Improvement in cognitive function after surgery for low-grade glioma

Perioperative Neurocognitive Function in Glioma Surgery

PURPOSE OF REVIEW

This review provides a concise overview of the recent literature regarding preoperative and postoperative neurocognitive functioning (NCF) in patients with glioma. Brief discussion also covers contemporary intraoperative brain mapping work, with a focus on potential influence of mapping upon NCF outcomes following awake surgery.

RECENT FINDINGS

Most patients with glioma exhibit preoperative NCF impairment, with severity varying by germ line and tumoral genetics, tumor grade, and lesion location, among other characteristics. Literature regarding postoperative NCF changes is mixed, though numerous studies indicate a majority of patients exhibit immediate and short-term worsening. This is often followed by recovery over several months; however, a substantial portion of patients harbor persisting declines. Decline appears related to surgically-induced structural and functional brain alterations, both local and distal to the tumor and resection cavity. Importantly, NCF decline may be mitigated to some extent by intraoperative brain mapping, including mapping of both language-mediated and nonverbal functions. Research regarding perioperative NCF in patients with glioma has flourished over recent years. While this has increased our understanding of contributors to NCF and risk of decline associated with surgical intervention, more work is needed to better preserve NCF throughout the disease course.

Incidence, risk factors, and clinical implications of postoperative blood in or near the resection cavity after glioma surgery

Introduction

Postoperative hematomas that require reoperation are a serious, but uncommon complication to glioma surgery. However, smaller blood volumes are frequently observed, but their clinical significance is less known.

Research question

What are the incidence rates, risk factors, and patient-reported outcomes of all measurable blood in or near the resection cavity on postoperative MRI in diffuse glioma patients?

Material and methods

We manually segmented intradural and extradural blood from early postoperative MRI of 292 diffuse glioma resections. Potential associations between blood volume and tumor characteristics, demographics, and perioperative factors were explored using non-parametric methods. The assessed outcomes were generic and disease-specific patient-reported HRQoL.

Results

Out of the 292 MRI scans included, 184 (63%) had intradural blood, and 212 (73%) had extradural blood in or near the resection cavity. The median blood volumes were 0.4 mL and 3.0 mL, respectively. Intradural blood volume was associated with tumor volume, intraoperative blood loss, and EOR. Extradural blood volume was associated with age and tumor volume. Greater intradural blood volume was associated with less headache and cognitive improvement, but not after adjustments for tumor volume.

Discussion and conclusions

Postoperative blood on early postoperative MRI is common. Intradural blood volumes tend to be larger in patients with larger tumors, more intraoperative blood loss, or undergoing subtotal resections. Extradural blood volumes tend to be larger in younger patients with larger tumors. Postoperative blood in or near the resection cavity that does not require reoperation does not seem to affect HRQoL in diffuse glioma patients.

Neuropsychological longitudinal study of patients with low-grade gliomas: Cognitive impairment

This study is part of a longitudinal research program, in which patients diagnosed with low-grade gliomas (LGG: n = 13), as well as healthy controls (n = 13), were consecutively recruited and neuropsychologically followed for 7 years. The patients are followed up regardless of variations in treatment. A composite score is used (Global Deficit Score: GDS) included cognitive measures where at least five patients had a negative change: information processing speed, speed of naming, construction ability, verbal fluency, non-verbal thinking, and immediate non-verbal memory. The most important finding in this 7-year follow-up study is that two-thirds of the patients developed cognitive impairment. The remaining third of the patients showed stability in their cognitive ability and were still alive 17 years after diagnosis. Younger patients with tumors in the right frontal or posterior regions showed a more favorable development. Patients with frontal tumors and a declined GDS show also significant changes in executive functions. Given the limited number, no firm conclusions can be drawn regarding the impact of tumor localization. The impact of LGG on cognition and the survival time after diagnosis varies considerably between patients. However, most of the patients (69%) showed cognitive impairment during the seven years we followed them.

Cognition, Emotional States and Health-Related Quality of Life in Awake Craniotomy for Glioma: A Case Series

BACKGROUND

Awake craniotomy is an effective procedure for optimizing the onco-functional balance of resections in glioma. However, limited data exists on the cognition, emotional states, and health-related quality of life (HRQoL) of patients with glioma who undergo awake craniotomy. This study aims to describe 1) perioperative cognitive function and emotional states in a multilingual Asian population, 2) associations between perioperative cognitive function and follow-up HRQoL, and 3) associations between preoperative emotional states and follow-up HRQoL.

