Cerebellar Mutism Syndrome: An Overview of the Pathophysiology in Relation to the Cerebrocerebellar Anatomy, Risk Factors, Potential Treatments, and Outcomes.

Cerebellar mutism syndrome (CMS) is one the most disabling postoperative neurological complications after posterior fossa surgery in children. CMS is characterized by a transient mutism with a typical onset demonstrated within 2 days postoperatively accompanied by associated ataxia, hypotonia, and irritability. Several hypotheses for the anatomical basis of pathophysiology and risk factors have been suggested. However, a definitive theory and treatment protocols have not yet been determined. Animal histological and electrophysiological studies and more recent human imaging studies have demonstrated the existence of a compartmentalized representation of cerebellar function, the understanding of which might provide more information on the pathophysiology. Damage to the dentatothalamocortical pathway and cerebrocerebellar diaschisis have been described as the anatomical substrate to the CMS. The risk factors, which include tumor type, brainstem invasion, tumor localization, tumor size, and vermal splitting technique, have not yet been clearly elucidated. The efficacy of potential pharmacological and speech therapies has been studied in small trials. Long-term motor speech deficits and associated cognitive and behavioral disturbances have now been found to be common among CMS survivors, affecting their development and requiring rehabilitation, leading to significant financial effects on the healthcare system and distress to the family. The aim of the present review was to outline the cerebellar anatomy and function and its connections in relationship to the pathophysiology and to refine the risk factors and treatment strategies for CMS.

The Selective Mutism Questionnaire: Data from typically developing children and children with selective mutism.

The core symptom of the anxiety disorder selective mutism (SM) is absence of speech in specific situations, such as at school. The most commonly used standardized instruments to assess speaking behavior are the parent-rated Selective Mutism Questionnaire (SMQ) and the teacher-rated School Speech Questionnaire (SSQ), scored from 0 to 3, indicating that speaking behavior never, seldom, often, and always occur. They were developed to assess severity of mutism and potential effects of treatment. However, prospective data on speaking behavior in typically developing children (TDs) are missing in the literature. The main aim of this study was to present data from TDs over time with previously reported data from children treated for SM, as a comparison. Participants were 64 children aged 3-9 years, 32 TDs who were a matched control group to 32 children with SM. At baseline, the mean SMQ and SSQ scores were ⩾2.5 in TDs and 0.5 in children with SM. The TDs did not show significant changes over time, while significantly increased speech was found in children with SM after treatment. Thus, our findings support the use of the SMQ/SSQ to assess baseline SM severity and to evaluate potential treatment effects in future studies.

Video self-modeling, fading, and reinforcement: An effective treatment package for children with selective mutism.

Three children aged 8 with selective mutism were treated with an intervention package that consisted of video self-modeling, stimulus fading, and reinforcement behavioral techniques for up to 8 weeks. Parents, teachers, and the researcher conducted a comprehensive assessment of participants' verbal behavior across multiple settings and throughout baseline, intervention, post-intervention, and 1-month follow-up phases of the study. Findings indicated participants' verbal communicative behavior increased significantly during post-intervention, and their progress was maintained at 1-month follow-up.

Alemtuzumab significantly improves posterior fossa syndrome presented as a relapse of multiple sclerosis.

BACKGROUND: Posterior fossa syndrome (PFS) is a rare manifestation of ponto-mesencephalic lesions frequently reported in post-surgical pediatric tumors, rarely described as a consequence of vascular, infective or inflammatory lesions. OBJECTIVE: The aim of this article is to report the clinical and neuroradiological characteristics of a patient with an acute PFS presentation as a relapse in relapsing-remitting MS, significantly responsive to Alemtuzumab treatment. CASE REPORT: 24-year-old patient affected by multiple sclerosis developed motor-cognitive and behavioral syndrome related to an extensive ponto-mesencephalic lesion under Fingolimod treatment. CONCLUSION: Our case highlights the significant and rapid effect of Alemtuzumab therapy on both cognitive and motor symptoms occurring during a MS relapse with atypical neuroradiological localization.

Liver Transplant Can Resolve Severe Neuropsychiatric Manifestations of Wilson Disease: A Case Report.

