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J Ilmberger

Publications and source records attributed to J Ilmberger.

At least 19 recordsLinked to original sources
PubMed2003

Surgical resection of gliomas WHO grade II and III located in the opercular region.

BACKGROUND: Surgery in the opercular region especially in the dominant hemisphere impose a major challenge for the neurosurgeon due to the close vicinity to functional important motor and speech areas. The purpose of the present study is to analyse on a homogenous patient group pre- and postoperative functional deficits with regard to different speech qualities (e.g. aphasia, apraxia), and to correlate these data with MR and intraoperative monitoring results. METHOD: Fourteen patients with suspected low grade astrocytomas in the opercular region consecutively treated by surgery were eligible for this study (histology revealed 3 WHO grade III tumours). Degree and duration of postoperative deficits were retrospectively evaluated according to tumour location and boundaries on MR, intraoperative neuromonitoring results and extent of tumour resection. FINDINGS: Postoperatively, 8 patients showed speech or language disturbances, in 4 patients combined with motor deficits mainly of the contralateral upper extremity. Fifty percent of the neuropsychologically tested patients exhibited speech apraxia while the other 50% had a true aphasic syndrome. Recovery of the latter deficits was in general faster and more complete. The severity and duration of postoperative deficits was in good correlation with the distance of the resection margin to the next positive stimulation point(s), and a distance of more than 0.5 cm proved to avoid major impairments. The distribution of functional important stimulation points in relation to the tumour extension was not predictable, and -- unexpectedly -- up to 50% of these sites were found overlaying the tumour. INTERPRETATION: Surgery for WHO grade II and III gliomas in the opercular region can result in speech apraxia or an aphasic syndrome with or without concomitant motor deficits. Intraoperative cortical electrical stimulation is essential in resecting tumours in the opercular region to avoid permanent morbidity.

Adolescent↗
PubMed2002

[Comparison of the Aachen Aphasia Test, clinical study and Aachen Aphasia Beside Test in brain tumor patients].

In the clinical routine examination of patients with brain tumors, aphasic symptoms are often not recognized. In order to document the incidence of such symptoms, three diagnostic methods of testing for aphasia were compared: the Aachen aphasia test (AAT), which is the German standard aphasia test, clinical examination, and the Aachen aphasia bedside test (AABT), which was designed to test patients in the acute phases of illness. In the AAT, 50% of patients with left-sided tumors and 36% of those with right-sided tumors showed aphasic disturbances. The AAT results were defined as the gold standard. Clinical examination showed only low sensitivity; less than half of the aphasic patients were diagnosed as such. The AABT also detected only about half of the patients with aphasic disturbances. The low sensitivity is caused mainly by the results of the patients with right-hemisphere tumors, in which the mental set of the examiner during clinical examination (aphasic symptoms are not expected in patients with right-hemisphere lesions) and the pattern of disturbances in the AABT (deficits may be less severe and different in nature) may prevent detection of aphasic symptoms. Both clinical examination and AABT are thus not suitable for aphasia diagnostics in brain tumor patients. As the AAT is very time-consuming in everyday clinical routine, however, the development of an aphasia screening test seems desirable.

Adolescent↗
PubMed2001

Performance in picture naming and word comprehension: evidence for common neuronal substrates from intraoperative language mapping.

Correlations of naming ability and performance in the Token Test are known from aphasia; however, the mechanisms underlying these correlations are unclear. Naming tasks are commonly used in intraoperative mapping for identification of cortical areas involved in language processing. In the present study, we measured performance in an elementary Token Test task, i.e., single word comprehension, during electrical stimulation of cortical sites at which this stimulation previously had disturbed the naming process. It was found that at about half of the sites at which naming could be disturbed electrical stimulation also led to disturbances in Token Test performance, indicating that there are common neural structures critical for performance in both tasks. These findings are discussed in terms of a multilayered semantic network in which the level of the simultaneous binding of features into concepts and the level of units that are organized with respect to semantic relations may be disturbed separately.

Adult↗
PubMed2001

The influence of essential oils on human attention. I: alertness.

