[fMRI and DTI in delayed development of number processing]. / fMRT und DTI bei Entwicklungsverzögerung der Zahlenverarbeitung.

The neuronal correlate of the current cultural performance arose from developmental processes that can be observed by functional and anatomical magnetic resonance imaging. The velocity of these maturation processes occurs differently between adolescents, causing implications for both school career and academic performance. Regarding spatial-numerical cognition the myelinization of the superior longitudinal bundle appears to be crucial because this fiber connection intermediates between the linguistic nature of number words and conception of their spatial-numerical magnitude. The neuroscientific observation of anatomical brain maturation and its influence on school-relevant number processing may be helpful for educational purposes as well as for school psychology.

[Functional MRI of speech]. / Funktionelle MRT der Sprache.

Speech is a multifactorial term. In relationship with our central organ, speech is a communication medium which in a complex manner includes the production and perception of verbal information. Even within this limitation, imaging exploration of the neuronal basis of verbal communication offers an extensive investigative field which can only be presented in this article as highlights. The main focus is on the technical hurdles of investigations into speech production using functional magnetic resonance imaging (fMRI) and solution options will be presented. The difficulties contained in this aspect are that spoken words can only be poorly assessed in the noise level of the measurements and that the movements of the mouth necessary for speech motoric can lead to technical imaging artefacts. Investigation techniques and designs will be discussed which allow a representation of speech-relevant brain centers despite these problems.

[Functional MRI of the hearing center]. / Funktionelle MRT des Hörzentrums.

Examination of the sense of hearing is a technically difficult undertaking especially with functional magnetic resonance imaging because the machine causes a high noise level during the measurement. This article describes the technical conditions which, nevertheless, allow the auditory capabilities to be tested. Furthermore, every switch point of the auditory pathway and the cortical areas involved, which are technically accessible in an investigation of the sense of hearing are pictorially described.

[Neuroimaging of color and spatial perception]. / "Neuroimaging" der Farb- und Raumwahrnehmung.

Spatial orientation and perception of distance are anchored in the visual system in the same way as color perception. However, different centers with different levels of expression are involved in the various aspects of visual processing starting from the primary visual cortex in the occipital lobes. In this article the investigation methods and designs are described by which the various functions within the visual system can be assigned to the appropriate specialized center in the parietal and temporal lobes using functional magnetic resonance imaging (fMRI).

Comparison of stent free cell area and cerebral lesions after unprotected carotid artery stent placement.

OBJECTIVE: This study evaluates the correlation between closed, semi-closed and open-cell stent design and the association between stent type and clinical outcome as well as magnetic resonance imaging (MRI) findings. DESIGN: A total of 194 patients who underwent unprotected carotid artery stenting (CAS) as well as diffusion-weighted magnetic resonance imaging (DW-MRI) before and after intervention were retrospectively reviewed. MATERIALS AND METHODS: Three stent designs were studied: closed cell, semi-closed cell and open cell. Spearman's Rho test was performed between the stent free cell area and the number and area of ischaemic lesions found after intervention. Adverse events were evaluated. RESULTS: There was no significant difference in clinical outcome between the three stent groups (Zilver, Cook Europe, Denmark; Smart, Codman, MA; and Wallstent, Stryker, MN, USA). A significant correlation was found between the stent free cell area and the number and area of new ischaemic lesions on DW-MRI (P = 0.023). There were significantly fewer new lesions with an open-cell design (Zilver; 12.76 mm(2) free cell area) than with a closed-cell design (Wallstent; 1.08 mm(2) free cell area). CONCLUSIONS: Open-cell stent was related to a lower number and area of silent cerebral ischaemic lesions after unprotected CAS. However, clinical outcome, measured by incidence of adverse events and clinical neurologic assessment, was not significantly different between patients with different stent designs.

Mutator effects and mutation signatures of editing deaminases produced in bacteria and yeast.

Enzymatic deamination of bases in DNA or RNA leads to an alteration of flow of genetic information. Adenosine deaminases edit RNA (ADARs, TADs). Specialized cytidine deaminases are involved in RNA/DNA editing in lipid metabolism (APOBEC1) and in innate (APOBEC3 family) and humoral (AID) immunity. APOBEC2 is required for proper muscle development and, along with AID, was implicated in demethylation of DNA. The functions of APOBEC4, APOBEC5, and other deaminases recently discovered by bioinformatics approaches are unknown. What is the basis for the diverse biological functions of enzymes with similar enzyme structure and the same principal enzymatic reaction? AID, APOBEC1, lamprey CDA1, and APOBEC3G enzymes cause uracil DNA glycosylase-dependent induction of mutations when overproduced ectopically in bacteria or yeast. APOBEC2, on the contrary, is nonmutagenic. We studied the effects of the expression of various deaminases in yeast and bacteria. The mutagenic specificities of four deaminases, hAID, rAPOBEC1, hAPOBEC3G, and lamprey CDA1, are strikingly different. This suggests the existence of an intrinsic component of deaminase targeting. The expression of yeast CDD1 and TAD2/TAD3, human APOBEC4, Xanthomonas oryzae APOBEC5, and deaminase encoded by Micromonas sp. gene MICPUN_56782 was nonmutagenic. A lack of a mutagenic effect for Cdd1 is expected because the enzyme functions in the salvage of pyrimidine nucleotides, and it is evolutionarily distant from RNA/DNA editing enzymes. The reason for inactivity of deaminases grouped with APOBEC2 is not obvious from their structures. This can not be explained by protein insolubility and peculiarities of cellular distribution and requires further investigation.