METHODS

This is a case series of 14 adult glioma patients who underwent awake craniotomy in Singapore. Cognition was assessed with the Montreal Cognitive Assessment and the Repeatable Battery for the Assessment of Neuropsychological Status, emotional states with the Depression, Anxiety and Stress Scale-21 Items, and HRQoL using the EuroQol-5D-5L, the European Organisation for Research and Treatment of Cancer (EORTC) QLQ-C30, and the European Organisation for Research and Treatment of Cancer (EORTC) QLQ-BN20.

RESULTS

Patients with better preoperative cognitive scores on all domains reported better HRQoL. Better postoperative immediate memory and language scores were associated with better HRQoL. Moderate preoperative depression scores and mild and moderate preoperative stress scores were associated with poorer HRQoL compared to scores within the normal range. Mild preoperative anxiety scores were associated with better HRQoL compared to scores within the normal range.

CONCLUSION

This descriptive case series showed that patients with higher preoperative cognitive scores reported better follow-up HRQoL, while patients who reported more preoperative depressive and stress symptomatology reported worse follow-up HRQoL. Future analytical studies may help to draw conclusions about whether perioperative cognition and emotional states predict HRQoL on follow-up.

Neurorehabilitation in brain tumours: evidences and suggestions for spreading of knowledge and research implementation

PURPOSE OF REVIEW

The last few decades have seen an increase in life expectancy in brain tumour patients; however, many patients report sensory-motor and cognitive disabilities due to the tumour itself, but also to the effect of anticancer treatments (surgery, radiotherapy, chemotherapy), supportive treatments, as well as individual patient factors. This review outlines the principles on which to base neurorehabilitation treatments, with the aim of stimulating an early rehabilitative management, in order to reduce disability and functional limitation and improve the quality of life of the persons affected by brain tumour.

RECENT FINDINGS

Although not definitive, evidences suggest that an early neurorehabilitative evaluation, performed with a multidisciplinary approach, may identify the different functional impairments that can affect people with brain tumour. Furthermore, identifying and classifying the person's level of functioning is useful for designing achievable recovery goals, through the implementation of tailored multidisciplinary rehabilitation programs. The involvement of different professional figures allows to treat all the components (physical, cognitive, psychological and participation) of the person, and to redesign one's life project, lastly improving the quality of life.

SUMMARY

Overall, the evidences suggest a critical need for the development of this clinical area by spreading the concept of rehabilitation among neuro-oncologists and producing high quality research.

Graph Theory Measures and Their Application to Neurosurgical Eloquence

Improving patient safety and preserving eloquent brain are crucial in neurosurgery. Since there is significant clinical variability in post-operative lesions suffered by patients who undergo surgery in the same areas deemed compensable, there is an unknown degree of inter-individual variability in brain 'eloquence'. Advances in connectomic mapping efforts through diffusion tractography allow for utilization of non-invasive imaging and statistical modeling to graphically represent the brain. Extending the definition of brain eloquence to graph theory measures of hubness and centrality may help to improve our understanding of individual variability in brain eloquence and lesion responses. While functional deficits cannot be immediately determined intra-operatively, there has been potential shown by emerging technologies in mapping of hub nodes as an add-on to existing surgical navigation modalities to improve individual surgical outcomes. This review aims to outline and review current research surrounding novel graph theoretical concepts of hubness, centrality, and eloquence and specifically its relevance to brain mapping for pre-operative planning and intra-operative navigation in neurosurgery.

Influences on cognitive outcomes in adult patients with gliomas: A systematic review

People with brain tumors, including those previously treated, are commonly affected by a range of neurocognitive impairments involving executive function, memory, attention, and social/emotional functioning. Several factors are postulated to underlie this relationship, but evidence relating to many of these factors is conflicting and does not fully explain the variation in cognitive outcomes seen in the literature and in clinical practice. To address this, we performed a systematic literature review to identify and describe the range of factors that can influence cognitive outcomes in adult patients with gliomas. A literature search was performed of Ovid MEDLINE, PsychINFO, and PsycTESTS from commencement until September 2021. Of 9,998 articles identified through the search strategy, and an additional 39 articles identified through other sources, 142 were included in our review. The results confirmed that multiple factors influence cognitive outcomes in patients with gliomas. The effects of tumor characteristics (including location) and treatments administered are some of the most studied variables but the evidence for these is conflicting, which may be the result of methodological and study population differences. Tumor location and laterality overall appear to influence cognitive outcomes, and detection of such an effect is contingent upon administration of appropriate cognitive tests. Surgery appears to have an overall initial deleterious effect on cognition with a recovery in most cases over several months. A large body of evidence supports the adverse effects of radiotherapy on cognition, but the role of chemotherapy is less clear. To contrast, baseline cognitive status appears to be a consistent factor that influences cognitive outcomes, with worse baseline cognition at diagnosis/pre-treatment correlated with worse long-term outcomes. Similarly, much evidence indicates that anti-epileptic drugs have a negative effect on cognition and genetics also appear to have a role. Evidence regarding the effect of age on cognitive outcomes in glioma patients is conflicting, and there is insufficient evidence for gender and fatigue. Cognitive reserve, brain reserve, socioeconomic status, and several other variables discussed in this review, and their influence on cognition and recovery, have not been well-studied in the context of gliomas and are areas for focus in future research.

