The role of parietal areas in number processing is well known. The significance of intraoperative functional mapping of these areas has been only partially explored, however, and only a few discordant data are available in the surgical literature with regard to the right parietal lobe. The purpose of this study was to evaluate the clinical impact of simple calculation in cortical electrostimulation of right-handed patients affected by a right parietal brain tumor.
Calculation mapping in awake surgery was performed in 3 right-handed patients affected by high-grade gliomas located in the right parietal lobe. Preoperatively, none of the patients presented with calculation deficits. In all 3 cases, after sensorimotor and language mapping, cortical and intraparietal sulcus areas involved in single-digit multiplication and addition calculations were mapped using bipolar electrostimulation.
In all patients, different sites of the right parietal cortex, mainly in the inferior lobule, were detected as being specifically related to calculation (multiplication or addition). In 2 patients the intraparietal sulcus was functionally specific for multiplication. No functional sites for language were detected. All sites functional for calculation were spared during tumor resection, which was complete in all cases without postoperative neurological deficits.
These findings provide intraoperative data in support of an anatomofunctional organization for multiplication and addition within the right parietal area. Furthermore, the study shows the potential clinical relevance of intraoperative mapping of calculation in patients undergoing surgery in the right parietal area. Further and larger studies are needed to confirm these data and assess whether mapped areas are effectively essential for function.
Address correspondence to: Alessandro Della Puppa, M.D., Department of Neurosurgery, University Hospital of Padova, Via Giustiniani 2, Azienda Ospedaliera di Padova, Padova 35128, Italy. email: email@example.com.
Please include this information when citing this paper: published online August 9, 2013; DOI: 10.3171/2013.6.JNS122445.
DuffauHCapelleLSichezJFaillotTAbdennourLLaw KouneJD: Intra-operative direct electrical stimulations of the central nervous system: the Salpêtrière experience with 60 patients. Acta Neurochir (Wien)141:1157–11671999
DuffauHGatignolPMandonnetEPeruzziPTzourio-MazoyerNCapelleL: New insights into the anatomo-functional connectivity of the semantic system: a study using cortico-subcortical electrostimulations. Brain128:797–8102005
MaldonadoILMoritz-GasserSde ChampfleurNMBertramLMouliniéGDuffauH: Surgery for gliomas involving the left inferior parietal lobule: new insights into the functional anatomy provided by stimulation mapping in awake patients. Clinical article. J Neurosurg115:770–7792011
Metz-LutzMKreminHDelocheG: Standardisation d'un test de dénomination orale. Contrôle des effets de l'âge, du sexe et du niveau de scolarité chez les sujets adultes nor maux. Rev Neuropsychol (Marseille)1:73–951991