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Biomedical subjects

R A Radtke

Publications and source records attributed to R A Radtke.

At least 19 recordsLinked to original sources
PubMed1997

Painful generalised clonic and tonic-clonic seizures with retained consciousness.

Two patients in whom consciousness and memory were retained during bilateral clonic or tonic-clonic seizures are reported on, and three patients reported on previously are reviewed. Ictal semiology differed from myoclonic and supplementary motor seizures, which are other seizure types characterised by bilateral motor movements and retained awareness. In the two new patients ictal pain was a prominent feature. It is proposed that propagation of seizure activity may be confined to the sensorimotor areas bilaterally while sparing the neural structures involved in maintaining consciousness and in processing language and memory. This unusual type of seizure may be misdiagnosed as a pseudoseizure. Detailed description of the ictal events and further laboratory evaluation including video-EEG monitoring may be necessary to make the distinction.

Adolescent↗
PubMed1997

Clinical and electrographic manifestations of lesional neocortical temporal lobe epilepsy.

To determine whether lesional neocortical temporal lobe epilepsy (NTLE) can be differentiated from mesial temporal lobe epilepsy (MTLE) during the noninvasive presurgical evaluation, we compared the historical features, seizure symptomatology, and surface EEG of 8 patients seizure free after neocortical temporal resection with preservation of mesial structures and 20 patients after anterior temporal lobectomy for MTLE. Seizure symptomatology of 107 seizures (28 NTLE, 79 MTLE) was analyzed. One hundred one ictal EEGs (19 NTLE, 82 MTLE) were reviewed for activity at seizure onset; presence, distribution, and frequency of lateralized rhythmic activity (LRA); and distribution of postictal slowing. Seizure symptomatology and EEG data were compared between groups, and sensitivity, specificity, and positive and negative predictive values were determined for variables that differed significantly. Multiple logistic regression was used to determine whether patients could be correctly classified as having MTLE or NTLE. MTLE patients were younger at onset of habitual seizures and more likely to have a prior history of febrile seizures, CNS infection, perinatal complications, or head injury. NTLE seizures lacked features commonly exhibited in MTLE, including automatisms, contralateral dystonia, searching head movements, body shifting, hyperventilation, and postictal cough or sigh. NTLE ictal EEG recordings demonstrated lower mean frequency of LRA that frequently had a hemispheric distribution, whereas LRA in MTLE seizures was maximal over the ipsilateral temporal region. We conclude that it may be possible to differentiate lesional NTLE from MTLE on the basis of historical features, seizure symptomatology, and ictal surface EEG recordings. This may assist in the identification of patients with medically refractory nonlesional NTLE who frequently require intracranial monitoring and more extensive or tailored resections.

Adult↗
PubMed1996

Predictors of outcome of epilepsy surgery: multivariate analysis with validation.

PURPOSE: To identify predictors of outcome of epilepsy surgery, using the Duke experience, applying multivariate analysis and validation techniques. To compare the results of different modeling algorithms. Few previous studies have reported multivariate analysis, or validated their results. METHODS: Records of 116 patients with focal resections for intractable epilepsy from January 1, 1980 through June 30, 1989 were analyzed. Primary outcome variable was patient's condition in second postoperative year: seizure free (except auras), or not. Three predictors of biologic interest were specified a priori for confirmatory analysis. Additional predictors were considered within exploratory analysis. Logistic regression techniques were applied to assess relations with pre- and postoperative predictors. Internal validity was assessed by repeated random selection of training and validation samples, used in conjunction with bootstrap techniques. RESULTS: By using multivariate analysis, percentage of epileptic EEG activity arising from the site of resection and either imaging localization or lack of use of invasive monitoring were the only statistically significant preoperative predictors for good outcome at 2 years. Presence of seizures within 2 months of surgery was a significant postoperative predictor for a poor outcome. Adding more variables did not result in significantly improved models. Use of validation techniques reduced the degree of optimism in the predictive value of the models. CONCLUSIONS: Pooling of data from multiple institutions is needed to attain the large sample sizes needed for multivariate analysis with validation.