Although liver transplant for decompensated cirrhosis secondary to Wilson disease is well accepted, the use of transplant for patients with severe neurologic manifestations of this condition remains controversial, and these can be perceived as a contraindication. Here, we describe a 45-year-old woman who presented with an incidental hepatocellular carcinoma at the time of transplant. The patient had severe neurologic manifestations of Wilson disease pretransplant, including dysarthria, hyperreflexia, asymmetrical ataxia, tremor, bradyphrenia, and shuffling gait. She underwent successful transplant from a hepatic and surgical standpoint, but her postoperative course was marked by protracted mutism, hypophonia, and fluctuating akinesia and immobility that did not respond promptly to withdrawal of calcineurin inhibitors or pramipexole but did respond robustly to amantadine. At 9 months posttransplant, there was marked neurologic improvement, and, at 18 months, she exhibited subtle memory and organizational difficulties but was fully ambulatory and otherwise completely functional. Our experience suggests that even patients with severe neurologic Wilson disease may recover after transplant, albeit slowly, demonstrating the need for a multidisciplinary approach, including pre- and posttransplant neurologic and neuropsychiatric consultations.

Cerebellar mutism syndrome in children with brain tumours of the posterior fossa.

BACKGROUND: Central nervous system tumours constitute 25% of all childhood cancers; more than half are located in the posterior fossa and surgery is usually part of therapy. One of the most disabling late effects of posterior fossa tumour surgery is the cerebellar mutism syndrome (CMS) which has been reported in up to 39% of the patients but the exact incidence is uncertain since milder cases may be unrecognized. Recovery is usually incomplete. Reported risk factors are tumour type, midline location and brainstem involvement, but the exact aetiology, surgical and other risk factors, the clinical course and strategies for prevention and treatment are yet to be determined. METHODS: This observational, prospective, multicentre study will include 500 children with posterior fossa tumours. It opened late 2014 with participation from 20 Nordic and Baltic centres. From 2016, five British centres and four Dutch centres will join with a total annual accrual of 130 patients. Three other major European centres are invited to join from 2016/17. Follow-up will run for 12 months after inclusion of the last patient. All patients are treated according to local practice. Clinical data are collected through standardized online registration at pre-determined time points pre- and postoperatively. Neurological status and speech functions are examined pre-operatively and postoperatively at 1-4 weeks, 2 and 12 months. Pre- and postoperative speech samples are recorded and analysed. Imaging will be reviewed centrally. Pathology is classified according to the 2007 WHO system. Germline DNA will be collected from all patients for associations between CMS characteristics and host genome variants including pathway profiles. DISCUSSION: Through prospective and detailed collection of information on 1) differences in incidence and clinical course of CMS for different patient and tumour characteristics, 2) standardized surgical data and their association with CMS, 3) diversities and results of other therapeutic interventions, and 4) the role of host genome variants, we aim to achieve a better understanding of risk factors for and the clinical course of CMS - with the ultimate goal of defining strategies for prevention and treatment of this severely disabling condition. TRIAL REGISTRATION: Clinicaltrials.gov : NCT02300766 , date of registration: November 21, 2014.

Novel LINS1 missense mutation in a family with non-syndromic intellectual disability.

Newer sequencing technologies decipher molecular variations and increase the knowledge of pathogenesis of complex diseases like intellectual disability (ID), affecting 2-3% of the population. We report a novel family with a missense mutation in LINS1 as a cause for non-syndromic ID. Clinical exome sequencing for ID related genes carried out for a male with dysmorphism, mutism, and cognitive delay was uninformative. Subsequently, "pathogenic" and "likely pathogenic" variants associated with other inherited disorders were searched for as secondary findings. Further, PCR-RFLP carried out in other family members confirmed the result. A novel missense variant (c.937G>A) in exon 5 of LINS1 was detected in the proband. His affected elder brother was homozygous and the parents were heterozygous respectively, for the mutation. No mutation was observed in his unaffected sister. Mutations in LINS1 were suspected in this non-syndromic ID case with mutism. LINS1 alterations affect ELAV1 expression and result in reduction in the commissural axonal growth, thus affecting peripheral and central neuronal function. LINS1 acts in association with ß-catenin to influence WNT1 signaling. It is hypothesized that mutations in LINS1 may alter HuR expression during neural differentiation, leading to ID in humans. © 2017 Wiley Periodicals, Inc.

Cerebellar mutism syndrome: cause and rehabilitation.

PURPOSE OF REVIEW: Mutism of cerebellar origin may occur in the context of various causes but is most frequent in children after resection of a large midline cerebellar tumour. In this review, the endeavour to reach a consensus on name and definition of postoperative mutism of cerebellar origin and associated symptoms is highlighted. In addition, progress in understanding of cause and risk factors for the syndrome is discussed as well as the rehabilitation issues. RECENT FINDINGS: Consensus on the term cerebellar mutism syndrome (CMS) has been reached. The exact pathogenesis of CMS remains unclear. Recently, attention was drawn to the hypothesis that thermal injury might be an important mechanism in the pathogenesis of CMS. Diffusion tensor imaging tractography was found to visualize the damage to relevant pathways that are associated with persistent impairments after recovery of CMS. There is still no established treatment for CMS to date. SUMMARY: By reaching a consensus on terminology and description of CMS, a firm basis has been created for future research. The pathogenesis of CMS seems multifactorial and important risk factors have been found. However, CMS cannot be effectively prevented yet and no established or specific treatment is available, apart from very general rehabilitation and cognitive interventions.