Systematic Review Registration

https://www.crd.york.ac.uk/prospero/, identifier CRD42017072976.

Recurrent Low-Grade Gliomas: Does Reoperation Affect Neurocognitive Functioning?

BACKGROUND

Reoperations in patients with recurrent low-grade gliomas (RLGG) were proposed to control tumor residual and delay the risk of malignant transformation over time.

OBJECTIVE

To investigate neurocognitive outcomes in patients with RLGG who underwent a second surgery with awake monitoring.

METHODS

In this retrospective study, patients who underwent a second awake surgery for RLGG were included. Patients had presurgical and 3-mo postsurgical neuropsychological assessments. Data were converted into Z-scores and combined by the cognitive domain. Number of patients with cognitive deficits (Z-score <-1.65), variations of Z-scores, and extent of resection (EOR) were analyzed.

RESULTS

Sixty-two patients were included (mean age: 41.2 ± 10.0 yr). None had permanent neurological deficits postoperatively. Eight patients (12.9%) had a cognitive deficit preoperatively. Four additional patients (6.5%) had a cognitive deficit 3 mo after reoperation. Among other patients, 13 (21.0%) had a mild decline without cognitive deficits while 29 (46.8%) had no change of their performances and 8 (12.9%) improved. Overall, 94.2% of the patients returned to work. There were no correlations between EOR and Z-scores. Total/subtotal resections were achieved in 91.9% of the patients (mean residual: 3.1 cm3). Fifty-eight patients (93.5%) were still alive after an overall follow-up of 8.3 yr.

CONCLUSION

Reoperation with awake monitoring in patients with RLGG was compatible with an early recovery of neuropsychological abilities. Four patients (6.5%) presented a new cognitive deficit at 3 mo postoperatively. Total/subtotal resections were achieved in most patients. Based on these favorable outcomes, reoperation should be considered in a more systematic way.

T2 FLAIR Hyperintensity Volume Is Associated With Cognitive Function and Quality of Life in Clinically Stable Patients With Lower Grade Gliomas

Survival outcomes for patients with lower grade gliomas (LrGG) continue to improve. However, damage caused both by tumor growth and by the consequences of treatment often leads to significantly impaired cognitive function and quality of life (QoL). While neuropsychological testing is not routine, serial clinical MRIs are standard of care for patients with LrGG. Thus, having a greater understanding of MRI indicators of cognitive and QoL impairment risk could be beneficial to patients and clinicians. In this work we sought to test the hypothesis that in clinically stable LrGG patients, T2 FLAIR hyperintensity volumes at the time of cognitive assessment are associated with impairments of cognitive function and QoL and could be used to help identify patients for cognitive and QoL assessments and interventions. We performed anatomical MR imaging, cognitive testing and QoL assessments cross-sectionally in 30 clinically stable grade 2 and 3 glioma patients with subjective cognitive concerns who were 6 or more months post-treatment. Larger post-surgical T2 FLAIR volume at testing was significantly associated with lower cognitive performance, while pre-surgical tumor volume was not. Older patients had lower cognitive performance than younger patients, even after accounting for normal age-related declines in performance. Patients with Astrocytoma, IDH mutant LrGGs were more likely to show lower cognitive performance than patients with Oligodendroglioma, IDH mutant 1p19q co-deleted LrGGs. Previous treatment with combined radiation and chemotherapy was associated with poorer self-reported QoL, including self-reported cognitive function. This study demonstrates the importance of appreciating that LrGG patients may experience impairments in cognitive function and QoL over their disease course, including during periods of otherwise sustained clinical stability. Imaging factors can be helpful in identifying vulnerable patients who would benefit from cognitive assessment and rehabilitation.

