Performing real time neuropsychological testing during awake craniotomy: are dexmedetomidine or propofol the same? A preliminary report.

PURPOSE: In awake surgery, the patient is sedated, but is also required to be sufficiently alert and collaborative during extensive neurocognitive testing. In the present preliminary report of a retrospective single-center study, a continuous series of 168 patients who underwent awake surgery for brain tumor located near eloquent areas, was investigated to observe the effect of dexmedetomidine (n = 58) compared with propofol (n = 110) on vigilance and collaboration required to perform extensive intra-operatory Real Time Neuropsychological Testing (RTNT). METHODS: We assigned a score to each patient, by using a scale that combines vigilance and collaboration in a 5 levels score (the higher score denoting higher level). RESULTS: The median interquartile range was significantly lower (range 3-5) for the dexmedetomidine group compared to the propofol one (range 4-5, p = .044). Patients with intra-operative seizures (p = .014) and/or electrocorticographic slow/epileptiform activity (p = .042), and patients in the propofol group who showed increased heart rate (p = .032) were those who obtained the lower scores (lower vigilance and collaboration level). CONCLUSION: The study shows that the effect of dexmedetomidine or propofol -based conscious sedation on ability to perform Real Time Neuropsychological Testing during awake surgery for supratentorial tumor resection is different. Although both permit high mean levels of vigilance and collaboration, the patient who received dexmedetomidine was more likely to show lower vigilance and collaboration during RTNT.

Phonological and surface dyslexia in individuals with brain tumors: Performance pre-, intra-, immediately post-surgery and at follow-up.

We address existing controversies regarding neuroanatomical substrates of reading-aloud processes according to the dual-route processing models, in this particular instance in a series of 49 individuals with brain tumors who performed several reading tasks of real-time neuropsychological testing during surgery (low- to high-grade cerebral neoplasms involving the left hemisphere). We explored how reading abilities in individuals with brain tumors evolve during and after surgery for a brain tumor, and we studied the reading performance in a sample of 33 individuals in a 4-month follow-up after surgery. Impaired reading performance was seen pre-surgery in 7 individuals with brain tumors, intra-surgery in 18 individuals, at immediate post-surgery testing in 26 individuals, and at follow-up in 5 individuals. We classified their reading disorders according to operational criteria for either phonological or surface dyslexia. Neuroimaging results are discussed within the theoretical framework of the dual-route model of reading. Lesion-mask subtraction analyses revealed that areas selectively related with phonological dyslexia were located-along with the left hemisphere dorsal stream-in the Rolandic operculum, the inferior frontal gyrus, the precentral gyrus, the supramarginal gyrus, the insula (and/or the underlying external capsule), and parts of the superior longitudinal fasciculus, whereas lesions related to surface dyslexia involved the ventral stream, that is, the left middle and inferior temporal gyrus and parts of the left inferior longitudinal fasciculus.

Junior-Real Time neuropsychological testing (j-RTNT) for a young patient undergoing awake craniotomy.

We developed a junior-real-time neuropsychological testing (j-RTNT) and used it during surgery of a right fronto-insular dysembryoplastic neuroepithelial tumor causing seizures in a 16 years old female. The j-RTNT included tasks from the battery NEPSY-II. Pre-surgery evaluation detected a below average performance in visuo-spatial planning, inhibition, visual attention, planning and borderline performance in speeded naming. The j-RTNT allows detecting sudden decreases that could be caused by resection. During surgery, ECoG was characterized by slow sharp activity and spikes on the electrodes exploring the right fronto-polar region. After the resection, spikes were not detected anymore. Immediate post-surgery performance resulted within the normal range, remained below average in visuo-spatial planning, and improved in inhibition, switching and in speeded naming. Follow-up revealed cognitive recovery. Neurological assessment was unremarkable and the patient was seizure free. No epileptic activity could be observed on follow-up EEG. fMRI data showed that in the follow-up vs. pre-surgery there was a higher recruitment of the right superior frontal gyrus, a region involved in the cognitive execution and cognitive control networks. The j-RTNT is feasible with young patients, goes beyond the testing of limited functions, assessing multiple times during resection several different functions to better monitoring the effects of resection.

Brain mapping: a novel intraoperative neuropsychological approach.

OBJECTIVE Awake surgery and mapping are performed in patients with low-grade tumors infiltrating functional brain areas for which the greater the resection, the longer the patient survival. However, the extent of resection is subject to preservation of cognitive functions, and in the absence of proper feedback during mapping, the surgeon may be less prone to perform an extensive resection. The object of this study was to perform real-time continuous assessment of cognitive function during the resection of tumor tissue that could infiltrate eloquent tissue. METHODS The authors evaluated the use of new, complex real-time neuropsychological testing (RTNT) in a series of 92 patients. They reported normal scoring and decrements in patient performance as well as reversible intraoperative neuropsychological dysfunctions in tasks (for example, naming) associated with different cognitive abilities. RESULTS RTNT allowed one to obtain a more defined neuropsychological picture of the impact of surgery. The influence of this monitoring on surgical strategy was expressed as the mean extent of resection: 95% (range 73%-100%). At 1 week postsurgery, the neuropsychological scores were very similar to those detected with RTNT, revealing the validity of the RTNT technique as a predictive tool. At the follow-up, the majority of neuropsychological scores were still > 70%, indicating a decrease of < 30%. CONCLUSIONS RTNT enables continuous enriched intraoperative feedback, allowing the surgeon to increase the extent of resection. In sharp contrast to classic mapping techniques, RTNT allows testing of several cognitive functions for one brain area under surgery.