Search

Background/aim: Many glioma patients struggle to return to work after surgery because of higher brain dysfunction. Although the right frontal lobe has historically been considered functionally silent, reports of performing awake surgery to evaluate higher brain functions in patients with tumors in this area have increased. We present two cases of patients who underwent awake surgery for malignant glioma in the right frontal lobe to preserve emotional recognition and facilitate an early return to work., Case Report: Case 1 was a 48-year-old right-handed woman employed as a nursery school teacher and case 2 was a 21-year-old right-handed man employed in sales. Both had contrast-enhancing right frontal lobe tumors exhibiting high signal intensity on fluid attenuated inversion recovery imaging and underwent awake surgery. During the operation, cortical mapping was performed using the Reading the Mind in the Eyes, calculation, and motor tasks. Resection of sites involved in motor and emotional recognition functions was avoided. In case 1, all regions of high signal intensity were completely resected; in case 2, all regions exhibiting enhancement were resected. Both patients were discharged home without neurological deficits and returned to work within 21 days after surgery., Conclusion: It may be important to focus not only on overall survival and progression-free survival in glioma patients, but also on factors associated with life satisfaction, such as time to return to work after surgery and time until work becomes difficult. Awake surgery aimed at preserving higher brain functions is useful and may also improve life satisfaction., (Copyright © 2024 International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.)

Time-to-contact (TTC) perception refers to the ability of an observer to estimate the remaining time before an object reaches a point in the environment, and is of crucial importance in daily life. Noninvasive correlational approaches have identified several brain areas sensitive to TTC information. Here we report the results of two studies, including one during an awake brain surgery, that aimed to identify the specific areas causally engaged in the TTC estimation process. In Study 1, we tested 40 patients with brain tumor in a TTC estimation task. The results showed that four of the six patients with impaired performance had tumors in right upper parietal cortex, although this tumoral location represented only six over 40 patients. In Study 2, 15 patients underwent awake brain surgery electrostimulation mapping to examine the implication of various brain areas in the TTC estimation process. We acquired and normalized to MNI space the coordinates of the functional areas that influenced task performance. Our results seem to demonstrate that the early stage of the TTC estimation process involved specific cortical territories in the ventral region of the right intraparietal sulcus. Downstream processing of TTC could also involve the frontal eye field (middle frontal gyrus) related to ocular search. We also found that deactivating language areas in the left hemisphere interfered with the TTC estimation process. These findings demonstrate a fine grained, cortical representation of TTC processing close to the ventral right intraparietal sulcus and complement those described in other human studies., (© 2020 Wiley Periodicals LLC.)

Background: During the latest decades, the hypothesis that the subjective experience of free will is determined by preconscious activity in the dominant dorsal medial frontal cortex (dMFC) has repeatedly challenged our commonly held concepts of moral responsibility., Aims of the Study: To investigate whether dMFC activity determines the sense of free will and to investigate the effects of resections in this area on quality of life (QoL)., Methods: A cohort of nine patients affected by transient declines in speech and movement skills after surgery involving the left dMFC answered questions about their post-operative, subjective experiences of volition in relation to symptoms. In eight cases, resections were performed as part of glioma surgery, and in the ninth case, a meningioma adjacent to the dMFC was resected. In addition, a QoL questionnaire was administrated before and after surgery., Results: None of the patients perceived the transient disabilities related to surgery as associated with a loss or absence of volition. No declines in QoL were detected after surgery. Two QoL domains showed improved function (motor dysfunction and future uncertainty)., Conclusions: The subjective sense of volition is not contingent on dMFC activity. Surgical resections of this area are not typically associated with declines in QoL., (© 2020 The Authors. Acta Neurologica Scandinavia published by John Wiley & Sons Ltd.)

