Neuropsychological Profile in Children with Posterior Fossa Tumors with or Without Postoperative Cerebellar Mutism Syndrome (CMS)

The development of fatigue after treatment for pediatric brain tumors does not differ between tumor locations

BACKGROUND

Children and adolescents treated for a brain tumor suffer from more fatigue than survivors of other types of childhood cancer. As tumor location might be predictive of fatigue, our aim was to investigate the longitudinal development of fatigue in children with brain tumors and risk factors for fatigue separately for different tumor locations.

METHODS

Fatigue was assessed 1235 times for 425 participants. Self-report versions of PedsQL Multidimensional Fatigue Scale were used to repeatedly assess fatigue from the end of treatment up to 8 years later. Mixed models were used to analyze fatigue over time and determinants separately for infratentorial (N = 205), supratentorial hemispheric (N = 91), and supratentorial midline tumors (N = 129).

RESULTS

Cognitive fatigue worsened with time, while sleep-rest and general fatigue first decreased and then increased. There was no difference in fatigue between the tumor locations, but the risk factors differed when stratified by location. Radiotherapy was associated with more fatigue for infratentorial tumors, and centralization of care was associated with less fatigue for the supratentorial midline tumors. For supratentorial hemispheric tumors, female sex was associated with more fatigue. Higher parental education was associated with less fatigue regardless of tumor location.

CONCLUSIONS

The development of fatigue seems to be more related to sociodemographic and treatment variables than to tumor location. Healthcare providers need to be aware that fatigue may develop in the years following end of treatment, and that patients with a low/middle educational family background might be more vulnerable and in need of targeted support.

Catatonia associated with pediatric postoperative cerebellar mutism syndrome

OBJECTIVE

To ascertain the presence of catatonia in cases of pediatric postoperative cerebellar mutism syndrome (PPCMS).

METHOD

A systematic review of PPCMS case reports of patients aged 0-17 years with sufficient clinical information to extract catatonic phenomena was undertaken following PRISMA guidelines. Standardized catatonia rating scales were applied to selected cases retrospectively to ascertain whether diagnostic criteria for catatonia were met. A case known to the authors is also presented.

RESULTS

Two hundred twenty-one suitable full-text articles were identified. Following screening and application of inclusion criteria, 51 articles were selected plus seven more from their references, reporting on 119 subjects. All cases met Bush and Francis (BF) diagnostic criteria for catatonia, 92.5% Pediatric Catatonia Rating Scale (PCRS), 52.9% ICD-11, and 44.5% DSM-5. All patients presented with mutism. The next most frequent signs were immobility/stupor (77.3%), withdrawal (35.3%), mannerisms (23.5%), and excitement/agitation (18.5%). Most cases presented with stuporous catatonia (75.6%). Catatonia most frequently occurred following resection of medulloblastoma (64.7%). Preoperative hydrocephalus occurred in 89 patients (74.8%).

CONCLUSION

Catatonia was frequent in this PPCMS sample, with a predominant stuporous variant; it should be considered in patients with PPCMS and assessed with reliable and validated instruments for prompt diagnosis and management.

Neuroanatomy of cerebellar mutism syndrome: the role of lesion location

Approximately 25% of paediatric patients who undergo cerebellar tumour resection develop cerebellar mutism syndrome. Our group recently showed that damage to the cerebellar deep nuclei and superior cerebellar peduncles, which we refer to as the cerebellar outflow pathway, is associated with an increased risk of cerebellar mutism syndrome. Here, we tested whether these findings replicate in an independent cohort. We evaluated the relationship between lesion location and the development of cerebellar mutism syndrome in an observational study of 56 paediatric patients ranging from five months to 14 years of age who underwent cerebellar tumour resection. We hypothesized that individuals who developed cerebellar mutism syndrome after surgery, relative to those who did not, would have lesions that preferentially intersect with: (i) the cerebellar outflow pathway and (ii) a previously generated 'lesion-symptom map' of cerebellar mutism syndrome. Analyses were conducted in accordance with pre-registered hypotheses and analytic methods (https://osf.io/r8yjv/). We found supporting evidence for both hypotheses. Compared to patients who did not develop cerebellar mutism syndrome, patients with cerebellar mutism syndrome (n = 10) had lesions with greater overlap with the cerebellar outflow pathway (Cohen's d = 0.73, P = 0.05), and the cerebellar mutism syndrome lesion-symptom map (Cohen's d = 1.1, P = 0.004). These results strengthen the association of lesion location with the risk of developing cerebellar mutism syndrome and demonstrate generalizability across cohorts. These findings may help to inform the optimal surgical approach to paediatric cerebellar tumours.

Correlates of performance on the Child and Adolescent Memory Profile (ChAMP) in a mixed pediatric sample

This study aimed to determine some of the factors that influence performance on a comprehensive test of verbal and visual memory in children, the Child and Adolescent Memory Profile (ChAMP) in a mixed clinical sample (n = 178; 56% male, 67% White, median age 12 years). We used hierarchical linear regression analyses with ChAMP standard scores as the dependent variable, and parental education as well as Wechsler Intelligence Scale for Children-Fifth Edition (WISC-V) factor index scores as the independent variables. WISC-V Processing Speed and (to a lesser extent) Working Memory were statistically significant predictors of most ChAMP Index scores. In addition, WISC-V Verbal Comprehension contributed to the model for ChAMP Verbal Memory, and WISC-V Visual Spatial to the model for ChAMP Visual Memory. In each case better performance on the WISC-V was predictive of higher scores on the ChAMP, with large effect sizes. WISC-V variables also mediated the positive effect of parental education on ChAMP scores. We conclude that clinicians should consider performance on measures of speed of processing, working memory, language and visual-spatial skills as potential influences on ChAMP results that may suggest a specific memory deficit.

National multicentered retrospective review of clinical and intraoperative factors associated with the development of cerebellar mutism after pediatric posterior fossa tumor resection

BACKGROUND

Cerebellar mutism (CM) is characterized by a significant loss of speech in children following posterior fossa (PF) surgery. The biological origin of CM remains unclear and is the subject of ongoing debate. Significant recovery from CM is less likely than previously described despite rigorous multidisciplinary neuro-rehabilitational efforts.

METHODS

A national multi-centered retrospective review of all children undergoing PF resection in four midsized Canadian academic pediatric institutions was undertaken. Patient, tumor and surgical factors associated with the post-operative development of CM were reviewed. Retrospective identification of PF surgery patients including those developing and those that did not (internal control).

