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C Oberwittler

Publications and source records attributed to C Oberwittler.

30 records · Page 2Linked to original sources
PubMed1992

The relation between functional deficits, motor and sensory conduction times and MRI findings in syringomyelia.

Opinions about the relation between the dimensions of the syrinx and the severity and distribution of symptoms in patients with syringomyelia are controversial. Therefore, this study investigates the relation of clinical symptoms, a disability score, quantified (1- and 2-dimensional) radiological findings (magnetic resonance imaging, MRI) and electrophysiological data (somatosensory and motor evoked potentials) in 22 patients with syringomyelia. There was a close relation between clinical symptoms and electrophysiological data. By both electrophysiological methods subclinical deficits could be detected. Furthermore, the results disclosed that the clinical symptoms, the degree of disability and the duration of the disease are not related to the dimensions of the syrinx or the electrophysiological results obtained by investigating the long ascending and descending spinal tracts of the lower limbs. Our findings suggest that, besides the syrinx, other factors not directly visible in the MRI are responsible for the development and progress of clinical symptoms.

Adolescent↗
PubMed1992

The influence of acetazolamide on cerebral low-flow regions in migraine--an interictal 99mTc-HMPAO SPECT study.

Acetazolamide, a carbonic anhydrase inhibitor, has proved to be useful in the assessment of "vasodilatory capacity" in cerebrovascular disease. To obtain further information on the nature of interictal low-flow regions in migraine, we reinvestigated 20 asymptomatic patients suffering from migraine with aura (n = 15) or without aura (n = 5) and who had either minor (n = 12) or marked (n = 8) regional hypoperfusion when examined in a previous 99mTc-HMPAO SPECT investigation. These patients received acetazolamide IV prior to tracer application. In 14/20 cases regional hypoperfusion resolved. Three patients with migraine with aura had less pronounced regional hypoperfusion compared to baseline. No change in baseline hypoperfusion was detectable in three older patients. No further decreases in flow were measured. In contrast to patients with cerebrovascular ischemia, in whom acetazolamide usually enhances low-flow regions, vasodilatory capacity appears intact in most migraine patients with interictal regional hypoperfusion. Thus, the "acetazolamide test" might be useful in the differential diagnosis of migraine with aura from transient cerebrovascular ischemia.

Acetazolamide↗
PubMed1992

MRI in ALS.

Explore the source record for details and available documents.

Amyotrophic Lateral Sclerosis↗
PubMed1992

Computer-aided classification of malignancy in astrocytomas. I. The value of nuclear parameters obtained by automated black and white image analysis.

Ninety-three selected cases of astrocytomas including glioblastomas (astrocytomas grades 1-4) were evaluated by means of Feulgen-stained microscopic slides for nuclear parameters obtained by automated black and white image analysis (ABWIA). The goal was to determine to what extent nuclear features evaluated by ABWIA were applicable as classifiers for the computer-aided numerical classification of malignancy in astrocytomas. Before the automated evaluation, all tumours had been subjectively graded according to the Mayo Clinic grading rules as delineated by Ringertz. Twenty-three nuclear parameters were evaluated and tested for their classification impact. With a model of five parameters (number of nuclei per area, mean of the convex form factor, extinction sum, extinction variation, and full-width-half-maximum of the extinction distribution) the highest reclassification rate of 75% correctly reclassified cases was obtained. Although this is a good result for a classification using only nuclear parameters, it is too poor for practical application. Thus, nuclear parameters evaluated by ABWIA alone are insufficient for numerical classification models assessing the malignant expression of astrocytomas.

Astrocytoma↗
PubMed1992

Computer-aided classification of malignancy in astrocytomas. II. The value of categorically evaluated histologic and non-histologic features for a numerical classifier.

The present study was carried out in order to obtain a numerical classifier for the assessment of the malignancy in astrocytomas including glioblastomas ('astrocytomas grade 4'). The attempt resulted in 'TESTAST 268', a classifier based on a reference sample of 268 tumours, 67 in each of four malignancy classes. TESTAST 268 aids the identification of astrocytomas with one of four malignancy classes by means of eight classification variables, five histologic and three non-histologic. Identification is achieved with the aid of linear discriminant functions, both according to Bayes' decision rule (BAYTEST) and by canonical discriminant analysis (CANTEST) using the squared Mahalanobis distance. The discriminant functions with the calibration of the reference sample of the 268 tumours may be implemented on personal and even small pocket computers for practical application.