[Music therapy for noisiform tinnitus. Concept development and evaluation]. / Musiktherapie bei nichttonalem Tinnitus (Tinnitusrauschen). Konzeptentwicklung und Behandlungsevaluation.

BACKGROUND: Music therapy in chronic tonal tinnitus according to the "Heidelberger model" presents an effective treatment, which is substantiated by neuroscientific and psychological evaluation. METHOD: The music therapy approach was specifically extended to include noisiform tinnitus, taking sound quality and cardiovascular influences into consideration. Outcome criteria were psychological tinnitus load, psychophysiologic parameters and brain imaging procedures. RESULTS: Psychological outcomes of the pilot study indicate that 21 of the 23 patients (i.e. more than 90%) achieved a reliable reduction of symptoms (TQ scores: pre: 40.1 ± 11.4; post: 27.9 ± 12.8; at 3-month-follow-up: 24.0 ± 12.2). Results of the imaging examinations demonstrated neuroplastic changes in the putamen and insula. Psychophysiological measurements indicate cardiovascular influences on noisiform tinnitus. DISCUSSION: Therapy success depends on the sound quality of the tinnitus; therefore, any treatment should take this into consideration. Cardiovascular influences were important insofar as active control of the heart rate was an important predictor of long-term therapy outcome. Overall, brain imaging data confirm the top-down-model of tinnitus generation.

Revascularization in acute ischaemic stroke using the penumbra system: the first single center experience.

BACKGROUND AND PURPOSE: This is the first single center experience illustrating the effectiveness of the penumbra system (PS) in the treatment of large vessel occlusive disease in the arena of acute ischaemic stroke. The PS is an innovative mechanical thrombectomy device, employed in the revascularization of large cerebral vessel occlusions in patients via the utilization of an aspiration platform. METHODS: This is a prospective, non-randomized controlled trial evaluating the clinical and functional outcome in 29 patients with acute intra-cranial occlusions consequent to mechanical thrombectomy by the PS either as mono-therapy or as an adjunct to current standard of care. Patients were evaluated by a neurologist and treated by our in house interventional neuro-radiologists. Primary end-points were revascularization of the occluded target vessel to TIMI grade 2 or 3 and neurological outcome as measured by an improvement in the NIH Stroke Scale (NIHSS) score after the procedure. RESULTS: Complete revascularization (TIMI 3) was achieved in 21/29 (72.4%) of patients. Partial revascularization (TIMI 2) was established in 4/29 (13.8%) of patients. Revascularization failed in four (13.8%) patients. Nineteen (19) patients (65.5%) had at least a four-point improvement in NIHSS scores. Modified Rankin scale scores of < or =2 were seen in 37.9% of patients. There were no device-related adverse events. Symptomatic intra-cranial hemorrhage occurred in 7% of patients. CONCLUSIONS: The PS has the potential of exercising a significant impact in the interventional treatment of ischaemic stroke in the future.

Hyperechogenicity of the substantia nigra in healthy controls is related to MRI changes and to neuronal loss as determined by F-Dopa PET.

Transcranial ultrasound (TCS) has been shown to reveal hyperechogenicity of the substantia nigra (SN) in Parkinsonian patients and in about 10% of healthy controls. It is hypothesized that SN hyperechogenicity in healthy subjects is a vulnerability marker for idiopathic Parkinson's disease (IPD). Although there is strong evidence that the echomarker results from increased local iron content, the exact pathophysiological mechanisms remain incompletely understood. Thus, prognostic impact can only be estimated. We examined 14 subjects with SN hyperechogenicity (SN+) (7 IPD patients and 7 controls) and 7 healthy controls without the echomarker (SN-) by a magnetic resonance imaging method (MRI; T2 relaxation times) known to reveal tissue inhomogeneity following abnormal iron content and by F-Dopa PET to assess nigrostriatal function.

Lesion load in unprotected carotid artery stenting.

