared to the younger group (from -21 to -49%; p<0.01). 2D-MRSI revealed decreased total NAA (-3.1% per decade; p<0.01) and NAA/Cr (-3.8% per decade; p<0.01), increased total Cho (+3.6% per decade; p<0.01) and Cho/Cr (+4.6% per decade; p<0.01) and increased total myo-Inositol (mI, +4.7% per decade; p<0.01) and mI/Cr (+5.4% per decade; p<0.01) and decreased NAA/Cho (-8% per decade; p<0.01) in semiovale WM. Results from single voxel spectroscopy revealed a significantly negative correlation of NAA/Cho in frontal (-13% per decade; p<0.01) and in temporal lobe (-7.4% per decade; p<0.01) as well as increased total Cr (10% per decade; p<0.01) in frontal lobe. Other results from single voxel measurements were not significant, but trends were comparable to that from multivoxel spectroscopy. CONCLUSION: Age-related changes measured with long echo time and short echo time 1H-MRS were comparable and cannot, therefore, be caused by different T2 relaxation times in young and old subjects, as suggested previously.

Postictal nose wiping: a lateralizing sign in temporal lobe complex partial seizures.

We report postictal nose wiping as a postictal symptom of localizing and lateralizing significance in focal epilepsy. We reviewed videotapes of 444 focal seizures in 101 patients who underwent prolonged video and EEG monitoring during presurgical epilepsy evaluation, and observed postictal nose wiping in 51.3% of 76 patients with temporal lobe epilepsy. The hand used to perform postictal nose wiping was ipsilateral to the side of seizure origin in 86.5% of all seizures and in 97.3% of all patients. We conclude that postictal nose wiping is a common, easily assessed symptom after focal seizures of temporal lobe origin that provides reliable lateralizing information on the side of seizure onset.

Propagation of interictal epileptic activity in temporal lobe epilepsy.

We recorded interictal spikes with closely spaced scalp electrodes and sphenoidal electrodes in four patients with temporal lobe epilepsy. We used multiple dipole modeling to study the number, three-dimensional intracerebral location, time activity, and functional relationship of the neuronal sources underlying the epileptic spike complexes. In all patients, we found two significant sources generating the interictal spikes which showed considerable overlap in both space and time. Source 1 was located in the mesiobasal temporal lobe and generated a restricted negativity at the ipsilateral sphenoidal electrode and a widespread positivity over the vertex. Source 2 could be attributed to the lateral temporal neocortex and was associated with a relatively restricted negativity at the ipsilateral temporal electrodes and a more widespread positivity over the contralateral hemisphere. The sources were well separated in space, with an average distance of 45 mm between them. The time activities of both sources showed similar biphasic patterns, with the mesial source leading the lateral source by approximately 40 msec, suggesting propagation of interictal epileptic activity from the mesiobasal to the lateral temporal lobe.

Epileptic negative myoclonus: An EEG-single-photon emission CT study indicating involvement of premotor cortex.

We report a combined EEG-single-photon emission CT (SPECT) study on a patient with epileptic negative myoclonus (ENM). Clinically, the ENM was characterized by brief repetitive lapses in postural tone of the right upper extremity when the arms were held outstretched, whereas no movement effect was observed during rest. Ictal EEG showed repetitive left frontal spikes with a maximum at electrodes EC1 and F1. EMG silent periods lasting from 100 to 200 ms followed the onset of the EEG transients by a latency of 20 to 40 ms. The N20 component of median nerve somatosensory evoked potentials-representing a biological marker of the location of central fissure-showed a phase reversal between electrodes P3 and C1 and thus was located considerably posterior to the spike maximum. We obtained accurate anatomic reference of cerebral blood flow changes visible on SPECT by a special coregistration technique of MRI and SPECT. SPECT performed during ENM showed a marked regional hyperperfusion in the left middle frontal gyrus and a less pronounced increase in tracer uptake in the left supramarginal gyrus. Our results suggest that ENM is generated by epileptic activity in the premotor area in the middle frontal gyrus corresponding to Brodmann's area 6.

