Cerebellar mutism syndrome: cause and rehabilitation

Evaluation of safety of fluoxetine for cerebellar mutism syndrome in children after posterior fossa surgery

BACKGROUND

Cerebellar mutism syndrome (CMS) occurs in 8-29 % of children undergoing posterior fossa tumor surgery. Its main symptoms are mutism and emotional lability. Although it is always transient, recovery time can be lengthy with long-term cognitive sequelae. There is no approved drug treatment for CMS, but some drugs are used in everyday medical practice. One of these is fluoxetine, which has been used for many years in our institution. The main objective of this study was to establish the safety profile of fluoxetine in this condition.

MATERIALS AND METHODS

The records of patients admitted to the pediatric intensive care unit after brain surgery at Angers University Hospital from 2010 to 2020 were reviewed. Children aged 2 years and older who underwent a posterior fossa tumor surgery and were diagnosed with CMS were included. Data on patient characteristics, prescription of fluoxetine treatment, side effects if any, and complete mutism duration were collected.

RESULTS

Among 246 patients admitted to the pediatric intensive care unit for brain surgery during the study period, 23 had CMS and eight were prescribed fluoxetine. No serious adverse event related to fluoxetine was reported. Complete mutism duration did not differ significantly between the fluoxetine group and the non-fluoxetine group(p = 0.22). However, the treatment was initiated after recovery from complete mutism in half of the treated patients.

CONCLUSION

This study suggests a positive safety profile of fluoxetine used in postoperative CMS. It does not answer the question of whether the treatment is effective for this indication. A randomized controlled trial based on a syndrome severity scale should be conducted to provide a more reliable assessment of the efficacy and safety of fluoxetine.

Cerebellar Mutism Syndrome After Posterior Fossa Tumor Surgery in Children-A Retrospective Single-Center Study

OBJECTIVE

Cerebellar mutism syndrome (CMS) is a well-known complication after posterior fossa tumor surgery in pediatric patients. We evaluated the incidence of CMS in our institute and analyzed its association with multiple risk factors, such as tumor entity, surgical approach, and hydrocephalus.

METHODS

All pediatric patients who had undergone intra-axial tumor resection in the posterior fossa between January 2010 and March 2021 were included in the retrospective analysis. Various data points, including demographic, tumor-associated, clinical, radiological, surgery-associated, complications, and follow-up data, were collected and statistically evaluated for an association with CMS.

RESULTS

A total of 63 surgeries in 60 patients were included. The median patient age was 8 years. Pilocytic astrocytoma was the most common tumor type (50%), followed by medulloblastoma (28%) and ependymomas (10%). Complete, subtotal, and partial resection was achieved in 67%, 23%, and 10%, respectively. A telovelar approach had been used the most often (43%) compared with a transvermian approach (8%). Of the 60 children, 10 (17%) had developed CMS and showed marked improvement but with residual deficits. The significant risk factors were a transvermian approach (P = 0.03), vermian splitting when added to another approach (P = 0.002), an initial presentation with acute hydrocephalus (P = 0.02), and hydrocephalus present after tumor surgery (P = 0.004).

CONCLUSIONS

Our CMS rate is comparable to those described in the literature. Despite the limitations of the retrospective study design, we found that CMS was not only associated with a transvermian approach but was also associated with a telovelar approach, although to a lesser extent. Acute hydrocephalus at the initial presentation necessitating urgent management was significantly associated with a greater incidence of CMS.

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 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.

Cerebellar mutism syndrome: From pathophysiology to rehabilitation

Cerebellar mutism syndrome (CMS) is a common complication following surgical resection of childhood tumors arising in the posterior fossa. Alteration of linguistic production, up to muteness and emotional lability, generally reported at least 24 h after the intervention, is the hallmark of post-operative CMS. Other associated traits include hypotonia and other cerebellar motor signs, cerebellar cognitive-affective syndrome, motor deficits from the involvement of the long pathways, and cranial neuropathies. Recovery usually takes 6 months, but most children are burdened with long-term residual deficits. The pathogenic mechanism is likely due to the damage occurring to the proximal efferent cerebellar pathway, including the dentate nucleus, the superior cerebellar peduncle, and its decussation in the mesencephalic tegmentum. Proven risk factors include brain stem invasion, diagnosis of medulloblastoma, midline localization, tumor size, invasion of the fourth ventricle, invasion of the superior cerebellar peduncle, left-handedness, and incision of the vermis. Currently, rehabilitation is the cornerstone of the treatment of patients with cerebellar mutism syndrome, and it must consider the three main impaired domains, namely speech, cognition/behavior, and movement.