RESULTS

The study identified 258 patients across the 4 centers between 2010 and 2020 (mean age 6.73 years; 42.2% female). Overall, CM was experienced in 19.5% of patients (N = 50). Amongst children who developed CM histopathology included medulloblastoma (35.7%), pilocytic astrocytoma (32.6%) and ependymoma (17.1%). Intraoperative impression of adherence to the floor of the 4th ventricle was positive in 36.8%. Intraoperative abrupt changes in blood pressure and/or heart rate were identified in 19.4% and 17.8% of cases. The clinical resolution of CM was rated to be complete, significant resolution, slight improvement, no improvement and deterioration in 56.0%, 8.0%, 20.0%, 14.0% and 2.0%, respectively. In the cohort of children who experienced post-operative CM as compared to their no-CM counterpart, proportionally more tumors were felt to be adherent to the floor of the 4th ventricle (56.0% vs 49.5%), intraoperative extent of resection was a GTR (74% vs 68.8%) and changes in heart rate were noted (≥ 20% from baseline) (26.0% vs 15.9%). However, a multiple regression analysis identified only abrupt changes in HR (OR 5.97, CI (1.53, 23.1), p = 0.01) to be significantly associated with the development of post-operative CM.

CONCLUSION

As a devastating surgical complication after posterior fossa tumor surgery with variable clinical course, identifying and understanding the operative cues and revising intraoperative plans that optimizes the child's neurooncological and clinical outcome are essential.

Long term neuropsychological outcomes of a pediatric ETANTR brain tumor: A case study

Survivors of pediatric brain tumors are at high risk for long-term neuropsychological difficulties. In the current case study, we present longitudinal neuropsychological data spanning 10 years (from age 9 to 19 years) of a patient with a rare, very large, bifrontal, embryonal tumor with abundant neuropil and true rosettes (ETANTR), which is typically associated with poor survivorship and significant neurological impact. Results demonstrated that the patient had largely intact cognitive functioning with specific difficulties in executive functioning, fine motor skills, and adaptive functioning at her most recent neuropsychology 10-year follow-up. These results highlight outcomes for a patient with remarkable resiliency in the context of numerous risk factors (a very large tumor size, multi-modal treatment, and seizure history). Patient protective factors (a high level of cognitive reserve, family support, and appropriate comprehensive educational services) likely contributed to the patient's favorable neuropsychological outcome. The patient's age at brain tumor diagnosis (9 years) and associated treatment was at a critical period of development for emerging higher order cognitive functions which likely impacted acquisition of executive functioning skills and secondarily adaptive skill outcomes. Consequently, pediatric brain tumor survivors with ETANTR or other frontal tumors require targeted screening of executive functions and proactive interventions.

Characterising the Long-Term Language Impairments of Children Following Cerebellar Tumour Surgery by Extracting Psycholinguistic Properties from Spontaneous Language

Following cerebellar tumour surgery, children may suffer impairments of spontaneous language. Yet, the language processing deficits underlying these impairments are poorly understood. This study is the first to try to identify these deficits for four levels of language processing in cerebellar tumour survivors. The spontaneous language of twelve patients who underwent cerebellar tumour surgery (age range 3-24 years) was compared against his or her controls using individual case statistics. A distinction was made between patients who experienced postoperative cerebellar mutism syndrome (pCMS) and those who did not. Time since surgery ranged between 11 months and 12;3 years. In order to identify the impaired language processing levels at each processing level (i.e., lexical, semantic, phonological and/or morphosyntactic) nouns and verbs produced in the spontaneous language samples were rated for psycholinguistic variables (e.g., concreteness). Standard spontaneous language measures (e.g., type-token ratio) were calculated as well. First, inter-individual heterogeneity was observed in the spontaneous language outcomes in both groups. Nine out of twelve patients showed language processing deficits three of whom were diagnosed with pCMS. Results implied impairments across all levels of language processing. In the pCMS-group, the impairments observed were predominantly morphosyntactic and semantic, but the variability in nature of the spontaneous language impairments was larger in the non-pCMS-group. Patients treated with cerebellar tumour surgery may show long-term spontaneous language impairments irrespective of a previous pCMS diagnosis. Individualised and comprehensive postoperative language assessments seem necessary, given the inter-individual heterogeneity in the language outcomes.

Oculomotor Impairments in Children After Posterior Fossa Tumors Treatment

Posterior fossa tumors (PFT) are the most common pediatric brain tumors, and the study of the somatic and cognitive status of PFT survivors still remains a critical problem. Since cerebellar damage can affect eye movement centers located in the vermis and hemispheres, such patients suffer from disturbances in visual perception, visual-spatial functions, reading, etc. Our investigation aimed at describing oculomotor impairments in PFT survivors linked to core oculomotor functions assessed through eye tracking method: gaze holding, reflexive saccades, and organization of voluntary saccades and their dependency on age at tumor diagnosis. Also, we investigated the relationship between oculomotor functions and ataxia measured with International Cooperative Ataxia Rating Scale (ICARS). A total of 110 children (patients and age-matched healthy controls, aged 9-17 years old) participated in the study. We found that the earlier the child had a tumor, the more impaired gaze holding (p = 0.0031) and fewer isometric saccades (p = 0.035) were observed at the time of examination. The above-mentioned functions in healthy controls improved with age. Visual scanning was also impaired compared to controls but was not related to age at diagnosis. A positive correlation between ICARS scores and number of hypermetric saccades (r = 0.309, p = 0.039), but no correlation with the number of hypometric saccades (r = - 0.008, p = 0.956). Furthermore, number of hypometric saccades did not differ between patients and controls (p = 0.238). Thus, primarily hypermetric saccades can be considered a prominent oculomotor symptom of cerebellar tumors. Our study provides basis for new methods of PFT diagnosis and rehabilitation procedure evaluation, both playing essential roles in modern pediatric neurooncology.

Language outcomes in children who underwent surgery for the removal of a posterior fossa tumor: A systematic review

BACKGROUND

Children who underwent posterior fossa tumor removal may have spoken or written language impairments. The present systematic review synthesized the literature regarding the language outcomes in this population. Benefits of this work were the identification of shortcomings in the literature and a starting point toward formulating guidelines for postoperative language assessment.

METHODS

A systematic literature search was conducted, identifying studies with patients who had posterior fossa surgery before 18 years of age. Included studies were narratively synthesized to understand language outcomes by language function (e.g., phonology, morphosyntax) at a group and individual level. Furthermore, the influence of several mediators (e.g., postoperative cerebellar mutism syndrome (pCMS), tumor type) was investigated. A critical evaluation of the language assessment tools was conducted.

RESULTS

The narrative synthesis of 66 studies showed that a broad spectrum of language impairments has been described, characterized by a large interindividual heterogeneity. Patients younger at diagnosis, receiving treatment for a high-grade tumor and/or radiotherapy and diagnosed with pCMS seemed more prone to impairment. Several gaps in language assessment remain, such as a baseline preoperative assessment and the assessment of pragmatics and morphosyntax. Further, there were important methodological differences in existing studies which complicated our ability to accurately guide clinical practice.

