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R Kuzniecky

Publications and source records attributed to R Kuzniecky.

At least 19 recordsLinked to original sources
PubMed2007

Cortical abnormalities in epilepsy revealed by local EEG synchrony.

Abnormally strong functional linkage between cortical areas has been postulated to play a role in the pathogenesis of partial epilepsy. We explore the possibility that such linkages may be manifest in the interictal EEG apart from epileptiform disturbances or visually evident focal abnormalities. We analyzed samples of interictal intracranial EEG (ICEEG) recorded from subdural grids in nine patients with medically intractable partial epilepsy, measuring interelectrode synchrony using the mean phase coherence algorithm. This analysis revealed areas of elevated local synchrony, or "hypersynchrony" which had persistent spatiotemporal characteristics that were unique to each patient. Measuring local synchrony in a subdural grid results in a map of the cortical surface that provides information not visually apparent on either EEG or structural imaging. We explore the relationship of hypersynchronous areas to the clinical evidence of seizure localization in each case, and speculate that local hypersynchrony may be a marker of epileptogenic cortex, and may prove to be a valuable aid to clinical ICEEG interpretation.

Adolescent↗
PubMed2004

Eclampsia, hippocampal sclerosis, and temporal lobe epilepsy: accident or association?

BACKGROUND: Up to 30% of patients with temporal lobe epilepsy (TLE) have no identifiable risk factors. OBJECTIVE: S: To report nine patients with TLE who had a history of eclampsia as the only risk factor for epilepsy and to investigate whether this possible association existed in a larger cohort of women with surgically treated TLE. METHODS: The clinical data, video-EEG, neuroimaging, and neuropathology of 195 consecutive women undergoing anterior temporal lobectomy (ATL) were reviewed. Risk factors for TLE, age at epilepsy onset, and occurrence of pregnancy were identified in each patient. RESULTS: Twenty-six women had no identifiable risk factors or seizures following a pregnancy. Nine of the 26 women had a history of eclampsia. The median age at the time of eclampsia was 16 years, and the latent period between the occurrence of eclampsia and onset of epilepsy ranged from 1 month to 2 years. The clinical, EEG, MRI, and neuropathologic findings were typical of hippocampal sclerosis (HS) and other than age at onset were no different from those of noneclampsia ATL patients. At mean follow-up of 57 months, seven patients were seizure-free and the other two markedly improved. CONCLUSION: Eclampsia may be a risk factor for TLE and HS.

Adolescent↗
PubMed2003

Frequency of epilepsy in patients with psychogenic seizures monitored by video-EEG.

This study examined the frequency of epilepsy in a consecutive series of patients who received a definitive diagnosis of psychogenic nonepileptic seizures (PNES) after completing inpatient video-EEG (VEEG) monitoring. Of the 1,590 patients receiving definitive diagnosis, 514 (32.3%) were diagnosed with PNES. Twenty-nine (5.3%) of these patients were found to have both PNES and epilepsy. When strict diagnostic criteria are applied, there is little overlap between epileptic seizures and PNES among patients referred for VEEG monitoring.

Alabama↗
PubMed2001

Bilateral hippocampal atrophy: consequences to verbal memory following temporal lobectomy.

