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R A Radtke

Publications and source records attributed to R A Radtke.

13 recordsLinked to original sources
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↗
PubMed1990

Neologistic speech automatisms during complex partial seizures.

There are no documented cases of seizures causing reiterative neologistic speech automatisms. We report an 18-year-old right-handed woman with stereotypic ictal speech automatisms characterized by phonemic jargon and reiterative neologisms. Video-EEG during the reiterative neologisms demonstrated rhythmic delta activity, which was most prominent in the left posterior temporal region. At surgery, there was an arteriovenous malformation impinging on the left supramarginal gyrus and the posterior portion of the superior temporal gyrus. Though intelligible speech automatisms can result from seizure foci in either hemisphere, neologistic speech automatisms may implicate a focus in the language-dominant hemisphere.

Adolescent↗
PubMed1990

Anterior temporal lobectomy for complex partial seizures: evaluation, results, and long-term follow-up in 100 cases.

We report evaluation and results in 100 patients who had undergone anterior temporal lobectomy for intractable complex partial seizures. Average follow-up was 9.0 years (range, 2 to 21 years). In the 2nd postoperative year, 63% were seizure free, 16% were significantly improved, and 21% were considered not significantly improved. Mean number of seizures in the last group was 27% of preoperative levels. Surgical results did not change significantly in subsequent postoperative years; good outcomes tended to persist over the longer term. We also examined the utility of continuous depth electrode monitoring in the evaluation of patients with independent bitemporal interictal epileptiform activity. Despite limited numbers of subjects in this category, there was a trend toward improved surgical outcome when such subjects were evaluated with depth electrodes.

Adolescent↗
PubMed1990

MR imaging in patients with temporal lobe seizures: correlation of results with pathologic findings.

Thirty-nine consecutive patients with medically intractable complex partial seizures were studied with electroencephalography and MR imaging to localize an epileptogenic focus for temporal lobectomy. The patients were divided into three groups on the basis of pathologic findings after lobectomy: Group 1 comprised 13 patients with neoplasms, hamartomas, or cysts; group 2 comprised 13 patients with moderate and severe mesial temporal sclerosis (one patient was included in both groups 1 and 2); and group 3 comprised 14 patients who underwent aspiration lobectomy, which yielded limited tissue for pathologic study so no pathologic diagnosis was made. The majority of the patients in group 3 were assumed to have mesial temporal sclerosis. Abnormal MR signal in the temporal lobe on T2-weighted images was graded as minimal increase (1+), intermediate or moderate increase (2+), and very significant increase (3+). An abnormal signal was demonstrated in 26 (67%) of the 39 patients. In group 1, the tumor/cyst subgroup, an abnormal signal was seen in all 13 patients. Most had 3+ signal. There was increased signal in eight (62%) of 13 patients in group 2 and in six (43%) of 14 patients in group 3. This study suggests that MR can detect almost all tumors and a significant number of mesial temporal sclerosis lesions in individuals with complex partial seizures. On the basis of this small series, individuals who exhibit significant signal (3+) can be expected to have neoplasms, hamartomas, or cysts, and patients who exhibit minimal signal (1+) will usually have mesial temporal sclerosis.

Adult↗
PubMed1989

Intraoperative brainstem auditory evoked potentials: significant decrease in postoperative morbidity.

Evoked potentials are commonly used for intraoperative monitoring of neural tissue under surgical threat despite the lack of unequivocal evidence demonstrating its effectiveness in preventing neural injury. This study retrospectively compares the auditory morbidity of posterior fossa microvascular decompressive surgery before and after the introduction of intraoperative brainstem auditory evoked potentials (BAEPs). All patients underwent a similar operative procedure performed by a single surgeon. The two groups were comparable with regards to age, sex, and indications for surgery. In the nonmonitored group, auditory morbidity had not declined with increasing experience of the surgeon. Ten of 152 patients (6.6%) suffered a profound hearing loss in the nonmonitored group. In the monitored group, none of 70 patients suffered a profound hearing loss. We attribute this significant decline (p = 0.02) in morbidity to the introduction of intraoperative BAEPs. We believe this to be the first demonstration of a significant decrease in operative morbidity directly associated with the use of intraoperative evoked potential monitoring.

Audiometry↗
PubMed1989

Polysomnographic assessment of DIMS: empirical evaluation of its diagnostic value.

