Biomedical subjects

H Lüders

Publications and source records attributed to H Lüders.

At least 37 records · Page 2Linked to original sources

PubMed1995

Automatisms with preserved responsiveness: a lateralizing sign in psychomotor seizures.

This is a report of a 1-year prospective study to investigate how often automatisms occur with preserved responsiveness in psychomotor seizures. Responsiveness is usually impaired or lost when automatisms occur during psychomotor seizures. However, there are several anecdotal reports in the literature of patients who have automatisms with preserved responsiveness (APRs). We evaluated 123 patients with temporal lobe epilepsy (57 patients [46%] left-sided, 48 patients [39%] right-sided, and 18 patients [15%] bitemporal) with video/EEG monitoring, testing responsiveness by asking the patient to respond verbally and to follow motor commands. Seven patients (5.6%) had preserved responsiveness in the presence of prominent automatisms (lip smacking, swallowing). In 15 seizures, the responsiveness was adequately tested (3.6 questions per period of automatism). Average seizure duration was 71.6 +/- 14.8 seconds (range, 45 to 100 seconds). Average duration of automatisms was 59.5 +/- 13.5 seconds (range, 40 to 80 seconds). Ictal EEG was localized over the right temporal area in nine seizures, over the right hemisphere in five, and was nonlocalizable in one seizure. APRs never occurred in left-sided psychomotor seizures and occurred in 10% of the right temporal cases. In conclusion, APRs reliably lateralized to the right side in temporal lobe epilepsy.

Adult↗

PubMed1994

Functional anatomy of the human supplementary sensorimotor area: results of extraoperative electrical stimulation.

Electrical stimulation studies have demonstrated that a "supplementary motor area" (SMA) exists in humans. However, its precise functional organization has not been well defined. We reviewed the extraoperative electrical stimulation studies of 15 patients with intractable epilepsy who were evaluated with chronically implanted interhemispheric subdural electrodes. SMA-type positive motor responses were elicited not only from the mesial portion of the superior frontal gyrus but also from its dorsal convexity, and from the paracentral lobule, cingulate gyrus, and precuneus. Sensory symptoms, that could not be attributed to stimulation of the primary sensory area, were elicited from the superior frontal and cingulate gyri in addition to the precuneus. Therefore, human SMA, as defined by electrical stimulation, is not always confined to the mesial portion of the superior frontal gyrus as described previously. It is also not strictly "motor" but "sensorimotor" in representation. We propose referring to this region as the "supplementary sensorimotor area" (SSMA). We observed a somatotopic organization within the SSMA with an order of lower extremity, upper extremity, and head from posterior to anterior. Sensory representation in an individual was either anterior or posterior to the positive motor representation but never both. There was a supplementary eye field within the head representation. A supplementary negative motor area was noted at the anterior aspect of the SSMA. No language area was demonstrated within the SSMA. The physiologic significance of the SSMA and functional consequences of its resection must be addressed in further studies.

Adolescent↗

PubMed1993

Comparison of scalp electroencephalogram with subdural electrocorticogram recordings and functional mapping in frontal lobe epilepsy.

We compared the findings of scalp electroencephalogram with subdural electrode array (SEA) recordings in 19 patients with refractory frontal lobe epilepsy. Prolonged scalp interictal recordings localized the epileptogenic zone in 12 patients; seven had no interictal sharp waves. The SEAs showed multifocal interictal sharp waves in all patients. Seven patients with localized seizure onset on scalp recording showed extensive ictal onset on the SEA recording. Five patients with lateralized seizure onset to one hemisphere on scalp recording were found to have ictal onset on SEA restricted to a smaller area. Because of the large epileptogenic zone found on SEA recordings, a complete resection was possible in only five (33%) of the 15 patients who had resections. Eight (53%) of the 15 patients benefited from surgery (mean follow-up, 4.6 years). The SEAs also allowed functional localization in most patients. From these data, we suggest that a localizing scalp electroencephalogram in patients with frontal lobe epilepsy may be misleading because SEA recordings show larger epileptogenic zones than anticipated. Furthermore, we postulate that the larger extensive epileptogenic zone may account for the poorer surgical outcome in patients with frontal lobe epilepsy compared with patients with temporal lobe epilepsy.

Adolescent↗

PubMed1993

Detection of changes in material-specific memory following temporal lobectomy using the Wechsler Memory Scale-Revised.

