Disrupted sensorimotor synchronization,but intact rhythm discrimination,in children treated for a cerebellar medulloblastoma

The aim of this study was to investigate the temporal abilities of children treated by surgery for a malignant tumor in the cerebellum, both in the perception and the production of rhythm. Children with a diagnosed medulloblastoma and age-matched control children were tested in a rhythm discrimination task and a sensorimotor synchronization task. Their motor and cognitive capabilities were also assessed through a battery of age-adapted neuropsychological tests. The results did not show any significant difference in performance between groups for the discrimination task. On the contrary, children with cerebellar lesions produced longer and more variable inter-tap intervals (ITI) in their spontaneous motor tempo (SMT) than did the control children. However, the length and, to a lesser extent, the variability of their SMT decreased after a synchronization phase, when they had been instructed to tap in synchrony with a beep. During the synchronization task, the children with medulloblastoma succeeded to modify the length of their ITI in response to an auditory rhythm, although with better success when the inter-stimuli intervals (ISI) were shorter than when they were longer than the ITIs of their own SMT. Correlational analyses revealed that children's poorer synchronization performance was related to lower scores in neuropsychological tests assessing motor dexterity and processing speed.     

小脑损伤患者的时间知觉

目的 通过对小脑损伤患者时间知觉的研究,了解小脑参与时间感知加工的可能机制.方法 采用时距复制任务,对26例小脑损伤患者和在年龄、利手及受教育程度上相匹配的26名健康对照者的时间知觉能力进行研究.试验包括持续呈现的视觉目标形式的3段标准时间(600ms、3和5 s),呈现结束后,延迟1或5 s进行复制.结果 小脑损伤组与健康对照组均对600 ms有高估,而对3和5 s有低估;与健康对照组比较,小脑损伤患者对600 ms时距复制[延迟时间为1和5 s的复制结果(s)分别为1.37±0.24、1.26±0.29]结果的差异均有统计学意义(Z=-5.247、-4.230,均P<0.01),而对3和5 s的时距复制结果(延迟时间为1和5 s)均无统计学意义(Z=-1.200、-0.092、-1.519、-0.723,均P>0.05).结论 小脑损伤患者对瞬时时间的感知明显受损,而对长时间的感知无损伤,提示小脑可能特异性地参与了毫秒时间感知的认知加工.     

Remediation of learning difficulties in children after treatment for a cerebellar medulloblastoma: a single-case study

In the process of establishing a methodology for individualized remediation programmes in children treated for cerebellar tumour, this study followed prospectively over 11 years a young child treated for a medulloblastoma at 18 months of age throughout the rehabilitation process. Repeated neuropsychological and academic evaluations evidenced temporary disruptive behaviour, deficient manual and visual abilities, attention and working memory difficulties, but preserved language abilities, in relation with vermian and left cerebellar damage. However, the described remediation programmes and interventions allowed the child to have fluent progression in school. Limits and benefits of rehabilitation are discussed.     

Midline cerebellar medulloblastoma in a seventy-one-year-old patient

BACKGROUND: Medulloblastoma is the most common malignant central nervous system tumour in children but, in contrast, quite rare in adults. Hemispheric, rather than midline, cerebellar medulloblastomas are more common in older children and adults. We present the unusual case of a 71-year-old man who presented with a fourth ventricular mass that proved to be a medulloblastoma. METHODS: A 71-year-old man presented with progressive balance problems, slurred speech and double vision. A CT scan of the brain revealed a hyperattenuating, partially calcified, avidly enhancing mass within the fourth ventricle. Diffusion weighted MRI showed restricted diffusion within the mass. The patient underwent a midline suboccipital craniotomy and a subtotal resection was achieved. RESULTS: Histological examination showed a densely cellular neoplasm composed of small cells with a tendency towards neuroblastic rosette formation. Most cells were strongly positive for neuron-specific enolase and synaptophysin. Ultrastructurally, tumour cells showed evidence of neuronal differentiation. These findings were consistent with a classical medulloblastoma. CONCLUSION: Adult medulloblastoma should be considered in the differential diagnosis of a partially calcified hyperattenuating mass within the fourth ventricle.     

Remediation of learning difficulties in children after treatment for a cerebellar medulloblastoma: A single-case study

In the process of establishing a methodology for individualized remediation programmes in children treated for cerebellar tumour, this study followed prospectively over 11 years a young child treated for a medulloblastoma at 18 months of age throughout the rehabilitation process. Repeated neuropsychological and academic evaluations evidenced temporary disruptive behaviour, deficient manual and visual abilities, attention and working memory difficulties, but preserved language abilities, in relation with vermian and left cerebellar damage. However, the described remediation programmes and interventions allowed the child to have fluent progression in school. Limits and benefits of rehabilitation are discussed.