Scientific research on the effects of essential oils on human behavior lags behind the promises made by popular aromatherapy. Nearly all aspects of human behavior are closely linked to processes of attention, the basic level being that of alertness, which ranges from sleep to wakefulness. In our study we measured the influence of essential oils and components of essential oils [peppermint, jasmine, ylang-ylang, 1,8-cineole (in two different dosages) and menthol] on this core attentional function, which can be experimentally defined as speed of information processing. Substances were administered by inhalation; levels of alertness were assessed by measuring motor and reaction times in a reaction time paradigm. The performances of the six experimental groups receiving substances (n = 20 in four groups, n = 30 in two groups) were compared with those of corresponding control groups receiving water. Between-group analysis, i.e. comparisons between experimental groups and their respective control groups, mainly did not reach statistical significance. However, within-group analysis showed complex correlations between subjective evaluations of substances and objective performance, indicating that effects of essentials oils or their components on basic forms of attentional behavior are mainly psychological.

Aromatherapy↗
PubMed2001

Functional magnetic resonance imaging of human olfaction.

Olfaction is our basic sense phylogenetically and embryologically. Little is known, however, about how the human brain encodes the quality of odors, odor-associated memories, and emotions. Olfactory information is projected from the olfactory bulb to the primary olfactory cortex, which is composed of the anterior olfactory nucleus, the olfactory tubercle, the piriform cortex, the amygdala, the periamygdaloid region, and the entorhinal cortex. From there, the primary olfactory cortex projects to secondary olfactory regions including the hippocampus, ventral striatum and pallidum, hypothalamus, thalamus, orbitofrontal cortex, agranular insular cortex, and cingulate gyrus. Functional MR studies using olfactory stimuli as paradigms show activation of many of these areas and can advance our understanding of odor perception in humans.

Adult↗
PubMed2000

Transcallosal interforniceal-transforaminal approach for removing lesions occupying the third ventricular space: clinical and neuropsychological results.

OBJECTIVE: The present study was undertaken to describe the clinical and prospective neuropsychological results for our group of 30 patients who were treated using a transcallosal interforniceal-transforaminal microsurgical approach. METHODS: The transcallosal interforniceal and transcallosal-transforaminal approaches were used to treat 30 patients with space-occupying lesions located in the anterior part of the third ventricle. We used a modified anterior transcallosal microsurgical approach, as described recently. The patients underwent extensive, pre- and postoperative, prospective neuropsychological testing, using a specially designed test battery. RESULTS: Twenty-three of 30 patients (77%) experienced excellent clinical outcomes (Glasgow Outcome Scale Grade V). The surgical procedures described in this report did not themselves impair attentional function. In both the early and late postoperative neuropsychological testing sessions, deficits in verbal memory were only rarely observed and were not noted to be correlated with the surgical procedures. The most relevant neuropsychological results for individual patients are reported in detail. CONCLUSION: The approach described here can be successfully used for the resection of various space-occupying lesions in the anterior part of the third ventricle. The anatomic landmarks we recently defined and described (for example, the midline vessel on the trunk of the corpus callosum, to direct the callosotomy) guide the surgical path. Furthermore, we recommend the use of neuropsychological test batteries for both scientific and rehabilitative purposes.

Adolescent↗
PubMed1999

[Noninvasive protocol for surgical treatment of focal epilepsies].

We present a non-invasive epilepsy surgery protocol, which includes EEG-video-monitoring, magnetic resonance imaging (MRI), interictal positron emission tomography (PET) and ictal single photon emission computerized tomography (SPECT). According to this non-invasive protocol 50 of 173 patients with medically intractable focal epilepsy underwent resective surgery. The localization of the epileptogenic zone was based on the congruence of the localizing results of EEG-video-monitoring, MRI, interictal PET and ictal SPECT. 46 (92%) of the patients had temporal and 4 (8%) had extratemporal epilepsies. 78% (n = 39) of all patients operated according to our non-invasive protocol were postoperatively completely or almost seizure free. Extramesiotemporal resections could be carried out without invasive EEG-recording if the epileptogenic zone was not adjacent to the eloquent cortex. We conclude from our results that in a considerable number of patients with medically intractable particularly temporal focal epilepsies, resective epilepsy surgery can be based on non-invasive EEG-evaluations and the risk of invasive recordings can be avoided.

Adolescent↗
PubMed1997

[Tumor surgery of the speech cortex in local anesthesia. Neuropsychological and neurophysiological monitoring during operations in the dominant hemisphere].

