1348 Neurosurgical forum Letters to the editor J Neurosurg / Volume 119 / November 2013 Cognitive assessment in glioma patients T o The ediTor: I read with great interest the article by Wu et al. 19 (Wu AS, Witgert ME, Lang FF, et al: Neu- rocognitive function before and after surgery for insular gliomas. Clinical article. J Neurosurg 115: 1115–1125, De- cember 2011), in which the authors demonstrated the exis- tence of common neurocognitive impairment in insular as well as noninsular gliomas, nonetheless with few statisti- cally signifcant differences in both groups at either the pre- or postoperative evaluation. Interestingly, recent advances in neuroimaging have allowed earlier diagnosis of gliomas, in patients with few symptoms (seizures) or even in asymptomatic patients (incidental discovery), especially diffuse low-grade glio- mas (LGGs). 12 As a consequence, as stated by Wu et al., a standard neurological examination is not accurate enough to objectively assess these patients. Thus, an extensive neuropsychological examination should be performed in a more systematic way. Indeed, in patients with LGGs, it was shown that more than 90% experienced at least some neurocognitive defcits ( for example, working memory disorders) prior to any treatment, whatever the location of the glioma (insular or noninsular). 15 In addition, a post- operative neuropsychological assessment is also crucial to better evaluate the possible impact of glioma resection on high-order functions. Therefore, the authors have to be congratulated for their original data, in particular regard- ing insular gliomas. However, such extensive cognitive examination should be more actively used to modulate therapeutic management. First of all, on the basis of the presurgical assessment, in- traoperative tasks must be adapted to optimize the reli- ability of functional mapping in awake patients through- out the resection. 3 For example, Wu et al. observed greater postoperative decline in the domains of visuoconstruction in patients with right-sided insular tumors. It is worth not- ing that awake surgery with mapping of spatial awareness (for example, line bisection task) can be achieved in right gliomas to avoid visuospatial impairments, such as hemi- neglect. 16 Awake surgery with language mapping may also be chosen for right-handed patients with right-hemisphere tumors when the presurgical assessment evidences even slight language disorders, showing the participation of the “right nondominant” hemisphere in this function. 17 In ad- dition, preoperative neuropsychological scores should be considered as refecting only a part of the real quality of life, which must be redefned for each patient according to his or her job, habits, hobbies, and projects. 2 Therefore, it can be important to map different languages as well as language switching in multilingual patients, 10 or to map calculation in a school teacher, 6 cross-modal judgment in a manager, 13 syntax in a writer, 18 and so forth. In the postoperative period, the immediate postsurgi- cal cognitive assessment can also be useful to build a spe- cifc rehabilitation program. In their report, Wu et al. did not discuss cognitive rehabilitation; a recent prospective randomized trial demonstrated the signifcant role of such rehabilitation in brain tumor patients. 8 In a surgical series of left insular LGG cases, patients benefted from specifc rehabilitation at home following resection, on the basis of postoperative cognitive examination that showed working memory defcit despite the lack of language impairment. 7 Interestingly, such neuropsychological scores after sur- gery, especially assessments of lexical access speed, may represent a good predictive factor of the long-term quality of life, in particular concerning return to work. 11 Mecha- nisms of brain plasticity underlying functional compensa- tion are likely elicited by LGG growth itself as well as by adapted rehabilitation. 4 Finally, long-term follow-up is essential (although not detailed by Wu et al.), particularly for LGG patients, with a long median survival. To this end, with the aim of better evaluating the beneft-risk ratio of a therapeutic strategy, it was recently proposed to calculate simultaneously (and not separately) both the functional and oncological gain of a treatment, by plotting time with quality of life (in- cluding objective neurocognitive assessment) versus time to malignant transformation in LGG. 9 This can be helpful in comparing subgroups of patients, such as those with insular gliomas versus those with noninsular gliomas. In- deed, as supported by the results reported by Wu et al., the same surgical treatment must be considered regard- less of whether the tumor is located within the insula or elsewhere in the brain—in agreement with the recent sur- gical series for insular gliomas that showed a low risk as- sociated with surgery and a signifcant impact on epilepsy control as well as an increase of median survival. 5,14 On the other hand, because the resection cannot be complete in all insular cases, combined therapeutic strategies might be considered, for instance by performing (neo)adjuvant chemotherapy. Of note, a recent study has evaluated both quality of life and neurocognition in patients who were treated with a combination of chemotherapy and surgical resection(s) for an LGG, showing an excellent tolerance of combined therapies. 1 In summary, longitudinal neurocognitive assess- ments—before and after each treatment—should be more widely performed in patients with gliomas, especially LGG, in a more active way, in order to 1) select the best surgical tasks during intraoperative mapping at the indi- vidual scale, 2) develop a specifc postoperative rehabili- tation, and 3) help in the determination of the best person- alized therapeutic strategy over years. hugues duffau, M.d., Ph.d. Gui de Chauliac Hospital Montpellier University Medical Center Institute for Neuroscience of Montpellier Hôpital Saint Eloi Montpellier, France