BACKGROUND: Bilateral hippocampal damage is a risk factor for memory decline after anterior temporal lobectomy (ATL). OBJECTIVE: To investigate verbal memory outcome in patients with temporal lobe epilepsy (TLE) with either unilateral or bilateral hippocampal atrophy as measured by MRI. METHODS: The authors selected 60 patients with TLE who had undergone ATL (left = 31, right = 29). They determined normalized MRI hippocampal volumes by cursor tracing 1.5-mm slices from three-dimensional MRI acquisition. Hippocampal volumes were defined as atrophic if the volumes were below 2 SD for control subjects. Bilateral hippocampal atrophy was present in 10 patients with left TLE and 11 patients with right TLE. The authors assessed acquisition, retrieval, and recognition components of verbal memory both before and after ATL. RESULTS: Groups did not differ across age, education, intelligence, age at seizure onset, or seizure duration. Seizure-free rates after ATL were 70% or higher for all groups. Before surgery, patients with left TLE displayed worse verbal acquisition performance compared with patients with right TLE. Patients with left TLE with bilateral hippocampal volume loss displayed the lowest performance across all three memory components. After surgery, both groups of patients with left TLE exhibited worse verbal memory outcome compared with patients with right TLE. Bilateral hippocampal atrophy did not worsen outcome in the patients with right TLE. A higher proportion of patients with left TLE with bilateral hippocampal atrophy experienced memory decline compared with the other TLE groups. CONCLUSION: Bilateral hippocampal atrophy in the presence of left TLE is associated with worse verbal memory before and after ATL compared with patients with unilateral hippocampal volume loss or right TLE with bilateral hippocampal volume loss.

Adolescent↗
PubMed2001

Mutations in the X-linked filamin 1 gene cause periventricular nodular heterotopia in males as well as in females.

Periventricular heterotopia (PH) is a human neuronal migration disorder in which many neurons destined for the cerebral cortex fail to migrate. Previous analysis showed heterozygous mutations in the X-linked gene filamin 1 (FLN1), but examined only the first six (of 48) coding exons of the gene and hence did not assess the incidence and functional consequences of FLN1 mutations. Here we perform single-strand conformation polymorphism (SSCP) analysis of FLN1 throughout its entire coding region in six PH pedigrees, 31 sporadic female PH patients and 24 sporadic male PH patients. We detected FLN1 mutations by SSCP in 83% of PH pedigrees and 19% of sporadic females with PH. Moreover, no PH females (0/7 tested) with atypical radiographic features showed FLN1 mutations, suggesting that other genes may cause atypical PH. Surprisingly, 2/24 males analyzed with PH (9%) also carried FLN1 mutations. Whereas FLN1 mutations in PH pedigrees caused severe predicted loss of FLN1 protein function, both male FLN1 mutations were consistent with partial loss of function of the protein. Moreover, sporadic female FLN1 mutations associated with PH appear to cause either severe or partial loss of function. Neither male could be shown to be mosaic for the FLN1 mutation in peripheral blood lymphocytes, suggesting that some neurons in the intact cortex of PH males may be mutant for FLN1 but migrate adequately. These results demonstrate the sensitivity and specificity of DNA testing for FLN1 mutations and have important functional implications for models of FLN1 protein function in neuronal migration.

Abnormalities, Multiple↗
PubMed2001

Postictal stability of proton magnetic resonance spectroscopy imaging (1H-MRSI) ratios in temporal lobe epilepsy.

Interictal proton (1H) MRS is increasingly used for seizure lateralization in patients with temporal lobe epilepsy (TLE). Studies reporting postictal 1H-MRS metabolite changes in patients with TLE are few and contradictory. The authors prospectively performed interictal and postictal proton magnetic resonance spectroscopy imaging (1H-MRSI) studies in seven patients with TLE. The authors found no consistent changes in metabolite peak area ratios between studies, suggesting that 1H-MRS ratios remain stable between interictal and postictal state in TLE.

Adolescent↗
PubMed2001

Magnetic resonance spectroscopic imaging in temporal lobe epilepsy: neuronal dysfunction or cell loss?