Con el propósito de establecer una metodología para los programas de remedio individualizados en niños tratados por tumores cerebelares, se estudiaron en forma prospectiva durante 11 años a niños de 18 meses de edad tratados por un meduloblastoma, a lo largo del proceso de rehabiitación. En relación al daño cerebelar y vermiano se pusieron en evidencia, a través de evaluaciones académicas y neuropsicológicas aplicadas en forma repetida, una conducta alterada en forma temporal, una deficiencia en las habilidades visuales y manuales, y la presencia de dificultades en la atención y en la memoria de trabajo, pero sin alteraciones en el lenguaje. Sin embargo, los programas de remedio y las intervenciones descritos le permitieron al niño tener una progreso correcto en la escuela. Se discuten los beneficios y los límites de la rehabilitación. Palabras clave: Cerebelo, meduloblastoma, remedio, resultado, rehabilitación en equipo     

Gangliogliomatous maturation in cerebellar medulloblastoma

Summary Two cases of gangliogliomatous maturation of cerebellar medulloblastomas are presented in support of Bailey and Cushing's concept of the medulloblast as a bipotential element capable of both neurogenesis and gliogenesis. The presence of mature but atypical neuronal and glial elements was demonstrated histologically by specific procedures. The suggestion is made that cellular maturation in cerebellar medulloblastomas, as in extracranial neuroblastomas, may be more frequent in females than in males.

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Zusammenfassung Zwei Fälle von cerebellarem Medulloblastom mit gangliogliomatöser Ausreifung werden beschrieben, welche die Bailey und Cushingsche Auffassung vom Medulloblasten als ein bipotentiales Element, das der Neurogenese und Gliogenese fähig ist, unterstützen. Reife aber atypische Nervenzellen und gliöse Elemente sind durch spezielle Methoden darstellbar. Es wird angenommen, daß eine celluläre Reifung in cerebellaren Medulloblastomen, ähnlich wie in extracranialen Neuroblastomen, häufiger bei weiblichen als bei männlichen Personen auftritt.

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Aided by a grant (5 Tl NB 5109-09) from the National Institute of Neurological Diseases and Blindness, Bethesda, Maryland.     

Differential prefrontal-like deficit in children after cerebellar astrocytoma and medulloblastoma tumor

Background  

This study was realized thanks to the collaboration of children and adolescents who had been resected from cerebellar tumors. The medulloblastoma group (CE+, n = 7) in addition to surgery received radiation and chemotherapy. The astrocytoma group (CE, n = 13) did not receive additional treatments. Each clinical group was compared in their executive functioning with a paired control group (n = 12). The performances of the clinical groups with respect to controls were compared considering the tumor's localization (vermis or hemisphere) and the affectation (or not) of the dentate nucleus. Executive variables were correlated with the age at surgery, the time between surgery-evaluation and the resected volume.     

Anatomo-functional study of the cerebellum in working memory in children treated for medulloblastoma

Introduction

Medulloblastoma is the most common malignant cerebral tumor during childhood, arising in the posterior fossa. Children treated for medulloblastoma often experience working memory (WM) deficits, affecting their quality of life and school performance. The aim of the present study undertaken to describe the cerebellar involvement in WM deficits observed in these children.

Seasonal variation in incidence of cerebellar medulloblastoma

The incidence of 16 cerebellar medulloblastoma admitted to the University Hospital of Leuven during the last 8 years shows a seasonal peak between September and December.     

Mutism after cerebellar medulloblastoma surgery.

The case of a 9-year-old boy is presented, who developed transient mutism after removal of a medulloblastoma in the region of the cerebellar vermis. The mutism disappeared within 6 months. Neither reduction of consciousness nor disturbances of caudal cranial nerves or phonation ever appeared. The case is discussed with regard to its phenomenology, pathogenesis, and etiology, corresponding case reports are also taken into consideration.     

Time perception in children: A neurodevelopmental approach

In this review, we discuss behavioral studies on time perception in healthy children that suggest the existence of a primitive “sense” of time in infants as well as research that has revealed the changes in time judgments that occur throughout childhood. Moreover, a distinction is made between implicit and explicit time judgments in order to take account of the different types of temporal judgments that emerge across ages. On the basis of both the neurobiological model of the internal clock proposed by Matell and Meck (2000), and of results of imaging studies in human adults, we then try to identify which of the neural structures underlying this primitive sense of time mature faster and which mature more slowly in order to explain the age-related variance in time judgments. To this end, we also present the small number of timing studies conducted among typically and non-typically developing children that have used functional magnetic resonance imaging (fMRI) as well as those that have assessed the cognitive capacities of such children on the basis of various neuropsychological tests.     