INTRODUCTION: The purpose of the study was to determine the incidence of new ischemic lesions found on diffusion-weighted MR imaging (DWI) in nonselected patients after unprotected carotid artery stent placement. MATERIALS AND METHODS: We retrospectively reviewed a nonrandomized cohort of 197 patients presenting with carotid occlusive disease who underwent unprotected carotid artery stent placement between 2003 and 2006. Mean degree of stenosis was 86.94% +/- 9.72. In all patients, DWI was obtained before and 24 h after stent placement. New lesions were evaluated according to size and location. RESULTS: In 59 of 197 patients (29.9%), new ischemic lesions were found on DWI in the vessel dependent area. In 23 of 197 patients (11.7%), new ischemic lesions were found in the vessel independent area. Combined stroke/death rate was 3.63%. CONCLUSION: In our series of unprotected carotid angioplasty with stent, we found new DWI lesions in 34% of the patients. Further studies should now show in how far protection devices can reduce these lesions.

Hyperperfusion syndrome after carotid stent angioplasty.

INTRODUCTION: This study assesses the incidence and causes of hyperperfusion syndrome occurring after carotid artery stenting (CAS). MATERIALS AND METHODS: We retrospectively reviewed the clinical database of 417 consecutive patients who were treated with CAS in our department to identify patients who developed hyperperfusion syndrome and/or intracranial hemorrhage. Magnetic resonance imaging (MRI) including fluid-attenuated inversion recovery and diffusion-weighted imaging was performed before and after CAS in 269 cases. A Spearman's rho nonparametric correlation was performed to determine whether there was a correlation between the occurrence/development of hyperperfusion syndrome and the patient's age, degree of stenosis on the stented and contralateral side, risk factors such as diabetes, smoking, hypertension, adiposity, gender and fluoroscopy time, and mean area of postprocedural lesions as well as preexisting lesions. Significance was established at p < 0.05. RESULTS: Of the 417 carotid arteries stented and where MRI was also completed, we found hyperperfusion syndrome in 2.4% (ten cases). Patients who had preexisting brain lesions (previous or acute stroke) were at a higher risk of developing hyperperfusion syndrome (p = 0.022; Spearman's rho test). We could not validate any correlation with the other patient characteristics. CONCLUSION: Extensive microvascular disease may be a predictor of hyperperfusion syndrome after carotid stent placement. We believe that further studies are warranted to predict more accurately which patients are at greater risk of developing this often fatal complication.

[Music therapy in chronic tonal tinnitus. Heidelberg model of evidence-based music therapy]. / Musiktherapie bei chronisch-tonalem Tinnitus. Heidelberger Modell evidenzbasierter Musiktherapie.

Tinnitus has a very high prevalence, with more than one million patients in the German population needing treatment for it. About 50% of them suffer from so-called tonal tinnitus, i.e., tinnitus with a well-defined frequency. Although tinnitus is one of the most common symptoms in ENT medicine, the existing treatments are polypragmatic and often lack a scientific foundation. Based on this fact, a novel music therapy concept was developed, evaluated, and scientifically substantiated (with psychological, audiological, and functional imaging procedures in the diagnosis and treatment). The advantages of the described therapy are the integration of known and well-proven acoustic and psychotherapeutic techniques. They were converted to specific music therapy interventions (resonance training, neuroauditive cortex reprogramming, and tinnitus desensitization). More than 190 patients suffering from chronic tonal tinnitus were effectively treated. The results indicate that the therapy is highly advantageous in terms of treatment duration, effectiveness, and follow-up stability compared with customary interventions. Furthermore, the results of brain imaging strongly suggest the usefulness of further investigation and discussion in the realm of neuronal tinnitus modeling.

Long-term results with Matrix coils vs. GDC: an angiographic and histopathological comparison.

INTRODUCTION: The aim of the study was to compare standard platinum Guglielmi detachable coils (GDC) with coated platinum coils (Matrix; both Boston Scientific, Fremont, CA) regarding handling, complications, occlusion and recanalization rate after 3 and 6A months. METHODS: Aneurysms in the right common carotid artery were created in 25 rabbits. The animals were divided into five groups of five animals each. The animals of group 1 (the control group) received no treatment of the induced aneurysms, the animals of groups 2 and 3 (killed at 3 and 6A months) were treated with standard GDC, and the animals of groups 4 and 5 (killed at 3 and 6A months) were treated with Matrix coils. RESULTS: Histopathological evaluation showed organized thrombus formation and connective tissue with neovascularization around the implanted coils in all the treated groups. The achieved occlusion rates in groups 2 and 3 were identical to those in groups 4 and 5. Thus the long-term results of aneurysm treatment with GDC and Matrix coils show no differences regarding occlusion and recanalization rates. The only noticeable difference was the difference in handling. More force was required to pushing the Matrix coils forward through the microcatheter and there was more friction in coil interaction in the aneurysm. CONCLUSION: The bioactive coating of the Matrix coil produces no significant benefit in achieving higher occlusion and lower recanalization rates, and the coil is more difficult to handle. Future bioactive coils must be shown to produce significantly better long-term results than GDC and their ease of handling has to be improved.