BACKGROUND: Magnetic resonance spectroscopy (MRS) has demonstrated consistent metabolic abnormalities in temporal lobe epilepsy. The reason for decreases in N-acetylated compounds are thought to be related to neuronal hippocampal cell loss as observed in hippocampal sclerosis. However, mounting evidence suggest that the N-acetylated compound decreases may be functional and reversible. OBJECTIVE: To establish whether the metabolic changes measured by MRS correlate to hippocampal cell loss in temporal lobe epilepsy. SUBJECTS AND METHODS: We prospectively performed quantitative hippocampal MR imaging volumetry and MRS imaging in 33 patients with intractable mesial temporal lobe epilepsy who were undergoing surgery. A neuronal-glial ratio of cornu ammonis and fascia dentata was obtained and correlated while validating the pathologic analysis by comparisons with specimens of age-matched autopsy control-case hippocampus (n = 14). RESULTS: The neuronal-glial ratio of the patient group was statistically significantly lower than in the control group for the cornu ammonis region (P<.001). Correlations of hippocampal volumes with cornu ammonis and neuronal-glial ratios revealed a significant interdependence (P<.01). However, correlations of the resected hippocampal creatine-N-acetylated compound ratio with the cornu ammonis or fascia dentata neuronal-glial ratios showed no significant interdependence (P>.8). CONCLUSIONS: Our findings support the concept that the metabolic dysfunction measured by MRS imaging and the hippocampal volume loss detected by MR imaging volumetry do not have the same neuropathologic basis. These findings suggest that the MRS imaging metabolic measures reflect neuronal and glial dysfunction rather than neuronal cell loss as previously assumed.

Adolescent↗
PubMed2001

Relationships among hippocampal volumetry, proton magnetic resonance spectroscopy, and verbal memory in temporal lobe epilepsy.

PURPOSE: To examine the relationship between hippocampal volumes, 1H magnetic resonance spectroscopy (MRS)-identified hippocampal metabolic function, and verbal memory in patients with unilateral mesial temporal lobe epilepsy (MTLE). METHODS: Hippocampal volumes, 1H MRS-derived hippocampal creatine to N-acetylaspartate (Cr/NAA), and verbal memory assessment were obtained preoperatively in 22 patients (six right, 16 left) with EEG-defined unilateral MTLE. RESULTS: Left hippocampal volume correlated significantly with left hippocampal Cr/NAA (r=-0.549, p < 0.01), whereas right volume correlated significantly with right Cr/NAA (r=-0.478, p < 0.05). Verbal memory correlated significantly with left hippocampal Cr/NAA (r=-0.594, p < 0.01), but not with left hippocampal volume or right hippocampal measures. CONCLUSIONS: Hippocampal volumes and 1H MRS-derived metabolite ratios are statistically related, but share only a small percentage of variance, suggesting separate but related pathophysiologic processes. Left hippocampal Cr/NAA appears to be more sensitive to verbal memory function than volumes.

Adult↗
PubMed2001

Correlation of scalp EEG and 1H-MRS metabolic abnormalities in temporal lobe epilepsy.

PURPOSE: To correlate the interictal spike field and region of seizure onset with the distribution of 1H-MRS abnormalities in temporal lobe epilepsy (TLE) and improve our understanding of the clinical significance of 1H-MRS abnormalities. METHODS: Scalp electroencephalogram (EEG) monitoring and proton magnetic resonance spectroscopy (1H-MRS) results were correlated in 31 consecutive patients with TLE. RESULTS: Lateralized 1H-MRS-based hippocampal abnormalities were recorded in 95% of the patients with unilateral interictal spikes, with a high degree of concordance for the lateralization side (90%). In 64% of the patients with normal or bilateral interictal EEG spikes, 1H-MRS provided lateralizing information. Bilateral 1H-MRS abnormalities, with or without lateralization, were 3 times more frequent than bitemporal EEG spikes. Anterior predominance of the 1H-MRS abnormalities was more frequent in patients with anterior temporal EEG spiking (50%), than in patients without this EEG distribution (18%). Similar association was noted between distribution of 1H-MRS abnormalities and region of EEG seizure onset. CONCLUSIONS: Our results show a moderate level of concordance between the distribution of 1H-MRS and EEG abnormalities. 1H-MRS identifies abnormalities contralateral to the predominant seizure focus more often than does EEG and may provide lateralizing information in patients with nonlateralizing interictal EEG.

Adult↗
PubMed2001

Verbal retention lateralizes patients with unilateral temporal lobe epilepsy and bilateral hippocampal atrophy.

