Biomedical subjects

W H Theodore

Publications and source records attributed to W H Theodore.

At least 73 records · Page 4Linked to original sources

PubMed1995

Hematoma-related seizures detected during subdural electrode monitoring.

A 28-year-old woman with epilepsy developed the new onset of paroxysmal tongue tingling during subdural electrode monitoring. Her symptoms coincided with electrographic seizure activity arising from an area of the perisylvian region that had not previously been involved in her habitual seizures. At electrode removal, a focal 2 x 2 cm hematoma was detected and evacuated from beneath these electrode contacts. Unexpected episodic events may represent nonhabitual seizure activity related to the surgical procedure.

Adult↗

PubMed1995

FDG-PET and volumetric MRI in the evaluation of patients with partial epilepsy.

We performed interictal FDG-PET- and MRI-based hippocampal volumetric measurements on 18 adult patients with complex partial epilepsy of temporal lobe origin in whom we had identified their ictal focus by video-telemetry EEG. Sixteen patients (89%) had regional hypometabolism, 11 (61%) had focal 1.5-tesla T2-weighted MRI (two structural abnormalities, nine hippocampal formation [HF] increased T2 signal), and nine (50%) had absolute HF atrophy ipsilateral to the temporal ictal focus. Ten (55%) had abnormal L/R HF ratios, nine ipsilateral to the EEG focus. All patients with abnormal MRI volumetric studies had focal PET abnormalities. Only seven had both abnormal HF volume ratios and T2 MRI (all increased HF T2 signal). There was a significant correlation between hippocampal volume and inferior mesial and lateral temporal lobe cerebral metabolic rate of glucose asymmetry index (p < 0.01), suggesting that hypometabolism may reflect hippocampal atrophy. PET is more sensitive than MRI volumetry in identifying the ictal focus but does not provide additional information when HF atrophy is present.

Adolescent↗

PubMed1995

Functional MRI during word generation, using conventional equipment: a potential tool for language localization in the clinical environment.

OBJECTIVE: To test the accuracy of bilateral language mapping using a standard clinical magnetic resonance (MR) imaging device during word generation. DESIGN: A study of normal volunteers. SETTING: Volunteers from the Washington, DC, area. PARTICIPANTS: Nine normal, right-handed, native English speakers (four women, five men, mean age 31 years). INTERVENTIONS: During four MR acquisition periods, subjects would alternately rest and silently generate words. Sagittal MR images covered the middle and inferior frontal gyri, insulae, and part of the temporal and parietal lobes bilaterally. MAIN OUTCOME MEASURES: (1) Anatomic maps of task-related signal changes obtained by comparing, in each voxel, the signal during word generation and rest periods, and (2) analysis of the time course of the signal. RESULTS: Maximum responses were in the left hemisphere, mainly in the frontal lobe (Broca's area, premotor cortex, and dorsolateral prefrontal cortex) but also in posterior regions such as Wernicke's area. In agreement with previous studies, some degree of task-related changes was present in a subset of the corresponding regions in the right hemisphere. CONCLUSION: Despite certain limitations, it is possible, using widely available MR equipment, to obtain results consistent with previous studies. The technique may have important implications for assessment of cognitive functions in patients with neurologic disorders in a clinical environment.

Adult↗

PubMed1995

Interictal metabolism and blood flow are uncoupled in temporal lobe cortex of patients with complex partial epilepsy.

