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Biomedical subjects

T R Henry

Publications and source records attributed to T R Henry.

At least 55 records · Page 3Linked to original sources

Psychogenic elaboration of simple partial seizures.

Seizures that cause loss of consciousness (LOC) can be classified as epileptic or nonepileptic based on evaluation of ictal semiology and analysis of changes in EEG events, recorded with continuous scalp EEG and video monitoring. We report 3 patients who had hippocampal electrographic seizures documented with intracranial EEG recording with no accompanying scalp EEG change immediately preceding psychogenic unresponsiveness. Each patient also had complex partial seizures (CPS) originating in the hippocampus. Some individuals can have complex interactions of epileptic and nonepileptic seizures.

Adult↗

Asymmetric hypsarrhythmia: clinical electroencephalographic and radiological findings.

Twenty-six children (16 boys and 10 girls) with hypsarrhythmia and infantile spasms (IS) were studied at the University of Michigan EEG Laboratory in a 4-year period. Six (2 boys, 4 girls), had asymmetric hypsarrhythmia with a preponderance of both slowing and epileptiform activity over one hemisphere. All 6 had the symptomatic form of IS, 4 with dysplastic conditions, 1 with porencephaly from a cerebral infarct, and 1 with hypoxicischemic encephalopathy. Five children had focal abnormalities on either physical examination or imaging studies. Four had the highest amplitude slowing and most epileptiform activity ipsilateral to the lesion, in 1, it was contralateral. Asymmetric hypsarrhythmia constituted 23% of cases with hypsarrhythmia examined at our EEG laboratory. The significant success in surgical therapy for some children with IS indicates the importance of identifying focal hemispheric abnormalities even if they are not apparent clinically. EEG may suggest focal changes not detected clinically or radiologically.

Brain↗

Temporal lobe central benzodiazepine binding in unilateral mesial temporal lobe epilepsy.

PET-demonstrated decreases in [11C]flumazenil binding occur in anterior mesial temporal structures on the side of epileptogenesis in unilateral mesial temporal lobe epilepsy. We performed quantitative autoradiography on anterior mesial and lateral temporal specimens from 11 subjects with unilateral mesial temporal lobe epilepsy and six neurologically normal controls to identify the predominant in vitro correlates of the decreased [11C]flumazenil binding. In anterior mesial temporal regions exhibiting the greatest neuronal cell loss, decreases in agonist and antagonist binding to type 1 and 2 (central) benzodiazepine binding sites were highly correlated with neuronal cell counts. Cell loss and decreased binding were particularly prominent in the lateral portion of hippocampal region CA1, adjacent to CA2. Lateral temporal central benzodiazepine binding was diffusely increased, achieving statistical significance in cortical laminae V and VI. These findings suggest that the predominant source of PET-demonstrated decreases in [11C]flumazenil binding in mesial temporal epilepsy is hippocampal sclerosis, rather than down-regulation of central benzodiazepine binding sites on surviving hippocampal neurons.

Adult↗

Asymmetric interictal glucose hypometabolism and cognitive performance in epileptic patients.

OBJECTIVE: To relate hemispheric metabolic asymmetries to cognitive performance in patients with unilateral mesial temporal lobe epilepsy. DESIGN: Asymmetrical cerebral glucose metabolisms on interictal fludeoxyglucose F 18 positron emission tomograms (FDG-PET) were correlated with cognitive measures. Analyses included partial correlations that controlled for the correlation between metabolic asymmetries of the lateral temporal lobe and other brain regions and the correlation of IQ scores with affected cognitive scores. SETTING: A university epilepsy surgery center. PATIENTS: Subjects included 13 patients who had intractable complex partial seizures originating from a mesial temporal lobe. INTERVENTION: Patients underwent FDG-PET scanning as part of their diagnostic work-up. Asymmetry indexes for cerebral metabolic rates were determined for whole hemisphere, lateral temporal lobe, mesial temporal lobe, frontal lobe, thalamus, and parietal lobe. MAIN OUTCOME MEASURES: The following cognitive domains were assessed: psychometric intelligence, mental control/attention, language, and verbal and nonverbal memory. Neuropsychological measures were obtained within 14 days of FDG-PET scanning. RESULTS: Relative reductions in glucose metabolism of the left hemisphere and left lateral temporal lobe correlated with a lower verbal IQ score and a lower score on a verbal memory task, recall of logical prose. Relative reduction in metabolism of the left side of the thalamus also correlated with lower scores for recall of logical prose. CONCLUSION: Relative hypometabolism of the left hemisphere correlates with lower cognitive performance. Hypometabolism of the left lateral temporal lobe and thalamus independently correlates with the verbal memory difficulties seen in this epileptic patient population.