Genital automatisms in complex partial seizures.

OBJECTIVE: To determine which brain region is responsible for the generation of sexual automatisms. METHODS: Ninety consecutive patients with medically refractory focal epilepsy (74 with temporal lobe and 16 with frontal lobe epilepsy) referred to an epilepsy monitoring unit were studied. The occurrence of the following sexual automatisms was assessed during prolonged video-EEG monitoring: 1) repeatedly grabbing or fondling the genitals and 2) pelvic or truncal thrusting or similar movements. RESULTS: Five patients repeatedly fondled or grabbed their genitals during or immediately after some of their seizures. All five had temporal lobe epilepsy, as evidenced from prolonged video-EEG monitoring, high-resolution MRI, and good to excellent outcome after epilepsy surgery. Sexual automatisms did not occur with frontal lobe epilepsy. CONCLUSION: Sexual automatisms cannot be related exclusively to frontal lobe seizures. As previously proposed, apparently sexual hypermotoric pelvic or truncal movements are common in frontal lobe seizures, but this study suggests that discrete genital automatisms, like fondling and grabbing the genitals, are more common in seizures evolving from the temporal lobe.

Clinical seizure lateralization in mesial temporal lobe epilepsy: differences between patients with unitemporal and bitemporal interictal spikes.

OBJECTIVE: To compare the reliability of clinical seizure lateralization in temporal lobe epilepsy patients with unitemporal and bitemporal independent interictal spikes and unilateral hippocampal atrophy or sclerosis (HA/HS) on MRI scan. PATIENTS AND METHODS: We studied 11 patients with unitemporal and 10 patients with bitemporal interictal spikes. We calculated a spike ratio by dividing the number of spikes ipsilateral to the side of HA/HS by those occurring contralaterally. RESULTS: Clinical seizure lateralization was correct, i.e., ipsilateral to the side of HA/HS, significantly more often in the unitemporal group. Spike ratios were significantly higher in seizures that were lateralized correctly as compared with both incorrectly and nonlateralized seizures. Within the individual patients, a significant positive correlation between spike ratios and the proportion of correctly lateralized seizures was found. We identified three categories of symptoms according to lateralization accuracy. Category 1 symptoms (version, postictal paresis, and early ictal vomiting/retching) lateralized to the side of HA/HS in 100% of patients in the uni- and bitemporal groups. Category 2 symptoms (dystonic posturing, mouth deviation, postictal dysnomia/dysphasia, and ictal speech) provided a 100% correct lateralization in the unitemporal but not in the bitemporal patients. Category 3 symptoms (nonversive early head turning and unilateral upper extremity automatisms) yielded erroneous lateralization in both patient groups. CONCLUSIONS: We conclude that reliable clinical seizure lateralization in mesial temporal lobe epilepsy can only be achieved in patients with unitemporal interictal spikes, whereas clinical lateralization in patients with bitemporal spikes must be viewed cautiously.

Preictal SPECT in temporal lobe epilepsy: regional cerebral blood flow is increased prior to electroencephalography-seizure onset.