We report on 30 cases where we have used cortical stimulation mapping to define the areas representing sensorimotor, language and speech functions under local anesthesia to facilitate resection of space-occupying lesions near these areas. Under the simplistic concept that Broca's area lies in the frontal operculum (inferior frontal gyrus) and that Wernicke's area is located in the posterior perisylvian area (superior temporal, angular and supramarginal gyri), we found language and speech function to be represented outside these areas in up to 4 stimulation sites of 15 patients. The results of cortical stimulation mapping were therefore essential to decide on the optimal access route to the lesions that were located subcortically and on the optimal resection plane in gliomas. After the limits of these areas and of the lesions had been established with stimulation mapping and with intrasurgical microscopic smear preparations, respectively, lesions were safely removed under continuous monitoring of sensorimotor, language and speech function. Immediately after surgery we encountered language and speech deficits in 9 patients (30%), which resolved completely in 5 and incompletely in 4 instances. Thus, language functions were normal in 26 patients (87%) at the end of the follow-up period. It is concluded that use of this technique allows safe and extensive resection of lesions that would otherwise have been considered hazardous to remove or inexcisable.

Adolescent↗
PubMed1997

Preoperative activation and intraoperative stimulation of language-related areas in patients with glioma.

OBJECTIVE: Evaluation of the accuracy of preoperative localization of language-related cortex by magnetic resonance imaging-guided positron emission tomography. METHODS: Patients with gliomas in the left dominant hemisphere were examined preoperatively with magnetic resonance imaging-guided positron emission tomography and intraoperatively by electrical stimulation of cortex. RESULTS: A verb generation task yielded more intense and better lateralized local increases of cerebral blood flow in the positron emission tomographic examination than did a naming task. Significant correspondence of preoperative and intraoperative findings was observed for the verb generation task. Cortical sites with aphasic disturbance during electrical stimulation had a significantly higher cerebral blood flow increase during preoperative activation than did sites without intraoperative language impairment. Areas with cerebral blood flow increases above an optimum threshold had 73% sensitivity and 81% specificity to predict aphasic disturbance during intraoperative stimulation. CONCLUSION: The data suggest that with further technical improvements, imaging of language function may become a preoperative diagnostic tool for patients with tumors close to language-related brain structures.

Adult↗
PubMed1996

Keeping in mind the mind: mental functions, networks and neurosurgery.

The object of the neurosurgeons daily endeavour, the human brain, is less well understood in its overall organization than any other organ. This puts the neurosurgeon in a very difficult position. However, a substantial body of knowledge has been accumulated during recent years, and scientists from a variety of different disciplines have worked out theoretical frameworks to accomodate the available data. Here we present some of the evolving concepts on the organization of the substrate of the mind. Review of the literature shows that application of mathematical neural network models to the nervous system is very successful in explaining function. An implicit aspect of neural network models is that information storage is not localized in certain neurons but that the information is stored as the global pattern of activity in the network. Because networks of the brain involve often millions of neurons, exact identification and comparison with the theoretical models is not possible today.

Brain↗
PubMed1995

[Function-controlled neurosurgery. Neurophysiologic and neuropsychological monitoring during surgery of the nervous system].

Neuromonitoring of neural structures has become increasingly common during surgery near cortical areas representing sensorimotor and language function (epilepsia, tumors), in the brain stem and the spinal cord (tumors), near cranial nerves (cerebellopontine angle tumors, trigeminal neuralgia, hemifacial spasm), and in the cauda equina (tumors, tethered spinal cord). The technical spectrum to monitor these operations includes electrical cortical stimulation to evoke sensorimotor phenomena and language disturbances, electroneurography and -myography of the cauda equina, motor cranial nerves and nuclei, and somatosensory, motor and acoustic evoked potentials. The goals of intraoperative neuromonitoring are: (1) minimizing the risk of suffering neurological and neuropsychological injury as a result of surgery; (2) extending the surgical spectrum to lesions that have previously been considered inoperable or hazardous to operate upon; (3) intraoperative electrophysiological documentation that the goal of surgery has been achieved; (4) intraoperative basic research.

Brain↗
PubMed1995

[Localization of cortical functions by electric stimulation and functional magnetic resonance tomography. Paradigms of neural stimulation].

In this review, localization of function is discussed with respect to distributed cortical areas involved in complex mental processing. After introducing the methodology of lesion studies, some results of studies using electrical cortical stimulation are presented. With respect to functional magnetic resonance imaging, results and problems from several experiments are reported, and further questions and perspectives regarding the two methods are outlined.

Arousal↗
PubMed1993

[Recovery of psychomotor and cognitive functions following anesthesia. Propofol/alfentanil and thiopental/isoflurane/ alfentanil].