To determine the utility of the Wechsler Memory Scale-Revised (WMS-R) in measuring material-specific memory changes, within-subject comparisons of the Verbal-Visual Memory Index discrepancy and discrepancy scores using short-term and delayed Logical Memory and Visual Reproduction subtests from the WMS-R were studied prior to and following temporal lobectomy among 30 patients with left temporal lobectomy, 30 with right temporal lobectomy, and 50 epileptic, non-surgical controls. The groups were matched on age, sex, handedness, age at seizure onset, duration of epilepsy, and presurgical Verbal and Performance IQ; the right temporal group had a higher mean educational level (p <.05). All surgical patients were left hemisphere dominant for speech; those who had persistent postoperative seizures were excluded from study. On retesting, left temporal lobectomy was associated with a marked change in short-term and delayed memory discrepancy scores primarily due to a drop in verbal memory. Right temporal lobectomy was not associated with a drop in visual memory, suggesting that the WMS-R appears to reflect decrements in material-specific memory following left but not right temporal lobectomy. The nonsurgical controls showed increases in both short-term and delayed memory discrepancy scores due to increases in short-term and delayed verbal memory. Relative to these controls, the absence of comparable increases in verbal memory among the right temporal patients suggests that right temporal lobectomy may be associated with risk to verbal memory.

Journal Article↗

PubMed1993

[Postoperative analgesia--a comparative study in laparoscopic cholecystectomy and lower abdominal laparotomy].

From September 1992 through February 1993 27 randomly chosen female patients were evaluated for differences in postoperative pain intensity (as determined by visual-analogue-scale (VAS)) and analgesic requirements via patient-controlled-analgesia (PCA), either after open lower-abdominal-laparotomy (n = 16, group 1) or after minimal-invasive-cholecystectomy (n = 11, group 2). The type of anaesthesia has been standardized, either as balanced or total intravenous anaesthesia. There were no statistically significant differences between the groups regarding to age, height, weight, intraoperative anaesthetic drug consumption, or duration of anaesthesia and surgery (205.6 vs 185.5 minutes; 139.1 vs 105.0 minutes). All patients could be extubated while still in the operation theatre. The 10-hour study period started after transfer to the recovery room. Heart- and respiratory-rate, systolic/diastolic blood pressure, endtidal pCO2, oxygen-saturation via pulsoxymetry (SaO2), and demands from PCA-pump were recorded, furthermore pain scores were determined every hour. The VAS-scores showed no significant differences between the two groups. The pain level as a whole was low, with the scores ranging from a maximum of 23.4 mm (group 1 after the first hour) to a minimum of 1.8 min (group 2 after 5, 8 an 10 hours). The overall analgesic requirements differed significantly (37.7 vs 17.3 mg piritramid, p < .01). There was a difference throughout the whole study period, although statistically significant only at the 1., 2. (p < .05), 5. and 6.-8. hour (p < .01). This study showed that pain scores were similar after laparoscopic upper or open lower abdominal surgery, both requiring adequate analgesic therapy.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1992

Recording of event-related potentials (P300) from human cortex.

Auditory event-related potentials were recorded simultaneously from chronically implanted subdural electrodes and from scalp electrodes in three patients who were being evaluated for surgical treatment of epilepsy. These three cases showed clearly defined scalp-P300 and scalp-N300. A cortex-P300 was recorded from the midtemporal area, and a cortex-N300 was recorded from the inferior frontal area with some reflection at the basal temporal region. There were no potentials from an interhemispheric region. We could not observe any component from the cortex studied corresponding to scalp-recorded N200. Therefore, while the activity generated from the mesial temporal lobe may only make minor contributions to scalp-P300, that generated from the midtemporal area might make a major contribution to the scalp-P300. Additionally, generators of N200, P300, and N300 are different from each other. These findings, together with previous reports regarding the generator source of P300, also suggest that P300 is a complex arising from multifactorial generator sources, including the midtemporal and inferior frontal area.

Acoustic Stimulation↗

PubMed1992

Subdural electrodes in the presurgical evaluation for surgery of epilepsy.

This article gives first an overview of the advantages and disadvantages of electrodes of progressively greater invasiveness used in the evaluation of patients who are candidates for surgery of epilepsy. The following sections discuss the design of subdural electrodes, their clinical indications, and the relative advantages and disadvantages of subdural electrodes when compared with other invasive techniques.

Brain Mapping↗

PubMed1992

Use of intracranial neurophysiologic recording techniques in the evaluation for epilepsy surgery in children.

Resective surgery is an accepted treatment modality for medically intractable focal epilepsy in children as well as in adult. During the presurgical evaluation processes, intracranial neurophysiologic recording of epileptiform abnormalities have been used much more commonly in adults and older adolescents than in infants and children. However, as infants and children are increasingly referred for early surgery in many centres, it may be necessary to study complex cases in some children with invasive electrodes in order to plan a safe and effective resection. This article gives first an overview of the rationale and indications, with case illustrations, for using these techniques. This is followed by general discussions on individual electrodes and their use in infants and children.