Adolescent↗
PubMed1996

X-linked malformations of neuronal migration.

Malformations of neuronal migration such as lissencephaly (agyria-pachygyria spectrum) are well-known causes of mental retardation and epilepsy that are often genetic. For example, isolated lissencephaly sequence and Miller-Dieker syndrome are caused by deletions involving a lissencephaly gene in chromosome 17p13.3, while many other malformation syndromes have autosomal recessive inheritance. In this paper, we review evidence supporting the existence of two distinct X-linked malformations of neuronal migration. X-linked lissencephaly and subcortical band heterotopia (XLIS) presents with sporadic or familial mental retardation and epilepsy. The brain malformation varies from classical lissencephaly, which is observed in males, to subcortical band heterotopia, which is observed primarily in females. The XLIS gene is located in chromosome Xq22.3 based on the breakpoint of an X-autosomal translocation. Bilateral periventricular nodular heterotopia (BPNH) usually presents with sporadic or familial epilepsy with normal intelligence, primarily in females, although we have evaluated two boys with BPNH and severe mental retardation. The gene for BPNH has been mapped to chromosome Xq28 based on linkage studies in multiplex families and observation of a subtle structural abnormality in one of the boys with BPNH and severe mental retardation.

Adult↗
PubMed1994

Neuronal migration disorders: positron emission tomography correlations.

We analyzed the interictal [18F]fluoro-2-deoxy-D-glucose positron emission tomography (PET) findings of 17 epileptic patients with neuronal migration disorders (NMDs). Fifteen patients had abnormal PET findings, i.e., focal hypometabolism in 9 patients and displaced metabolic activity of normal gray matter in 6. All 15 patients had magnetic resonance imaging (MRI) abnormalities; however, PET abnormality assisted in the identification of NMDs on MRI in 3 patients. Two patients with negative MRI also had negative PET studies. PET hypometabolism appeared to correlate with severity of neuronal dysgenesis or temporal lobe involvement, or both. Displaced metabolic activity of gray matter is regarded as a unique interictal [18F]fluoro-2-deoxy-D-glucose-PET finding in NMD. This study demonstrates variable metabolic patterns in NMD and that PET may be a useful complement to MRI in the evaluation of NMD.

Adult↗
PubMed1994

Ipsilateral subcortical atrophy associated with temporal lobectomy.

Stereologic methods for determining the volume of cerebral structures in vivo via magnetic resonance imaging have identified unilateral hippocampal atrophy among patients with complex partial epilepsy of temporal lobe origin. Metabolic imaging has also identified altered metabolism in temporal as well as extratemporal regions among these patients. As the temporal cortex and subcortical nuclei of the limbic system are reciprocally connected with striatal projection fields, we examined the putamen nuclei for evidence of associated extratemporal volume asymmetry in patients before and after temporal lobectomy. There was no evidence of preoperative putamen volume asymmetry, but a significant postoperative decrement in ipsilateral putamen volume was observed. The magnitude of postsurgical putamen volume asymmetry was correlated with the duration of time since resection. Progressive degeneration of extratemporal projections of the temporal lobe may occur in association with temporal lobectomy.

Adolescent↗
PubMed1994

BAEPs in infants with myelomeningocele and later development of Chiari II malformation-related brainstem dysfunction.

Thirty-seven infants with myelomeningocele received brainstem auditory evoked potentials (BAEPs) at a median age of eight days. No infant had brainstem dysfunction at the time of testing. Median follow-up was at 30 months. Of 12 infants who subsequently developed brainstem dysfunction at a median age of three months, 11 had had abnormal neonatal BAEPs. In contrast, only 10 of 25 infants who did not develop brainstem dysfunction had abnormal BAEPs. The mean average I-V interpeak latencies was greater among those who developed symptoms than among those who did not. Neonatal BAEPs can identify a group of asymptomatic infants with myelomeningocele who need close follow-up for the subsequent development of brainstem dysfunction.