PURPOSE: To examine the lateralization utility of preoperative verbal retention in patients with and without bilateral hippocampal atrophy. METHODS: The sample consisted of 74 patients with EEG-defined unilateral temporal lobe epilepsy (TLE) who had also undergone volumetric magnetic resonance imaging (MRI). Verbal retention was operationalized by the Logical Memory percentage retention subtest (LM%) of the Wechsler Memory Scale. Patients were divided into groups with (a) bilaterally normal hippocampal volumes, (b) unilateral atrophy, or (c) bilateral atrophy. Two different thresholds (empirically derived vs. normative) were used to lateralize on the basis of LM%. LM% lateralization was then examined by group using chi2, sensitivity, positive predictive values, and odds ratios. Analyses were also conducted separately in the subset of patients who were seizure free after surgery. RESULTS: Mean LM% performance was significantly lower in patients with left versus right TLE in the subset with bilateral hippocampal atrophy (p = 0.018), but not in patients with a normal MRI (p = 0.918) or unilateral atrophy (p = 0.087). The odds of a correct lateralization by LM% increased from 1.67 in patients with normal MRI to 36.11 in patients with bilateral hippocampal atrophy. The power of a right and left lateralization prediction by LM% was 100% and 75%, respectively, in patients with bilateral hippocampal atrophy. Similar results were obtained when analysis was restricted to patients who were seizure free after surgery. CONCLUSIONS: Preoperative verbal retention as measured by LM% may provide meaningful lateralization information in patients who are difficult to lateralize via MRI.

Adolescent↗
PubMed2001

Comparative cognitive effects of carbamazepine and gabapentin in healthy senior adults.

PURPOSE: This study compared the cognitive effects of carbamazepine (CBZ) and gabapentin (GBP) in healthy senior adults by using a randomized, double-blind crossover design. METHODS: Thirty-four senior adults were randomized to receive one of the two drugs followed by a 5-week treatment period. A 4-week washout phase preceded initiation of the second drug. Antiepileptic drugs (AEDs) were titrated to target doses of either CBZ (800 mg/day) or GBP (2,400 mg/day). Primary outcome measures were standardized neuropsychological tests of attention/vigilance, psychomotor speed, motor speed, verbal and visual memory, and the Profile of Mood State (POMS), yielding a total of 17 variables. Each subject received cognitive testing at predrug baseline, end of first drug phase, end of second drug phase, and 4 weeks after completion of the second drug phase. RESULTS: Fifteen senior adults (mean age, 66.5 years; range, 59-76 years) completed the study. Seniors completing the study did not differ significantly from noncompleting seniors in terms of demographic features or baseline cognitive performances. Fifteen of the 19 seniors not completing the study dropped out while receiving CBZ. Adverse events were frequently reported for both AEDs, although they were more common for CBZ. Mean serum levels for the completers were within midrange clinical doses (CBZ, 6.8 microg/ml; GBP, 7.1 microg/ml). Significant differences between CBZ and GBP were found for only one of 11 cognitive variables, with better attention/vigilance for GBP, although the effect was modest. Performances on the nondrug average were significantly better on 45% of cognitive variables compared with CBZ and 36% compared with GBP. The overall pattern of means favored GBP over CBZ on 15 of 17 (p < 0.001), nondrug over CBZ on 17 of 17 (p < 0.0000), and nondrug over GBP on eight of 17 (NS). CONCLUSIONS: Mild cognitive effects were found for both AEDs compared with the nondrug average condition. The magnitude of difference between the two AEDs across the cognitive variables was modest. Self-reported mood was not significantly affected by either AED. However, overall tolerability and side-effect profile of CBZ were poorer than those of GBP in senior adults at doses and titration rates reported in this study.

Acetates↗
PubMed2001

Reproducibility of proton magnetic resonance spectroscopy imaging measurements of normal human hippocampus at 1.5 T: clinical implications.