Postoperative MRI features of cerebellar mutism syndrome: a retrospective cohort study

OBJECTIVE

In this study, the authors aimed to investigate the relationship between postoperative MRI features and cerebellar mutism syndrome.

METHODS

A retrospective cohort of patients who underwent tumor resection from July 2013 to March 2021 for midline posterior fossa tumors was investigated. All patients were followed up at least once. Clinical data were extracted from medical records and follow-up databases. Two neuroradiologists independently reviewed preoperative and postoperative MRI. Univariable and multivariable analyses were performed to compare the postoperative cerebellar mutism syndrome (pCMS) and non-pCMS groups. Correlation analysis was performed using the Spearman correlation coefficient analysis.

RESULTS

Of 124 patients, 47 (37.9%) developed pCMS. The median follow-up duration was 45.73 (Q1: 33.4, Q3: 64.0) months. The median duration of mutism was 45 days. The median tumor size was 48.8 (Q1: 42.1, Q3: 56.8) mm. In the univariable analysis, abnormal T2-weighted signal of the left dentate nucleus (DN) (74.5% in the pCMS group vs 36.4% in the non-pCMS group, p < 0.001), right DN (83.0% vs 40.3%, p < 0.001), left superior cerebellar peduncle (SCP) (74.5% vs 27.3%, p < 0.001), right SCP (63.8% vs 23.4%, p < 0.001), left middle cerebellar peduncle (MCP) (51.1% vs 26.0%, p = 0.008), and right MCP (61.7% vs 26.0%, p < 0.001); male sex (83.0% vs 45.5%, p < 0.001); vermis 3 impairment (49.4% vs 19.1%, p = 0.002); solid tumor (91.5% vs 72.7%, p = 0.022); and hydrocephalus (72.3% vs 45.5%, p = 0.006) were more frequent in the pCMS group than in the non-pCMS group. Multivariable logistic analysis showed that male sex (adjusted OR 4.08, p = 0.010) and the cerebro-cerebellar circuit score of T2-weighted images (adjusted OR 2.15, p < 0.001) were independent risk factors for pCMS. The cerebro-cerebellar circuit score positively correlated with the duration of mutism. In Cox regression analysis, the cerebro-cerebellar integrated circuit injury score of T2 (adjusted HR 0.790, 95% CI 0.637-0.980; p = 0.032) and injury of vermis 3 (adjusted HR 3.005, 95% CI 1.197-7.547; p = 0.019) were independently associated with the duration of mutism.

CONCLUSIONS

Male sex and cerebro-cerebellar circuit damage are independent risk factors for pCMS. The cerebro-cerebellar circuit score indicates the duration of mutism.

Power and connectivity changes on electroencephalogram in postoperative cerebellar mutism

INTRODUCTION

Cerebellar mutism syndrome is a debilitating postoperative neurological complication following posterior fossa surgery in children. It is characterized by a significant lack or loss of speech. Injury to the dentato-thalamo-cortical pathway is thought to be the main anatomical substrate of cerebellar mutism syndrome; however, few studies have investigated the physiological changes using computed electroencephalogram.

CASE REPORT

Herein, we report a case of a nine-year-old girl who developed cerebellar mutism syndrome after excision of an ependymoma of the fourth ventricle and was followed up with evaluation of aphasia, gross motor function, and scalp electroencephalograms. Her language, dysmetria and gait ataxia gradually improved until day 605 after onset. Computed electroencephalogram analyses were performed for the relative power spectrum and connectivity at each frequency band. On the three electroencephalograms at days 109, 299, and 605 after onset, the relative power spectrum at the delta band transiently decreased and then increased, and the relative power spectrums at theta, beta, and gamma bands transiently increased and then decreased. Only the relative power spectrum in the alpha band continuously increased in the occipital area. Additionally, brain connectivity in the delta, beta, and gamma bands increased continuously.