CONCLUSION

Children who had posterior fossa surgery seem to be at risk for postoperative language impairment. These results stress the need for language follow-up in posterior fossa tumor survivors.

A systematic review of pediatric neuropsychological outcomes with proton versus photon radiation therapy: A call for equity in access to treatment

OBJECTIVE

There is increasing interest in the utilization of proton beam radiation therapy (PRT) to treat pediatric brain tumors based upon presumed advantages over traditional photon radiation therapy (XRT). PRT provides more conformal radiation to the tumor with reduced dose to healthy brain parenchyma. Less radiation exposure to brain tissue beyond the tumor is thought to reduce neuropsychological sequelae. This systematic review aimed to provide an overview of published studies comparing neuropsychological outcomes between PRT and XRT.

METHOD

PubMed, PsychINFO, Embase, Web of Science, Scopus, and Cochrane were systematically searched for peer-reviewed published studies that compared neuropsychological outcomes between PRT and XRT in pediatric brain tumor patients.

RESULTS

Eight studies were included. Six of the studies utilized retrospective neuropsychological data; the majority were longitudinal studies (n = 5). XRT was found to result in lower neuropsychological functioning across time. PRT was associated with generally stable neuropsychological functioning across time, with the exception of working memory and processing speed, which showed variable outcomes across studies. However, studies inconsistently included or considered medical and sociodemographic differences between treatment groups, which may have impacted neuropsychological outcomes.

CONCLUSIONS

Despite methodological limitations, including limited baseline neuropsychological evaluations, temporal variability between radiation treatment and first evaluation or initial and follow-up evaluations, and heterogenous samples, there is emerging evidence of sociodemographic inequities in access to PRT. With more institutions dedicating funding towards PRT, there may be the opportunity to objectively evaluate the neuropsychological benefits of patients matched on medical and sociodemographic variables.

Genetic susceptibility to cognitive decline following craniospinal irradiation for pediatric central nervous system tumors

BACKGROUND

Survivors of pediatric central nervous system (CNS) tumors treated with craniospinal irradiation (CSI) exhibit long-term cognitive difficulties. Goals of this study were to evaluate longitudinal effects of candidate and novel genetic variants on cognitive decline following CSI.

METHODS

Intelligence quotient (IQ), working memory (WM), and processing speed (PS) were longitudinally collected from patients treated with CSI (n = 241). Genotype-by-time interactions were evaluated using mixed-effects linear regression to identify common variants (minor allele frequency > 1%) associated with cognitive performance change. Novel variants associated with cognitive decline (P < 5 × 10-5) in individuals of European ancestry (n = 163) were considered replicated if they demonstrated consistent genotype-by-time interactions (P < .05) in individuals of non-European ancestries (n = 78) and achieved genome-wide statistical significance (P < 5 × 10-8) in a meta-analysis across ancestry groups.

RESULTS

Participants were mostly males (65%) diagnosed with embryonal tumors (98%) at a median age of 8.3 years. Overall, 1150 neurocognitive evaluations were obtained (median = 5, range: 2-10 per participant). One of the five loci previously associated with cognitive outcomes in pediatric CNS tumors survivors demonstrated significant time-dependent IQ declines (PPARA rs6008197, P = .004). Two variants associated with IQ in the general population were associated with declines in IQ after Bonferroni correction (rs9348721, P = 1.7 × 10-5; rs31771, P = 7.8 × 10-4). In genome-wide analyses, we identified novel loci associated with accelerated declines in IQ (rs116595313, meta-P = 9.4 × 10-9), WM (rs17774009, meta-P = 4.2 × 10-9), and PS (rs77467524, meta-P = 1.5 × 10-8; rs17630683, meta-P = 2.0 × 10-8; rs73249323, meta-P = 3.1 × 10-8).

CONCLUSIONS

Inherited genetic variants involved in baseline cognitive functioning and novel susceptibility loci jointly influence the degree of treatment-associated cognitive decline in pediatric CNS tumor survivors.

Neurocognitive outcomes in pediatric brain tumors after treatment with proton versus photon radiation: a systematic review and meta-analysis

BACKGROUND

Advances in cancer treatments, particularly the development of radiation therapy, have led to improvements in survival outcomes in children with brain tumors. However, radiation therapy is associated with significant long-term neurocognitive morbidity. The present systematic review and meta-analysis aimed to compare the neurocognitive outcomes of children and adolescents with brain tumors treated with photon radiation (XRT) or proton therapy (PBRT).

METHODS

A systematic search was conducted (PubMed, Embase, Cochrane, and Web of Science from inception until 02/01/2022) for studies comparing the neurocognitive outcomes of children and adolescents with brain tumors treated with XRT vs. PBRT. The pooled mean differences (expressed as Z scores) were calculated using a random effects method for those endpoints analyzed by a minimum of three studies.

RESULTS

Totally 10 studies (n = 630 patients, average age range: 1-20 years) met the inclusion criteria. Patients who had received PBRT achieved significantly higher scores (difference in Z scores ranging from 0.29-0.75, all P < 0.05 and significant in sensitivity analyses) after treatment than those who had received XRT for most analyzed neurocognitive outcomes (i.e., intelligence quotient, verbal comprehension and perceptual reasoning indices, visual motor integration, and verbal memory). No robust significant differences (P > 0.05 in main analyses or sensitivity analyses) were found for nonverbal memory, verbal working memory and working memory index, processing speed index, or focused attention.

CONCLUSIONS

Pediatric brain tumor patients who receive PBRT achieve significantly higher scores on most neurocognitive outcomes than those who receive XRT. Larger studies with long-term follow-ups are needed to confirm these results.

Neuroanatomy of Cerebellar Mutism Syndrome: The Role of Lesion Location

Approximately 25% of pediatric patients who undergo cerebellar tumor resection develop cerebellar mutism syndrome (CMS). Our group recently showed that damage to the cerebellar deep nuclei and superior cerebellar peduncles, which we refer to as the cerebellar outflow pathway, is associated with increased risk of CMS. Here, we tested whether these findings replicate in an independent cohort. We evaluated the relationship between lesion location and the development of CMS in an observational study of 56 pediatric patients who underwent cerebellar tumor resection. We hypothesized that individuals that developed CMS after surgery (CMS+), relative to those that did not (CMS-) would have lesions that preferentially intersected with: 1) the cerebellar outflow pathway, and 2) a previously generated 'lesion-symptom map' of CMS. Analyses were conducted in accordance with pre-registered hypotheses and analytic methods (https://osf.io/r8yjv/). We found supporting evidence for both hypotheses. Compared with CMS- patients, CMS + patients (n = 10) had lesions with greater overlap with the cerebellar outflow pathway (Cohen's d = .73, p = .05), and the CMS lesion-symptom map (Cohen's d = 1.1, p = .004). These results strengthen the association of lesion location with risk of developing CMS and demonstrate generalizability across cohorts. These findings may help to inform the optimal surgical approach to pediatric cerebellar tumors.

