Karin S. Walsh

The cerebellar mutism syndrome and its relation to cerebellar cognitive function and the cerebellar cognitive affective disorder.

The postoperative cerebellar mutism syndrome (CMS), consisting of diminished speech output, hypotonia, ataxia, and emotional lability, occurs after surgery in up to 25% of patients with medulloblastoma and occasionally after removal of other posterior fossa tumors. Although the mutism is transient, speech rarely normalizes and the syndrome is associated with long-term adverse neurological, cognitive, and psychological sequelae. The clinical, neuroradiographic, and neuropsychological findings associated with CMS as well as possible mechanisms of injury are reviewed. Theories about the pathophysiology of CMS have evolved along with our understanding of the cerebellum as an important structure in the distributive neurocircuitry underlying complex speech, cognition, and behavior. CMS shares many similarities with the cerebellar cognitive affective syndrome, more commonly described in adults and consisting of disturbances of executive function, visuospatial skills, nonmotor language, and affect regulation. Future directions include more thorough neuropsychological characterization, functional and diffusion tensor imaging studies, and investigations into the underlying differences that may make some patients more vulnerable to CMS.

Lovastatin as Treatment for Neurocognitive Deficits in Neurofibromatosis Type 1: Phase I Study

In a neurofibromatosis type 1 murine model, treatment with lovastatin reversed cognitive disabilities. We report on a phase I study examining the safety and tolerability of lovastatin in children with neurofibromatosis type 1. Twenty-four children with neurofibromatosis type 1 underwent a dose-escalation protocol for 3 months to identify the maximum tolerated dose and potential toxicity. Minimal side effects were evident, and no child experienced dose-limiting toxicity. Cognitive evaluations were completed before and after treatment, and the results suggested improvement in areas of verbal and nonverbal memory. Additional analyses, using reliable change indices, indicated improvements exceeding those of test-retest or practice effects in some participants. These observations may be analogous to the improvements observed in a neurofibromatosis type 1 murine model treated with lovastatin, although further study and replication are required. The safety and preliminary cognitive results support the need for a larger phase II trial in this population.

Symptomatology of autism spectrum disorder in a population with neurofibromatosis type 1

Aim  Difficulties in neurocognition and social interaction are the most prominent causes of morbidity and long‐term disability in children with neurofibromatosis type 1 (NF1). Symptoms of attention‐deficit–hyperactivity disorder (ADHD) have also been extensively recognized in NF1. However, systematic evaluation of symptoms of autism spectrum disorder (ASD) in children with NF1 has been limited.

Intellectual and academic outcome following two chemotherapy regimens and radiotherapy for average-risk medulloblastoma: COG A9961

Assess the intellectual and academic outcomes as well as risk factors associated with treatment for average‐risk medulloblastoma in childhood using 23.4 Gy of craniospinal radiotherapy plus adjuvant chemotherapy.

Consensus paper on post-operative pediatric cerebellar mutism syndrome: the Iceland Delphi results

IntroductionConfusion has surrounded the description of post-operative mutism and associated morbidity in pediatric patients with cerebellar tumors for years. The heterogeneity of definitions and diagnostic features has hampered research progress within the field, and to date, no international guidelines exist on diagnosis, prevention, treatment, or follow-up of this debilitating condition. An international group of clinicians and researchers from multiple relevant disciplines recently formed a cohesive panel to formulate a new working definition and agree upon standardized methods for diagnosis and follow-up.MethodsConsensus was obtained using the modified nominal group technique, involving four rounds of online Delphi questionnaires interspersed with a structured consensus conference with lectures, group work, and open discussion sessions.ResultsA new, proposed definition of “post-operative pediatric CMS” was formed, preliminary recommendations for diagnostic and follow-up procedures were created, two working groups on a new scoring scale and risk prediction and prevention were established, and areas were identified where further information is needed.DiscussionThe consensus process was motivated by desire to further research and improve quality of life for pediatric brain tumor patients. The Delphi rounds identified relevant topics and established basic agreement, while face-to-face engagement helped resolve matters of conflict and refine terminology. The new definition is intended to provide a more solid foundation for future clinical and research work. It is thought as a consensus for moving forward and hopefully paves the way to developing a standard approach to this challenging problem with the advent of better scoring methods and ultimate goal of reducing the risk of CMS.

