Biomedical subjects

Siegfried Bien

Publications and source records attributed to Siegfried Bien.

4 recordsLinked to original sources

PubMed2003

Language lateralization in patients with temporal lobe epilepsy: a comparison of functional transcranial Doppler sonography and the Wada test.

This study prospectively investigates whether noninvasive functional transcranial Doppler sonography (fTCD) is a useful tool to determine hemispheric language lateralization in the presurgical evaluation of patients with medically intractable temporal lobe epilepsy (TLE). fTCD results were compared with the Wada test as the gold standard. Wada test and fTCD were performed in 13 patients suffering from TLE. fTCD continuously measured blood flow velocities in both middle cerebral arteries, while the patient was performing a cued word generation task. During the Wada test, spontaneous speech, comprehension, reading, naming, and repetition were investigated. A laterality index (LI) was obtained by both procedures. Due to a lack of an acoustic temporal bone window, fTCD could not be performed in two patients (15%). In 9 of the remaining 11 patients hemispheric language dominance was found on the left side, in 1 patient on the right side, and 1 patient showed bihemispheric language representation. In all patients fTCD and the Wada test were in good agreement regarding hemispheric language lateralization, and the LI of both techniques were highly correlated (r = 0.776, P = 0.005). fTCD gives predictions of hemispheric language dominance consistent with the Wada test results even in children, patients with low IQ, and nonnative speakers. It is an alternative to the Wada test in determining language lateralization in patients with temporal lobe epilepsy.

Adolescent↗

PubMed2003

Intraoperative spinal digital subtraction angiography: technique and results.

OBJECTIVE: To evaluate technical and methodological aspects of intraoperative spinal digital subtraction angiography (ISDSA) in our clinical practice and to assess its practicability, safety, and accuracy for the surgical treatment of spinal vascular malformations. METHODS: Between August 1997 and February 2002, a total of 30 patients were treated either surgically (n = 18) or endovascularly (n = 12) for spinal vascular lesions at our institution. The clinical records of five patients who underwent ISDSA were analyzed retrospectively. The thoracic segment was involved in three patients and the medullary cone in two. RESULTS: ISDSA could be performed in four cases. In one patient, the segmental artery could not be probed sufficiently while the patient was prone. No complications occurred from the application of ISDSA. The method was beneficial for the neurosurgeon in all but one patient because the vascular anatomy of the malformation was shown with respect to the surgical approach, including the nidus, and immediate resection control could be performed before wound closure. The duration of the procedure was prolonged by 45 minutes on average. CONCLUSION: ISDSA is safe and effective, especially in surgery for complex vascular and recurrent malformations. Benefits to the patient outweigh the additional expense and prolongation of the surgical procedure.

Adolescent↗

PubMed2002

Brain activation modulated by the comprehension of normal and pseudo-word sentences of different processing demands: a functional magnetic resonance imaging study.

Recent data from lesion and brain imaging studies have questioned the well-established assumption of a close functional-anatomic link between syntax and Broca's area and semantics and Wernicke's area. In the present study we used functional magnetic resonance imaging (fMRI) to investigate the neuroanatomical correlates of semantic and syntactic functions and possible interdependencies between the related brain systems. In a completely crossed design we varied syntactic processing demands (easy vs difficult to process word order sequences) and the meaningfulness of sentences (real- vs pseudo-word sentences). In comparison to a backward speech condition we found an activation of the left perisylvian region, including the left inferior frontal cortex and the left superior and middle temporal gyri. Semantic in contrast to pseudo-word sentences elicited a stronger activation in both the anterior and the posterior perisylvian cortex. Syntactic difficulty had its strongest effect within the left inferior frontal region and this effect was more pronounced for semantic than nonsemantic speech. These results suggest that semantic and syntactic language functions are mediated by partly specialized brain systems but that there nevertheless exists a substantial functional overlap of the involved brain structures.

Adult↗

PubMed2002

Speech processing activates visual cortex in congenitally blind humans.

Neurophysiological recordings and neuroimaging data in blind and deaf animals and humans suggest that perceptual functions may be organized differently after sensory deprivation. It has been argued that neural plasticity contributes to compensatory performance in blind humans, such as faster speech processing. The present study employed functional magnetic resonance imaging (fMRI) to map language-related brain activity in congenitally blind adults. Participants listened to sentences, with either an easy or a more difficult syntactic structure, which were either semantically meaningful or meaningless. Results show that blind adults not only activate classical left-hemispheric perisylvian language areas during speech comprehension, as did a group of sighted adults, but that they additionally display an activation in the homologueous right-hemispheric structures and in extrastriate and striate cortex. Both the perisylvian and occipital activity varied as a function of syntactic difficulty and semantic content. The results demonstrate that the cerebral organization of complex cognitive systems such as the language system is significantly shaped by the input available.

Adult↗