This investigation examined the diagnostic value of polysomnography (PSG) for evaluating disorders of initiating and maintaining sleep (DIMS). The sample consisted of 100 outpatients who presented to the Duke Sleep Disorders Center with a complaint of chronic insomnia. All patients were given comprehensive medical, psychiatric, behavioral, and ambulatory PSG evaluations. Sleep disorder diagnoses were assigned using the criteria of the Association of Sleep Disorders Centers. Overall, PSG yielded important diagnostic information in 65% of the sample: 34% were given a primary sleep disorder diagnosis that was heavily dependent on PSG data [periodic movements of sleep (PMS) = 25%, apnea = 3%, and subjective insomnia = 6%]; 15% were given a secondary diagnosis of one of these three disorders; and PSG ruled out suspected PMS in 9% and sleep apnea in 7% of the sample. Patients greater than 40 years of age had a significantly higher rate of positive PSG findings than younger patients. Using only the clinical exam, two experienced sleep clinicians were able to predict only 14 of 25 PMS cases and one of three cases of sleep apnea. Based on these data, we suggest using PSG routinely with older insomniacs and with younger patients who fail initial treatment.

Adult↗
PubMed1988

Intraoperative monitoring of auditory and brain-stem function.

Extensive clinical experience has demonstrated that intraoperative brain stem auditory evoked potentials (BAEPs) are a reliable method of monitoring auditory and brain stem function during posterior fossa surgery. An intraoperative BAEP change identifies possible neurophysiologic compromise and allows adjustment of the surgical approach in an attempt to avoid permanent neurologic injury. The use of BAEPs intraoperatively has been associated with a significant decline in postoperative auditory morbidity. Supplementation of this technique with direct eighth nerve recordings and/or upper extremity somatosensory evoked potentials offers further improvement in identifying possible surgical threat to auditory or brain stem function.

Brain Diseases↗
PubMed1986

Abnormal sensory evoked potentials in amyotrophic lateral sclerosis.

We have reviewed sensory evoked potential (EP) findings in 17 patients with amyotrophic lateral sclerosis (ALS). Somatosensory EPs were abnormal in 7 of 16 patients after lower-extremity stimulation and in 2 of 16 patients after upper-extremity stimulation. Brainstem auditory EP abnormalities were found in 2 of 12 patients. No abnormalities were noted on pattern reversal visual EPs in 12 patients. Overall, 47% of all ALS patients studied had at least one EP abnormality. EP evidence of CNS sensory dysfunction in ALS is more frequent than that noted clinically or pathologically and offers further support to previous observations of sensory system involvement in ALS.

Adult↗
PubMed1985

Limitations of brain stem auditory evoked potentials for intraoperative monitoring during a posterior fossa operation: case report and technical note.

We have encountered an example of the insensitivity of brain stem auditory evoked potentials (BAEPs) for monitoring the brain stem during a posterior fossa operation. The addition of somatosensory evoked potential recording to conventional BAEP protocols is readily accomplished and is likely to improve the sensitivity of intraoperative electrophysiological assessment of brain stem function.

Brain Stem↗
PubMedDate not supplied

MR imaging in patients with temporal lobe seizures: correlation of results with pathologic findings.

Thirty-nine consecutive patients with medically intractable complex partial seizures were studied with electroencephalography and MR imaging to localize an epileptogenic focus for temporal lobectomy. The patients were divided into three groups on the basis of pathologic findings after lobectomy: Group 1 comprised 13 patients with neoplasms, hamartomas, or cysts; group 2 comprised 13 patients with moderate and severe mesial temporal sclerosis (one patient was included in both groups 1 and 2); and group 3 comprised 14 patients who underwent aspiration lobectomy, which yielded limited tissue for pathologic study so no pathologic diagnosis was made. The majority of the patients in group 3 were assumed to have mesial temporal sclerosis. Abnormal MR signal in the temporal lobe on T2-weighted images was graded as minimal increase (1+), intermediate or moderate increase (2+), and very significant increase (3+). An abnormal signal was demonstrated in 26 (67%) of the 39 patients. In group 1, the tumor/cyst subgroup, an abnormal signal was seen in all 13 patients. Most had 3+ signal. There was increased signal in eight (62%) of 13 patients in group 2 and in six (43%) of 14 patients in group 3. This study suggests that MR can detect almost all tumors and a significant number of mesial temporal sclerosis lesions in individuals with complex partial seizures. On the basis of this small series, individuals who exhibit significant signal (3+) can be expected to have neoplasms, hamartomas, or cysts, and patients who exhibit minimal signal (1+) will usually have mesial temporal sclerosis.

Brain Neoplasms↗