UNLABELLED: Peri-ictal SPECT provides unique information on the dynamic changes in regional cerebral blood flow (rCBF) that occur during seizure evolution and, thus, could be useful in clarifying the poorly understood interplay of the interictal and ictal states in human focal epilepsy. The regional hyperperfusion observed on ictal SPECT is generally believed to be a consequence of electrical seizure activity. However, recent studies using invasive long-term cortical CBF monitoring have demonstrated that rCBF changes occur up to 20 min prior to ictal electroencephalography (EEG) onset. Because of apparent technical difficulties, no preictal SPECT studies have been reported so far. Therefore, we present our results on two patients with temporal lobe epilepsy in whom preictal SPECT scans were performed fortuitously under continuous video-EEG monitoring control. METHODS: Technetium-99m-hexamethyl propyleneamine oxime was injected 11 min (Patient 1) and 12 min (Patient 2) before clinical and EEG seizure onset, as documented from simultaneous video-EEG monitoring in two patients with temporal lobe epilepsy. We obtained accurate anatomical reference of CBF changes visible on SPECT by a special coregistration technique of MRI and SPECT. RESULTS: Whereas interictal SPECT showed a hypoperfusion of the temporal lobe ipsilateral to the seizure focus, on preictal SPECT, a significant increase in rCBF in the epileptic temporal lobe could be observed. These rCBF changes were not accompanied by any significant changes of the ongoing EEG. CONCLUSION: Our study provides evidence that rCBF is increased in the epileptic temporal lobe several minutes before EEG seizure onset. Thus, rCBF changes observed on peri-ictal SPECT scan cannot be considered a mere consequence of EEG seizure activity but may rather reflect a change in neuronal activity precipitating the transition from the interictal to the ictal state.

C677T MTHFR mutation and factor V Leiden mutation in patients with TIA/minor stroke: a case-control study.

A common C677T mutation in the gene for the enzyme 5,10-methylenetetrahydrofolate reductase (5,10-MTHFR) has been linked to elevated levels of homocysteine and was therefore suspected to be a candidate genetic risk factor for arterial occlusive disease. Another mutation, factor V Leiden, has been established as a common hereditary risk factor for venous thrombosis, but its role in arterial disease remains controversial. We investigated the prevalence of both the C677T MTHFR mutation and the factor V Leiden mutation in 81 patients with transient ischemic attack (TIA) or minor stroke (MS) and in 81 age- and sex-matched control subjects free from clinically manifest vascular disease. We further compared clinical and laboratory data as well as clinical course of patients carrying the factor V Leiden mutation alone or in combination with the C677T MTHFR mutation and mutation-free patients. The prevalence of the MTHFR mutation did not differ between patients and control subjects with 11.1% homozygous carriers in both groups (OR for homozygous carriers 1.0; 95% CI 0.38-2.66). However, there was a trend towards a higher prevalence of carriers of factor V Leiden in patients (12.3%) than in control subjects (4.9%) (OR 2.75; 95% CI 0.83-9.17;p=0.09). Furthermore, we found some evidence that the combined occurrence of the C677T MTHFR mutation and factor V Leiden might unfavorably affect the clinical course of the disease, but the number of respective patients was small. Larger studies with a greater number of carriers of both the C677T MTHFR mutation and factor V Leiden seem therefore warranted.

The relation between erythrocyte volume and folate levels is influenced by a common mutation in the methylenetetrahydrofolate reductase (MTHFR) gene (C677T).

BACKGROUND: The enzyme 5,10 methylenetetrahydrofolate reductase (MTHFR) plays an important role in folate metabolism and folate-dependent reactions. Homozygosity for a common polymorphism in the MTHFR gene (C677T, Ala to Val) is associated with an increased risk of neural tube defects and hyperhomocysteinemia in individuals with low folate levels. Homozygous carriers of the polymorphism with adequate folate levels, on the other hand, seem to be at lower risk for colorectal cancer. Homozygous carriers of the polymorphism (5-15% of the white population) probably represent a subpopulation with increased folate needs. Hematological sequelae of folate deficiency have been recognized for a long time. However, no data exist concerning the relation between the C677T MTHFR polymorphism, folate levels, and hematological parameters. METHODS: We investigated associations between the C677T MTHFR polymorphism, folate levels, total plasma homocysteine, and hematological parameters in 94 patients with cerebrovascular disease (transient ischemic attack/minor stroke) and in 82 healthy subjects. RESULTS: Homozygous carriers (VV) of the polymorphism with low folate levels showed significantly higher homocysteine levels than mutation-negative (AA) and heterozygous (AV) subjects (P = 0.038). Furthermore, VV subjects in the lowest folate quartile exhibited significantly higher mean erythrocyte volumes (MCV) and a tendency towards higher erythrocyte hemoglobin content (MCH) than AA and AV subjects (P = 0.008 and 0.069, respectively). Although MCV was not influenced by folate levels in AA and AV subjects, in VV subjects a significant inverse correlation with folate levels could be demonstrated (P = 0.544 and 0.020, respectively). CONCLUSION: We demonstrate an association between the C677T polymorphism, folate levels, and hematological parameters. The elevation of MCV in homozygous carriers of the polymorphism with low folate levels indicates impaired DNA synthesis and/or methylation in these subjects. Considering our data and the results of previous studies, the polymorphism may have contrary effects on homocysteine metabolism and DNA synthesis/methylation dependent on a subject's folate supply. Although the polymorphism is disadvantageous in homozygous carriers with low folate levels, its presence may be beneficial in individuals with adequate folate supply.