Postacute Cognitive Rehabilitation for Adult Brain Tumor Patients

Intrinsic brain tumors often occur within functional neural networks, leading to neurological impairment and disability of varying degrees. Advances in our understanding of tumor-network integration, human cognition and language processing, and multiparametric imaging, combined with refined intraoperative tumor resection techniques, have enhanced surgical management of intrinsic brain tumors within eloquent areas. However, cognitive symptoms impacting health-related quality of life, particularly processing speed, attention, concentration, working memory, and executive function, often persist after the postoperative recovery period and treatment. Multidisciplinary cognitive rehabilitation is the standard of care for addressing cognitive impairments in many neurological diseases. There is promising research to support the use of cognitive rehabilitation in adult brain tumor patients. In this review, we summarize the history and usefulness of postacute cognitive rehabilitation for adult brain tumor patients.

Neuropsychological assessments before and after awake surgery for incidental low-grade gliomas

OBJECTIVE

Early surgery in presumed asymptomatic patients with incidental low-grade glioma (ILGG) has been suggested to improve maximal resection rates and overall survival. However, no study has reported on the impact of such preventive treatment on cognitive functioning. The aim of this study was to investigate neuropsychological outcomes in patients with ILGG who underwent preventive surgery.

METHODS

This was a retrospective analysis of a consecutive series of patients with ILGG who underwent awake surgery and who had presurgical and 3-month postsurgical neuropsychological assessments. Data were normalized into z-scores and regrouped by cognitive domains. Clinicoradiological data, histomolecular profile, and differences in z-scores (Δz-scores) were analyzed.

RESULTS

Forty-seven patients were included (mean age 39.2 ± 11.3 years). Twenty-eight patients (59.6%) underwent supratotal or total resections. All patients were still alive after a mean follow-up of 33.0 ± 30.8 months. Forty-one patients (87.2%) had stable (n = 34, 72.3%) or improved (Δz-score > 1; n = 7, 14.9%) neurocognitive outcomes after surgery. Six patients (12.8%) presented a slight impairment (Δz-score < -1) in at least one cognitive domain. The mean presurgical and postsurgical z-scores were comparable except in the psychomotor speed and attention domain. A significant correlation between presurgical executive functioning and tumor volume was reported, whereas the extent of resection and histomolecular profile did not impact neuropsychological outcomes.

CONCLUSIONS

Early surgical treatment in presumed asymptomatic patients with ILGG was associated with stable or improved neuropsychological outcomes in 87.2% of patients at 3 months, with only mild cognitive decline observed in 6 patients. In return, supratotal or total resections were achieved in most patients, and all patients were still alive at the end of the follow-up.

Characterization of cognitive function in survivors of diffuse gliomas using resting-state functional MRI (rs-fMRI)

As treatments for diffuse gliomas have advanced, survival for patients with gliomas has also increased. However, there remains limited knowledge on the relationships between brain connectivity and the lasting changes to cognitive function that glioma survivors often experience long after completing treatment. This resting-state functional magnetic resonance imaging (rs-fMRI) study explored functional connectivity (FC) alterations associated with cognitive function in survivors of gliomas. In this pilot study, 22 patients (mean age 43.8 ± 11.9) with diffuse gliomas who completed treatment within the past 10 years were evaluated using rs-fMRI and neuropsychological measures. Novel rs-fMRI analysis methods were used to account for missing brain in the resection cavity. FC relationships were assessed between cognitively impaired and non-impaired glioma patients, along with self-reported cognitive impairment, non-work daily functioning, and time with surgery. In the cognitively non-impaired patients, FC was stronger in the medial prefrontal cortex, rostral prefrontal cortex, and intraparietal sulcus compared to the impaired survivors. When examining non-work daily functioning, a positive correlation with FC was observed between the accumbens and the intracalcarine cortices, while a negative correlation with FC was observed between the parietal operculum cortex and the cerebellum. Additionally, worse self-reported cognitive impairment and worse non-work daily functioning were associated with increased FC between regions involved in cognition and sensorimotor processing. These preliminary findings suggest that neural correlates for cognitive and daily functioning in glioma patients can be revealed using rs-fMRI. Resting-state network alterations may serve as a biomarker for patients’ cognition and functioning.