Adolescent↗

PubMed1991

[Pasteurella multocida as the cause of disease outbreaks in commercial poultry flocks].

Six cases of fowl cholera in growing turkeys and 3 in adult breeder chickens of the broiler type as well as one case each of a Pasteurella (P.) multocida-associated disease in ducklings and goslings were described in consideration of own laboratory findings and available informations of the case history. Furthermore a report is given on a treatment strategy successfully used in turkeys with highly acute fowl cholera. All the P. multocida strains isolated culturally could be assigned to the subspecies multocida. In one case Bordetella avium, Salmonella (S.) arizonae and S. hadar were additionally cultured form part of turkeys submitted. P. multocida and Moraxella (Pasteurella) anatipestifer could be determined as the causative agents of the disease of ducklings and goslings. P. multocida strains from turkeys were identified serologically as serovars A:3.4 (3x), F:3.4 (2x) and A:3 (1x); those from the breeder chickens as A:3 (3x); and one each from ducklings and goslings as F:3.4 and -:3. (uncapsulated). No death occurred in turkeys with clinical signs of a highly acute fowl cholera if the treatment of the affected birds was started with an intravenous injection of sulfadimethoxine and continued with a combination of sulfachlorpyridazine (SCP) and trimethoprim (TMP) given in the drinking water for 5 days. However relapse occurred 2-3 days after withdrawal of the drug, although the therapy was clinically highly effective. The recurrence of the disease could be prevented reliably if the turkeys were vaccinated with an effective oil-based bacterin and subsequently treated with the SCP-TMP combination given in drinking water over a 12 day period.

Animals↗

PubMed1991

Etiologic factors for unitemporal vs bitemporal epileptiform discharges.

We compared the etiologic factors and clinical characteristics of 30 patients with unitemporal vs those of 30 patients with bitemporal independent (minimum 20% from one side) interictal epileptiform discharges on extracranial electroencephalograms. Febrile seizures occurred significantly more frequently in the unitemporal (40%) than in the bitemporal (17%) group. Mass lesions were more common in the bitemporal group, and seven of 10 patients with mass lesions showed bitemporal interictal epileptiform discharges. There were no statistically significant differences in age at onset, frequency of seizures, duration of epilepsy, and history of central nervous system infection or trauma between the two groups. A history of febrile seizures or central nervous system infection that may be expected to cause diffuse cerebral injury does not appear to be the major factor predisposing to the development of bitemporal interictal epileptiform discharges.

Adolescent↗

PubMed1991

Event-related brain potentials as indicators of visual recognition and detection of criminals by their use.

An event-related potential (ERP) was recorded, using photographs as stimuli, in 12 subjects for attended, 9 subjects for non-attended conditions and 14 subjects for a simulated criminal investigation. An ERP was detected only when a subject recognized a familiar image (target) mixed with other, unfamiliar images (non-target), regardless of whether he was asked to attend to or neglect the target image. ERPs in the subject who watched each picture but tried to ignore the relevant picture (non-attended) were more activated at the parietal region than at the central region, in contrast with ERPs in the subjects who paid attention to each picture without trying to ignore the relevant picture (attended). In the simulated criminal investigation, only a simulated thief, but not a simulated innocent subject elicited ERP only after the picture of a criminal site or thing was intermingled with pictures bearing no relationship to the crime. These findings indicate that the ERP using photographs as stimuli is useful as an objective indicator of crime-relevance.

Adult↗

PubMed1991

Basal temporal language area.

Language interference was elicited by electrical stimulation of the dominant basal temporal region in 8 out of 22 cases and in none of 7 cases with subdural electrodes implanted over the nondominant temporal lobe. Language interference was elicited by stimulation of electrodes placed over the fusiform gyrus 3-7 cm from the tip of the temporal lobe. Electrical stimulation of the basal temporal language area produced a global receptive and expressive aphasia with speech arrest at high stimulus intensities. Other higher cortical function, for example copying complex designs or memory of nonverbal information was intact, in spite of the total inability to process verbal information. At lower stimulus intensities partial aphasias with a predominant receptive component occurred. Surgical resection of the basal temporal language area produces no lasting language deficit.

Adolescent↗

PubMed1991

Intracranial recordings of movement-related potentials to voluntary saccades.