Health-related quality of life (HRQOL), activity of daily living (ADL) and depressive mood disorder in temporal lobe epilepsy patients.

We determined the interrelations of chronological age, age at seizure onset, duration of seizure disorder, cognitive functioning (IQ), scales of activities of daily living, depressive mood disorder and measures of health-related quality of life (HRQOL). Furthermore, we investigated the association of the laterality of seizure onset zone and absence/presence of hippocampal atrophy and/or sclerosis (HA/HS) with measures of HRQOL, activities of daily living (ADL) and depressive mood disorder. In the setting of pre-surgical epilepsy evaluation, a sample of 56 patients with temporal lobe epilepsy (TLE) was studied using the Bonner Skalen für Epilepsie (BPSE) and the depression inventory D-S of von Zerssen. Patients reported high levels of dependency on others and poor coping capabilities. Our data also showed specific ADL-behaviour suggesting social withdrawal and isolation. Our results indicate emotional impairment as a major problem in TLE, because 45% of our patients scored in the depressive range of the D-S depression scale. Depression score was found to be a powerful predictor of self-reported quality of life after adjusting for seizure-related variables, demographic variables and cognitive functioning (IQ). The only scale showing a significant laterality effect was ADL-home. No relationship between the dependent measures of HRQOL, ADL-social, ADL-cultural, depressive mood disorder and laterality of the epileptogenic zone or absence/presence of HA/HS was found. HRQOL and depressive mood disorder are strongly interrelated indicating that patients with depressive symptoms report lower quality of life and specific patterns of ADL. HRQOL, ADL and depressive mood disorder are largely independent of biological markers such as laterality of seizure onset zone and absence/presence of HA/HS in TLE.

[The postictal state. A clinically oriented observation of patients with epilepsy]. / Der postiktale Zustand. Eine klinisch orientierte Betrachtung bei Patienten mit Epilepsie.

UNLABELLED: Epileptic seizures are followed by dynamic alterations in neurologic function in the postictal period which have received little attention by clinicians over a long period of time. We therefore retrospectively studied videotapes of 160 patients with focal epilepsy who underwent presurgical evaluation, for the occurrence of postictal symptoms to determine whether these phenomena have any localizing or lateralizing value in defining the seizure onset zone. RESULTS: (1) We found postictal paresis in 22 of 160 patients (18.8%) in each case contralateral to the hemisphere of seizure onset. (2) 'Perservative' automatisms which start during the ictus and continue in the postictal period occurred in 25.2% of 135 patients with temporal lobe epilepsy but not in patients with frontal lobe epilepsy. (3) Sexual automatisms defined as manipulations of the genitals were found exclusively in patients with temporal lobe epilepsy (in 5.9% of 135 patients). (4) Postictal 'Nose-wiping' was evident in 51.3% of 76 temporal lobe epilepsy patients but only in 12.0% of 25 extratemporal lobe epilepsy patients and was performed with the hand ipsilateral to the hemisphere of seizure onset in 86.5% of all temporal lobe seizures. (5) Postictal language disturbances were observed only in patients with temporal lobe epilepsy (34% of 97 patients) and pointed to a seizure onset in the dominant hemisphere in 80.8%. We conclude that postictal phenomena can provide reliable information for the localization of the seizure onset zone in patients with complex partial seizures. Thus, more attention should be given to the postictal state during presurgical epilepsy monitoring.