Achieving consensus for clinical trials: the REiNS International Collaboration.

The neurofibromatoses (NF)—including neurofibromatosis 1 (NF1), neurofibromatosis 2 (NF2), and schwannomatosis—are related tumor-suppressor syndromes characterized by a predisposition to multiple tumor types and other disease manifestations, which often result in functional disability, reduced quality of life, pain, and, in some cases, malignancy. With increasing knowledge of the biology and pathogenesis of NF, clinical trials with targeted agents directed at NF tumors have become available. Most clinical trials for patients with NF have used designs and endpoints similar to oncology trials. However, differences in the disease manifestations and natural history of NF (compared to cancers) require the development of new designs and endpoints to perform meaningful NF clinical trials. The Response Evaluation in Neurofibromatosis and Schwannomatosis (REiNS) International Collaboration was established in 2011 at the Childrens Tumor Foundation meeting to achieve consensus within the NF community about the design of future clinical trials, with a specific emphasis on endpoints. The REiNS Collaboration includes 7 working groups that focus on imaging of tumor response; functional, visual, patient-reported, and neurocognitive outcomes; whole-body MRI; and disease biomarkers. This supplement includes the first series of recommendations by the REiNS Collaboration. The hope is that these recommendations will be used by members of the group and by researchers outside of the REiNS International Collaboration to standardize the measurement of outcomes and thus improve clinical trials for patients with NF. Ultimately, we plan to engage industry partners and national regulatory agencies in this process to facilitate the approval of drugs for patients with NF.

Randomized placebo-controlled study of lovastatin in children with neurofibromatosis type 1

Objective: To assess the efficacy of lovastatin on visuospatial learning and attention for treating cognitive and behavioral deficits in children with neurofibromatosis type 1 (NF1). Methods: A multicenter, international, randomized, double-blind, placebo-controlled trial was conducted between July 2009 and May 2014 as part of the NF Clinical Trials Consortium. Children with NF1 aged 8–15 years were screened for visuospatial learning or attention deficits (n = 272); 146 children demonstrated deficits at baseline and were randomly assigned to lovastatin (n = 74; 40 mg/d) or placebo (n = 70). Treatment was administered once daily for 16 weeks. Primary outcomes were total errors on the Cambridge Neuropsychological Test Automated Battery Paired Associate Learning task (visuospatial learning) and the Score subtest from the Test of Everyday Attention for Children (sustained attention). Secondary outcomes measured executive function, attention, visuospatial skills, behavior, and quality of life. Primary analyses were performed on the intention-to-treat population. Results: Lovastatin had no significant effect on primary outcomes after 16 weeks of treatment: visuospatial learning (Cohen d = −0.15, 95% confidence interval −0.47 to 0.18) or sustained attention (Cohen d = 0.19, 95% confidence interval −0.14 to 0.53). Lovastatin was well tolerated, with no increase in reported adverse events compared to placebo. Conclusions: Lovastatin administered once daily for 16 weeks did not improve visuospatial learning or attention in children with NF1 and is not recommended for amelioration of cognitive deficits in this population. ClinicalTrials.gov identifier: This study was registered at ClinicalTrials.gov (NCT00853580) and Australian New Zealand Clinical Trials Registry (ACTRN12607000560493). Classification of evidence: This study provides Class I evidence that for children with NF1, lovastatin does not improve visuospatial learning or attention deficits.