Astrocytoma↗
PubMedDate not supplied

Inhibitory period and late muscular responses after transcranial magnetic stimulation in healthy children.

Transcranial magnetic stimulation (TMS) was investigated in 24 healthy children between the ages of 3 and 14 years in order to study late muscular responses (as they are observed in adults) as a function of age and maturation. Muscular responses were recorded bilaterally from the biceps muscle. An early muscular response and several late phenomena can be elicited in children. (i) An inhibitory period following the primary response could preferentially be recorded contralaterally. (ii) During facilitation, a late response was recorded bilaterally. (iii) Without facilitation (during 'relaxation'), late responses were recorded bilaterally with a latency of between 50-400 ms. The latency of the latter responses depended on the age of the children, and may therefore be useful in monitoring the maturation of the central motor system in infants. Due to small side-to-side differences, the inhibitory period may be of diagnostic value in children for detection of unilateral dysfunction of the central nervous system.

Adolescent↗
PubMedDate not supplied

Numerical grading of astrocytomas.

Ninety-three astrocytomas from biopsy material including glioblastomas ('astrocytomas grade 4') were graded according to Kernohan (1949) by light microscopy. Feulgen sections were subjected to an automated microscopic analysis to obtain morphometric-densitometric data of the tumour cell nuclei. These quantitative and reproducible data showed a significant correlation with malignancy expressed in terms of Kernohan and prove automated image analysis to be a valuable tool in the grading of gliomas. This is in particular true if the nuclear parameters determined by image analysis are completed by histologic features which were recorded semiquantitatively by subjective light microscopic evaluation as is usual in clinic pathologic diagnosis of brain tumours. A quadratic discriminant analysis of morphometric-densitometric data of tumour cell nuclei and semiquantitative microscopic data gave a 94% agreement with subjective grading.

Astrocytoma↗
PubMedDate not supplied

Sympathetic skin response in patients with amyotrophic lateral sclerosis.

To determine a possible involvement of the autonomic nervous system in amyotrophic lateral sclerosis (ALS), measurement of the sympathetic skin response (SSR) was performed in 15 patients with definite ALS. Findings were compared with those in 20 normal controls. In ALS patients the mean SSR latencies recorded from the palms and soles were both significantly prolonged (p < 0.05) and the amplitudes were reduced as compared with normal persons. In 5 patients, SSR potentials were completely lacking in one or even more extremities. Our data strongly suggest subclinical involvement of the autonomic nervous system in ALS as assessed by the SSR response. In our patients the extent of autonomic dysfunction was not related to the stage or the duration of disease.

Adult↗
PubMedDate not supplied

Involvement of the autonomic nervous system in patients with syringomyelia--a study with the sympathetic skin response.

In order to determine the function of the autonomic nervous system in syringomyelia, the sympathetic skin response (SSR) was performed in 13 patients with syringomyelia and 20 healthy controls. SSR was recorded from both palms and soles. In patients with syringomyelia, we found absent responses, prolonged latencies and reduced amplitudes. SSRs could be recorded in 15 out of the examined 26 upper extremities. The latencies were prolonged in 12 of these cases. In the lower limbs, 11 SSRs could be obtained. In 4 of these cases the latencies were prolonged. The SSR latencies recorded from the palms and soles were both significantly prolonged (p < 0.05) and the amplitudes were reduced (p < 0.05) as compared to normal persons. Our data strongly suggest involvement of the autonomic nervous system in syringomyelia as assessed by the SSR response (in upper and lower extremities). In our patients, the extent of autonomic dysfunction was not related to the stage or the duration of disease.

Adult↗
PubMedDate not supplied

Somatosensory evoked potentials after magnetic stimulation at different points of the body in normal subjects and in patients with syringomyelia.

Somatosensory evoked potentials (SEPs) were elicited by magnetic stimulation of the tibial nerve, gastrocnemic muscle and by stimulation over the spinous processes of lumbar vertebra 5 (L 5), thoracic vertebra 9 (Th 9) and cervical vertebra 7 (C 7). The first SEP-positivity (P1-latency) was measured in a group of 20 controls and in another group of 18 patients with syringomyelia. The P1-latencies of the latter group following the stimulations over Th 9 and C 7 were significantly longer than those of the controls. Furthermore a correlation between electrophysiological findings and clinical data of the patients could be proven. Thus the method emerged as an appropriate tool for the investigation of the central part of the sensory system and for the diagnosis of spinal abnormalities.

Adult↗