We used positron emission tomography (PET) with 18F-2-deoxyglucose (FDG) and 15O water in 20 patients with complex partial seizures to compare glucose metabolism and blood flow in temporal lobe epileptic foci identified by ictal scalp-sphenoidal video-EEG telemetry. Glucose metabolism was measured 20 minutes after blood flow without moving the patient from the scanner. We also studied 11 patients with 99mTc-HMPAO single-photon emission computed tomography (SPECT). Both local cerebral metabolic rate of glucose (LCMRGlc) and regional cerebral blood flow (rCBF) were significantly decreased in temporal cortex ipsilateral to the EEG focus. However, LCMRGlc was reduced by 11.2% in inferior lateral and 11.1% in inferior mesial temporal cortex and rCBF by only 3.2% and 6.1%. The ratio of LCMRGlc to rCBF was significantly reduced in inferior lateral temporal cortex ipsilateral to the ictal focus (p < 0.009). Moreover, using standardized criteria, blinded raters found that 16 of 20 patients had focal FDG-PET hypometabolism, all in the epileptogenic region; 10 of 20 had focal 15O water PET hypoperfusion, but it was falsely lateralized in two of these 10; and five of 11 had focal 99mTc-HMPAO SPECT hypoperfusion, but it was falsely lateralized in two of these five. Our data suggest that interictal glucose metabolism and blood flow may be uncoupled in epileptogenic cortex.

Adult↗

PubMed1994

Postictal behavior. A clinical and subdural electroencephalographic study.

OBJECTIVE: To examine postictal behaviors after temporal lobe complex partial seizures (CPSs) and to correlate these behavioral phenomena with side of origin and ictal spread pattern. DESIGN: Review language and other behavioral phenomena after seizures defined by subdural electroencephalography. SETTINGS: A surgical epilepsy center. PATIENTS: We studied postictal behavior following 65 CPSs in 18 patients with left hemisphere language dominance using subdural electrode recordings. INTERVENTION: Subdural electrodes. MAIN OUTCOME MEASURES: Language function, affect, orientation, and postictal automatisms. RESULTS: Following the CPS ictal discharge, the mean interval for initial nonreflexive response to an environmental stimulus was 43 seconds (left foci, 57 seconds; right foci, 29 seconds; not significantly) and for first correct verbal response was 219 seconds (left foci, 275 seconds; right foci, 167 seconds; not significant). Impaired comprehension with fluent but unintelligible speech, as well as anomia, occurred after seizures arising from either temporal lobe. All nine seizures followed by global or nonfluent aphasia originated on the left side. Paraphasic errors were significantly more common after left temporal CPSs. Prolonged disorientation for place and flat affect were significantly more common after right temporal CPS. Postictal automatisms were frequent and included rubbing of the face, fumbling and picking hand movements, and repetitive oral movements. CONCLUSIONS: Postictal paraphasias, disorientation for place, and flat affect most likely reflect the functions of the area from which seizures arise but not the areas involved by spread.

Adolescent↗

PubMed1994

The dynamics of metabolic change following seizures as measured by positron emission tomography with fludeoxyglucose F 18.

OBJECTIVE: To examine the time course of alterations in glucose metabolism in relation to the interval from the last seizure, focus laterality, seizure frequency, and seizure type. DESIGN: Metabolic study with the use of positron emission tomography with fludeoxyglucose F 18. Blinded scan evaluation with use of a standard template. Multivariate regression analysis of positron emission tomographic data. SETTING: National Institutes of Health Clinical Center, Bethesda, Md. PATIENTS: Thirty-two adults with intractable partial epilepsy and lateralized seizure onset documented by video-electroencephalographic monitoring. MAIN OUTCOME MEASURE: Normalized metabolic rate for glucose ipsilateral and contralateral to the epileptic focus. RESULTS: The most dramatic changes occurred in inferior temporal regions; the midtemporal region was affected as well. Effects lasting 48 hours were found after both simple and complex partial seizures. The time course was different for the two types of seizures. The inferior temporal metabolic rate ipsilateral to the focus increased compared with the interictal rate during the 24-hour period following simple partial seizures; a nadir occurred in the second 24 hours. The rate then rose to an intermediate level after 48 hours. The relative to an intermediate level after 48 hours. The relative regional increase in ipsilateral metabolism following complex partial seizures persisted for 48 hours before falling. CONCLUSION: The brain may take longer than 24 hours after a partial seizure to return to its baseline state.

Adolescent↗

PubMed1994

Positron emission tomographic measurement of cerebral blood flow and temporal lobectomy.