Intellectual Outcome in Molecular Subgroups of Medulloblastoma

Purpose To evaluate intellectual functioning and the implications of limiting radiation exposure in the four biologically distinct subgroups of medulloblastoma: wingless (WNT), sonic hedgehog (SHH), Group 3, and Group 4. Patients and Methods A total of 121 patients with medulloblastoma (n = 51, Group 4; n = 25, Group 3; n = 28, SHH; and n = 17, WNT), who were treated between 1991 and 2013 at the Hospital for Sick Children (Toronto, Ontario, Canada), Childrens National Health System (Washington, DC), or the Lucile Packard Childrens Hospital (Palo Alto, CA), had intellectual assessments. First, we compared intellectual trajectories between subgroups. Next, we evaluated the effect of treatment with reduced-dose craniospinal irradiation (CSI) plus a tumor bed boost versus treatments that deliver higher CSI doses and/or larger boost volumes to the brain (all other treatments) within subgroups. Linear mixed modeling was used to determine the stability or change in intelligence scores over time. Results Intellectual outcomes declined comparably in each subgroup except for processing speed; SHH declined less than Group 3 ( P = .04). SHH had the lowest incidence of cerebellar mutism and motor deficits. Treatment with reduced-dose CSI plus a tumor bed boost was associated with preserved intellectual functioning in WNT and Group 4 patients considered together (ie, subgroups containing patients who are candidates for therapy de-escalation), and not in Group 3 or SHH. Across all subgroups, patients in the all other treatments group declined over time (all P < .05). Conclusion SHH patients appear to have the most distinct functional (ie, motor deficits and mutism) outcomes and a unique processing speed trajectory. Only WNT and Group 4 patients seem to benefit from limiting radiation exposure. Our findings highlight the value of conducting subgroup-specific analyses, and can be used to inform novel biologically based treatment protocols for patients with medulloblastoma.

Everyday executive function in standard-risk acute lymphoblastic leukemia survivors

We aimed to evaluate parent-rated executive function (EF) in pediatric standard risk acute lymphoblastic leukemia (SR-ALL) survivors compared to a healthy comparison (HC) group. We hypothesized that SR-ALL survivors would have greater reported executive dysfunction compared to HC, and that those younger at the time of treatment would demonstrate greater EF difficulties. A sample of 256 SR-ALL survivors evaluated an average nine years after treatment were compared to HC matched for gender, assessment age, and maternal education. Profile analysis was used to compare the groups across EF scales on the BRIEF. The prevalence of clinical elevations in the groups was compared via chi square, and odds ratios were calculated. Regression models were applied to examine the role of age at diagnosis and age at assessment in reported EF. Results indicated that SR-ALL survivors’ mean scores of EF are similar to HC, except for flexibility and initiation. Survivors were rated as having clinical impairments with flexibility, initiation, working memory, and emotional control at rates two to three times that of HC. The risk of working memory and self-monitoring deficits was greater in survivors who were older when assessed. There was no relationship between age at diagnosis or treatment regimen on EF. These findings suggest sparing of extensive and severe EF deficits in SR-ALL survivors overall. However, a subset of survivors displays clinically significant executive dysfunction. There appears to be a heightened susceptibility to disrupted metacognitive functions as survivors age. This has implications for how we monitor neurocognitive development and functioning of SR-ALL survivors, and highlights opportunities for cognitive interventions.

Neurocognitive Profile in a Case of Maple Syrup Urine Disease

Maple Syrup Urine Disease (MSUD) is a metabolic disease with associated enzyme deficiency and an inability to break down amino acids. Neurotoxic levels can occur resulting in neurological sequelae. Information regarding cognitive functions has suggested greater verbal than visuospatial abilities. Specific neuropsychological functions have not been studied. The objective of this study is to examine the neuropsychological profile in a case of MSUD. We present a case study of a 7-year-old female who has a history of late diagnosis (7 days of age) and poor metabolic control. Consistent with existing literature, a profile of stronger verbal reasoning and memory skills compared with visual-perceptual and nonverbal memory was revealed. Additional weaknesses were demonstrated with attention, emerging executive functions, and fine motor control. The results suggest that while previously described nonverbal reasoning and visuospatial impairments are present, there is likely a more complex pattern of neuropsychological impairments in children with MSUD, especially those with poor metabolic control.