Presurgical Language fMRI and Postsurgical Deficits: A Single Centre Experience

Abstract

The determination of hemisphere dominance for language processing (i.e., language lateralization) is an important consideration for successful surgical planning of epilepsy and brain tumour patients, when the tissue to be resected is in close proximity to language-related areas of the brain. Knowledge of language lateralization aids in the prognosis of language impairment and new memory deficits following surgery, as well as the risk associated with delaying surgery 1 . Traditionally, lateralization of language function has been determined using the intracarotid sodium amobarbital procedure, or Wada test 2 , which involves an intracarotid injection of a barbiturate into one brain hemisphere followed by a neuropsychological examination of the other hemisphere's language function. However, there are ABSTRACT: Background: In this study, we conducted a retrospective investigation of our initial single-centre experience with the clinical use of functional magnetic resonance imaging (fMRI) of hemisphere dominance for language processing (i.e., language lateralization). We demonstrated its association with surgical outcome and its potential impact on surgical planning and patient management. Methods: Fifty-two cases were reviewed, covering the period from July 2007 to July 2010. Clinical fMRI reports were examined to determine the hemisphere dominance for language processing. Neurological reports were examined to determine if new language deficits were present post-surgery. Neurosurgeon notes were also reviewed to determine if fMRI had an impact on surgical planning. Results: Of the cases reviewed, 49 (94%) generated conclusive fMRI. Eleven (22%) patients exhibited fMRI language lateralization contralateral to pathology; zero of nine of these patients that had surgery experienced post-surgical deficits. Twenty-two (44%) patients exhibited fMRI language lateralization ipsilateral to pathology; three of 13 of these patients that had surgery experienced post-surgical deficits. Sixteen (34%) patients exhibited bilateral lateralization of language; five of 13 of these patients that had surgery experienced post-surgery deficits. Several post-fMRI reports indicated that fMRI results had an impact on surgical planning. Conclusions: Our results suggest that fMRI demonstrations of language processing within the hemisphere ipsilateral to pathology (either ipsilateral alone or bilateral) is associated with a greater risk for post-surgical language deficits, and in these cases, fMRI results should be taken into consideration for pre-surgical planning. Les rapports neurologiques ont été examinés pour déterminer s'il existait de nouveaux déficits langagiers après la chirurgie. Nous avons également examiné les notes du neurochirurgien pour déterminer si l'IRMf avait eu un impact sur la planification de la chirurgie. Résultats : Parmi les dossiers examinés, 49 (94%) contenaient un examen IRMf concluant. Onze patients (22%) avaient une latéralisation du langage contralatérale à la pathologie et aucun parmi neuf de ces patients qui ont s...