We used positron emission tomography (PET) and bolus injection of H2(15O) to measure interictal cerebral blood flow (CBF) in 32 patients who had temporal lobectomy for uncontrolled complex partial seizures. Seizure focus localization was confirmed by ictal video-electroencephalographic (video-EEG) telemetry, and patients who had imaging findings suggesting the presence of a tumor were excluded. PET-CBF studies were interpreted using a standard template by raters blinded to EEG and clinical data, and were not used in surgical planning. After surgery, patients were followed for 32 +/- 18 months. Twenty-six patients were seizure free and 6 had persistent seizures. Mean lateral temporal hypoperfusion was 8 +/- 14% in patients who became seizure free and 9 +/- 6% in patients with persistent seizures. Fourteen patients had at least 15%, and 11 at least 20% hypoperfusion, but were not more likely to be seizure free. Three additional patients had 15 to 20% hypoperfusion in the temporal lobe contralateral to their EEG focus. PET measurement of CBF using bolus H2(15O) should not be used to help select patients for temporal lobectomy.

Brain↗

PubMed1994

Anticonvulsant withdrawal-emergent psychopathology.

We prospectively investigated psychopathology in 32 epilepsy inpatients openly withdrawn from all antiepileptic drugs (AEDs) prior to entering a controlled trial of an investigational AED. Psychiatric ratings and seizures increased significantly with AED discontinuation. Anxiety and depression were the most prominent symptoms. Thirty-eight percent of patients developed moderate-to-severe psychopathology, and 28% dropped out of the study at various stages due to psychiatric symptoms. In 22 patients openly restarted on AEDs, psychiatric ratings returned to baseline within 2 weeks. Increases in partial seizures were weakly related to emergent anxiety and depression. Increases in generalized seizures were related to increases in global impairment but not to increases in specific psychopathology. AED withdrawal-emergent psychopathology was not fully explained by increases in seizures, demographic factors, or psychiatric history and may be partially due to pharmacodynamic effects following drug discontinuation.

Anticonvulsants↗

PubMed1994

The secondarily generalized tonic-clonic seizure: a videotape analysis.

We studied 120 generalized tonic-clonic seizures (GTCSs) in 47 patients with video-EEG telemetry. GTCSs were preceded by antecedent seizures, including 13 simple partial, 70 complex partial, 17 simple partial leading to complex partial, seven tonic, seven clonic, and one typical absence. We divided GTCSs into the following phases: onset of generalization, pretonic clonic, tonic, tremulousness, and clonic. The mean GTCS duration was 62 seconds. There was a non-significant trend toward longer duration on reduced antiepileptic drug doses. Marked heterogeneity in GTCS phenomenology was present; only 27% of seizures included all five phases. Individual phase duration and clinical expression, including tonic and clonic phases, was highly variable. The clinical phenomena suggest that multiple cortical and subcortical routes of spread may exist. When GTCSs last longer than 2 minutes, intravenous antiepileptic drug treatment should be initiated.

Adolescent↗

PubMed1993

The effect of naloxone on cerebral blood flow and glucose metabolism in patients with complex partial seizures.

We used positron emission tomography with [15O]water and [18F]fluoro-2-deoxyglucose (FDG) to study the effect of naloxone on cerebral blood flow (CBF) and glucose metabolism (LCMRglc) in patients with complex partial seizures. There was no effect on glucose metabolism, but blood flow was reduced 7-12% 45-60 min after infusion of 1 mg/kg naloxone, as was the degree of lateral temporal CBF asymmetry in patients with > 10% baseline hypoperfusion. Endogenous opiates are involved in regulation of human CBF, and possibly in hypoperfusion in epileptic foci. Since [18F]FDG PET measures mean LCMRglc over the tracer uptake and scanning periods, it is inferior to [15O]H2O PET for detecting drug effects which may be time dependent.

Brain↗

PubMed1993

Measurement of whole temporal lobe and hippocampus for MR volumetry: normative data.