CONCLUSION

We report a case of cerebellar mutism syndrome with recovery of language, dysmetria and gait ataxia in 20 months. Electroencephalogram analyses indicated transient changes in the powers of brain activity and continuous improvements in connectivity during the long follow-up, reflecting the plasticity and remodeling of brain function after cerebellar mutism syndrome. Power and connectivity analyses for EEG might be a tool to investigate underlying pathophysiology of cerebellar mutism syndrome.

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.

Cerebellar Mutism Syndrome in Children After Surgery for a Posterior Fossa Tumor: Patient Characteristics and Recovery

Background: Cerebellar mutism syndrome (CMS) is a potential complication that may be experienced by children undergoing a resection of a posterior fossa tumor. Symptoms include mutism and emotional lability; additional symptoms may include hypotonia, difficulty swallowing, ataxia, and changes in cognition. The recovery of children experiencing CMS symptoms can be variable. In this retrospective chart review study, we identified the presenting characteristics of CMS in a cohort of children and compared them to matched-controls who did not develop CMS and examined recovery patterns during the year after diagnosis. Methods: Patients were identified through the program database. Children between ages 3 and 18 years who had a craniotomy for a posterior fossa tumor at our institution were included. For each CMS case, two control cases were selected to match the type of central nervous system tumor, sex, age group, and surgery date. Patient characteristics were abstracted from the patient's electronic medical record and the CMS survey was used to score CMS cases. Results: Seventeen children with CMS and 34 children without CMS were included in the review. Among children with CMS, 53% experienced mutism for less than 4 weeks; ataxia persisted beyond 4 weeks for more than 88% of the children and was still present in 71% 1 year after diagnosis. Clinical characteristics did not differ between the case and control groups. Discussion: CMS symptoms interfere with the child's quality of life and ongoing development. Study findings inform nurses providing anticipatory guidance and support to patients experiencing CMS and their families.

Structural damage burden and hypertrophic olivary degeneration in pediatric postoperative cerebellar mutism syndrome

Cerebellar mutism syndrome (CMS) occurs in one out of four children after posterior fossa tumor surgery, with open questions regarding risk factors, pathophysiology, and prevention strategies. Because of similarities between several cerebellar syndromes, a common pathophysiology with damage to the dentato-thalamo-cortical and dentato-rubro-olivary pathways has been proposed. Hypertrophic olivary degeneration (HOD) is an imaging correlate of cerebellar injury observed for instance in stroke patients. Aim of this study was to investigate whether the occurrence and severity of CMS correlates with the extent of damage to the relevant anatomical structures and whether HOD is a time-dependent postoperative neuroimaging correlate of CMS. We performed a retrospective single center study of CMS patients compared with matched non-CMS controls. CMS occurred in 10 children (13% of the overall cohort) with a median age of 8 years. Dentate nucleus (DN) injury significantly correlated with CMS, and superior cerebellar peduncle (SCP) injury was associated by tendency. HOD was observed as a dynamic neuroimaging phenomenon in the postoperative course and its presence significantly correlated with CMS and DN injury. Children who later developed HOD had an earlier onset and tended to have longer persistence of CMS. These findings can guide surgical measures to protect the DN and SCP during posterior fossa tumor resections and to avoid a high damage burden (i.e., bilateral damage). Development of intraoperative neuromonitoring of the cerebellar efferent pathways as well as improved preoperative risk stratification could help to establish a patient-specific strategy with optimal balance between degree of resection and functional integrity.

Improved prediction of postoperative paediatric cerebellar mutism syndrome using an artificial neural network

Background

Postoperative paediatric cerebellar mutism syndrome (pCMS) is a common but severe complication which may arise following the resection of posterior fossa tumours in children. Two previous studies have aimed to preoperatively predict pCMS, with varying results. In this work, we examine the generalisation of these models and determine if pCMS can be predicted more accurately using an artificial neural network (ANN).