Investigating lesion location in relation to cerebellar mutism following pediatric tumor resection

Background and Objectives

Approximately 25% of pediatric patients who undergo cerebellar tumor resection develop cerebellar mutism syndrome (CMS). Our group recently showed that damage to the cerebellar outflow pathway is associated with increased risk of CMS. Here, we tested whether these findings replicate in an independent cohort.

Methods

We evaluated the relationship between lesion location and the development of CMS in an observational study of 56 pediatric patients who underwent cerebellar tumor resection. We hypothesized that individuals that developed CMS after surgery (CMS+), relative to those that did not (CMS-) would have lesions that preferentially intersected with: 1) the cerebellar outflow pathway, and 2) a previously generated 'lesion-symptom map' of CMS. Analyses were conducted in accordance with pre-registered hypotheses and analytic methods (https://osf.io/r8yjv/).

Results

We found supporting evidence for both hypotheses. Compared with CMS- patients, CMS+ patients (n=10) had lesions with greater overlap with the cerebellar outflow pathway (Cohen's d=.73, p=.05), and the CMS lesion-symptom map (Cohen's d=1.1, p=.004).

Discussion

These results strengthen the association of lesion location with risk of developing CMS and demonstrate generalizability across cohorts. These findings may help to inform the optimal surgical approach to pediatric cerebellar tumors.

Psychological and Psychiatric Aspects of Brain and Spinal Cord Tumors

Central nervous system (CNS) tumors are mainly diagnosed by physical symptoms such as paralysis, visual field defect, seizure, and loss of consciousness. The psychological and psychiatric background of CNS tumors, whether in preoperative or postoperative period, has long been a neglected topic; however, lately, many authors and researchers have paid more attention to these manifestations. Neurocognition is a subset of parameters, including attention, memory, mood, emotions, language production, personality, executive function, problem-solving, calculation, and spatial cognition, making up the patient's cognitive performance. Also, it is worthy to say that neurocognition is considered a parameter of quality of life (QoL). Currently, we know that neurocognitive disorders are a group of symptoms presenting by the patients. These symptoms may be the first picture of CNS lesions, which result in incorrect treatment, a higher financial burden on the patient and health system, and finally, poorer QoL and performance scale if they are not diagnosed early. Psychological and psychiatric problems such as depression, anxiety, and phobia following the CNS tumors have two aspects. These may present before any treatment resulting from the tumoral mass effect, peritumoral edema, or cerebral tissue disruption due to the space-occupying lesion. On the other hand, we can see these features after a kind of therapy such as surgery, medical therapy, or adjuvant therapy. Sometimes, the CNS tumors lead to psychosocial complications postoperatively. Indeed, considering tumor surgery complications, some patients may find various degrees of deficits that make the patient isolated either socially or professionally. Obviously, the improvement rate and outcome of this specific situation depend on the mechanism of occurrence and its causes. For instance, postoperative symptom relief would be expected when the symptoms are related to the tumoral mass effect. Getting familiar with this constellation of the symptoms, realizing them, and then localizing them to the correct area of the CNS are very crucial. Accordingly, because of their importance in QoL, their influence on patient's survival even more than the extent of resection of the tumor, and somehow their ignorance, we will discuss different neurocognitive manifestations related to CNS tumors in this chapter.

Sociocultural variables have a major impact on participation in patients treated for paediatric posterior fossa tumours

BACKGROUND

This study investigates the severeness of participation barriers in patients surviving paediatric posterior fossa tumours (PFT) many years after treatment. In the past, aetiological studies on adverse outcome have primarily focused on pathobiological risk factors. The current analysis aims to investigate the importance of environmental variables.

METHODS

On average, 10 years after diagnosis, educational and social difficulties of 42 patients surviving paediatric PFT (mean age 17 years) were inquired using a self-constructed questionnaire following the Psychosocial Resource-Orientated Assessment (PREDI). Educational or social participation barriers were defined by self- and/or proxy-reported difficulties in school or in peer relationships. Accordingly, the children and adolescents were categorized into groups of adequate and limited participation. Subsequently, the study identified potential pathobiological (treatment type, hydrocephalus, tumour relapse, gender, age at diagnosis, seizures and cerebellar mutism) and environmental (parental and maternal education, siblings, main language, discrepancies between personal and environmental values, regular physical activity and private living space) risk factors and investigated whether patients with adequate and limited participation differed in the number of risk factors.

RESULTS

Almost one decade after treatment, two thirds of patients experienced educational and/or social difficulties. Patients with limited participation were more frequently associated with environmental factors such as low maternal education degree, siblings, main language other than German, discrepancies between societal and personal values and irregular physical activity, as well as the pathobiological risk factors treatment type, hydrocephalus, tumour relapse, cerebellar mutism and seizures. These variables significantly discriminated between patients with and without limited participation.

CONCLUSIONS

Limited participation in patients treated for paediatric PFT is common. Next to pathobiological, also environmental risk factors play a major role in educational and social participation barriers. This highlights the fact that solely considering pathobiology is not sufficient when investigating risk factors for the emergence of late sequelae. Future aetiological studies must adopt a biopsychosocial perspective.

A presurgical voxel-wise predictive model for cerebellar mutism syndrome in children with posterior fossa tumors

BACKGROUND

This study aimed to investigate cerebellar mutism syndrome (CMS)-related voxels and build a voxel-wise predictive model for CMS.

METHODS

From July 2013 to January 2022, 188 pediatric patients diagnosed with posterior fossa tumor were included in this study, including 38 from a prospective cohort recruited between 2020 and January 2022, and the remaining from a retrospective cohort recruited in July 2013-Aug 2020. The retrospective cohort was divided into the training and validation sets; the prospective cohort served as a prospective validation set. Voxel-based lesion symptoms were assessed to identify voxels related to CMS, and a predictive model was constructed and tested in the validation and prospective validation sets.

RESULTS

No significant differences were detected among these three data sets in CMS rate, gender, age, tumor size, tumor consistency, presence of hydrocephalus and paraventricular edema. Voxels related to CMS were mainly located in bilateral superior and inferior cerebellar peduncles and the superior part of the cerebellum. The areas under the curves for the model in the training, validation and prospective validation sets were 0.889, 0.784 and 0.791, respectively.

CONCLUSIONS

Superior and inferior cerebellar peduncles and the superior part of the cerebellum were related to CMS, especially the right side, and voxel-based lesion-symptom analysis could provide valuable predictive information before surgery.

Long-term postoperative quality of life in childhood survivors with cerebellar mutism syndrome

Background

To investigate the long-term quality of life (QoL) of children with cerebellar mutism syndrome (CMS) and explore the risk factors for a low QoL.