Fluorodeoxyglucose positron emission tomography/computed tomography findings in a patient with cerebellar mutism after operation in posterior fossa.

Cerebellar mutism is a transient period of speechlessness that evolves after posterior fossa surgery in children. Although direct cerebellar and brain stem injury and supratentorial dysfunction have been implicated in the mediation of mutism, the pathophysiological mechanisms involved in the evolution of this kind of mutism remain unclear. Magnetic resonance imaging revealed dentatothalamocortical tract injuries and single photon emission computed tomography showed cerebellar and cerebral hypoperfusion in patients with cerebellar mutism. However, findings with 18F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT) in this group of patients have not been documented previously. In this clinical case, we report a patient who experienced cerebellar mutism after undergoing a posterior fossa surgery. Right cerebellar and left frontal lobe hypometabolism was shown using FDG PET/CT. The FDG metabolism of both the cerebellum and the frontal lobe returned to normal levels after the resolution of the mutism symptoms.

Posterior fossa syndrome: Review of the behavioral and emotional aspects in pediatric cancer patients.

Medulloblastoma, the most common malignant brain tumor of childhood, occurs in the posterior fossa, the part of the intracranial cavity that contains the brainstem and the cerebellum. The cerebellum is involved in many complex aspects of human behavior and function, and when it is disrupted or insulted, this can lead to significant sequelae in children with posterior fossa tumors. A constellation of impairing and distressing symptoms, including mutism, ataxia/hypotonia, and emotional lability, develops in approximately 25% of children after the surgical resection of posterior fossa tumors. These symptoms may impede treatment and frequently require intervention in order for children to be able to participate in their care. The eventual recovery of speech occurs for most, but with slowly improving dysarthria over many months. Behavioral changes and emotional lability also occur. This phenomenon has been classified differently by different investigators over the past 35 years. For the purposes of this article, the term posterior fossa syndrome is used to refer to the neuropsychiatric and behavioral features that compose this condition. The current review summarizes the development of the clinical understanding of this phenomenon with a focus on near- and long-term psychosocial and psychiatric implications. Also, clinical examples of the presentation, management, and lasting implications of this syndrome are provided. This review is intended to be a resource for clinicians who treat affected children. Cancer 2017;123:551-559. © 2016 American Cancer Society.

An auditory-neuroscience perspective on the development of selective mutism.

Selective mutism (SM) is a relatively rare psychiatric disorder of childhood characterized by consistent inability to speak in specific social situations despite the ability to speak normally in others. SM typically involves severe impairments in social and academic functioning. Common complications include school failure, social difficulties in the peer group, and aggravated intra-familial relationships. Although SM has been described in the medical and psychological literatures for many years, the potential underlying neural basis of the disorder has only recently been explored. Here we explore the potential role of specific auditory neural mechanisms in the psychopathology of SM and discuss possible implications for treatment.

Austistic Children: Bodily Factors in the Use of Language.

This paper addresses factors other than symbolic capacity that can influence the use of language by children on the autism spectrum. Chief among the issues considered are the influence of bodily experience on the articulation of words and the influence of fantasies concerning bodily relationships on the construction of words and sentences. It is suggested that such considerations may shed light on the behavior of those children on the autism spectrum whose symbolic capacity is greater than might be assumed from their use of language, and also on that of some children with selective mutism.

Abnormalities in auditory efferent activities in children with selective mutism.

Two efferent feedback pathways to the auditory periphery may play a role in monitoring self-vocalization: the middle-ear acoustic reflex (MEAR) and the medial olivocochlear bundle (MOCB) reflex. Since most studies regarding the role of auditory efferent activity during self-vocalization were conducted in animals, human data are scarce. The working premise of the current study was that selective mutism (SM), a rare psychiatric disorder characterized by consistent failure to speak in specific social situations despite the ability to speak normally in other situations, may serve as a human model for studying the potential involvement of auditory efferent activity during self-vocalization. For this purpose, auditory efferent function was assessed in a group of 31 children with SM and compared to that of a group of 31 normally developing control children (mean age 8.9 and 8.8 years, respectively). All children exhibited normal hearing thresholds and type A tympanograms. MEAR and MOCB functions were evaluated by means of acoustic reflex thresholds and decay functions and the suppression of transient-evoked otoacoustic emissions, respectively. Auditory afferent function was tested by means of auditory brainstem responses (ABR). Results indicated a significantly higher proportion of children with abnormal MEAR and MOCB function in the SM group (58.6 and 38%, respectively) compared to controls (9.7 and 8%, respectively). The prevalence of abnormal MEAR and/or MOCB function was significantly higher in the SM group (71%) compared to controls (16%). Intact afferent function manifested in normal absolute and interpeak latencies of ABR components in all children. The finding of aberrant efferent auditory function in a large proportion of children with SM provides further support for the notion that MEAR and MOCB may play a significant role in the process of self-vocalization.