Adult↗

Hippocampal neuronal loss and regional hypometabolism in temporal lobe epilepsy.

The pathophysiology of widespread interictal hypometabolism in temporal lobe epilepsy is unknown but might reflect neuronal loss and diaschisis. We found no significant correlation between any cortical region's metabolism on preoperative [18F]fluorodeoxyglucose positron emission tomography and neuronal density of resected hippocampi in 40 patients. We conclude that hippocampal neuronal loss and diaschisis cannot account for the regional interictal hypometabolism of temporal lobe epilepsy.

Epilepsy, Temporal Lobe↗

Disruption of mitochondrial calcium homeostasis following chronic doxorubicin administration.

Doxorubicin (Adriamycin) is an anthracycline antibiotic with broad antineoplastic activity. However, the clinical success is limited by the incidence of cumulative cardiomyopathy. In vitro, doxorubicin elicits a cyclosporine A-sensitive release of calcium from cardiac mitochondria. It has been suggested that this leads to mitochondrial calcium cycling and depolarization of membrane potential, which may account for the inhibition of mitochondrial respiration and cytotoxicity observed with the drug. Implication of a similar mechanism in the manifestation of clinical doxorubicin toxicity requires evidence for a disruption of mitochondrial calcium homeostasis following chronic in vivo administration. Cardiac mitochondria isolated from doxorubicin-treated rats (2 mg/kg/week, s.c. x 13 weeks) had a lower RCR but no change in ADP/O compared to controls and exhibited an enhanced cyclosporine A-sensitive release of mitochondrial calcium. Associated with this was a calcium-induced depolarization of membrane potential, which was inhibited by either cyclosporine A or ruthenium red suggesting the induction of mitochondrial calcium cycling following chronic doxorubicin treatment. The persistence of these effects on mitochondrial calcium regulation 4-7 days after the last drug treatment is consistent with the cumulative cardiotoxicity associated with doxorubicin therapy. Cardiac mitochondria isolated from rats treated with iminodaunorubicin, a noncardiotoxic analog of doxorubicin, showed no differences from control suggesting that this disruption of mitochondrial calcium homeostasis in vivo may be an important determinant of the cardiomyopathy observed clinically with doxorubicin.

Analysis of Variance↗

Uncomplicated stereotactic and open neurosurgical procedures in patients with factor VII deficiency.

Factor VII deficiency is characterized by epistaxis, bruising, hemarthrosis, menorrhagia, gastrointestinal bleeding, hematuria, and intracranial hemorrhage during infancy. Causes of acquired factor VII deficiency include liver disease, Vitamin K deficiency, and warfarin administration. Congenital factor VII deficiency is an autosomal recessive disorder, with the homozygotes having a severe deficiency and the heterozygotes a moderate deficiency of factor VII. Orthopedic, gynecological, cardiothoracic, and abdominal surgical procedures have been successfully performed in patients with factor VII deficiency both with and without factor VII replacement. We present two patients with moderate and moderately severe factor VII deficiency who successfully underwent intracranial procedures using plasma during the perioperative period for factor VII replacement. One patient successfully underwent stereotactic placement of mesial temporal lobe depth electrodes and subdural strip electrodes followed by anterior temporal lobectomy for medically refractory seizures. The second patient successfully underwent craniotomy for an olfactory groove meningioma. No bleeding complications were encountered with any of the three intracranial procedures performed. These cases represent the first reported cases of successful intracranial procedures in patients with factor VII deficiency, other than shunting procedures performed for intraventricular hemorrhage during infancy.

