Biomedical subjects

M Okujava

Publications and source records attributed to M Okujava.

7 recordsLinked to original sources

PubMed2006

Amygdala fMRI lateralizes temporal lobe epilepsy.

OBJECTIVE: To characterize the clinical value of an fMRI task activating the amygdala in controls and patients with mesial temporal lobe epilepsy (MTLE). METHODS: A fearful face fMRI paradigm using video sequences was developed and investigated in 17 patients with epilepsy (12 had MTLE [6 right- and 6 left-sided]) and 17 healthy control subjects. Reproducibility was demonstrated by reimaging 12 of the control subjects. In addition, parahippocampal activation was measured using Roland's Hometown Walking Task within the same session in all patients and in nine of the control subjects. RESULTS: A fearful face paradigm led to significant amygdala activation (p < 0.001) in all subjects. Amygdala activation was bilateral in control subjects and clearly lateralized in patients with MTLE. Dissociated amygdala and parahippocampal activation was found in three MTLE patients. A combination of results from both fMRI paradigms improved the lateralization of the side of seizure onset in patients with MTLE. CONCLUSIONS: fMRI activation of the amygdala evoked by an animated fearful face paradigm is strong, reproducible, and specific in individual subjects. The combination of the fearful face paradigm and Roland's Hometown Walking Task provides a more reliable presurgical mapping of mesial temporal lobe structures.

Adolescent↗

PubMed2004

Bilateral mesial temporal lobe epilepsy: comparison of scalp EEG and hippocampal MRI-T2 relaxometry.

OBJECTIVE: Bilateral hippocampal abnormality is frequent in mesial temporal lobe sclerosis and might affect outcome in epilepsy surgery. The objective of this study was to compare the lateralization of interictal and ictal scalp EEG with MRI T2 relaxometry. MATERIAL AND METHODS: Forty-nine consecutive patients with intractable mesial temporal lobe epilepsy (MTLE) were studied with scalp EEG/video monitoring and MRI T2 relaxometry. RESULTS: Bilateral prolongation of hippocampal T2 time was significantly associated with following bitemporal scalp EEG changes: (i) in ictal EEG left and right temporal EEG seizure onsets in different seizures, or, after regionalized EEG onset, evolution of an independent ictal EEG over the contralateral temporal lobe (left and right temporal asynchronous frequencies or lateralization switch; P = 0.002); (ii) in interictal EEG both left and right temporal interictal slowing (P = 0.007). Bitemporal T2 changes were not, however, associated with bitemporal interictal epileptiform discharges (IED). Lateralization of bilateral asymmetric or unilateral abnormal T2 findings were associated with initial regionalization of the ictal EEG in all but one patient (P < 0.005), with lateralization of IED in all patients (P < 0.005), and with scalp EEG slowing in 28 (82,4%) of 34 patients (P = 0.007). CONCLUSION: Our data suggest that EEG seizure propagation is more closely related to hippocampal T2 abnormalities than IED. Interictal and ictal scalp EEG, including the recognition of ictal propagation patterns, and MRI T2 relaxometry can help to identify patients with bitemporal damage in MTLE. Further studies are needed to estimate the impact of bilateral EEG and MRI abnormal findings on the surgical outcome.

Action Potentials↗

PubMed2003

Language lateralization by Wada test and fMRI in 100 patients with epilepsy.

Comparing the determination of language dominance using fMRI with results of the Wada test in 100 patients with different localization-related epilepsies, the authors found 91% concordance between both tests. The overall rate of false categorization by fMRI was 9%, ranging from 3% in left-sided temporal lobe epilepsy (TLE) to 25% in left-sided extratemporal epilepsy. Language fMRI might reduce the necessity of the Wada test for language lateralization, especially in TLE.

Adult↗

PubMed2002

Measurement of temporal lobe T2 relaxation times using a routine diagnostic MR imaging protocol in epilepsy.

