Between- and within-site variability of fMRI localizations.

This study provides first data about the spatial variability of fMRI sensorimotor localizations when investigating the same subjects at different fMRI sites. Results are comparable to a previous patient study. We found a median between-site variability of about 6 mm independent of task (motor or sensory) and experimental standardization (high or low). An intraclass correlation coefficient analysis using data quality measures indicated a major influence of the fMRI site on variability. In accordance with this, within-site localization variability was considerably lower (about 3 mm). We conclude that the fMRI site is a considerable confound for localization of brain activity. However, when performed by experienced clinical fMRI experts, brain pathology does not seem to have a relevant impact on the reliability of fMRI localizations. Hum Brain Mapp 37:2151-2160, 2016. © 2016 Wiley Periodicals, Inc.

Variability of clinical functional MR imaging results: a multicenter study.

PURPOSE: To investigate intersite variability of clinical functional magnetic resonance (MR) imaging, including influence of task standardization on variability and use of various parameters to inform the clinician whether the reliability of a given functional localization is high or low. MATERIALS AND METHODS: Local ethics committees approved the study; all participants gave written informed consent. Eight women and seven men (mean age, 40 years) were prospectively investigated at three experienced functional MR sites with 1.5- (two sites) or 3-T (one site) MR. Nonstandardized motor and highly standardized somatosensory versions of a frequently requested clinical task (localization of the primary sensorimotor cortex) were used. Perirolandic functional MR variability was assessed (peak activation variability, center of mass [COM] variability, intraclass correlation values, overlap ratio [OR], activation size ratio). Data quality measures for functional MR images included percentage signal change (PSC), contrast-to-noise ratio (CNR), and head motion parameters. Data were analyzed with analysis of variance and a correlation analysis. RESULTS: Localization of perirolandic functional MR activity differed by 8 mm (peak activity) and 6 mm (COM activity) among sites. Peak activation varied up to 16.5 mm (COM range, 0.4-16.5 mm) and 45.5 mm (peak activity range, 1.8-45.5 mm). Signal strength (PSC, CNR) was significantly lower for the somatosensory task (mean PSC, 1.0% ± 0.5 [standard deviation]; mean CNR, 1.2 ± 0.4) than for the motor task (mean PSC, 2.4% ± 0.8; mean CNR, 2.9 ± 0.9) (P < .001, both). Intersite variability was larger with low signal strength (negative correlations between signal strength and peak activation variability) even if the task was highly standardized (mean OR, 22.0% ± 18.9 [somatosensory task] and 50.1% ± 18.8 [motor task]). CONCLUSION: Clinical practice and clinical functional MR biomarker studies should consider that the center of task-specific brain activation may vary up to 16.5 mm, with the investigating site, and should maximize functional MR signal strength and evaluate reliability of local results with PSC and CNR.

Percutaneous vertebroplasty in vertebral compression fractures of benign or malignant origin: a prospective study of 1188 patients with follow-up of 12 months.

BACKGROUND: Vertebral body fractures are a source of high costs for the health care system and will continue to be one as the population ages. Cost-effective treatment is thus all the more important. In this study, we evaluated patients' quality of life during the first 12 months after they had undergone percutaneous vertebroplasty for vertebral body fractures which were refractory to conservative treatment. Our analysis took the causes of the fractures into account. METHODS: Pain, mobility, and need for analgesics were assessed prospectively on verbal rating scales one day before and one day after vertebroplasty, as well as over a follow-up period of up to 12 months. The same examiner interviewed each patient at all time points to obtain this information. RESULTS: 1188 patients underwent vertebroplasty for 1980 vertebral body fractures; the most common etiology was osteoporosis (75%). There was statistically relevant improvement in all three of the variables studied from the day before the procedure to the last follow-up, regardless of the cause of fracture (p<0.01). Most of the clinical benefit was already evident on the day after the procedure. Patients with fractures due to osteoporosis experienced further statistically relevant improvement by 6 months after treatment. CONCLUSION: Percutaneous vertebroplasty immediately relieves the pain of vertebral body fractures, improves patients' mobility, and lowers their consumption of analgesics. There can be further clinical improvement up to 6 months after the procedure, particularly in patients with fractures due to osteoporosis. As osteoporosis is the most common cause of vertebral body fractures, this patient group is important not just clinically, but economically as well.