Movement-related potentials evoked by voluntary and self-initiated horizontal saccades were recorded from subdural electrodes placed over the lateral (premotor and motor cortex) and the mesial (supplementary motor area) surfaces of the frontal lobe, in four patients with intractable focal seizures. An extremely localized bereitschaftspotential showing approximately the same latencies and amplitudes was simultaneously recorded from the frontal eye field and supplementary motor area (SMA). Our data suggest that both regions are equally active prior to saccades and do not support the view that the SMA acts as a supramotor cortex, being activated during the planning of the movement and the primary motor cortex only later on, close to the execution of the movement. In addition, we never observed the spike potential in our intracranial recordings, thus supporting the hypothesis of its extracerebral origin.

Adult↗

PubMed1991

Second operation after the failure of previous resection for epilepsy.

We present our surgical experience with second operations in 15 patients with recurrent intractable partial seizures after resection for epilepsy. The interval from the first operation until the first recurrence of seizures ranged from 1 day to 7 months (mean, 62 days). The interval between the first and second operations ranged from 3 months to 12 years (mean, 38 months). Detailed video-electroencephalographic interictal and ictal recording was performed in all patients (invasive electrodes were used in 11 patients). Ictal onset was shown to be remote from the zone of previous resection in 3 of 15 cases (all 3 extratemporal and in the ipsilateral hemisphere). Recurrent seizures arose from the area of previous extratemporal resection in 2 of 15 patients, and from the area of previous temporal resection in 10 of 15 patients. Both cases of extratemporal recurrences and 3 of the 10 cases of temporal lobe recurrences in the area of previous resection were associated with residual unresected structural lesion. Of the 10 patients with local temporal recurrence, 6 had proven epileptogenicity in the residual mesial structures, and 4 had residual epileptogenicity in the unresected lateral temporal lobe. The patients have been monitored for 8 to 82 months (mean, 18 months) after the second operation: 7 patients (47%) have remained seizure-free and another 5 (33%) have achieved a reduction in seizure frequency of more than 90%. There was no mortality or significant morbidity in this series. We conclude that the extent and distribution of residual epileptogenicity after failed epilepsy surgery are highly variable.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMed1991

Prediction of cognitive change as a function of preoperative ability status among temporal lobectomy patients seen at 6-month follow-up.

The relationship between preoperative ability levels and postoperative changes in cognitive function was examined among 23 left (LTL) and 19 right (RTL) temporal lobectomy patients using a battery of memory, language, and visuospatial tasks administered approximately 3 months before surgery and at 6 months follow-up. Higher preoperative performances on the memory and language measures were associated with larger decrements in postsurgical scores among the LTL patients. The RTL group showed no consistent relationship between preoperative ability levels and subsequent postsurgical cognitive changes. Based on the present data, we constructed base-rate tables for the Wechsler Memory Scale-Revised indicating the likelihood of measurable gains or losses in memory as a function of presurgical ability level for patients undergoing LTL. While tentative, these data provide a useful and practical guide for counseling prospective epilepsy patients of the attendant cognitive risks of LTL.

Analysis of Variance↗

PubMed1991

Outcome of psychogenic seizures in children and adolescents compared with adults.

We compared outcome of psychogenic seizures documented by video-EEG in 18 nonepileptic children and adolescents (ages 8 to 18; median, 14.5 years old) and 20 adults (ages 25 to 56; median, 34.0 years old). Outcome was significantly better for the younger patients at 1 year, 2 years, and 3 years after diagnosis. At these follow-up times, the percentages of children and adolescents free of psychogenic attacks were 73%, 75%, and 81%; at the same follow-up times, the percentages of adults free of psychogenic attacks were only 25%, 25%, and 40%. Factors leading to better outcome for younger patients may have been different psychological mechanisms at different ages of onset and greater effectiveness with earlier intervention.

Adolescent↗

PubMed1991

[The effect of magnetic resonance treatment on chicken embryos].

Nuclear Magnetic Resonance (NMR) is of increasing diagnostic importance especially in human medicine. To evaluate possible side effects of this technology, embryonated chicken eggs were used as a model. Different fields (static magnetic field [1 oder 4 T], variable magnetic field [gradient] or high frequency field) were applied before the beginning and at the fifth day of incubation for different times (18.8, 37.6, 56 or 75.1 min, resp.). According to the criteria embryo-mortality, hatching-rate or vitality of the chickens, influences of the NMR-treatment were not observed.

Animals↗

PubMed1990

EEG mapping for surgery of epilepsy.

This report describes the objectives, problems, and current techniques associated with using EEG maps in the management of surgery of epilepsy. The purpose of EEG mapping in epilepsy is to precisely identify and characterize epileptogenic zones of the brain. Such zones may be single or multiple, pointlike or diffuse, and may be near or distant from the recording electrodes. The resulting measured electric fields are used to obtain information which, when analyzed in light of all the complementary clinical information, can frequently help to localize and describe the epileptic foci with more precision.

Adult↗