The authors investigate the reproducibility of metabolite signals measured with proton magnetic resonance spectroscopy (1H-MRS) acquired from the human hippocampus in controls and in a phantom. Two 1H-MRS studies separated by 3 weeks were performed in 8 healthy volunteers and in a phantom. N-acetyl compounds (NA), choline (Ch), and creatine (Cr) peak areas and ratios were measured and compared using percentage variation, and Pearson Correlation Coefficient at the level of every voxel, the level of 1 hippocampus (5 voxels), and the level of 2 hippocampi (10 voxels). Sensitivity for observing clinically significant between-session 1H-MRS changes was evaluated using the reliable change index. Reproducibility measures for metabolite peak areas were only moderately concordant with percentage variation ranging from 14% to 20% for NA, Cho, and Cr. Stability was much improved when NA ratios and sum of multiple voxels were considered. Between-session NA/(Cho + Cr) changes greater than 22%, 12%, and 10% in one given participant can be detected with a 90% confidence interval when considered at the single-voxel level, the level of a single hippocampus, or the level of both hippocampi, respectively. Left-right asymmetry indices showed similar and limited inter-hemispheric asymmetry in repeated examination. This study suggests that 1H-MRS reproducibility performance is adequate for the study and monitoring of human hippocampus function when NA ratios and the sum of multiple voxels are considered. Individual metabolite peaks and single-voxel measurements have low reproducibility at 1.5 T and should be used only with clearly established statistical parameters.

Adult↗
PubMed2000

Adult myoclonic epilepsy: a distinct syndrome of idiopathic generalized epilepsy.

The authors present 11 cases of idiopathic generalized epilepsy that began in adulthood at a mean age of 39 years. All patients had myoclonic jerks, five had absence seizures, and nine had infrequent generalized tonic-clonic seizures. A majority had a family history of seizures. EEG in all patients showed generalized epileptiform abnormalities, whereas neuroimaging and neurologic examination results were normal. This series appears to represent a previously undescribed idiopathic generalized epilepsy syndrome of adult myoclonic epilepsy.

Adult↗
PubMed2000

Occipitoparietal epilepsy, hippocampal atrophy, and congenital developmental abnormalities.

PURPOSE: Diagnostic uncertainty may arise in patients with occipitoparietal epilepsy when there is neuroimaging evidence of a posterior quadrant lesion and coexistent hippocampal abnormalities ("dual pathology"). It is not known whether hippocampal atrophy (HA) in these patients results from seizure propagation to temporolimbic structures or whether it is part of the pathological process underlying the occipitoparietal epilepsy. Clarification of this issue may have a significant bearing on the management of these patients. METHODS: We studied 20 patients with occipitoparietal epilepsy and neuroimaging or pathologic evidence of a congenital developmental abnormality. Normalized hippocampal volumes were obtained in all patients. The medical records and video-EEG recordings were analyzed to correlate the MRI findings with clinical data, seizure semiology, and EEG findings. RESULTS: HA was found in seven patients (35%). Neuroimaging abnormalities concordant with the side of HA were seen in all cases. There was clinical or EEG evidence of temporal spread in 12 patients. There was no correlation between the presence of HA and temporal lobe spread. The only clinical factor associated with HA in this series was a younger age of seizure onset. CONCLUSIONS: HA in patients with occipitoparietal epilepsy due to congenital developmental abnormalities is most likely to be a marker of a more widespread process related to a common pathogenesis during prenatal or perinatal development. HA in these patients is unlikely to be the result of secondary spread from an extrahippocampal focus. Surgical treatment should be tailored toward the primary epileptogenic zone rather the site of seizure spread.

Adolescent↗
PubMed2000

Predictive value of MRI-identified mesial temporal sclerosis for surgical outcome in temporal lobe epilepsy: an intent-to-treat analysis.