Procedure

This cross-sectional study investigated children who underwent posterior fossa surgery using an online Pediatric Quality of Life Inventory questionnaire. CMS and non-CMS patients were included to identify QoL predictors.

Results

Sixty-nine patients were included (male, 62.3%), 22 of whom had CMS. The mean follow-up time was 45.2 months. Children with CMS had a significantly lower mean QoL score (65.3 vs. 83.7, p < 0.001) and subdomain mean scores (physical; 57.8 vs. 85.3, p < 0.001; social: 69.5 vs. 85.1, p = 0.001; academic: p = 0.001) than those without CMS, except for the emotional domain (78.0 vs. 83.7, p = 0.062). Multivariable analysis revealed that CMS (coefficient = -14.748.61, p = 0.043), chemotherapy (coefficient = -7.629.82, p = 0.013), ventriculoperitoneal (VP) shunt placement (coefficient = -10.14, p = 0.024), and older age at surgery (coefficient = -1.1830, p = 0.007) were independent predictors of low total QoL scores. Physical scores were independently associated with CMS (coefficient = -27.4815.31, p = 0.005), VP shunt placement (coefficient = -12.86, p = 0.025), and radiotherapy (coefficient = -13.62, p = 0.007). Emotional score was negatively associated with age at surgery (coefficient = -1.92, p = 0.0337) and chemotherapy (coefficient = -9.11, p = 0.003). Social scores were negatively associated with male sex (coefficient = -13.68, p = 0.001) and VP shunt placement (coefficient = -1.36, p = 0.005), whereas academic scores were negatively correlated with chemotherapy (coefficient = -17.45, p < 0.001) and age at surgery (coefficient = -1.92, p = 0.002). Extent of resection (coefficient = 13.16, p = 0.021) was a good predictor of higher academic scores.

Conclusion

CMS results in long-term neurological and neuropsychological deficits, negatively affecting QoL, and warranting early rehabilitation.

The Cerebellar Mutism Syndrome: Risk Assessment, Prevention and Treatment

Cerebellar mutism syndrome (CMS) has received increasing attention over the last decades as a complication of posterior fossa tumour surgery in children. Risk factors, aetiological aspects, and treatment measures of the syndrome have been investigated, yet the incidence of CMS remains unchanged. Overall, we are currently able to identify patients at risk, but we are unable to prevent it from occurring.Once CMS sets in, several symptomatic pharmacological treatments have been suggested, but only in smaller case series and not in randomized controlled trials, and it is not clear whether the treatment or time itself had a helpful effect.Within weeks to months, most patients regain their ability to speak after a phase with mutism or severely reduced speech; however, many patients continue to have speech and language deficits. At this point, anti-cancer treatment with chemotherapy and radiotherapy may be of focus more than the prognosis of CMS; however, many patients continue to have speech and language problems for months and years to come, and they are at high risk of other neurocognitive sequelae as well.Without reliable measures to prevent or treat the syndrome, we may look towards improving the prognosis of speech and neurocognitive functioning in these patients. As speech and language impairment is the cardinal symptom and late effect of CMS, the effect of intense and early-onset speech and language therapy as a standard of care in these patients should be investigated in relation to its effect on regaining speech capacity.

The Entity of Cerebellar Mutism Syndrome: A Narrative Review Centered on the Etiology, Diagnostics, Prevention, and Therapeutic Options

Cerebellar mutism syndrome (CMS), also known as posterior fossa syndrome, is an entity that entails a constellation of signs and symptoms which are recorded in a limited number of pediatric patients who have been operated on mainly for tumors involving the posterior cranial fossa, and more precisely, the region of the vermis. Medulloblastoma seems to constitute the most commonly recognized pathological substrate, associated with this entity. The most prevalent constituents of this syndrome are noted to be a, often transient, although protracted, language impairment, emotional lability, along with cerebellar and brainstem dysfunction. Apart from that, a definite proportion of involved individuals are affected by irreversible neurological defects and long-lasting neurocognitive impairment. A bulk of literature and evidence based on clinical trials exist, which reflect the continuous effort of the scientific community to highlight all perspectives of this complex phenomenon. There are several circumstances that intervene in our effort to delineate the divergent parameters that constitute the spectrum of this syndrome. In summary, this is implicated by the fact that inconsistent nomenclature, poorly defined diagnostic criteria, and uncertainty regarding risk factors and etiology are all constituents of a non-well-investigated syndrome. Currently, a preliminary consensus exists about the identification of a group of diagnostic prerequisites that are managed as sine qua non, in our aim to document the diagnosis of CMS. These include language impairment and emotional lability, as proposed by the international Board of the Posterior Fossa Society in their consensus statement. It is common concept that midline tumor location, diagnosis of medulloblastoma, younger age at diagnosis, and preoperatively established language impairment should be accepted as the most determinant predisposing conditions for the establishment of this syndrome. A well-recognized pathophysiological explanation of CMS includes disruption of the cerebellar outflow tracts, the cerebellar nuclei, and their efferent projections through the superior cerebellar peduncle. Despite the relative advancement that is recorded regarding the diagnostic section of this disease, no corresponding encouraging results are reported, regarding the available treatment options. On the contrary, it is mainly targeted toward the symptomatic relief of the affected individuals. The basic tenet of our review is centered on the presentation of a report that is dedicated to the definition of CMS etiology, diagnosis, risk factors, clinical presentation, and clinical management. Apart from that, an effort is made that attempts to elucidate the paramount priorities of the scientific forum, which are directed toward the expansion our knowledge in the era of diagnostics, prevention, and therapeutic options for patients suffering from CM, or who are at risk for development of this syndrome.

Comparison of Neurocognitive Functioning and Fine Motor Skills in Pediatric Cancer Survivors and Healthy Children

Background: The late treatment outcomes of pediatric brain tumors and of hematopoietic and lymphoid tissue tumors are an important focus of both rehabilitation and research. Neurocognitive and motor disorders induce further learning problems impeding social-emotional adaptation throughout a whole lifespan. Core deficits in short-term and working memory, visuospatial constructional ability, verbal fluency, and fine motor skills underlie distorted intellectual and academic achievement. This study aimed to assess the individual differences in cognitive ability and fine motor skills of pediatric tumor survivors and the age-matched healthy controls. Methods: A total of 504 tumor survivors after treatment and 646 age-matched healthy controls underwent neurocognitive and fine motor assessments. Findings: The group of tumor survivors scored significantly worse in both neurocognitive and fine motor skill in compared with the healthy control group. The pediatric brain tumor survivors (PBT group) performed worse in cognitive (p < 0.001 for verbal fluency and p < 0.001 for visuospatial constructional ability) and motor tests (p < 0.001) compared to the healthy controls. Hematopoietic and Lymphoid Tissues tumors survivors (THL group) performed worse in verbal fluency (p < 0.01) and visuospatial constructional test (p < 0.001) compared to the control group. Furthermore, the PBT group had worse results in visuospatial constructional ability (p < 0.05) and fine motor (p < 0.001) ability than the THL group. Significant differences between females and males were found in fine motor test performance in the PBT group (p < 0.05), as well as in verbal fluency (p < 0.01) and visuospatial constructional ability (p < 0.01) in the control group. Neurocognitive and fine motor skill characteristics in the THL group did not correlate with age.