Recent changes in the medical system have resulted in a significant increase of ambulatory surgical procedures. Therefore, a safe and short postoperative recovery period and, especially, the full recovery of complex psychological function after general anaesthesia have become increasingly important. In the present study we investigated the recovery of psychomotor and cognitive function after general anaesthesia with propofol/alfentanil and thiopentone/isoflurane/alfentanil. PATIENTS AND METHODS. Institutional approval and informed consent was obtained in 40 female ASA I or II patients undergoing diagnostic laparoscopy. As oral premedication the patients received chloracepat (10-20 mg) 45 min before the start of anaesthesia. Anaesthesia was induced in group I with propofol (2.5 mg/kg) and maintained with propofol (6-12 mg/kg/h)/alfentanil (0.05 mg/kg) and 50% N2O in O2. The patients of group II received thiopentone (5 mg/kg) for induction and isoflurane (0.5-1.5 vol%)/alfentanil (0.05 mg/kg) and 50% N2O in O2 for maintenance of general anaesthesia. In particular we measured the following parameters: (1) The recovery time, defined as the interval between the termination of the anesthetic and the patient's correct recall of her birth date. (2) The choice reaction times to optical stimuli (red or green light), which was used as a parameter for attention and psychomotor function. (3) The score in the "Zahlen-Verbindungs-Test" in which the patients had to connect numbers from 1 to 90 in correct order. This is also a parameter to quantify attention and psychomotor function. (4) The digit span which is a value derived from the number of correctly reproduced digits from a list presented to the patients. It is a measure of numerical memory. (5) The Munich Verbal Learning Test, which is the German version of the California Verbal Learning Test. It represents the number of correctly reproduced words from a previously presented list and is a measure of the verbal memory. (6) The Wisconsin Card Sorting Test, which serves to test the ability to plan and act and to form terms and concepts. (7) The State-Trait Anxiety Inventory, to quantify state anxiety. (8) Pain score, using a visual analogue scale. The tests were performed at four measurement points: the day before the operation and 30, 60, and 240 min after recovery. The "Zahlen-Verbindungs-Test", the digit span and the Munich Verbal Learning Test were presented in four parallel forms to minimize learning effects. For statistical analysis of the data the Wilcoxon test was employed within groups and the Mann-Whitney test between groups. RESULTS. The groups were comparable in age, weight, height and level of education. No significant difference was found between them in operation or anaesthesia time or in the total dosage of alfentanil. Recovery time in the propofol group was, at 10 min, significantly shorter than in the isoflurane group, with 16 min. Choice reaction times were significantly increased 30 min after recovery from anaesthesia in both groups. In the propofol group they returned to normal after 60 min, whereas in the isoflurane group significant increases could be observed even 240 min after recovery from the anaesthetic. Choice reaction times were significantly longer in the isoflurane group than in the propofol group 60 min and 240 min after anaesthesia. In the "Zahlen-Verbindungs-Test" the patients showed significantly worse results 30 min and 60 min after anaesthesia. The propofol group tended to be better than the isoflurane group, but the difference did not reach statistical significance. Also in the digit span, the scores were significantly lower 30 min after recovery from the anaesthetic. Here again the propofol group tended to be a little better than the isoflurane group 30 min, 60 min and 240 min after anaesthesia. In the Munich Verbal Learning Test both groups had lower scores 30 min and 60 min, the isoflurane group also 240 min, after recovery...

Adult↗
PubMed1991

Memory dysfunction in Parkinson patients: an analysis of verbal learning processes.

The German version of the California verbal learning test (Münchner Gedächtnis-Test) was administered to compare memory functions of 45 Parkinson patients and 32 healthy controls. Although the Parkinson patients were within their age norm in their performance on standard intelligence and memory tests, a significant pattern of impaired learning was observed with the MGT. While learning capacity showed a linear increase, it was altogether lower than that of healthy normals. Parkinson patients have difficulty organizing new material and applying useful strategies. When offered useful cues, they can apply these for a while, but soon loose these strategies again. They are more irritated by distractors than healthy people. Once material is learned and stored, it hampers the learning of new material. Also, new information disturbs the reproduction of formerly acquired information.

Female↗
PubMed1990

Stimulus anticipation in following rhythmic acoustical patterns by tapping.

Subjects followed rhythmic acoustical sequences by finger-tapping. Tapping onset preceded stimulus onset by a value close to 30 ms. It is suggested that this temporal difference might correspond to one cycle of a hypothetical timing mechanism in the brain which has been observed with other experimental paradigms.

Auditory Perception↗