Network atrophy in temporal lobe epilepsy: a voxel-based morphometry study.

BACKGROUND: Recent evidence suggests that temporal lobe epilepsy affects a neuronal network rather than a single circumscribed structure within the temporal lobe. Thus, in mesial temporal lobe epilepsy (mTLE) with hippocampal sclerosis gray matter abnormalities have been found beyond the hippocampus in extrahippocampal regions by means of voxel-based morphometry (VBM). On the contrary, in cryptogenic or MRI-negative TLE (cTLE) no consistent gray matter abnormalities in VBM studies have been reported. METHODS: We used optimized VBM with modulation to detect gray matter abnormalities compared to healthy controls in patients with mTLE and cTLE. Twenty-two patients with mTLE (right/left TLE 13:9), 17 patients with cTLE (right/left TLE 7:10), and 12 healthy controls were enrolled in the study. RESULTS: In mTLE we found decreased gray matter volume (GMV) beyond the hippocampus in the ipsilateral thalamus. GMV decrease was more widespread in patients with left-sided seizure focus including the left parahippocampal and superior temporal gyrus, frontal regions, cerebellum, and the right cingulum. In cTLE, decreased GMV was observed in the frontal and orbitofrontal cortex, the cerebellum, neocortical temporal regions, and in the right parahippocampal cortex. Again, patients with left-sided seizure focus had a more widespread and extensive GMV decrease including regions such as the right and left cingulum. CONCLUSION: We found evidence for distinct neuronal network damage in mesial temporal lobe epilepsy (mTLE) and cryptogenic TLE (cTLE) which is more widespread in patients with left-sided seizure focus. Atrophy of the cingulum was a common feature in left- but not in right-sided mTLE and cTLE.

Combining ictal surface-electroencephalography and seizure semiology improves patient lateralization in temporal lobe epilepsy.

PURPOSE: The study goal was to assess the concordance of ictal surface-EEG and seizure semiology data in lateralizing intractable temporal lobe epilepsy (TLE) and to examine the benefits of the combined use of these two methods. METHODS: We independently analyzed the ictal recordings and clinical symptoms associated with 262 seizures recorded in 59 TLE patients. Each seizure was lateralized on the basis of (i) its associated ictal surface-EEG pattern according to a predefined lateralization protocol and (ii) its associated ictal and postictal seizure semiology according to strictly defined clinical criteria. Individual patients were also lateralized based on these data. RESULTS: Ictal surface-EEG findings lateralized 62.6% of seizures and 64.4% of patients. Seizure semiology findings lateralized 46.2% of seizures and 78.0% of patients. There was a high degree of concordance between lateralizations based on these two methods, for both individual seizures and individual patients. Combination of the information from the two methods allowed for lateralization in a greater proportion of both seizures (79.8%) and patients (94.9%). Combined EEG-seizure lateralization was concordant with the side of operation in 33 of 34 patients who underwent successful surgery (Engel's surgical outcome class I/II). CONCLUSIONS: In TLE, there is a high agreement between the lateralization of individual seizures and patients, which is based on ictal surface-EEG findings and seizure semiology. Furthermore, combination of these two methods improves the lateralization of individual seizures and patients. Thus, standardized combined EEG-seizure analysis is a valuable noninvasive tool in the presurgical evaluation of TLE.

Anterior Frontal Cortex and the Effect of Proactive Interference in Paired Associate Learning: A DC Potential Study.