Background: Patients with frontal glioma might experience cognition alterations together with potential dysfunction of resting-state networks (RSNs). To understand the altered patterns of the intrinsic activity and underlying network interactions between the cognitive-related RSNs is of great importance., Objective: This study aimed to investigate the characteristics of the altered RSNs, including default mode network, executive control network, and salience network and further elucidate the possible functional reorganization of RSNs in patients with frontal glioma., Methods: Thirteen patients with frontal glioma and 10 healthy controls (HCs) were enrolled in this study. Independent component analysis was performed to identify the characteristics of the selected RSNs activity. Further, functional connectivity analysis was applied to investigate the relationship between the altered regions. Subsequently, partial correlation analysis was performed to examine associations between the neural activity of RSNs and neurocognitive characteristics., Results: Compared with the HCs group, the patient group exhibited significant differences in functional connectivity among default mode network, executive control network, and salience network. In addition, the number of the significant functional connectivities between the paired seeds observed in the patients was greater than that in HCs and significantly increased functional connectivity was detected between left posterior cingulate cortex and right angular gyrus. Furthermore, altered neural activities in the RSNs of patients with frontal glioma were positively associated with certain aspects of cognitive function., Conclusions: Our results suggested underlying network functional reorganization of the triple unifying RSNs in patients with frontal glioma, providing novel insights for improving understanding of brain function., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Objective: Extended margin tumor resection beyond the abnormal area detected by magnetic resonance imaging, defined as supratotal resection, could improve the outcomes of patients with lower grade gliomas (LGGs). The aim of the present study was to assess the surgical outcomes of awake brain mapping to achieve supratotal resection with determination of the normal brain tissue boundaries beyond the tumor of frontal LGGs, in both dominant and nondominant hemispheres., Methods: We analyzed the data from 9 patients with diffuse frontal LGGs who had undergone supratotal resection with awake surgery from January 2016 to November 2017., Results: The frontal aslant tract was identified as the functional boundary in 4 of 5 left frontal tumor cases (80%). Working memory impairments during dorsolateral prefrontal cortex stimulation with digit span and/or visual N-back tasks were detected in all 4 patients (100%) with right-frontal tumor. The neurocognitive outcomes were significantly improved after surgery, as shown by the mean Wechsler adult intelligence scale III scores for verbal intelligence quotient (P = 0.04) and verbal comprehension (P = 0.03) and the mean Wechsler memory scale-revised scores for generalized memory (P = 0.04) and delayed recall (P = 0.04)., Conclusions: The results of the present study have provided evidence that awake mapping can enable the preservation of higher neurocognitive function, including working memory and spatial cognition in patients with nondominant right frontal tumors. Despite the small number of cases, our findings suggest the surgical benefit of awake surgery for supratotal resection of diffuse frontal LGGs., (Copyright © 2018 Elsevier Inc. All rights reserved.)

A person can be appraised as an individual or as a member of a social group. In the present study we tested whether the knowledge about social groups is represented independently of the living and non-living things. Patients with frontal and temporal lobe tumors involving either the left or the right hemisphere performed three tasks--picture naming, word-to-picture matching and picture sorting--tapping the lexical semantic knowledge of living things, non-living things and social groups. Both behavioral and voxel-based lesion-symptom mapping (VLSM) analyses suggested that social groups might be represented differently from other categories. VLSM analysis carried out on naming errors revealed that left-lateralized lesions in the inferior frontal gyrus, amygdala, insula and basal ganglia were associated with the lexical-semantic processing of social groups. These findings indicate that the social group representation may rely on areas associated with affective processing., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

Background: Brain tumor patients often associated with losses of the small-world configuration and neurocognitive functions before operations. However, few studies were performed on the impairments of frontal lobe low-grade gliomas (LGG) after tumor resection using small-world network features., Methodology/principal Findings: To detect differences in the whole brain topology among LGG patients before and after operation, a combined study of neurocognitive assessment and graph theoretical network analysis of fMRI data was performed. We collected resting-state fMRI data of 12 carefully selected frontal lobe LGG patients before and after operation. We calculated the topological properties of brain functional networks in the 12 LGG, and compared with 12 healthy controls (HCs). We also applied Montreal Cognitive Assessment (MoCA) in a subset of patients (n = 12, including before and after operation groups) and HCs (n = 12). The resulting functional connectivity matrices were constructed for all 12 patients, and binary network analysis was performed. In the range of 0.05 ≤ Kcos t ≤ 0.35, the functional networks in preoperative LGG and postoperative one both fitted the definition of small-worldness. We proposed Knet = 0.20 as small-world network interval, and the results showed that the topological properties were found to be disrupted in the two LGG groups, meanwhile the global efficiency increased and the local efficiency decreased. Lnet in the two LGG groups both were longer than HCs. Cnet in the LGG groups were smaller than HCs. Compared with the Hcs, MoCA in the two LGG groups were lower than HCs with significant difference, and the disturbed networks in the LGG were negatively related to worse MoCA scores., Conclusions: Disturbed small-worldness preperty in the two LGG groups was found and widely spread in the strength and spatial organization of brain networks, and the alterated small-world network may be responsible for cognitive dysfunction in frontal lobe LGG patients.