We measured the volumes of the entire length of temporal lobe and hippocampal formation from coronal images in 29 healthy young adults to take into account normal side-to-side variation. Although whole-brain, temporal lobe, and left hippocampal volumes were significantly smaller in women, normalizing measurements for the whole brain eliminated intersex temporal lobe and hippocampal differences. There was a weak but significant inverse correlation between age and normalized hippocampal, but not temporal lobe or whole-brain, volume. In contrast to previous studies, we found no significant side-to-side differences in the sizes of temporal lobes or hippocampi. When performing MR volumetry, it is important to include the entire length of the hippocampal formation.

Adult↗

PubMed1993

Carbamazepine withdrawal: effects of taper rate on seizure frequency.

We prospectively investigated the effects of rate of carbamazepine (CBZ) withdrawal and CBZ level on seizure type and frequency in 12 epilepsy patients withdrawn completely from antiepileptic drugs prior to entering an investigational monotherapy trial. Patients withdrawn from CBZ rapidly (over 4 days) experienced significantly more generalized tonic-clonic seizures (GTCSs) and GTCS clusters than did those withdrawn slowly (over 10 days). Complex partial seizure (CPS) frequency did not differ between the two groups. CPSs preceded GTCSs, with GTCSs occurring in the majority of patients after CBZ had been discontinued, at subtherapeutic or absent CBZ levels. Two of six patients who had been tapered rapidly and all six patients who had been tapered slowly were able to enter the investigational monotherapy trial.

Adult↗

PubMed1992

Cerebral metabolism and depression in patients with complex partial seizures.

Twenty-three patients with complex partial seizures were evaluated with 18F-2-deoxyglucose positron emission tomography and with the Beck Depression Inventory. Five of 10 patients with left and zero of eight with right temporal electroencephalographic foci had depressive symptoms; one of five patients with poorly localized electroencephalographic foci also scored in the depressed range. Temporal, frontal, caudate, and thalamic normalized glucose metabolic rates among five patients with depressive symptoms and well-localized left temporal epileptogenic regions were compared with five patients without depressive symptoms but with similar electroencephalographic characteristics. Multifactorial analysis of variance yielded a significant nonlateralized mood by region interaction. Of nine individual regions compared, only inferior frontal cortex showed a significant difference in normalized regional metabolic rate between depressed and nondepressed patients. Metabolism in this region also distinguished patients with depressive symptoms from normal control subjects. Depressive symptoms in patients with complex partial seizures are associated with a bilateral reduction in inferior frontal glucose metabolism, compared with patients without depressive symptoms and normal control subjects. The frontal lobe hypometabolism observed in patients with depressions associated with epilepsy, Parkinson's disease, and primary affective disorder suggests that similar frontal lobe metabolic disturbances could underlie these conditions.

Adolescent↗

PubMed1992

Temporal lobectomy for uncontrolled seizures: the role of positron emission tomography.

We evaluated the role of positron emission tomography (PET) with [18F]deoxyglucose (FDG) (FDG-PET) for planning surgery in 53 patients who had temporal lobectomy for uncontrolled seizures at National Institutes of Health from 1981 to 1990. Investigators blinded to PET data used results of telemetered video-electroencephalographic ictal monitoring and other standard criteria to decide whether subdural electrodes (22 patients, i.e., the "invasive" group) should be implanted or surgery performed. PET scans were analyzed using a standard regional template. Mean lateral but not mesial temporal asymmetry was significantly higher in patients who became seizure free (p < 0.03). Patients with > or = 15% hypometabolism were significantly more likely to be seizure free in the entire study population and the invasive subgroup. Visual identification of hypometabolism was less accurate. When a clear temporal ictal surface electroencephalographic focus was present, FDG-PET provided less additional information. FDG-PET may be particularly valuable if the surface electroencephalographic scan is nonlocalizing. In addition to helping to identify the seizure focus, it may allow limitation of invasive electrode placement to those necessary for functional mapping. When PET is used to identify epileptic foci, quantitative measurements of asymmetry should be made.

Brain↗

PubMed1992

Rational use of antiepileptic drug levels.