Methods

An overview of reviews was performed to identify risk factors for pCMS, and a retrospective dataset collected as per these defined risk factors from children undergoing resection of primary posterior fossa tumours. The ANN was trained on this dataset and its performance evaluated in comparison to logistic regression and other predictive indices via analysis of receiver operator characteristic curves. Area under the curve (AUC) and accuracy were calculated and compared using a Wilcoxon signed rank test, with p&lt;0.05 considered statistically significant.

Results

204 children were included, of whom 80 developed pCMS. The performance of the ANN (AUC 0.949; accuracy 90.9%) exceeded that of logistic regression (p&lt;0.05) and both external models (p&lt;0.001).

Conclusion

Using an ANN, we show improved prediction of pCMS in comparison to previous models and conventional methods.

The surgical resection of dysplastic cerebellar gangliocytoma assisted by intraoperative sonography: illustrative case

BACKGROUND

Dysplastic gangliocytoma of the cerebellum (Lhermitte-Duclos disease) is an extremely rare, slow-growing hereditary mass lesion that is mainly characterized by both specific neuroradiological features and secondary hydrocephalus. Patients may present with symptoms of cerebellar mass lesion and increased intracranial pressure. As an important part of Cowden syndrome, Lhermitte-Duclos disease in adults is typically marked by PTEN gene mutation.

OBSERVATIONS

The clinical management of a 31-year-old woman who suffered Lhermitte-Duclos disease was introduced in this case report. Subtotal resection was performed with the assistance of intraoperative sonography to relieve obstructive hydrocephalus, and prophylactic C1 laminectomy was performed to prevent possible postoperative progression of the residual lesion. Perioperative care and surgical process were clearly revealed in an accompanying video. Intraoperative sonography of Lhermitte-Duclos disease presents hyperechoic distorted thickening cortices surrounded by hypoechoic edema belt. The patient did not report any significant neurological complications or sequelae after the lesion resection.

LESSONS

The authors first reported the use of intraoperative sonography in resection of adult-onset Lhermitte-Duclos disease. Hopefully, the educative case report can provide a feasible experience in the diagnosis and treatment of Lhermitte-Duclos disease.

The medical therapy for cerebellar mutism syndrome: a case report and literature review

PURPOSE

Cerebellar mutism syndrome (CMS) represents a major complication affecting many children that undergo surgery for posterior fossa lesions. Etiology and pathophysiology are still not fully understood. CMS deeply influences quality of life and recovery of these patients. An effective treatment has not been defined yet. This case-based review aims at analyzing the available evidence and knowledge to better delineate this phenomenon and to determine whether CMS can be successfully treated with pharmacological therapy.

METHODS

Systematic research and retrieval of databases were conducted analyzing all papers where medical treatment of CMS was reported. A summary of the latest understanding and reports regarding definition, clinical manifestations, pathophysiology, management, and outcome of CMS has been conducted.

RESULTS

Consensus on definition of this syndrome is lacking. CMS is the term accepted by the Posterior Fossa Society in 2016. Pathophysiology is still poorly understood but the most likely mechanism is injury along proximal components of the efferent cerebellar pathway. Nine papers describing positive effects of pharmacological therapy for CMS have been identified. Fluoxetine, zolpidem, bromocriptine, and midazolam are the drugs that seem to alleviate symptoms of CMS and improve recovery. To date, cognitive rehabilitation and physiotherapy are the only treatment options available.

CONCLUSION

CMS has deep impact on affected children and their families. Despite attempts to identify preventive measures and treatment, cases still occur on a regular basis. Pharmacological treatments have been proposed to help reduce the symptoms of CMS with some promising results, but reports are limited; therefore, further studies are needed.