Assessment of neurocognitive function in association with WHO grades in gliomas

OBJECTIVE

High-grade gliomas are fast-growing and may exhibit more severe neurocognitive function (NCF) decline compared with low-grade gliomas. A comprehensive understanding of the NCF in patients with glioma may be critical for developing effective glioma treatments and rehabilitation interventions. This study evaluated NCF more comprehensively in patients with glioma using the Wechsler Adult Intelligence Scale-Third Edition (WAIS-III) and the Wechsler Memory Scale-Revised (WMS-R), and also determined the differences in NCF in relation with the WHO grades of gliomas.

METHODS

Thirty-five patients with newly diagnosed glioma were reviewed in the present study. The patients were divided into three groups, Grade II, III, and IV, based on the World Health Organization's classification of tumors of the central nervous system. NCF was assessed using the WAIS-III and WMS-R.

RESULTS

There were 14 (40.0%), 7 (20.0%), and 14 (40.0%) patients in the grade II, grade III, and grade IV groups, respectively. The results of the Kruskal-Wallis test showed significant differences in all the scores of the WAIS-III and WMS-R between grade II and grade IV. The scores of the WAIS-III and WMS-R in grade IV patients were borderline for NCF disorders, except in the attention/concentration domain. On the other hand, grade II and III groups had normal scores.

CONCLUSION

Therefore, patients with a grade IV glioma presented NCF decline compared to grade II and III glioma. In contrast, the results of the WAIS-III and WMS-R indicated that the NCF of patients with grades II and III glioma was intact.

Cognitive impact of lower-grade gliomas and strategies for rehabilitation

Outcomes for patients with lower-grade gliomas (LrGGs) continue to improve with advances in molecular characterization and treatment. However, cognitive sequela from the tumor and its treatment leave a significant impact on health-related quality of life for these patients. Several factors affect each patient's cognition, such as tumor location, treatment, medication, and comorbidities. However, impairments of processing speed, attention, concentration, working memory, and executive function are common across LrGG patients. Cognitive rehabilitation strategies, well established in traumatic brain injury and stroke populations, are based on neural plasticity and functional reorganization. Adapting these strategies for implementation in patients with brain tumors is an active area of research. This article provides an overview of cognitive domains commonly impaired in LrGG patients and evidence for the use of cognitive rehabilitation strategies to address these impairments with the goal of improving health-related quality of life in this patient population.

Brain connectomics applied to oncological neuroscience: from a traditional surgical strategy focusing on glioma topography to a meta-network approach

The classical way for surgical selection and planning in cerebral glioma mainly focused on tumor topography. The emerging science of connectomics, which aims of mapping brain connectivity, resulted in a paradigmatic shift from a modular account of cerebral organization to a meta-network perspective. Adaptive behavior is actually mediated by constant changes in interactions within and across large-scale delocalized neural systems underlying conation, cognition, and emotion. Here, to optimize the onco-functional balance of glioma surgery, the purpose is to switch toward a connectome-based resection taking account of both relationships between the tumor and critical distributed circuits (especially subcortical pathways) as well as the perpetual instability of the meta-network. Such dynamic in the neural spatiotemporal integration permits functional reallocation leading to neurological recovery after massive resection in structures traditionally thought as "inoperable." This better understanding of connectome increases benefit/risk ratio of surgery (i) by selecting resection in areas deemed "eloquent" according to a localizationist dogma; (ii), conversely, by refining intraoperative awake cognitive mapping and monitoring in so-called non-eloquent areas; (iii) by improving preoperative information, enabling an optimal selection of intrasurgical tasks tailored to the patient's wishes; (iv) by developing an "oncological disconnection surgery"; (v) by defining a personalized multistep surgical strategy adapted to individual brain reshaping potential; and (vi) ultimately by preserving environmentally and socially appropriate behavior, including return to work, while increasing the extent of (possibly repeated) resection(s). Such a holistic vision of neural processing can enhance reliability of connectomal surgery in oncological neuroscience and may also be applied to restorative neurosurgery.

Neuropsychological outcomes following supratotal resection for high-grade glioma: a review

PURPOSE

Supratotal resection (SpTR) of high-grade glioma (HGG), in which surgical removal of the tumor is extended outside the margins of the preoperative radiographic abnormality, has been suggested to improve overall survival (OS) and progression free survival (PFS) in patients harboring tumors of non-eloquent cortex when compared to gross total resection (GTR). While current literature demonstrates these findings without an increase in post-operative complications or neurological deficits, there remains a paucity of data examining the neuropsychological outcomes of SpTR for HGG. As quality of life dramatically influences survival rates in these patients, it is crucial for neurosurgeons, neuro-oncologists, and neuropsychiatrists to understand the behavioral and cognitive outcomes following SpTR, such that optimal treatment strategies can be tailored for each patient.