[Morphology of the optic chiasm in albinism]. / Morphologie des Chiasma opticum bei Albinismus.

Albinism is associated with a misrouting of fibers at the optic chiasm where the majority of fibers cross to the contralateral side. The cause of this abnormal decussation pattern reflects a disturbance of cell cycle regulation in the development of the retina which is in part controlled by melanin. Growing axons from retinal ganglion cells therefore arrive later than usual at the optic chiasm and are misrouted contralaterally. This atypical decussation leads to morphological changes of the optic chiasm including a reduced chiasm width with larger angles between optic nerves and tracts which can be shown by magnetic resonance imaging.

Cognitive changes after carotid artery stenting.

INTRODUCTION: We aimed to test changes in cognitive performance after carotid artery stenting (CAS). METHOD: Ten patients were neuropsychologically tested at least 24 h before and 48 h after CAS. To diminish thromboembolic events, we used a proximal protection device. The following neuropsychological tests were selected: The Mini Mental State Examination (MMSE), symbol digit test and subtests of the Consortium to Establish a Registry for Alzheimer's Disease (CERAD) battery (verbal fluency, constructional practice, word list memory and delayed recall). Affective state was determined by the Beck Depression Score (BDS). RESULTS: No patient suffered from depression (BDS <1) or dementia (MMSE 29.9+/-1.5). Nine of the ten patients (P=0.12) showed increased speed in the Number Connection Test (NCT) (corresponding to trail making test). Most patients showed better or similar results concerning delayed recall (P=0.31). No change was observed in the symbol digit test, word list memory, verbal fluency or constructional practice. Better results concerning NCT and delayed recall after carotid stenting might be due to improved brain perfusion. CONCLUSION: After CAS, cognitive and memory performance seem to improve. Further studies with different time intervals and more refined testing, as well as perfusion-weighted imaging, are needed.

[Imaging cervical myelo- and radiculopathy]. / Stellenwert von Myelographie, Myelo-CT und MRT in der Diagnostik der zervikalen Radikulo- und Myelopathie.

PURPOSE: This article gives an overview of the diagnostic possibilities available in the diagnosis of cervical myelo- and radiculopathy. We compared conventional myelography, CTM, and MRI. MATERIAL AND METHODS: Twenty-five patients with clinical evidence of cervical myelo- or radiculopathy were included. Sagittal and transverse T1-weighted (T1w) TSE and T2-weighted (T2w) TSE sequences were compared with myelography and CTM. Statistical analysis was performed using Wilcoxon's -test. RESULTS: Disc herniation could be depicted in CTM as well as in MRI. The extent of herniation did not differ between CTM and T1w. The extent of herniation seemed higher on T2w than on T1w (p <0.001). Foraminal encroachment was easier to diagnose in CTM. When regarding transverse T1w and T2w images simultaneously, a missing root in MRI corresponded to a missing root in CTM and conventional myelography and vice versa. Our data demonstrated the relative inability of MRI to determine whether the compression is by soft tissue or bony structures. CONCLUSION: The present study proposes that MRI, when available, should be the imaging method of first choice in patients with suspected radiculo- and myelopathy.

Impact of different stimulation types on orthostatic tremor.

OBJECTIVE: Primary orthostatic tremor (OT) is thought to be generated by a unique supraspinal tremor generator. Here we studied the effect of ipsi- and contralateral stimulation of the central and peripheral nervous system on OT. METHODS: In 7 patients with primary OT, surface EMG was recorded from both tibialis anterior muscles. We performed transcranial magnetic stimulation (TMS) over the vertex, and lumbar magnetic stimulation (LMS) over the lumbar spine. Supramaximal electrical nerve stimuli were applied to the tibial or peroneal nerve at the knee. Proprioceptive input was evoked by rhythmical submaximal stimulation of the tibial, peroneal or sural nerve at the ankle. RESULTS: TMS reset OT significantly in the contralateral as well as the ipsilateral tibialis anterior muscle. The resetting in both muscles was identical. In contrast, peripheral input by means of LMS, supra- or submaximal nerve stimulation had no impact on OT. CONCLUSIONS: Transcranial magnetic stimulation of one cortical leg area resets OT in both legs whereas OT is not modified by any peripheral stimuli applied in this study. SIGNIFICANCE: Our results support the hypothesis of n unique supraspinal OT generator. This generator receives a modulating input from the motor cortex.