Cerebellum and Prematurity: A Complex Interplay Between Disruptive and Dysmaturational Events

The cerebellum plays a critical regulatory role in motor coordination, cognition, behavior, language, memory, and learning, hence overseeing a multiplicity of functions. Cerebellar development begins during early embryonic development, lasting until the first postnatal years. Particularly, the greatest increase of its volume occurs during the third trimester of pregnancy, which represents a critical period for cerebellar maturation. Preterm birth and all the related prenatal and perinatal contingencies may determine both dysmaturative and lesional events, potentially involving the developing cerebellum, and contributing to the constellation of the neuropsychiatric outcomes with several implications in setting-up clinical follow-up and early intervention.

Living with the cerebellar mutism syndrome: long-term challenges of the diagnosis

BACKGROUND

After posterior fossa tumour surgery, up to 39% of children experience postoperative cerebellar mutism syndrome (CMS) characterized by mutism and other motor and cognitive impairments. There is a lack of knowledge on the patient-reported challenges and long-term needs. Consequently, no specific recommendations exist for rehabilitative and supportive interventions for patients with CMS. The aims of this study were to explore the patients' experiences related to the sequelae of CMS, to identify challenges and needs regarding support and rehabilitation in the period of growing from child to adult and to add perspectives for future developments of supportive care and rehabilitative guidelines.

METHODS

Ten semi-structured interviews were conducted with young adults diagnosed with CMS as children. A thematic analysis identified four themes describing challenges impacting aspects of the participants' lives.

RESULTS

Four main themes were identified and highlight the rehabilitative need for focus on verbal and non-verbal communication skills in addition to the physical impairments. We found that brain tumour survivors with CMS can benefit from social and educational rehabilitation, straightforward and truthful information, support in structuring their everyday lives and increased public knowledge of CMS.

CONCLUSION

Children with CMS face a variety of challenges affecting many aspects of their everyday lives. They should be entitled to the elements of a current rehabilitation initiative for childhood cancer to support patients' social disability and educational decline. Finally, we identified a need for an official information publication.

A Focus on the Cerebellum: From Embryogenesis to an Age-Related Clinical Perspective

The cerebellum and its functional multiplicity and heterogeneity have been objects of curiosity and interest since ancient times, giving rise to the urge to reveal its complexity. Since the first hypothesis of cerebellar mere role in motor tuning and coordination, much more has been continuously discovered about the cerebellum’s circuitry and functioning throughout centuries, leading to the currently accepted knowledge of its prominent involvement in cognitive, social, and behavioral areas. Particularly in childhood, the cerebellum may subserve several age-dependent functions, which might be compromised in several Central Nervous System pathologies. Overall, cerebellar damage may produce numerous signs and symptoms and determine a wide variety of neuropsychiatric impairments already during the evolutive age. Therefore, an early assessment in children would be desirable to address a prompt diagnosis and a proper intervention since the first months of life. Here we provide an overview of the cerebellum, retracing its morphology, histogenesis, and physiological functions, and finally outlining its involvement in typical and atypical development and the age-dependent patterns of cerebellar dysfunctions.

Longitudinal associations between exposure to anesthesia and neurocognitive functioning in pediatric medulloblastoma

AIM

To examine whether anesthesia exposure is associated with neurocognitive decline in pediatric medulloblastoma.

METHODS

Patients were treated at St. Jude Children's Research Hospital and completed ≥2 protocol-directed neurocognitive assessments (n = 107) as part of a multisite clinical trial for pediatric medulloblastoma (NCT00085202). Patients received risk-adapted craniospinal photon irradiation, followed by four cycles of high-dose chemotherapy and stem cell rescue. Neurocognitive testing was completed at study baseline (after surgery and <2 weeks of starting radiation therapy) and annually for 5 years. Data on anesthesia exposure during treatment was abstracted from medical records.

RESULTS

Patients were 10.2 years at diagnosis on average (SD = 4.5; 37% female, 73% average-risk). Mean cumulative anesthesia duration was 20.4 h (SD = 15.2; range 0.7-55.6 h). In the overall group, longer anesthesia duration was associated with greater declines in IQ (Estimate = -0.08, P < 0.001), attention (Estimate = -0.10, P < .001) and processing speed (Estimate = -0.13, P < 0.001). Similar results were shown in subgroups of patients who were <7 years at diagnosis (IQ = -0.14, P = 0.027; Attention = -0.25: P = 0.011), ≥7 years at diagnosis (Attention = -0.07, P = 0.039; Processing Speed = -0.08, P = 0.022), treated for high-risk disease (IQ = -0.09, P = 0.024; Attention = -0.11, P = 0.034; Processing Speed = -0.13, P = 0.001), or treated for average-risk disease (IQ = -0.05, P = .022; Attention = -0.08, P = 0.011; Processing Speed = -0.10, P < 0.001).