METHODS

We performed a comprehensive review of the available literature regarding survival, neuropsychological, and quality of life (QOL) outcomes following SpTR for HGG. We also review neuropsychological and QOL outcomes following GTR for HGG to serve as a framework for better understanding potential implications of SpTR.

RESULTS

While results are limited following SpTR for HGG, available data suggests similar outcomes to those seen in patients undergoing GTR of HGG, as well as low-grade glioma. These include a short-term decline in neuropsychological functioning post-surgically with a return to baseline across most neurocognitive domains occurring within several months. Memory and attention remain relatively diminished at long term follow-up.

CONCLUSIONS

Limited data exist examining postoperative cognitive and behavioral outcomes following SpTR for HGG. While the available data suggests a return to baseline for many neurocognitive domains, attention and memory deficits may persist. However, sample sizes are relatively small and have not been examined in the context of QOL and OS/PFS. More rigorous pre- and post-surgical neuropsychological assessment will help shed light on the long-term cognitive and behavioral effects of SpTR in the setting of HGG and inform clinical care and counseling when SpTR is considered.

Pre-operative Neurocognitive Function Was More Susceptible to Decline in Isocitrate Dehydrogenase Wild-Type Subgroups of Lower-Grade Glioma Patients

Background: Neuropsychological deficits frequently occur in diffuse lower-grade glioma (DLGG) patients, but their relationship with molecular subgroups based on the 2016 World Health Organization (WHO) Classification of Tumors of the Central Nervous System (CNS) is unclear. Methods: All patients enrolled for this study were divided into different subgroups according to the molecular-integrated 2016 CNS WHO and morphology-centric 2007 CNS WHO to compare their neurocognitive function (NCF) dysfunction. Univariate and multivariate analyses were used to assess the independent factors for NCF decline. The performance of NCF changes for discrimination of IDH and 1p19q status was evaluated by receiver operating characteristic (ROC). Results: There was no significant difference in the clinical characteristics among the molecular and morphologic subgroups. In the molecular subgroups, significant differences in NCF alterations were found in terms of attention function, working memory and executive function in grade II glioma patients; in addition to these changes in NCF, memory function and abstract thinking were also significantly different in grade III glioma patients. The pairwise comparison further confirmed that patients with astrocytoma (A)/anaplastic astrocytoma (AA) with isocitrate dehydrogenase wild-type (IDHwt) glioma were more susceptible to severe cognitive decline in terms of the NCF performance described above. For the morphologic subgroups, only working memory was significantly different in grade III glioma patients. The distribution proportion was significantly different among each subgroup of DLGG (grade II, P = 0.001; grade III, P = 0.002). The proportion of extensive NCF decline (≥5 tests) was 4, 12, and 50% in the IDH mutant oligodendroglioma (IDHm-O), IDHm-A, and IDHwt-A subgroups, and this proportion was 33, 60, and 93% in the IDHm-AO, IDHm-AA, and IDHwt-AA subgroups, respectively. In multivariate regression analysis, molecular types were independent factors for NCF alterations after adjusted the factors of tumor and demographics (p < 0.05). ROC curves suggested combined NCF tests model showed an advantage in the differentiation of IDH status. Conclusions: NCF alteration is closely related to molecular-integrated subgroups with varying degrees and frequencies in DLGG. Patients with IDHwt gliomas are more susceptible to suffer from severe and extensive NCF decline than other subgroups.

Cognitive functioning in patients with low-grade glioma: effects of hemispheric tumor location and surgical procedure

OBJECTIVE

The authors evaluated the cognitive performance of patients with low-grade glioma (LGG) before and after surgery, and specifically investigated 1) the effects of hemispheric tumor location and 2) the type of surgery (either with or without intraoperative stimulation mapping [ISM]).

METHODS

Patients underwent neuropsychological assessment 1 day before (T0) and 3 months after (T3) surgery. ISM targeted motor and/or language functions, but no other cognitive functions. Using 2-way mixed ANOVAs, differences between groups (i.e., for patients with right- vs left-sided lesions and normative controls [NCs], and also for patients operated on with vs without ISM and NCs), effects over time (T0-T3), and interaction effects in cognitive functioning were explored. Individual changes over time were assessed with reliable change indices for each neuropsychological test.