This contribution focuses on neurophysiological correlates of the cerebral processes subserving the control of proactive interference. Event-related negative shifts of the scalp-recorded cortical steady potential (negative DC shifts) were measured in 17 right-handed normals during two tasks of paired associate learning. The control condition was a standard word pair learning task in which unrelated word pairs were presented. In the experimental condition, proactive interference was maximized by presenting very similar words and by requiring negative transfer, i.e., by having them reappear, but in different pairings. Proactive interference leads to increased anterior frontal negative DC shifts. Furthermore, centrotemporal negative DC shifts predicted subsequent cued recall performance. In spite of elaborative strategies, an effect of subsequent mnestic performance on the P300 was observed.

Vestibular processing in human paramedian precuneus as shown by electrical cortical stimulation.

The authors describe a 16-year-old patient with recurrent episodes of epileptic linear self-motion perception and occasional body tilts. Intracranial seizure monitoring located the seizure onset, caused by a circumscribed ependymoma, in the right paramedian precuneus. Electrical cortical stimulation of this area could reproduce the same vestibular sensations, which ceased after lesionectomy. The findings implicate the paramedian area of the precuneus in the processing of static and dynamic vestibular, probably otolithic, information.

Postictal paresis in focal epilepsies--incidence, duration, and causes: a video-EEG monitoring study.

BACKGROUND: Although familiar to every neurologist, postictal paresis (PP) has only rarely been analyzed systematically. OBJECTIVE: To describe the frequency and duration of PP in patients undergoing video-EEG monitoring, the semiology characteristics of seizures preceding PP, and the pattern of associated symptoms and signs. METHODS: The records of 513 consecutive patients who underwent prolonged video-EEG monitoring during presurgical epilepsy evaluation were reviewed for postictal motor deficit. Three hundred twenty-eight patients fulfilled the inclusion criteria. The videotapes of patients with PP were subsequently analyzed with a careful analysis of ictal motor phenomena at the side of the PP. RESULTS: PP was found in 44 patients (13.4%). PP was always unilateral and always contralateral to the seizure focus and had a median duration of 173.5 seconds (range 11 seconds to 22 minutes). Of all seizures with PP, 77.8% were accompanied by evident and 9.7% by very slight ictal motor phenomena ipsilateral to the side of PP, whereas 9.7% of the seizures showed no motor signs (two seizures [2.8%] could not be evaluated for motor phenomena). The most common ictal lateralizing sign was unilateral clonic activity in 55.6% of all seizures. Concomitant dystonic posturing was found in 47.9% and ictal limb immobility in 24.6% of the seizures. PP was of longer duration if ictal clonic activity was present and after tonic-clonic seizures. CONCLUSIONS: PP is relatively frequent (13.4%), is easy to detect, and has a high lateralizing value. The high incidences of dystonic posturing and of ictal limb immobility in our patients with PP may indicate that an active inhibitory process is involved in its pathogenesis.

A case of startle epilepsy and SSMA seizures documented with subdural recordings.

PURPOSE: To study the mechanisms of startle-induced supplementary sensorimotor area (SSMA) seizures. METHODS: We present a patient investigated with indwelling subdural grid electrodes covering both the SSMA and the dorsolateral frontal lobe. RESULTS: We found a simultaneous seizure onset in the right dorsolateral premotor cortex and the right SSMA. High-resolution magnetic resonance imaging (MRI) showed a small subcortical lesion adjacent to the right SSMA. The patient became seizure free after resection of the lesion and the ictal-onset zone. CONCLUSIONS: We conclude that an extended region of abnormally excitable tissue within the frontal lobe could facilitate the generation of startle-induced seizures. We speculate that a widespread epileptogenic zone could help to explain why some patients with SSMA or dorsolateral frontal lobe seizures are more likely to have startle-induced seizures.

Relation of interictal spike frequency to 1H-MRSI-measured NAA/Cr.