CONCLUSION

Greater anesthesia exposure is a risk factor for clinically significant neurocognitive decline, in addition to factors of age at diagnosis and treatment risk arm. This result is notable as there are evidence-based strategies that can limit the need for anesthesia. Limiting anesthesia exposure, as feasible, may mitigate neurocognitive late effects, and thus, improve quality of life for survivors.

Functional tracts of the cerebellum-essentials for the neurosurgeon

The cerebellum is historically implicated in motor coordination, but accumulating modern evidence indicates involvement in non-motor domains, including cognition, emotion, and language. This correlates with the symptoms observed in postoperative cerebellar mutism syndrome (CMS). Profound knowledge of cerebellar functional topography and tractography is important when approaching cerebellar tumors, as surgical trauma to relevant structures of cerebellar pathways plays a role in the pathogenesis of CMS. The aim of this systematic review is to provide a concise overview of relevant modern neuroimaging data and cerebellar functional tracts with regard to neurosurgical procedures.

Bromocriptine for the treatment of postoperative cerebellar mutism syndrome in pediatric patients: Three case reports

INTRODUCTION

Cerebellar mutism syndrome (CMS) is a common complication after posterior fossa tumor resection. It is characterized by a significant lack or loss of speech. Its biological origin remains unclear and there are no standardized treatments. However, bromocriptine seems to be a possible treatment for this condition.

CASE REPORT

In this paper, we present three cases of pediatric patients (4, 5, and 17-year old) who developed CMS after posterior fossa tumor surgery. They were treated with bromocriptine to improve neurological symptoms.Management and outcome: Bromocriptine was started at a low dose and was progressively increased to reach the minimum effective dose. After four months of treatment, a normal and fluid speech was observed in the three patients. No discontinuation due to adverse events were reported.

DISCUSSION

Bromocriptine has shown to be an effective and safe treatment for CMS in pediatric patients after posterior fossa tumor resection.

Cerebellar mutism syndrome: current approaches to minimize risk for CMS

PURPOSE

Cerebellar mutism syndrome (CMS) is a serious source of morbidity following posterior fossa surgery in the pediatric population. However, methods for effectively decreasing its incidence and impact remain unclear. It is our aim to examine the impact of adjusting surgical factors, namely the use of a telovelar approach and avoidance of cavitronic ultrasonic aspirator, on the incidence of CMS in our population as well as outlining potential pre-, intra-, and postoperative factors that may contribute to its development.

METHODS

Retrospective review was performed to identify patients undergoing posterior fossa surgery for resection of a medulloblastoma. Demographic, surgical, and postoperative data were collected. These data were analyzed for possible correlations to the risk of developing CMS via univariate analysis. For factors found to be significant, a multivariate analysis was performed to assess their independence.

RESULTS

Seven of 65 patients (10.8%) developed CMS postoperatively. Factors found to be significantly associated with a higher risk of CMS were the degree of retraction utilized during the procedure (p = 0.0000) and incision of the vermis (p = 0.0294). Although they did not reach the threshold of statistical significance, tumor vascularity (p = 0.19), adoption of a transvermian approach (p = 0.19), and lack of intraoperative imaging (p = 0.17) exhibited strongly suggestive trends towards a correlation with CMS.

DISCUSSION

In an effort to reduce the incidence and severity of CMS in our population, our institution adopted surgical practices that minimize tissue trauma and mitigate postoperative edema. This included the use of a telovelar over a transvermian approach to obviate the need for vermian incision, avoidance of the CUSA, and minimization of heavy retraction during surgery. This was successful in reducing the incidence of CMS from 39% in our medulloblastoma patients to 10.8%. The development of CMS after posterior fossa surgery appears to be a "two-hit" phenomenon requiring a combination of existing predisposition, surgical injury, and postoperative exacerbation. Therefore, it is critical to identify the factors involved at each stage and investigate treatments to target them appropriately.