RESULTS

In total, 77 patients with LGG were included (38 and 39 patients with right- and left-sided lesions, respectively; and 42 patients with and 35 patients without ISM). The majority of patients who were operated on with ISM had left-sided lesions. Patients with right- and left-sided lesions scored significantly lower on 6 and 3 out of 8 tests, respectively, compared to NCs. No significant differences between hemispheric groups were found at T0 or at T3. Patients with left-sided lesions showed significant deterioration of performance on verbal memory and sustained attention over time. Patients who underwent operation with versus without ISM scored significantly lower on 6 and 3 out of 8 tests, respectively, compared to NCs. Patients in the ISM group scored significantly lower on the Stroop test, shifting attention test, and verbal fluency test than patients without ISM. Also, the ISM group showed a significant decline in mean cognitive flexibility and sustained attention performance over time.

CONCLUSIONS

Cognitive impairments were found in patients irrespective of hemispheric tumor location, whereby patients who were operated on with ISM performed slightly worse after surgery than patients without ISM. The authors conclude that there is room for improvement of cognitive functioning in surgically treated patients with LGG. The use of specific tests for higher cognitive functions during surgery may potentially improve functional outcome, but that is to be determined in future studies and balanced against oncological outcome. Implementation of neuropsychological assessments into the clinical management of patients with LGG should be encouraged, to inform and alert patients and clinicians on the status of cognitive functioning.

Impaired neurocognitive function in glioma patients: from pathophysiology to novel intervention strategies

PURPOSE OF REVIEW

This review succinctly summarizes the recent literature regarding etiological contributors to impaired neurocognitive function (NCF) in adult patients with glioma. A brief overview of intervention and prevention strategies is also provided.

RECENT FINDINGS

A majority of patients with glioma exhibit NCF deficits, most frequently in memory and executive functioning. Impairments are often disabling and associated with reduced quality of life and survival. Cause is multifactorial and includes the tumour itself, treatments received and associated comorbidities. Although modern techniques such as brain mapping, dosing modifications and prophylactic medication aim to improve the NCF outcomes following neurosurgical resection and radiation therapy, a sizeable proportion of patients continue to evidence treatment-related NCF declines related to adverse effects to both local and distributed cerebral networks. Numerous patient and tumour characteristics, including genetic markers and sociodemographic factors, influence the pattern and severity of NCF impairment. Some rehabilitative and pharmacologic approaches show promise in mitigating NCF impairment in this population, though benefits are somewhat modest and larger scale intervention studies are needed.

SUMMARY

Research regarding NCF in patients with glioma has dramatically proliferated, providing insights into the mechanisms underlying impaired NCF and pointing to potential interventions, though further work is needed.

Isocitrate Dehydrogenase, Patient-Reported Outcomes, and Cognitive Functioning of Glioma Patients: a Systematic Review

PURPOSE OF REVIEW

Isocitrate dehydrogenase (IDH) mutation status has important prognostic implications in glioma patients, with IDH wild-type (IDH-WT) gliomas being associated with worse prognosis and shorter survival when compared with IDH mutant (IDH-mut) gliomas. Optimization of quality of life is a priority in the management of glioma patients. The goal of this systematic review was to identify studies that explored the association of IDH mutation status with patient-reported outcomes (PROs) and cognitive functioning of glioma patients.

RECENT FINDINGS

Studies that evaluated the association of IDH mutation status with PROs and/or cognitive functioning of glioma patients were identified from the Pubmed/MEDLINE, Clarivate analytics, and Google Scholar databases. Eight studies (7 journal articles and 2 conference abstracts) with a total of 658 low-grade glioma and high-grade glioma patients investigated the association of cognitive functioning and/or QoL with IDH status. IDH-WT status was associated with greater cognitive impairment relative to IDH-Mut status in three studies, while one study did not find the association between IDH status and perioperative cognitive functioning. One study reported worse postoperative cognitive functioning patients with IDH-WT vs. IDH-mut gliomas. In one study, IDH-WT status was linked to greater impairment on physical and communication functioning after surgery. IDH-WT gliomas are associated with greater cognitive burden than IDH-Mut tumors. The association of IDH status with QoL remains less clear. Assessment of IDH status should be considered when evaluating QoL and cognitive complaints of glioma patients. Further studies linking glioma molecular phenotypes with PROs and cognitive functioning are encouraged.

Longitudinal association of subjective prospective and retrospective memory and depression among patients with glioma

PURPOSE

This study investigated the levels of depression, subjective prospective memory (PM), and subjective retrospective memory (RM) among Chinese glioma patients and explored the bi-directional relationships between depression and memory impairment, including subjective PM and RM.