We report the longitudinal case study of a right-handed patient harboring two frontal tumors that benefited from bilateral simultaneous surgery. The tumors were WHO Grade II gliomas located in the left inferior frontal area (including the cingulate gyrus) and the right anterior superior frontal gyrus. The double tumor resection was guided by direct electrical stimulation of brain areas while the patient was awake. Neuropsychological assessments were administered before and after the surgery to analyse how the brain functions in the presence of two frontal gliomas that affect both hemispheres and reacts to a bilateral resection, which can brutally compromise the neuronal connectivity, progressively established during the infiltrating process. We showed that both the tumor infiltration and their bilateral resection did not lead to a "frontal syndrome" or a "dysexecutive syndrome" predicted by the localization models. However, a subtle fragility was observed in fine-grain language, memory and emotional skills. This case study reveals the significance of brain plasticity in the reorganization of cognitive networks, even in cases of bilateral tumors. It also confirms the clinical relevance of hodotopical brain models, which considers the brain to be organized in parallel-distributed networks around cortical centers and epicenters.

Assessing the subjective experience of others in terms of mental states, a brain function referred to as mentalizing, is achieved in the brain through a set of low-level perceptual and high-level inference-based processes. Because of its recurrent implication in fMRI studies, the right frontal cortex, especially in its inferolateral and dorsomesial parts, is posited to be a "core system" in the sustenance of these neurocognitive mechanisms. In this context, we reasoned that if the right frontal cortex is really crucial for mentalizing, its surgical resection, following diffuse low-grade glioma invasion, should induce irreversible impairments. To test this hypothesis, we designed a longitudinal experimental setup in which ten patients harboring a low-grade glioma in right frontal areas were assessed just before, immediately after and three months after a brain surgery. Two well-validated behavioral tasks, thought to evaluate both aspects of mentalizing, were administered. The results obtained provide evidence that widespread surgical excisions of the right prefrontal cortex do not induce a long-term worsening of both aspects of mentalizing, although some transitory effects are observed immediately after the surgery. They suggest also for the first time in the same sample of patients a possible double functional dissociation between low-level perceptual (posterior inferolateral prefrontal) and high-level inference-based (dorsomesial prefrontal) mentalizing processes. This overall finding challenges the traditional view according to which the right frontal cortex is an "essential cortical node" in the mentalizing network since it might be expected that massive surgical excisions of this brain area would have induced more definitive impairments., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

We investigated the presence of cognitive impairment, in adults with presumed low-grade glioma at early stage of disease prior to major treatments, in relation to neurological symptoms and radiological characteristics of the tumour. Sixteen patients were evaluated. A subset of patients was identified with clearly impaired cognition. Patients with cognitive impairment often had large tumours in the left frontal lobe, were relatively young, and most of them were males. We conclude that cognitive dysfunction may be present already at early stage of disease, and that early identification of patients at risk is warranted.

Background: Recent advances on functional mapping have enabled us to conduct surgery on gliomas within the eloquent area. The objective of the article is to discuss the feasibility of a planned fractionated strategy of resection on low-grade gliomas (LGGs) involving Broca's area. We report the first surgical series of planned fractionated resections on LGGs within Broca's area, focusing on language functional reshaping., Methods: Four patients were treated with fractionated operations for LGGs involving Broca's area. All cases underwent conventional magnetic resonance (MR) scanning, language functional MR and diffusion tensor imaging (DTI) before operation. The resections were then performed on patients under awake anesthesia using intraoperative electrical stimulation (IES) for functional mapping. Pre- and post-operative neuro-psychological examinations were evaluated., Results: Total resections were achieved in all cases as confirmed by the postoperative control MR. After transient language worsening, all patients recovered to normal 3-6 months later. Language functional MR scannings have shown language functional cortical and subcortical pathway reorganization (in the perilesion or contra-lateral hemisphere) after the operation. All patients returned to a normal socioprofessional life., Conclusions: By utilizing the dynamic interaction between brain plasticity and fractionated resections, we can totally remove the tumor involving Broca's structure without inducing permanent postoperative deficits and even improve the quality of life.