Arnold-Chiari Malformation↗
PubMed1994

Focal cerebral metabolic abnormality in a patient with continuous spike waves during slow-wave sleep.

We report an 11-year-old boy with continuous spike-wave discharges during sleep accompanied by partial motor and atypical absence seizures, psychomotor regression, and severe behavior problems. During wakefulness, epileptiform discharges occurred over the right parietal region, suggesting that the continuous spike-wave discharges during sleep were a manifestation of secondary bilateral synchrony. Bilateral suppression of the spike-and-wave activity was observed after right-sided intracarotid amobarbital injection, further supporting the impression of secondary bilateral synchrony. The right superior temporoparietal increase in metabolic activity during continuous spike-wave discharges and noncontinuous spike-wave discharges was seen on [18F]fluorodeoxyglucose positron emission tomography and supports a right temporoparietal focus in our case. The presence of a focal abnormality suggests that surgical therapy may be effective.

Amobarbital↗
PubMed1994

Treatment of radiation-induced nervous system injury with heparin and warfarin.

When radiation is used to treat nervous system cancer, exposure of adjacent normal nervous system tissue is unavoidable, and radiation-induced injury may occur. Acute injury is usually mild and transient, but late forms of radiation-induced nervous system injury are usually progressive and debilitating. Treatment with corticosteroids, surgery, and antioxidants is often ineffective. We treated 11 patients with late radiation-induced nervous system injuries (eight with cerebral radionecrosis, one with a myelopathy, and two with plexopathies, all unresponsive to dexamethasone and prednisone) with full anticoagulation. Some recovery of function occurred in five of the eight patients with cerebral radionecrosis, and all the patients with myelopathy or plexopathy. Anticoagulation was continued for 3 to 6 months. In one patient with cerebral radionecrosis, symptoms recurred after discontinuation of anticoagulation and disappeared again after reinstitution of treatment. We hypothesize that anticoagulation may arrest and reverse small-vessel endothelial injury--the fundamental lesion of radiation necrosis--and produce clinical improvement in some patients.

Adult↗
PubMed1993

Complex partial seizures and mesial temporal sclerosis: evaluation with fast spin-echo MR imaging.

PURPOSE: This study was performed to determine the sensitivity and specificity of fast spin-echo (FSE) magnetic resonance (MR) imaging in detecting mesial temporal sclerosis. MATERIALS AND METHODS: Twenty-one patients with a diagnosis of complex partial seizures were studied. Criteria for abnormality included visual detection of hippocampal MR signal abnormality and atrophy or significantly decreased hippocampal volume determined by using MR morphometric techniques. RESULTS: The overall sensitivity and specificity of MR imaging in demonstrating correct lateralization of seizure focus were both 100%. The positive predictive value of FSE MR imaging was 100%. The negative predictive value was 50%. CONCLUSION: The authors recommend FSE MR imaging of the hippocampus as the imaging technique of choice in the evaluation of patients with complex partial seizures for mesial temporal sclerosis.

Adult↗
PubMed1993

Temporal lobe hypometabolism on PET: predictor of seizure control after temporal lobectomy.

To investigate the relationship of temporal lobe hypometabolism demonstrated on PET to surgical outcome and underlying pathology, we reviewed 30 consecutive epilepsy patients who underwent interictal PET studies with 18F fluorodeoxyglucose before temporal lobectomy. Two interpreters blindly reviewed the PET studies and graded them for degree, extent, and location of temporal lobe hypometabolism. Pathologic analysis of en bloc resected tissue showed mesial temporal sclerosis (n = 22), astrocytoma (n = 2), and no pathologic diagnosis (n = 6). Outcome (24 to 40 months' follow-up) was rated as seizure-free (21 patients), significantly improved (five patients), and not significantly improved (four patients). Both the degree and extent of the temporal lobe hypometabolism demonstrated on PET were strongly associated with subsequent seizure control. Pathologic findings, however, did not correlate with degree of PET hypometabolism or subsequent outcome. These data demonstrate that in patients judged to have temporal lobe epilepsy, the presence of temporal lobe hypometabolism is associated with a positive outcome after ipsilateral temporal lobectomy.