OBJECTIVE: To determine the applicability of a fast spin-echo (FSE) pulse sequence for T2 relaxation time measurements in diagnostic imaging of temporal lobe epilepsy (TLE) and in epilepsy research. To compare FSE T2-relaxometry to the measurements with multi-echo sequence and visual assessment of MR scans. METHODS: MR imaging and T2 relaxometry was performed with widely used 1.5 T scanner only. Fast dual-echo sequence (TE-14/85 ms) and multi-echo pulse sequence were used for T2 measurements. Normal ranges of T2 values in regions of interest in temporal lobe were estimated in 20 healthy controls. Sixty-five patients with intractable focal epilepsy were studied. Fifty-five patients had TLE, three multilobar focal epilepsy and seven extratemporal focal epilepsy. RESULTS: T2 measurements with the FSE showed good reproducibility in the test objects and control subjects. In one TLE case unilateral focal T2 changes were not identified visually. T2-relaxometry was more sensitive than visual inspection of MR scans in assessing bilateral hippocampal changes: there were 15 cases with abnormal bilateral T2 values. Visually bilateral changes were detected in six out of these 15 cases (40%). In six cases (40%) only unilateral changes were diagnosed visually, and in three cases (20%) bilateral changes were classified as probable with qualitative evaluation. T2 relaxation time measurement supplied additional objective data in cases with ambiguous hippocampal changes on visual assessment: T2-relaxometry confirmed hippocampal abnormalities in seven cases judged visually as probable. In four cases with the suspicion of hippocampal changes T2 values appeared to be normal. CONCLUSION: In TLE patients, images constructed from FSE sequences can be used to estimate T2 relaxation times easily and reliably. T2 measurements are an objective method to diagnose structural changes in the temporal lobe. T2-relaxometry is most helpful to assess bilateral hippocampal abnormalities, and thus might have an impact on estimating postsurgical outcome.

Adolescent↗

PubMed2001

Carbamazepine reduces memory induced activation of mesial temporal lobe structures: a pharmacological fMRI-study.

BACKGROUND AND PURPOSE: It is not known whether carbamazepine (CBZ; a drug widely used in neurology and psychiatry) influences the blood oxygenation level dependent (BOLD) contrast changes induced by neuronal activation and measured by functional MRI (fMRI). We aimed to investigate the influence of CBZ on memory induced activation of the mesial temporal lobes in patients with symptomatic temporal lobe epilepsy (TLE). MATERIAL AND METHODS: Twenty-one individual patients with refractory symptomatic TLE with different CBZ serum levels and 20 healthy controls were studied using BOLD fMRI. Mesial temporal lobe (MTL) activation was induced by a task that is based on the retrieval of individually familiar visuo-spatial knowledge. The extent of significant MTL fMRI activation was measured and correlated with the CBZ serum level. RESULTS: In TLE patients, the extent of significant fMRI activation over both MTL was negatively correlated to the CBZ serum level (Spearman r = -0.654, P < 0.001). Activation over the supposedly normal MTL, i.e. contralateral to the seizure onset of TLE patients, was smaller than the averaged MTL activation in healthy controls (P < 0.005). Age, duration of epilepsy, side of seizure onset, and intelligence were not correlated to the extent of the significant BOLD-response over both MTL in patients with TLE. CONCLUSIONS: In TLE patients, carbamazepine reduces the fMRI-detectable changes within the mesial temporal lobes as induced by effortful memory retrieval. FMRI appears to be suitable to study the effects of chronic drug treatment in patients with epilepsy.

Adolescent↗

PubMed2001

Memory fMRI lateralizes temporal lobe epilepsy.

BACKGROUND: The assessment of mesial temporal lobe (MTL) function is important for the diagnosis and treatment of temporal lobe epilepsy (TLE) and other brain diseases. Declarative memory depends on the integrity of the MTL region. OBJECTIVE: To investigate hemispheric asymmetries of MTL activity in patients with symptomatic TLE. METHODS: With use of blood oxygenation level-dependent fMRI, hemispheric asymmetries in MTL activation of 30 individual patients with refractory symptomatic TLE and 17 healthy control subjects were studied. Activation was induced by a task employing mental navigation and recall of landmarks based on the retrieval of individually familiar visuospatial knowledge. RESULTS: The study demonstrated that the memory task used reliably activated MTL structures in individual control subjects and patients with refractory TLE including children, older subjects, and patients with low formal IQ. Interhemispheric differences in MTL activation lateralized the side of seizure onset in 90% of patients with symptomatic unilateral TLE. In contrast, healthy control subjects did not show a systematic asymmetry of MTL activation. Correlations between MTL activation and neuropsychological measures suggest that the fMRI-detectable MTL changes were specifically related to memory rather than to memory-independent visuospatial abilities. CONCLUSION: fMRI of memory-induced MTL activation lateralizes the side of seizure onset in patients with refractory symptomatic TLE and may provide complementary information for presurgical evaluation.

Adolescent↗

PubMed2001

Cavernous angioma associated with ipsilateral hippocampal sclerosis.

We report two cases with extratemporal cavernous angioma (CA) and coexisting ipsilateral hippocampal sclerosis. Classically dual pathology is defined as the association of hippocampal sclerosis with an extrahippocampal lesion. Subtle changes in hippocampus might be overlooked in the presence of an unequivocal extrahippocampal abnormality. Seizure outcome after epilepsy surgery in cases with dual pathology is less favourable if only one of the lesions is removed. Dual pathology must always be considered in diagnostic imaging of patients with intractable epilepsy and CA.

Adult↗