Predicting neurocognitive function in pediatric brain tumor early survivorship: The neurological predictor scale and the incremental validity of tumor size

BACKGROUND

The Neurological Predictor Scale (NPS) quantifies cumulative exposure to conventional treatment-related neurological risks but does not capture potential risks posed by tumors themselves. This study evaluated the predictive validity of the NPS, and the incremental value of tumor location and size, for neurocognitive outcomes in early survivorship following contemporary therapies for pediatric brain tumors.

PROCEDURE

Survivors (N = 69) diagnosed from 2010 to 2016 were administered age-appropriate versions of the Wechsler Intelligence Scales. Hierarchical multiple regressions examined the predictive and incremental validity of NPS score, tumor location, and tumor size.

RESULTS

Participants (51% female) aged 6-20 years (M = 13.22, SD = 4.09) completed neurocognitive evaluations 5.16 years (SD = 1.29) postdiagnosis. The NPS significantly predicted Full-Scale Intelligence Quotient (FSIQ; ΔR2  = .079), Verbal Comprehension Index (VCI; ΔR2  = 0.051), Perceptual Reasoning Index (PRI; ΔR2  = 0.065), and Processing Speed Index (PSI; ΔR2  = 0.049) performance after controlling for sex, age at diagnosis, and maternal education. Tumor size alone accounted for a significant amount of unique variance in FSIQ (ΔR2  = 0.065), PRI (ΔR2  = 0.076), and PSI (ΔR2  = 0.080), beyond that captured by the NPS and relevant covariates. Within the full model, the NPS remained a significant independent predictor of FSIQ (β = -0.249, P = 0.016), VCI (β = -0.223, P = 0.048), and PRI (β = -0.229, P = 0.037).

CONCLUSIONS

Tumor size emerged as an independent predictor of neurocognitive functioning and added incrementally to the predictive utility of the NPS. Pretreatment disease burden may provide one of the earliest markers of neurocognitive risk following contemporary treatments. With perpetual treatment advances, measures quantifying treatment-related risk may need to be updated and revalidated to maintain their clinical utility.

Male Predisposition in Cerebellar Mutism Syndrome: a Cohort Study

The aim of this study was to explore the association between sex and cerebellar mutism syndrome and to examine other potential risk factors. This ambispective cohort study examined 218 pediatric patients (132 boys) with a posterior fossa tumor who underwent tumor resection from July 2013 to March 2021. The patients' demographics and tumor characteristics were examined and statistically analyzed to explore the associations among the variables. Multivariable and subgroup analyses were conducted to validate the independent risk factors for cerebellar mutism syndrome (CMS). The male and female patients did not differ significantly in terms of age, tumor size, tumor location, tumor consistency, VP shunt placement before resection, extent of resection, or surgeon, as well as with respect to the presence of hydrocephalus or paraventricular edema. The overall incidence of CMS was 32.6%. The incidence of CMS was significantly higher in male patients than that in female patients (41.7% vs. 18.6%; P = 0.001). In the multivariable analysis, male sex (adjusted odds ratio [OR], 3.27; P = 0.001), solid tumor consistency (adjusted OR, 5.61; P = 0.001), midline location (adjusted OR, 3.78; P = 0.004), and hydrocephalus (adjusted OR, 2.56; P = 0.047) were independent risk factors for the CMS. Chi-square analysis revealed that solid tumor consistency and midline location were associated with medulloblastoma (P < 0.001). Male patients had a higher risk of developing CMS after a posterior fossa tumor resection. Midline location, solid tumor consistency, and hydrocephalus were independent risk factors for CMS.

Cerebellar Mutism Syndrome in Pediatric Neuro-oncology: A Multidisciplinary Perspective and Call for Research Priorities

Cerebellar mutism syndrome (CMS), also known as posterior fossa syndrome, occurs in a subset of children after posterior fossa tumor resection, most commonly medulloblastoma. Patients with this syndrome exhibit often transient, although protracted, symptoms of language impairment, emotional lability, cerebellar, and brainstem dysfunction. However, many patients experience persistent neurological deficits and lasting neurocognitive impairment. Historically, research and clinical care were hindered by inconsistent nomenclature, poorly defined diagnostic criteria, and uncertainty surrounding risk factors and etiology. Proposed diagnostic criteria include two major symptoms, language impairment and emotional lability, as proposed by the international Board of the Posterior Fossa Society in their consensus statement as well as other experts in this field. Risk factors most commonly associated with development of CMS include midline tumor location, diagnosis of medulloblastoma and specific tumor subtype, younger age at diagnosis, and preoperative language impairment. A proposed etiology of CMS includes disruption of the cerebellar outflow tracts, the cerebellar nuclei, and their efferent projections through the superior cerebellar peduncle. Treatment for CMS remains supportive. Herein, we present a comprehensive overview of CMS etiology, diagnosis, risk factors, clinical presentation, and clinical management. In addition, we identify essential multidisciplinary research priorities to advance diagnostics, prevention, and intervention efforts for patients with, or at risk for, development of CMS.

A review of long-term deficits in memory systems following radiotherapy for pediatric posterior fossa tumor

INTRODUCTION

In recent years, progress in pediatric posterior fossa tumor (PFT) treatments has improved survival rates. However, the majority of survivors present neurocognitive sequelae that impact academic achievement.

METHODS

This review examines the literature from 2000 to 2020 on long-term outcomes in different memory systems for survivors of pediatric PFT, considering the impact of radiotherapy which is a well-known prognostic factor for global neurocognitive function.

RESULTS

Of the 43 articles selected, 31 explored working memory, 19 episodic memory, 9 semantic memory and 2 procedural memory. Irradiated survivors had scores of < -2 standard deviation (SD) (n = 4 studies/25) or between -2SD and -1SD (n =7 studies/25) for working memory; < -1SD for anterograde memory (n = 11/13), with a progressive decline in these two memory systems; < -1SD (n = 4/7) in semantic memory, and a deficit in perceptual-motor procedural learning (n = 1/1). Reducing craniospinal irradiation dose, limiting tumor bed boosts, and using proton therapy seem to have had a beneficial effect with better preservation of the memory score and a reduction in the decline over time. Non-irradiated survivors had memory systems that were less affected, with preservation of anterograde memory and maintenance of long-term stability.