Adult↗

Interictal metabolic anatomy of mesial temporal lobe epilepsy.

OBJECTIVE--To examine patterns of temporal and extratemporal regional interictal glucose hypometabolism in individual patients with unilateral mesial temporal lobe epilepsy (TLE). Previous reports disagree on which extratemporal areas can be hypometabolic in TLE. DESIGN--Case series of patients with TLE who underwent interictal fludeoxyglucose F 18 positron emission tomography, compared quantitatively with normal positron emission tomography. SETTING--Patients referred for surgical treatment of medically refractory complex partial seizures. PATIENTS AND OTHER PARTICIPANTS--Ten normal volunteers; 27 patients with TLE selected to exclude seizures of bilateral temporal or extratemporal onset. RESULTS--Regional hypometabolism occurred in 25 patients. Hypometabolic regions were ipsilateral to seizure onset and included lateral temporal (in 78% of patients), mesial temporal (70%), thalamic (63%), basal ganglial (41%), frontal (30%), parietal (26%), and occipital (4%). Specific patterns of temporal and extratemporal hypometabolism varied considerably across the TLE group. CONCLUSIONS--Any of the previously reported anatomic areas of hypometabolism can occur in individual patients with TLE. The prevalence of thalamic hypometabolism suggests a pathophysiologic role for the thalamus in initiation or propagation of temporal lobe seizures or in the interictal cognitive dysfunction of TLE.

Adult↗

Ictal patterns in generalized epilepsy.

Ictal EEG may be of great benefit in facilitating accurate classification of the underlying seizure disorder in some patients and thus guiding further investigation and management. Ictal recordings in patients with generalized epilepsies are protean in their manifestations and yet may have considerable overlap. Classification is only possible through careful synthesis of all available clinical and electrophysiological data. Although the underlying pathophysiological mechanisms of the generalized epilepsies remain uncertain, evidence from EEG recordings tends to support Gloor's concept of corticoreticular epilepsy.

Cerebral Cortex↗

In vivo cerebral metabolism and central benzodiazepine-receptor binding in temporal lobe epilepsy.

Positron emission tomography measured interictal cerebral glucose metabolism with [18F]fluorodeoxyglucose and central benzodiazepine-receptor binding with [11C]flumazenil in 10 mesial temporal lobe epilepsy (TLE) patients and in normal subjects. Eight TLE patients had mesial temporal, lateral temporal, and thalamic hypometabolism ipsilateral to EEG ictal onsets, with additional extratemporal hypometabolism in four. One had unilateral anterior mesial temporal hypometabolism only, and one had normal metabolism. Each patient had decreased benzodiazepine-receptor binding in the ipsilateral anterior mesial temporal region, without neocortical changes. Thus, interictal metabolic dysfunction is variable and usually extensive in TLE, whereas decreased central benzodiazepine-receptor density is more restricted to mesial temporal areas. Metabolic patterns in TLE may reflect diaschisis, while benzodiazepine-receptor changes may reflect localized neuronal and synaptic loss that is specific to the epileptogenic zone. [11C]Flumazenil imaging may be useful in presurgical evaluation of refractory complex partial seizures.

Adult↗

A percutaneous epidural screw electrode for intracranial electroencephalogram recordings.

A new epidural electrode for monitoring brain electrical activity is described. The electrode is a tapered screw that is easily inserted percutaneously and removed without general anesthesia. The epidural screw has been used without complications for ictal and interictal electroencephalogram recordings in four patients with medically refractory complex-partial seizure disorders. The epidural screw electrode offers the advantages of easy insertion and removal, patient comfort, artifact-free electroencephalogram recordings, and minimal risk of intracranial infection or hemorrhage.