Antiepileptic drug (AED) levels are obtained frequently in clinical practice, but their complex relation to seizures or drug toxicity often makes interpretation of the results difficult. Research studies have not always taken into account clinical, as well as pharmacokinetic and pharmacodynamic, factors which may influence the drug level-effect relationship. AED levels should be drawn at an appropriate time in relation to drug ingestion and clinical symptoms. Systematic investigations in selected patients, during which several levels are obtained, may be more rewarding than routine measurements in a large clinic population.

Carbamazepine↗

PubMed1992

PET imaging of opiate receptor binding in human epilepsy using [18F]cyclofoxy.

We used [18F]cyclofoxy (CF), a potent opiate antagonist with affinity for mu and kappa receptors, and the Scanditronix PC1024-7B PET scanner to study 14 patients with complex partial seizures (CPS), and 14 normal controls. Epileptic foci were localized by prolonged EEG-video monitoring. EEG was recorded continuously during each scan. Immediately before CF administration, [15O]labeled water was used to measure cerebral blood flow, and showed hypoperfusion ipsilateral to the EEG focus. Blood samples (corrected for radiolabeled metabolites) and tissue time-activity data were acquired over 90 min following bolus CF injection. Anatomic regions were outlined directly on the PET images. A kinetic model was used to derive the total volume of distribution (Vt) in each brain region. Specific binding (Vs) was determined by substracting non-specific binding (Vt) measured in a receptor-poor brain region (occipital cortex). Regions with high Vs included mesial temporal lobes, thalamus, basal ganglia, and frontal cortex. Individual patients appeared to have higher binding in temporal lobe ipsilateral to the EEG focus, but there was no asymmetry for the patients as a group in mean Vt or Vs in anterior mesial, posterior mesial, anterior lateral, posterior lateral temporal cortex, thalamus, basal ganglia, or, for Vt, in regions of low specific binding: occipital lobe, parietal lobe, cerebellum.

Adolescent↗

PubMed1992

Comparison of PET measurements of cerebral blood flow and glucose metabolism for the localization of human epileptic foci.

We compared the relative sensitivity of two interictal PET techniques, bolus injection of [15O] labeled water for estimation of cerebral blood flow (H2(15)O CBF-PET), and 18F 2-deoxyglucose (18FDG-PET) for cerebral glucose metabolism (CMRglc), and T2-weighted magnetic resonance imaging, in 28 patients with medically intractable complex partial seizures undergoing evaluation for surgery. There were statistically significant associations between lateralization by 18FDG-PET, and MRI, but not H2(15)O CBF-PET, and lateralization of the epileptic focus as defined by scalp-sphenoidal ictal EEG. Fifteen patients had surgery or subdural electrodes. 18FDG-PET was more closely associated with a good outcome than H2(15)O CBF-PET, which, in addition, showed hypoperfusion contralateral to the epileptic temporal lobe in several cases. H2(15)O sensitivity may have been reduced by technical factors, but 18FDG-PET appears to be more specific for localization of epileptic zones.

Adult↗

PubMed1992

Viscosity and social cohesion in temporal lobe epilepsy.

Clinical case reports suggest that viscosity, the behavioural tendency to talk repetitively and circumstantially about a restricted range of topics, is common in patients with temporal lobe epilepsy (TLE). Such patients are also reported to exhibit heightened levels of social cohesion, the tendency to become interpersonally "clingy". This "sticky" interpersonal style may be particularly common in TLE patients with a left sided temporal lobe seizure focus. To test this hypothesis, self-report and observer rating scales were developed to assess both viscosity and social cohesion. Subjects consisted of patients with right, left, or bilateral temporal lobe seizure foci, absence or primary generalised tonic-clonic seizures, psychiatric controls (panic disorder patients), and normal controls. Elevations on the viscosity scale were observed primarily in TLE patients with left or bilateral seizure foci. Viscosity scores also correlated with seizure duration and left handedness. No group differences were observed on the social cohesion scale. These findings are consistent with the hypothesis that viscosity results from subtle interictal language disturbances, although other pathogenetic mechanisms are discussed.

Anomia↗