PURPOSE: Magnetic resonance imaging (MRI) accurately identifies mesial temporal sclerosis (MTS), but prediction of successful surgical outcome ranges from 62% to 96% in published studies. Prior investigations only used patients who had received anterior temporal lobectomy (ATL), potentially overestimating the predictive value of MRI-identified MTS (MRI-MTS). METHODS: The authors performed an intent-to-treat analysis of 90 consecutive patients assessed for possible ATL, including 13 who did not undergo ATL because of inconclusive intracranial ictal EEG. Four (31%) of these 13 patients had unilateral mesial temporal abnormalities on their MRIs. RESULTS: The positive predictive value of MRI-MTS for seizure cessation decreased from 0.69 to 0.63 after adjustment for these additional false positive results. Four previous studies had revealed a positive predictive value of 0.75 (0.72 after similar adjustment). CONCLUSIONS: The authors conclude that the predictive value of MRI-MTS for outcome from ATL may be overestimated by small retrospective studies of highly selected postoperative patients.

Adolescent↗
PubMed2000

Familial perisylvian polymicrogyria: a new familial syndrome of cortical maldevelopment.

Two familial X-linked dominant syndromes of cortical maldevelopment have recently been described: double cortex/lissencephaly syndrome and bilateral periventricular nodular heterotopia. We report on 12 kindreds with familial perisylvian polymicrogyria (FPP) presenting at 10 centers, examine the clinical presentation in these familial cases, and propose a possible mode of inheritance. The clinical and radiological pattern was variable among the 42 patients, with clinical differences among the families and even within members of the same family. Pseudobulbar signs, cognitive deficits, epilepsy, and perisylvian abnormalities on imaging studies were not found in all patients. When present, they displayed a spectrum of severity. The only clear correlation in this study was between bilateral imaging findings and abnormal tongue movements and/or pronounced dysarthria. Most of the families provided evidence suggestive of, or compatible with, X-linked transmission. On the other hand, the pedigrees of 2 families ruled out X-linked inheritance. The most likely mode of inheritance for these 2 families was autosomal dominant with decreased penetrance; however, autosomal recessive inheritance with pseudodominance could not be ruled out in 1 family. We conclude that FPP appears to be genetically heterogeneous. However, most of the families probably represent a third previously undescribed X-linked syndrome of cortical maldevelopment.

Adolescent↗
PubMed1999

Cognitive correlates of 1H MRSI-detected hippocampal abnormalities in temporal lobe epilepsy.

OBJECTIVES: To examine associations between 1H magnetic resonance spectroscopic imaging (1H MRSI)-detected hippocampal creatine to N-acetylaspartate (Cr/NAA) ratios and neuropsychological measures sensitive to mesial temporal lobe function. BACKGROUND: The measurement of 1H MRSI-detected hippocampal metabolites has proved effective in determining extent and lateralization of neuronal damage. However, relationships between 1H MRSI-detected hippocampal metabolic abnormalities and specific areas of cognitive functioning have received limited attention compared to other studies using MRI volumetry or cerebral blood flow techniques. METHODS: We analyzed right and left hippocampal Cr/NAA ratios in 46 adult mesial temporal lobe epilepsy patients (32 left, 14 right) by 1H MRSI at high magnetic field (4.1 T). We examined the relationship between the right and left Cr/NAA hippocampal ratios to measures of verbal and visual memory, intelligence, attention, visuoperception, and confrontation naming. RESULTS: Measures of episodic verbal memory (n = 33) and visual confrontation naming (n = 46) were selectively associated with left hippocampal metabolic function (p<0.004), whereas neuronal function of the right hippocampal region was strongly associated with performance on a measure of facial recognition (n = 46; p<0.02). CONCLUSIONS: This study shows that specific areas of cognitive function are related to hippocampal neuronal metabolic abnormalities as detected by spectroscopic imaging. The current study indicates that 1H MRSI offers a complimentary technique to structural imaging studies in the study of mesial temporal lobe epilepsy and may enhance understanding of the role of hippocampal function in complex cognitive systems.

Adult↗