Adolescent↗
PubMed1993

Spontaneous temporal encephalocele. Case report.

The authors report a 36-year-old woman with a 23-year history of simple and complex partial seizures who was treated surgically for an anteroinferior temporal encephalocele, with resolution of the seizure disorder. This patient's presentation, findings, and response to treatment are typical of those associated with anteroinferior temporal encephalocele, and different from the clinical patterns of four other types of spontaneous temporal encephalocele.

Adolescent↗
PubMed1993

Use of in vivo desensitization to treat a patient's claustrophobic response to nasal CPAP.

Continuous positive airway pressure (CPAP) has proven to be a safe, effective treatment for sleep apnea patients. However, many patients display claustrophobic reactions to the CPAP nasal mask and cannot tolerate this treatment. The current report describes the successful application of in vivo desensitization with a male apnea patient who initially failed CPAP therapy due to his claustrophobia. Over the course of treatment, the patient became able to tolerate using his CPAP device throughout his nocturnal sleep periods. Moreover, follow-up visits scheduled 6 months and again at 6 1/2 years after behavioral treatment showed that the patient continued to use CPAP on a regular basis. It is concluded that in vivo desensitization therapy may be useful in assisting claustrophobic patients to tolerate nasal CPAP. Results are discussed in view of the specific features of the case presented, and future applications of this behavioral procedure are encouraged.

Adult↗
PubMed1992

Accuracy and interobserver reliability of scalp ictal EEG.

We studied the accuracy and reliability of scalp ictal EEG in 137 complex partial seizures (119 temporal and 18 extratemporal) in 35 patients in whom we knew the correct site of seizure origin because all patients had been seizure-free for more than 2 years after seizure surgery. Three electroencephalographers independently determined side of seizure origin based on activity at onset of electrographic seizure (ASO), rhythmic theta and alpha (RTA), postictal findings (PIF), and the electrographic seizure as a whole. When all seizures were analyzed, including those with generalized features or obscured by artifact, we determined side of seizure onset correctly in 76% to 83% of temporal seizures and 47% to 65% of extratemporal seizures. In most of the remainder, a lateralization judgment was impossible. When analysis was confined to those seizures in which lateralization was possible, we correctly lateralized 93% to 99% of temporal seizures and 89% to 100% of extratemporal seizures. Interobserver reliability was excellent. RTA and PIF were more accurate than ASO. RTA was significantly more common in temporal seizures. Our data indicate that lateralization by scalp EEG is highly accurate and reliable.

Electroencephalography↗
PubMed1992

Periodic limb movement variability in older DIMS patients across consecutive nights of home monitoring.

Older difficulty initiating and/or maintaining sleep (DIMS) patients who met criteria for periodic limb movement disorder (PLMD) were monitored for three consecutive nights in their homes using ambulatory polysomnography (PSG). Correlational analyses of the group data suggested little night-to-night variability in either movement indices or movement-related arousal indices for this sample. However, within-subjects comparisons suggested considerable variability in these indices and other sleep measures across nights. Nevertheless, for most subjects, the variability noted for these indices appeared to have little effect on PLMD severity classification or clinical treatment decisions derived from blind examinations of PSGs. Further, the initial PSG study generally led to a representative severity classification and clinical decision. Additional research is needed to determine the generalizability of these results to younger subjects, patients with complaints of excessive somnolence and other methods of home PSG monitoring.

Age Factors↗