Pathological crying induced by deep brain stimulation.

Pathological crying (PLC)--an affective gesture without any or an adequate emotion--occurs with various diseases. A recent theory suggests that PLC is caused by a disruption of higher order cortical association areas from the cerebellum which computes profiles of psychomotor responses. We report a patient with Parkinson's disease who developed PLC during stimulation of the subthalamic nucleus (STN) predominantly of the right hemisphere. Positron emission tomography imaging showed thalamo-ponto-cerebellar activation during such stimulation. These findings indicate that the STN and possibly also ponto-cerebellar pathways are involved in psychomotor control and in the modulation of PLC.

Functional modularity of the medial prefrontal cortex: involvement in human empathy.

To investigate medial frontal lobe mediation of human empathy, the authors analyzed the activation areas in statistical parametric maps of 80 studies reporting neural correlates of empathic processing. The meta-analysis revealed 6 spatially distinct activation clusters in the medial part of the frontal lobe dorsal to the intercommissural plane. The most dorsal cluster coincided with the left supplementary motor area (SMA). Rostrally adjacent was a cluster that overlapped with the right pre-SMA. In addition, there were 3 left-hemispheric and 1 right-hemispheric clusters located at the border between the superior frontal and anterior cingulate gyrus. A broad spectrum of cognitive functions were associated with these clusters, including attention to one's own action, which was related to activations in the SMA, and valuation of other people's behavior and ethical categories, which was related to activations in the most rostroventral cluster. These data complement the consistent observation that lesions of the medial prefrontal cortex interfere with a patient's perception of own bodily state, emotional judgments, and spontaneous behavior. The results of the current meta-analysis suggest the medial prefrontal cortex mediates human empathy by virtue of a number of distinctive processing nodes. In this way, the authors' findings suggest differentiated aspects of self-control of behavior.

Functional clusters in the human parietal cortex as revealed by an observer-independent meta-analysis of functional activation studies.

The human parietal cortex is a highly differentiated structure consisting of cytoarchitectonically defined subareas that are specifically connected with other cortical and subcortical areas. Based on evidence from neurophysiological studies in subhuman primates these subareas are supposed to be functionally highly specialized. Here, we reviewed 51 different neuroimaging studies on healthy subjects with activation of the parietal lobe in statistical parametric maps. Running a cluster analysis on the stereotactic coordinates of the centers of gravity of the activation areas and plotting them into Talairach space showed a high consistency of the mean activation foci for similar paradigms across different laboratories and functional imaging modalities. Our meta-analysis exposed seven distinct pairs of quite symmetrically distributed subareas of the parietal cortex of each hemisphere as well as three unpaired regions that are critically involved in the generation of limb and eye movements in egocentric and allocentric coordinates, but also in attention, memory and cognitive problem solving. These data highlights the modular organization of the human parietal lobe. By its locally interspersed distributed circuits it orchestrates specialized cognitive subfunctions interfacing perception and action. Our meta-analysis provides a new framework for understanding information processing in the human parietal cortex.

Gender-specific differences of hypometabolism in mTLE: implication for cognitive impairments.

PURPOSE: To determine gender differences of hypometabolism and their implications for cognitive impairment in patients with medically refractory mesial temporal lobe epilepsy (mTLE). METHODS: Regional cerebral glucose metabolism (rCMRGlu) was studied in 42 patients (21 male, 21 female) with either left- or right-sided mTLE (22 left, 20 right) and in 12 gender- and age-matched healthy controls during resting wakefulness and in 12 sex- and age-matched healthy controls. Clinical characteristics were balanced across the patient subgroups. All patients were subjected to neuropsychological assessment: 41 patients had histologic changes of definite or probable hippocampal sclerosis. RESULTS: Data analysis based on pixel-by-pixel comparisons and on a laterality index of regions of interest (ROIs) showed significant depressions of the mean rCMRGlu extending beyond the mesiotemporal region and temporolateral cortex to extratemporal regions including the frontoorbital and insular cortex in mTLE patients. Extramesiotemporal hypometabolism prevailed in the male patients. Metabolic asymmetry in temporal and frontal regions was related to performance in the Trail-Making Test and WAIS-R subitems. CONCLUSIONS: Our data showed a gender-specific predominance of extramesiotemporal hypometabolism in male patients with mTLE related to abnormalities of temporal and frontal lobe functions.