Bone Screws↗

Clinical evaluation of interictal fluorine-18-fluorodeoxyglucose PET in partial epilepsy.

Interictal [18F]fluorodeoxyglucose (FDG) positron emission tomography (PET) is useful in presurgical evaluation of medically refractory partial epilepsies. Limited replicability of image interpretation may restrict this application. We investigated interpretation replicability in 241 18F-FDG studies performed with three different tomographs in partial epilepsy patients. Two investigators independently interpreted the studies with a standardized evaluation protocol and without knowledge of the subjects. Replicability of these unbiased interpretations in detection of regional hypometabolism was best for studies performed with the highest performance tomograph. Interictal 18F-FDG studies performed with this tomograph revealed regional hypometabolism in 62% of patients who had normal cerebral magnetic resonance imaging (MRI). Replicability of interpretations in detecting regional hypometabolism was adequate for clinical application of interictal 18F-FDG studies performed with any of the tomographs.

Adolescent↗

Quantifying interictal metabolic activity in human temporal lobe epilepsy.

The majority of patients with complex partial seizures of unilateral temporal lobe origin have interictal temporal hypometabolism on [18F]fluorodeoxyglucose positron emission tomography (FDG PET) studies. Often, this hypometabolism extends to ipsilateral extratemporal sites. The use of accurately quantified metabolic data has been limited by the absence of an equally reliable method of anatomical analysis of PET images. We developed a standardized method for visual placement of anatomically configured regions of interest on FDG PET studies, which is particularly adapted to the widespread, asymmetric, and often severe interictal metabolic alterations of temporal lobe epilepsy. This method was applied by a single investigator, who was blind to the identity of subjects, to 10 normal control and 25 interictal temporal lobe epilepsy studies. All subjects had normal brain anatomical volumes on structural neuroimaging studies. The results demonstrate ipsilateral thalamic and temporal lobe involvement in the interictal hypometabolism of unilateral temporal lobe epilepsy. Ipsilateral frontal, parietal, and basal ganglial metabolism is also reduced, although not as markedly as is temporal and thalamic metabolism.

Brain↗

Presurgical evaluation for partial epilepsy: relative contributions of chronic depth-electrode recordings versus FDG-PET and scalp-sphenoidal ictal EEG.

One hundred fifty-three patients with medically refractory partial epilepsy underwent chronic stereotactic depth-electrode EEG (SEEG) evaluations after being studied by positron emission tomography (PET) with 18F-fluorodeoxyglucose (FDG) and scalp-sphenoidal EEG telemetry. We carried out retrospective standardized reviews of local cerebral metabolism and scalp-sphenoidal ictal onsets to determine when SEEG recordings revealed additional useful information. FDG-PET localization was misleading in only 3 patients with temporal lobe SEEG ictal onsets for whom extratemporal or contralateral hypometabolism could be attributed to obvious nonepileptic structural defects. Two patients with predominantly temporal hypometabolism may have had frontal epileptogenic regions, but ultimate localization remains uncertain. Scalp-sphenoidal ictal onsets were misleading in 5 patients. For 37 patients with congruent focal scalp-sphenoidal ictal onsets and temporal hypometabolic zones, SEEG recordings never demonstrated extratemporal or contralateral epileptogenic regions; however, 3 of these patients had nondiagnostic SEEG evaluations. The results of subsequent subdural grid recordings indicated that at least 1 of these patients may have been denied beneficial surgery as a result of an equivocal SEEG evaluation. Weighing risks and benefits, it is concluded that anterior temporal lobectomy is justified without chronic intracranial recording when specific criteria for focal scalp-sphenoidal ictal EEG onsets are met, localized hypometabolism predominantly involves the same temporal lobe, and no other conflicting information has been obtained from additional tests of focal functional deficit, structural imaging, or seizure semiology.

Adolescent↗