Cerebellar mutism.

Mutism of cerebellar origin is a well-described clinical entity that complicates operations for posterior fossa tumors, especially in children. This review focuses on the current understanding of principal pathophysiological aspects and risk factors, epidemiology, clinical characteristics, treatment strategies, and outcome considerations. The PubMed database was searched using the term cerebellar mutism and relevant definitions to identify publications in the English-language literature. Pertinent publications were selected from the reference lists of the previously identified articles. Over the last few years an increasing number of prospective studies and reviews have provided valuable information regarding the cerebellar mutism syndrome. Importantly, the clarification of principal terminology that surrounds the wide clinical spectrum of the syndrome results in more focused research and more effective identification of this entity. In children who undergo surgery for medulloblastoma the incidence of cerebellar mutism syndrome was reported to be 24%, and significant risk factors so far are brainstem involvement and midline location of the tumor. The dentate-thalamo-cortical tracts and lesions that affect their integrity are considered significant pathophysiological issues, especially the tract that originates in the right cerebellar hemisphere. Moderate and severe forms of the cerebellar mutism syndrome are the most frequent types during the initial presentation, and the overall neurocognitive outcome is not as favorable as thought in the earlier publications. Advanced neuroimaging techniques could contribute to identification of high-risk patients preoperatively and allow for more effective surgical planning that should focus on maximal tumor resection with minimal risk to important neural structures. Properly designed multicenter trials are needed to provide stronger evidence regarding effective prevention of cerebellar mutism and the best therapeutic approaches for such patients with a combination of pharmacological agents and multidisciplinary speech and behavior augmentation.

Cerebellar mutism.

Cerebellar mutism occurs in about 25% of children following posterior fossa tumor surgery. It is usually accompanied by other neurological and behavioral disturbances. Mutism is transient in nature lasting several days to months and is frequently followed by dysarthria. In addition, impairment of language and other neuropsychological functions can be found after long term follow up in the majority of patients. The pathophysiological background of mutism may be higher speech dysfunction mediated by crossed cerebello-cerebral diaschisis which is frequently found during the mute period. Foremost injury to the bilateral dentatothalamocortical tract appears to be critical for the development of cerebello-cerebral diaschisis and subsequent mutism. Direct cerebellar injury is the likely reason for persisting deficits after the mute period. Minimization of injury to the dentatothalamocortical tract during surgery may be promising in the prevention of mutism. While there is no established treatment of mutism, early speech and rehabilitation therapy is recommended.

Evaluation of children with selective mutism and social phobia: a comparison of psychological and psychophysiological arousal.

Although children with social phobia (SP) and selective mutism (SM) present similarly in a clinical setting, it remains unclear whether children with SM are unable to speak due to overwhelming anxiety, or whether withholding speech functions as an avoidance mechanism. A total of 35 children (ages 5-12 years) with either SM (n = 10), SP (n = 11), or no diagnosis (n = 14) participated in the current study. Measurements included clinician, child, and parent ratings as well as behavioral observations and psychophysiological measures. Independent evaluators and clinicians rated children with SM as more severely impaired, more anxious, and less socially effective, but the groups did not differ in self- or parent-reported anxiety. Psychophysiological measures indicated that children in the SM group experienced less arousal than other children during social interaction tasks. The authors postulate that lack of speech may serve as an avoidance mechanism and thus account for this lack of arousal.

Dysarthria and mutism.

Dysarthria is a speech disorder associated with impairments of intelligibility, smoothness, loudness, and clarity of articulations. Dysarthria involves disability of reproducing various physical, tonal, and sound features of speech sounds in oral speech; unintelligible and slurred articulation with swallowing of sounds is characteristic. Articulatory movements and speech are slow, patients complain to the sensations of a 'thick' tongue and 'porridge' in the mouth. Patients'phrases are constructed correctly, vocabulary is not affected, and the grammatical structure of words is preserved. Reading, writing, internal speech, and understanding of speech are unaffected. Several types of dysarthria have been described on the basis of the lesion locations. Dysarthria can be associated with lacunar syndromes as well. Mutism represents a condition when patient cannot speak and answer the questions, but remains conscious and is able to produce written speech.