CONCLUSION

Memory deficits are a core feature in survivors of pediatric PFT, especially when treatment requires radiotherapy. To limit these effects, dose constraints for specific brain areas involved in memory should be defined. During long-term follow-up, specific attention is essential to identify these deficits in order to limit their impact on the quality of life.

Evaluating the diagnostic validity of the Cerebellar Cognitive Affective Syndrome (CCAS) in pediatric posterior fossa tumour patients

Background

The aim of this case-control study was to investigate the severity of the cerebellar cognitive affective syndrome (CCAS) in patients treated for pediatric posterior fossa tumors (PFT) and evaluate its diagnostic validity and predictive value for long-term effects.

Methods

Using neuropsychological test data from 56 patients with PFT (average age: 14 years), the severity of deficits in the CCAS core areas (executive functions, verbal functions, visuospatial abilities and emotions/behaviour) was examined. Neuropsychological and academic long-term outcomes of patients with CCAS were compared to two control groups of PFT patients (treated with either surgery or surgery followed by radio-/chemotherapy) without the syndrome. Risk factors associated with various deficits were considered.

Results

All but one PFT patient suffered from slight to severe impairments in at least one CCAS domain, while complete CCAS occurred in 35.7%. Seven years after tumor diagnosis CCAS patients performed worse in information processing, logical reasoning, verbal functions, visuospatial skills, and executive functioning and required more special educational support compared to the control groups. CCAS patients performed equally poor as patients treated with chemo-/radiotherapy in tasks measuring information processing speed. Risk factors were significantly associated with deficits in information processing speed but not CCAS emergence.

Conclusions

Deficits in the core CCAS domains are commonly found in PFT patients, but varying in severity, which suggests the syndrome to be continuous rather than dichotomous. However, the validity of CCAS diagnosis was low and unspecific. The exclusion of relevant functions typically impaired in PFT patients (eg, information processing) resulted in difficulties being overlooked.

Risk factors for postoperative cerebellar mutism syndrome in pediatric patients: a systematic review and meta-analysis

OBJECTIVE

A review article assessing all the risk factors reported in the literature for postoperative cerebellar mutism syndrome (pCMS) among children remains absent. The authors sought to perform a systematic review and meta-analysis to evaluate this issue.

METHODS

PubMed, Embase, and Web of Science were queried to systematically extract potential references. The articles relating to pCMS were required to be written in the English language, involve pediatric patients (≤ 18 years of age), and provide extractable data, which included a comparison group of patients who did not develop pCMS. The quality of the included studies was evaluated using the Newcastle-Ottawa Scale. Data were pooled using RevMan 5.4, and publication bias was assessed by visual inspection for funnel plot asymmetry. The study protocol was registered through PROSPERO (ID: CRD42021256177).

RESULTS

Overall, 28 studies involving 2276 patients were included. Statistically significant risk factors identified from univariate analysis were brainstem invasion (OR 4.28, 95% CI 2.23-8.23; p < 0.0001), fourth ventricle invasion (OR 12.84, 95% CI 4.29-38.44; p < 0.00001), superior cerebellar peduncle invasion (OR 6.77, 95% CI 2.35-19.48; p = 0.0004), diagnosis of medulloblastoma (OR 3.26, 95% CI 1.93-5.52; p < 0.0001), medulloblastoma > 50 mm (OR 8.85, 95% CI 1.30-60.16; p = 0.03), left-handedness (OR 6.57, 95% CI 1.25-34.44; p = 0.03), and a vermis incision (OR 5.44, 95% CI 2.09-14.16; p = 0.0005). On the other hand, a tumor located in the cerebellar hemisphere (OR 0.23, 95% CI 0.06-0.92; p = 0.04), cerebellar hemisphere compression (OR 0.23, 95% CI 0.11-0.45; p < 0.0001), and intraoperative imaging (OR 0.36, 95% CI 0.18-0.72; p = 0.004) reduced the risk of pCMS.

CONCLUSIONS

This study provides the largest and most reliable review of risk factors associated with pCMS. Although some risk factors may be dependent on one another, the data may be used by surgeons to better identify patients at risk for pCMS and for intervention planning.

Spatiotemporal changes in along-tract profilometry of cerebellar peduncles in cerebellar mutism syndrome

Cerebellar mutism syndrome, characterised by mutism, emotional lability and cerebellar motor signs, occurs in up to 39% of children following resection of medulloblastoma, the most common malignant posterior fossa tumour of childhood. Its pathophysiology remains unclear, but prior studies have implicated damage to the superior cerebellar peduncles. In this study, the objective was to conduct high-resolution spatial profilometry of the cerebellar peduncles and identify anatomic biomarkers of cerebellar mutism syndrome. In this retrospective study, twenty-eight children with medulloblastoma (mean age 8.8 ± 3.8 years) underwent diffusion MRI at four timepoints over one year. Forty-nine healthy children (9.0 ± 4.2 years), scanned at a single timepoint, served as age- and sex-matched controls. Automated Fibre Quantification was used to segment cerebellar peduncles and compute fractional anisotropy (FA) at 30 nodes along each tract. Thirteen patients developed cerebellar mutism syndrome. FA was significantly lower in the distal third of the left superior cerebellar peduncle pre-operatively in all patients compared to controls (FA in proximal third 0.228, middle and distal thirds 0.270, p = 0.01, Cohen's d = 0.927). Pre-operative differences in FA did not predict cerebellar mutism syndrome. However, post-operative reductions in FA were highly specific to the distal left superior cerebellar peduncle, and were most pronounced in children with cerebellar mutism syndrome compared to those without at the 1-4 month follow up (0.325 vs 0.512, p = 0.042, d = 1.36) and at the 1-year follow up (0.342, vs 0.484, p = 0.038, d = 1.12). High spatial resolution cerebellar profilometry indicated a site-specific alteration of the distal segment of the superior cerebellar peduncle seen in cerebellar mutism syndrome which may have important surgical implications in the treatment of these devastating tumours of childhood.

Reading in Children Who Survived Cerebellar Tumors: Evidence from Eye Movements

Cerebellar tumors often affect the eye movement centers located in vermis, negatively affecting cognitive development and learning abilities in children. Previous research has established that patients who survived cerebellar tumors tend to demonstrate various saccadic impairments (e.g., hypermetria) and poor gaze stability as compared to healthy controls. The aim of the current study was to evaluate the influence of oculomotor deficits in such patients on reading parameters. A total of 112 children (8–17 y.o.), 65 of whom survived cerebellar tumors, participated in the study. The study design included several oculomotor and reading tasks. Eye movements were recorded every 1/60 s monocularly with an Arrington eye tracker. We observed profound reading impairments in the patients as compared to healthy children, including longer reading time, greater numbers of fixations and regressive saccades, and longer fixation durations. We also found significant correlations between changes in basic oculomotor functions and reading parameters. The patients also demonstrated gaze fixation instability, large number of fixations, and long scanpath reflecting the return of the gaze to the already counted objects. Thus, oculomotor changes caused by cerebellar tumor and its treatment led to disturbances in such neurocognitive activity as reading. Our findings emphasize the necessity of considering these deficits in cerebellar tumor survivors when designing rehabilitation protocols.

