We describe how a neuropsychological evaluation in patients with brain tumors should be performed, specifically in the case of low-grade gliomas. Neuropsychological examination is crucial before starting any treatment as well as during the follow-up, since it can improve neurosurgery techniques and reveal potential cognitive effects of chemotherapy and radiotherapy, besides planning rehabilitation. We underline that sensitive and wide-ranging tests are required; specific tasks based on the lesion site should be added. Moreover, some tests can provide additional information about the evolution of the tumor. A careful, thorough examination improves quality of life.
The cortical and subcortical neural correlates underlying item and order information in verbal short-term memory (STM) were investigated by means of digit span in 29 patients with direct electrical stimulation during awake surgery for removal of a neoplastic lesion. Stimulation of left Broca's area interfered with span, producing significantly more item than order errors, as compared to the stimulation of the supramarginal/angular gyrus, which also interfered with span but, conversely, produced more order than item errors. Similarly, stimulation of the third segment of the left superior longitudinal fasciculus (SLF-III), also known as anterior segment of the arcuate fascicle (AF), produced more order than item errors. Therefore, we obtained two crucial results: first, we were able to distinguish between content and order information storage. Second, we demonstrated that the SLF-III is involved in transferring order information from Geschwind's area to Broca's area. In a few patients, we demonstrated that also order information of nonverbal material was disrupted by left supramarginal gyrus stimulation. Order information is thus likely stored in the supramarginal gyrus, possibly independently from the nature of the material. Hum Brain Mapp 38:3011-3024, 2017. © 2017 Wiley Periodicals, Inc.
Emotion processing impairments are common in patients undergoing brain surgery for fronto-temporal tumour resection, with potential consequences on social interactions. However, evidence is controversial concerning side and site of lesions causing such deficits. This study investigates visual and auditory emotion recognition in brain tumour patients with the aim of clarifying which lesion sites are related to impairments in emotion processing from different modalities. Thirty-four patients were evaluated, before and after surgery, on facial expression and emotional prosody recognition; voxel-based lesion-symptom mapping (VLSM) analyses were performed on patients' post-surgery MRI images. Results showed that patients' performance decreased after surgery in both visual and auditory modalities, but, in general, recovered 3 months after surgery. In facial expression recognition, left brain-damaged patients showed greater post-surgery deterioration than right brain-damaged ones, whose performance specifically decreased for sadness and fear. VLSM analysis revealed two segregated areas in the left hemisphere accounting for post-surgery scores for happy (fronto-temporo-insular region) and surprised (middle frontal gyrus and inferior fronto-occipital fasciculus) facial expressions. Our findings demonstrate that surgical removal of tumours in the fronto-temporal region produces impairment in facial emotion recognition with an overall recovery at 3 months, suggesting a partially different representation of positive and negative emotions in the left and right hemispheres for visually - but not auditory - presented emotions; moreover, we show that deficits in specific expression recognition are associated with discrete lesion locations.
The functional organization of left and right hemispheres is different, and hemispheric asymmetries are thought to underlie variations in brain function across individuals. In this study, we assess how differences between hemispheres are reflected in Asymmetric Functional Connectivity (AFC), which provides a full description of how the brain's connectivity structure during resting state differs from that of the same brain mirrored over the longitudinal fissure. In addition, we assess how AFC varies across subjects. Data were provided by the Human Connectome Project, including 423 resting state and combined language task fMRI data sets, and the pattern of AFC was established for all subjects. While we could quantify the symmetry of brain connectivity at 95%, significant asymmetries were observed, consisting foremost of: (1) higher correlations between language areas in the left hemisphere than between their right hemisphere homologues. (2) Higher correlations between language homologue areas in the right hemisphere and left default mode network, than between language areas in the left hemisphere and the default mode network in the right hemisphere. The extent to which subjects exhibited this pattern correlated with language lateralization and handedness. Further exploration in intersubject variation in AFC revealed several additional patterns, one involving entire hemispheres, and another correlations with limbic areas. These results show that language is an important, but not only determinant of AFC. The additional patterns of AFC require further research to be linked to specific asymmetric neuronal states or events.
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