What role does meaning selection play in word comprehension, and what neural systems support this selection process? Most words have multiple meanings and are therefore ambiguous. This is true of both homonymous words (words that have multiple unrelated meanings) and polysemous words (words that have multiple related meanings). The extant evidence indicates that meaning selection is an integral part of homonym comprehension. However, it is not known whether meaning selection extends to polysemous words, or what neural systems support meaning selection during comprehension. Prior neuroimaging and neuropsychological evidence suggest that the left inferior frontal gyrus (LIFG) may play a role in resolving competition during language processing. We therefore sought to test the hypotheses that meaning selection is part of polysemous word comprehension, and that the LIFG resolves meaning competition during word comprehension. We tested healthy participants on a version of the triplet lexical decision task, with polysemous and homonymous stimuli. Results suggest that the meanings of polysemous words, like the meanings of homonyms, are selected based on context. However, homonymous and polysemous words differed in how meaning frequency affected meaning selection. We then administered the triplet lexical decision task to patients with LIFG damage to examine whether this region plays a role in context-dependent meaning selection. Results support the hypothesis that the LIFG serves as a top-down biasing mechanism that facilitates rapid meaning selection during word comprehension. We conclude that context-dependent meaning selection is an integral part of word comprehension for both homonyms and polysemous words, and that the LIFG facilitates this selection process.

Seventy-seven patients with different cerebral lesions were tested on a rule-detection task where the stimuli were designed in such a way as to minimize the activation of pre-existing schemata. Patients with lesions involving the frontal lobes were poorer at achieving set than patients with lesions elsewhere. In addition, the anteriorly-lesioned group showed a greater tendency to guess and were more likely to abandon a correct rule once it had been attained, but there were no differences between the groups in incidence of perseverative responses. Various plausible explanations of these results are examined, with the most favoured account suggesting that anterior patients show an exaggerated willingness to adopt bizarre hypotheses.

This study examined the memory performance of patient RK who developed substantial memory impairments due to a hypothalamic glioma but in the absence of any evidence of frontal disturbance. RK was evaluated on both tests of anterograde and retrograde memory for temporal context. In the first experiment he exhibited marked deficits on a list discrimination task even when recognition performance was well within control range. Experiment 2 confirmed this disproportionate impairment of temporal order memory and showed that RK's list discrimination deficit was as severe as that found in alcoholic Wernicke-Korsakoff Syndrome patients. Experiment 3 showed that RK's temporal discrimination deficit was not a general deficit in discrimination because he performed normally on a spatial discrimination test of comparable difficulty to the temporal task. Experiment 4 examined RK's memory for deceased famous people and his ability to indicate the half decade in which they died. RK's performance was indistinguishable from controls whereas WKS patients were extremely impaired. This study adds to the view that frontal damage is not a necessary condition for impairment on anterograde measures of temporal context memory. However, further evidence from this study indicates that temporal judgments about pre-existing memories may depend on intact frontal lobe functioning.

The aim of this study was to demonstrate that the inability to set adequate sub-goals in a cognitive task is a sensitive indicator of programming deficit after frontal lobe lesion. Sixty-one patients with focal cerebral lesions and 25 control subjects were studied with a modified Digit Symbol task, in which the score depended on the adequacy of the sub-goals set by the subject. This score was compared to that on the standard condition, in which the subject was requested to work as quickly as possible without self-selected goals. The results confirmed the prediction that patients with anterior lesions set less adequate sub-goals than patients with posterior lesions and, unlike the latter patients, have a more pronounced deficit on the performance with self-selected goals than on the standard condition. In particular patients with left frontal lobe lesions underestimated their capabilities in relation to task requirements.

Thirty-two subjects with unilateral cerebral tumors were assessed for the use of hypotheses and cognitive strategies during a visual discrimination task. Subjects with frontal lobe lesions attained fewer concepts and used fewer appropriate hypotheses than subjects with tumors confined to the posterior hemisphere, although there was no difference in total hypotheses used. Lose-stay errors were committed with greater frequency among patients with frontal lobe lesions, although not all subjects with frontal lobe tumors exhibited this error tendency. The results of hypothesis sampling and a second visual discrimination transfer task suggested that the frontal lobe deficit was related to difficulty in attending to multiple cues and in monitoring feedback to segregate relevant from irrelevant sources of information.