Development and application of a diagnostic and severity scale to grade post-operative pediatric cerebellar mutism syndrome

The post-operative pediatric cerebellar mutism syndrome (CMS) affects about one-third of children and adolescents following surgical removal of a posterior fossa tumor (PFT). According to the Posterior Fossa Society consensus working definition, CMS is characterized by delayed-onset mutism/reduced speech and emotional lability after cerebellar or 4th ventricle tumor surgery in children, and is frequently accompanied by additional features such as hypotonia and oropharyngeal dysfunction/dysphagia. The main objective of this work was to develop a diagnostic scale to grade CMS duration and severity. Thirty consecutively referred subjects, aged 1-17 years (median 8 years, IQR 3-10), were evaluated with the proposed Post-Operative Pediatric CMS Survey after surgical resection of a PFT and, in case of CMS, for 30 days after the onset (T₀) or until symptom remission. At day 30 (T₁), CMS was classified into mild, moderate, or severe according to the proposed scale. CMS occurred in 13 patients (43%, 95% C.I.: 25.5-62.6%), with mild severity in 4 cases (31%), moderate in 4 (31%), and severe in 5 (38%). At T₁, longer symptom persistence was associated with greater severity (p = 0.01). Greater severity at T₀ predicted greater severity at T₁ (p = 0.0001). Children with a midline tumor location and those aged under 5 years at diagnosis were at higher risk of CMS (p = 0.025 and p = 0.008, respectively). In conclusion, the proposed scale is a simple and applicable tool for estimating the severity of CMS at its onset, monitoring its course over time, and providing an early prognostic stratification to guide treatment decisions.

Processing Speed and Time since Diagnosis Predict Adaptive Functioning Measured with WeeFIM in Pediatric Brain Tumor Survivors

Simple Summary

Brain tumor (BT) survivors show difficulties in adaptive functioning (AF) and in acquiring independence (e.g., graduating, finding employment, building strong relationships, and being independent). The aim of our observational retrospective study is to explore the contribution of different clinical and cognitive variables in explaining and predicting the AF outcomes of BT survivors, measured with the Functional Independence Measure for Children (WeeFIM). The analysis demonstrated that processing speed and time since diagnosis are the main explanatory variables. Other clinical factors, such as age at diagnosis and hydrocephalus, differentially influence functional skills according to distinct domains (i.e., self-care, mobility, and cognition). The identification of the clinical factors influencing AF could suggest targets on which to focus attention. By successfully assessing, understanding, and managing AF, it will be possible to improve its management in pediatric BT survivors.

Abstract

(1) Background: Brain tumor (BT) survivors show difficulties in the acquisition of developmental milestones, related to academic achievement, vocational employment, social relationships, and autonomy. The skills underlying adaptive functioning (AF) are usually damaged in BT survivors due to the presence of the brain tumor, treatment-related factors, and other neurological sequelae. In this study, we aimed to explore the contribution of different cognitive factors in children with BT to AF, considering diagnosis-related variables. (2) Methods: Standardized cognitive assessment was undertaken and clinical information was collected from a retrospective cohort of 78 children with a BT, aged between 6 and 18 year old at the time of the assessment. Regression models were computed to investigate the influence of the selected variables on daily functional skills as measured by the Functional Independence Measure for Children (WeeFIM). (3) Results: The analyses showed that the main explanatory variables are processing speed and time since diagnosis. Other clinical variables, such as age at diagnosis and hydrocephalus, differentially influence functional skills according to distinct domains (i.e., self-care, mobility, and cognition). (4) Conclusions: The main explanatory variables of AF that emerged in our models point to a potential target of improving AF management in pediatric BT survivors.

A Paravermal Trans-Cerebellar Approach to the Posterior Fossa Tumor Causes Hypertrophic Olivary Degeneration by Dentate Nucleus Injury

Simple Summary

Posterior fossa tumor surgery is challenging due to the proximity and exposure of cerebellar structures. A favorable operative approach is unknown. Following lesions to the dentato–rubro–olivary-pathway, a neurodegenerative disease called hypertrophic olivary degeneration (HOD) can occur. This study for the first time demonstrates that paravermal trans-cerebellar approaches are associated with a significantly higher likelihood of HOD on MRI when compared to other approaches. This finding can well be attributed to dentate nucleus (DN) injury. Furthermore, cerebellar mutism syndrome (CMS) was discussed in the literature to be correlated with HOD due to a functional overlap of pathways involved. We found no such correlation in this study, but HOD was shown to be a reliable indicator for surgical disruption of efferent cerebellar pathways involving the DN. Henceforth, neurosurgeons should consider more midline or lateral approaches in posterior fossa surgery to spare the DN whenever feasible, and focus on cerebellar functional anatomy in their preoperative planning.

Abstract

Background: In brain tumor surgery, injury to cerebellar connectivity pathways can induce a neurodegenerative disease called hypertrophic olivary degeneration (HOD), along with a disabling clinical syndrome. In children, cerebellar mutism syndrome (CMS) is another consequence of damage to cerebello–thalamo–cortical networks. The goal of this study was to compare paravermal trans-cerebellar to other more midline or lateral operative approaches in their risk of causing HOD on MR-imaging and CMS. Methods: We scanned our neurosurgical database for patients with surgical removal of pilocytic astrocytoma, ependymoma and medulloblastoma in the posterior fossa. Fifty patients with a mean age of 22.7 (±16.9) years were identified and analyzed. Results: HOD occurred in n = 10/50 (20%) patients within four months (median), always associated with contralateral dentate nucleus (DN)-lesions (p < 0.001). Patients with paravermal trans-cerebellar approach significantly more often developed HOD (7/11; 63.6%) when compared to other approaches (3/39; 7.7%; p < 0.001). Injury to the DN occurred more frequently after a paravermal approach (8/11 vs. 13/39 patients; p < 0.05). CMS was described for n = 12/50 patients (24%). Data indicated no correlation of radiological HOD and CMS development. Conclusions: A paravermal trans-cerebellar approach more likely causes HOD due to DN-injury when compared to more midline or lateral approaches. HOD is a radiological indicator for surgical disruption of cerebellar pathways involving the DN. Neurosurgeons should consider trajectories and approaches in the planning of posterior fossa surgery that spare the DN, whenever feasible.