PURPOSE: Whereas EEG spiking and decreases of the neuronal marker N-acetyl-aspartate (NAA) both localize well the epileptic focus, the significance of the intensity of these variables is unclear. Therefore we investigated whether the frequency of interictal surface spikes is related to the degree of N-acetyl-aspartate/creatine (NAA/Cr) ratio decrease as measured by proton magnetic resonance (MR) spectroscopic imaging (1H-MRSI) in patients with intractable partial epilepsy. METHODS: We retrospectively studied 14 patients, nine with temporal lobe epilepsy and five with frontal lobe epilepsy. Spikes that occurred during prolonged video-EEG monitoring from electrodes placed according to the International 10-20 system were counted blinded to the 1H-MRSI results. Eight electrode positions (F3/4, C3/4, T3/4, T5/6) were assigned to underlying brain subregions in the 1H-MRSI volume of interest. We converted NAA/Cr ratios into z-scores (NAA/Cr(z)) to compared NAA/Cr values directly across subregions. We calculated Spearman rank-order (p) and Pearson product-moment (r) correlations between spike frequency and NAA/Cr(z) values overall, as well as within each brain subregion. RESULTS: We found an overall negative relation between spike-frequency data and NAA/Cr(z) data (p = -0.341). When analyzing only spiking subregions, this negative relation became slightly stronger (p = -0.442; r = -0.338). When data from the eight sites were considered separately, this negative relation remained in most instances. CONCLUSIONS: Our results reveal a trend toward higher interictal spike frequencies on surface EEG in regions of pronounced neuronal metabolic damage or dysfunction. This suggests that both variables parallel an underlying pathologic substrate, although the pathophysiologic processes may be distinct.

Genetic and nongenetic factors influencing plasma homocysteine levels in patients with ischemic cerebrovascular disease and in healthy control subjects.

Moderately elevated plasma homocysteine levels have been established as an independent risk factor for atherosclerosis and its complications, including cerebrovascular disease. A common mutation (C677T) in the gene encoding for the enzyme methylenetetrahydrofolate reductase (MTHFR) has been linked to increased plasma homocysteine levels in homozygous carriers, particularly in the presence of low folate levels. However, the results of most of the previous studies suggest that the C677T MTHFR mutation is not a significant risk factor for arterial disease. This discrepancy might, at least partly, be due to the fact that plasma homocysteine levels are influenced by several other factors, including age, gender, renal function, and vitamin status. We investigated the relation between plasma homocysteine levels, the C677T MTHFR mutation, and these other factors in a population of 96 patients with transient ischemic attacks or minor strokes and in 96 age- and sex-matched healthy control subjects. We further tested the value of a multivariate model for the prediction of plasma homocysteine levels under particular consideration of the MTHFR mutation status. In the patients, plasma homocysteine levels were significantly higher than in the healthy control subjects. With regard to the MTHFR mutation, the distribution of the C/C, C/T, and T/T genotypes was not significantly different between patients and healthy control subjects. Univariate (linear regression) analysis revealed significant (positive) correlations between plasma homocysteine levels on the one hand and age and creatinine on the other, the latter particularly in subjects with creatinine levels in the upper quartile. Significant (negative) correlations were found between plasma homocysteine levels, vitamin B12, and folate levels. However, these relations could much better be expressed by means of a multiplicative regression model. T/T subjects exhibited slightly higher homocysteine levels than C/C and C/T subjects; however, the differences between the 3 genotypes were not significant. Multivariate (stepwise regression) analysis revealed age, vitamin B12 levels, folate levels, and creatinine levels as significant independent variables influencing plasma homocysteine levels, whereas the MTHFR mutation status and gender were removed from the model. Considering all 192 subjects, only 28.8% of the variance of plasma homocysteine levels could be accounted for by the model. However, in homozygous carriers of the MTHFR mutation, the predictive power of the model is very high, explaining 76.1% of the variance of plasma homocysteine levels. According to our results, the C677T mutation does not constitute a major risk factor for transient ischemic attack or minor stroke, even under consideration of other possibly confounding factors that are known to affect plasma homocysteine levels. However, it is possible to predict plasma homocysteine levels in homozygous carriers of the mutation with high accuracy. The knowledge of the MTHFR mutation status may therefore help to identify subjects at high risk for hyperhomocysteinemia.