title: Inter-hemispheric language functional reorganization in low-grade glioma patients after tumour surgery.
abstract: Despite many claims of functional reorganization following tumour surgery, empirical studies that investigate changes in functional activation patterns are rare. This study investigates whether functional recovery following surgical treatment in patients with a low-grade glioma in the left hemisphere is linked to inter-hemispheric reorganization. Based on literature, we hypothesized that reorganization would induce changes in the spatial pattern of activation specifically in tumour homologue brain areas in the healthy right hemisphere. An experimental group (EG) of 14 patients with a glioma in the left hemisphere near language related brain areas, and a control group of 6 patients with a glioma in the right, non-language dominant hemisphere were scanned before and after resection. In addition, an age and gender matched second control group of 18 healthy volunteers was scanned twice. A verb generation task was used to map language related areas and a novel technique was used for data analysis. Contrary to our hypothesis, we found that functional recovery following surgery of low-grade gliomas cannot be linked to functional reorganization in language homologue brain areas in the healthy, right hemisphere. Although elevated changes in the activation pattern were found in patients after surgery, these were largest in brain areas in proximity to the surgical resection, and were very similar to the spatial pattern of the brain shift following surgery. This suggests that the apparent perilesional functional reorganization is mostly caused by the brain shift as a consequence of surgery. Perilesional functional reorganization can however not be excluded. The study suggests that language recovery after transient post-surgical language deficits involves recovery of functioning of the presurgical language system.
authors.affiliation: Department of Medical Psychology and Neuropsychology, University of Tilburg, Tilburg, The Netherlands; Department of Neurosurgery, St. Elisabeth Hospital, Tilburg, The Netherlands; Brain Center Rudolf Magnus, Department of Neurology and Neurosurgery, University Medical Center Utrecht, Utrecht, The Netherlands.
authors.forename: Gert
authors.initials: G
authors.lastname: Kristo
authors.affiliation: Brain Center Rudolf Magnus, Department of Neurology and Neurosurgery, University Medical Center Utrecht, Utrecht, The Netherlands.
authors.forename: Mathijs
authors.initials: M
authors.lastname: Raemaekers
authors.affiliation: Department of Neurosurgery, St. Elisabeth Hospital, Tilburg, The Netherlands.
authors.forename: Geert-Jan
authors.initials: GJ
authors.lastname: Rutten
authors.affiliation: Department of Medical Psychology and Neuropsychology, University of Tilburg, Tilburg, The Netherlands.
authors.forename: Beatrice
authors.initials: B
authors.lastname: de Gelder
authors.affiliation: Brain Center Rudolf Magnus, Department of Neurology and Neurosurgery, University Medical Center Utrecht, Utrecht, The Netherlands. Electronic address: n.f.ramsey@umcutrecht.nl.
authors.forename: Nick F
authors.initials: NF
authors.lastname: Ramsey
mesh_terms: D000328:Adult; D001921:Brain / Q000503:physiopathology* / Q000601:surgery; D001931:Brain Mapping; D001932:Brain Neoplasms / Q000503:physiopathology* / Q000601:surgery; D005260:Female; D005910:Glioma / Q000503:physiopathology* / Q000601:surgery; D006801:Humans; D007802:Language; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009473:Neuronal Plasticity / Q000502:physiology*
keywords: Functional reorganization; Language; Low-grade glioma; Surgery; Variability