Cerebellar mutism syndrome

Cerebellar mutism most commonly, but not exclusively, develops in children after surgery for midline cerebellar or intraventricular tumors in the posterior fossa, typically medulloblastoma. Cerebellar mutism syndrome (CMS) comprises a complex set of neurologic and neurocognitive signs and symptoms, the cardinal and central component of which is an initially profound but usually reversible speech disorder. As such, CMS is currently recognized as an extreme form of the so-called cerebellar cognitive affective syndrome (Schmahmann syndrome). The putative cause of CMS is a substantial surgical injury to the proximal components of the bilateral efferent cerebellar pathways, disrupting cerebellar input to the supratentorial brain. The resultant cerebellocerebral diaschisis may lead to supratentorial cortical perfusion depression with frontal predominance. The speech disorder is, therefore, likely an apraxia. As our understanding of the mechanism and the clinical spectrum of CMS evolves, clinically useful preoperative risk stratification schemes, adjustments to surgical strategies and techniques, and possible early therapeutic-rehabilitative measures are being sought and developed to reduce the burden of this severe and particularly handicapping chronic morbidity on affected individuals and their families.

Risk factors for development of postoperative cerebellar mutism syndrome in children after medulloblastoma surgery

OBJECTIVE Postoperative cerebellar mutism syndrome (pCMS) occurs in 7%-50% of children after cerebellar tumor surgery. Typical features include a latent onset of 1-2 days after surgery, transient mutism, emotional lability, and a wide variety of motor and neurobehavioral abnormalities. Sequelae of this syndrome usually persist long term. The principal causal factor is bilateral surgical damage (regardless of tumor location) to any component of the proximal efferent cerebellar pathway, which leads to temporary dysfunction of cerebral cortical regions as a result of diaschisis. Tumor type, cerebellar midline location, and brainstem involvement are risk factors for pCMS that have been identified repeatedly, but they do not explain its latent onset. Ambiguous or negative results for other factors, such as hydrocephalus, postoperative meningitis, length of vermian incision, and tumor size, have been reached. The aim of this study was to identify perioperative clinical, radiological, and laboratory factors that also increase risk for the development of pCMS. The focus was on factors that might explain the delayed onset of pCMS and thus might provide a time window for taking precautionary measures to prevent pCMS or reduce its severity. The study was focused specifically on children who had undergone surgery for medulloblastoma. METHODS In this single-center retrospective cohort study, the authors included 71 children with medulloblastoma, 28 of whom developed pCMS after primary resection. Clinical and laboratory data were collected prospectively and analyzed systematically. Variables were included for univariate and multivariate analysis. RESULTS Univariate regression analysis revealed 7 variables that had a significant influence on pCMS onset, namely, tumor size, maximum tumor diameter > 5 cm, tumor infiltration or compression of the brainstem, significantly larger decreases in hemoglobin (p = 0.010) and hematocrit (p = 0.003) in the pCMS group after surgery than in the no-pCMS group, significantly more reported incidents of severe bleeding in the tumor bed during surgery in the pCMS group, preoperative hydrocephalus, and a mean body temperature rise of 0.5°C in the first 4 days after surgery in the pCMS group. Multiple regression analysis revealed that tumor size, tumor infiltration into or compression of the brainstem, and higher mean body temperature in the first 4 postoperative days were independent and highly significant predictors for pCMS. CONCLUSIONS The authors confirmed earlier findings that tumor-associated preoperative conditions, such as a maximum tumor diameter ≥ 5 cm and infiltration into or compression of the brainstem, are associated with a higher risk for the development of pCMS. Most importantly, the authors found that a 0.5°C higher mean body temperature in the first 4 postoperative days increased the odds ratio for the development of pCMS almost 5-fold. These data suggest that an important focus for the prevention of pCMS in children who have undergone medulloblastoma surgery might be rigorous maintenance of normothermia as standard care after surgery.