METHODS

Seventy-one participants with glioma were assessed for depression, PM, and RM at two time points (Time 1: within 48 h of being hospitalized; Time 2: two weeks after surgery). A cross-lagged path analysis was conducted to examine the bi-directional relationships between depression and memory.

MAIN RESULTS

Depression at T1 predicted memory impairment total scores (β = 0.22, P = 0.011) and RM (β = 0.29, P < 0.001) at T2. However, depression at TI could not predict PM at T2 (β = 0.15, P = 0.090). Memory, whether PM or RM, at T1 could not predict depression at T2 (β = 0.07, P = 0.497; β = 0.00, P = 0.978; β = 0.06, P = 0.321).

CONCLUSIONS

Depression can affect RM memory impairment among glioma patients. Oncology nurses should preoperatively screen for depression in glioma patients to identify high-risk groups, for whom emotional interventions and memory training should be carried out to reduce postoperative RM memory impairment.

Effects of surgery on neurocognitive function in patients with glioma: a meta-analysis of immediate post-operative and long-term follow-up neurocognitive outcomes

PURPOSE

This study aims to identify the neuropsychological tests commonly used for assessment in each neurocognitive domain, and quantify the post-operative changes in neurocognitive function in the immediate post-operation and follow-up.

METHODS

With the use of the PubMed, a comprehensive search of the English literature was performed following PRISMA (Preferred Reporting Items for Systematic reviews and Meta-Analyses) guidelines. There were 1021 publications identified for screening. Standardized mean differences (SMD) in neuropsychological task performance were calculated both for immediate post-operation (up to 1 week) and follow-up (up to 6 months).

RESULTS

Out of 12 studies which met the inclusion criteria, 11 studies were analyzed in this meta-analysis, with a total of 313 patients (age range 18-82, 50% males) with intracranial gliomas (45% high-grade, 55% low-grade). Complex attention, language and executive function were the most frequently tested neurocognitive domains. Surgery had a positive impact in the domains of complex attention, language, learning and memory tasks in the immediate post-operative period and sustained improvement at follow-up. In contrast, surgery was found to negatively impact performance for executive function in the immediate post-operative period with sustained decline in performance in the long term.

CONCLUSIONS

This meta-analysis suggests that surgery for glioma confers a benefit for the domains of complex attention, language, learning and memory, while negatively affecting executive function, in the periods immediately after surgery and at 6 months follow-up. In addition, awake surgery seemed to confer a beneficial effect on neurocognitive functions. Future research should attempt to standardize a battery of neuropsychological tests for patients undergoing surgical resection for glioma, perhaps with a particular focus on executive function.

Awake craniotomy in glioma surgery: is it necessary?

INTRODUCTION

The awake craniotomy has evolved from its humble beginnings in ancient cultures to become one of the most eloquent modern neurosurgical procedures. The development of intraoperative mapping techniques like direct electrostimulation of the cortex and subcortical white matter have further argued for its place in the neurosurgeon's armamentarium. Yet the suitability of the awake craniotomy with intraoperative functional mapping (ACWM) to optimize oncofunctional balance after peri-eloquent glioma resection continues to be a topic of active investigation as new methods of intraoperative monitoring and some unfavorable outcome data question its necessity.

EVIDENCE ACQUISITION

The neurosurgery and anesthesiology literatures were scoured for English-language studies that analyzed or reviewed the ACWM or its components as applied to glioma surgery via the PubMed, ClinicalKey, and OvidMEDLINE® databases or via direct online searches of journal archives.

EVIDENCE SYNTHESIS

Information on background, conceptualization, standard techniques, and outcomes of the ACWM were provided and compared. We parceled the procedure into its components and qualitatively described positive and negative outcome data for each. Findings were presented in the context of each study without attempt at quantitative analysis or reconciliation of heterogeneity between studies. Certain illustrative studies were highlighted throughout the review. Overarching conclusions were drawn based on level of evidence, expert opinion, and predominate concordance of data across studies in the literature.

CONCLUSIONS

Most investigators and studies agree that the ACWM is the best currently available approach to optimize oncofunctional balance in this difficult-to-treat patient population. This qualitative review synthesizes the most currently available data on the topic to provide contemporaneous insight into how and why the ACWM has become a favorite operation of neurosurgeons worldwide for the resection of gliomas from eloquent brain.