小脑半球髓母细胞瘤的诊断和治疗

目的：探讨小脑半球髓母细胞瘤的临床特点。方法：收集经手术证实的小脑半球髓母细胞瘤16例,对其临床资料进行回顾性分析。其中男10例,女6例,平均年龄20.3岁,常见症状和体征为高颅压征和共济失调,术前有脑积水者6例,占37.5%,16例患者均行开颅肿瘤切除术。结果：本组患者13例获随访,术后平均生存时间为74.9个月,术后5年生存率为65.2%。结论：小脑半球髓母细胞瘤与中线区髓母细胞瘤的发病年龄、临床症状及预后均有所不同,临床上较易误诊,小脑半球髓母细胞瘤发病年龄较大,转移较少,预后较好。     

The evaluation of function and the ultrasonographic picture of thyroid in children treated for medulloblastoma

Purpose  

Medulloblastoma (MB) is one of the most frequent and sensitive to radiation aggressive brain tumor in children. Abnormalities of the thyroid function are common complications of head and neck irradiation for childhood cancer. The aim of this study was to assess thyroid function in children treated for medulloblastoma according to the treatment protocol phase.     

57例髓母细胞瘤的临床回顾性分析

目的 研究髓母细胞瘤的临床特点及显微外科手术治疗的I临床疗效. 方法 回顾性分析经显微手术治疗的57例髓母细胞瘤患者的临床和随访资料.对髓母细胞瘤的显微外科手术技巧进行探讨. 结果 肿瘤全切除42例,近全切除13例.部分切除2例.全部病例均打通中脑导水管.术前有脑积水者43例,术后手术疗效明显,脑积水减少至16例.且较术前均有不同程度改善,其中10例术后需行分流术.术后两年内肿瘤复发19例,中枢神经系统种植转移8例.最早术后20 d肿瘤复发.术后2年生存率68.4%(截至2006年7月病例),术后5年生存率49.1%(截至2003年7月病例). 结论 应用显微外科手术全切除肿瘤和术后全中枢轴放疗可使髓母细胞瘤患者取得较好的临床疗效.     

Melanotic medulloblastoma in children

Purpose

We report a case of melanotic medulloblastoma in a child. Reviewing the literature, we discuss the characteristics, therapeutic method, and prognosis of melanotic medulloblastoma in children.

Materials and methods

A 2-year-old girl was admitted with a mass located in the pineal region and presented obstructive hydrocephalus. The mass was subtotally resected through a slit-corpus?Cfornix approach. Thereafter, intraoperative direct third ventriculostomy was performed. The histopathological diagnosis of the mass suggested melanotic medulloblastoma.

Results

The MRI done at 4?days after surgery showed that the lateral ventricle normalized and the hydrocephalus was resolved. Thereafter, the patient underwent a Gamma Knife. The patient recovered well during the 8-month follow-up.

Conclusions

Melanotic medulloblastoma is a malignant tumor of childhood. It usually occurs at young age and might involve the vermis cerebelli, the fourth ventricle, and the pineal region. Surgery combined with radiotherapy and chemotherapy is recommended for children. But, it still requires observation to determine their long-term prognosis.     

Outcome of medulloblastoma in children treated with reduced-dose radiation therapy plus adjuvant chemotherapy

Medulloblastoma is the most common malignant brain tumor in children. Post-surgical craniospinal irradiation (CSI; 30-36 Gy) plus local boost radiation therapy (RT; 54-56 Gy) is a standard treatment for children with medulloblastoma who are over 3 years old, resulting in a 5-year overall survival (OS) rate of 46% to 65% in average-risk patients and 50% in high-risk patients. The addition of chemotherapy has the benefit of reducing complications from radiation and improving the OS rate. Using this approach, the estimated 5-year OS rates for patients with average- and high-risk medulloblastomas treated with different protocols are 65% to 85% and 16% to 70%, respectively. In this study, we determined the outcome of patients with average- and high-risk medulloblastomas treated with reduced dosage CSI and chemotherapy with an oral etoposide-based regimen. The study included 49 patients, with a mean age of 7.7 ± 3.4 years. Twenty-six patients (53%) were classified as average-risk and 23 patients (47%) as high-risk. In the average-risk group, the 5-year progression free survival (PFS) rate was 62.9% ± 10% and the 5-year OS rate was 70.4% ± 9.5%. In the high-risk group the 5-year PFS rate was 48.9% ± 13% and the 5-year OS rate was 49.7% ± 13%. In the average-risk group, patients who received CSI of either 24 Gy (n = 20) or 36 Gy (n = 9) showed no difference in their 5-year PFS and OS rates. We found that patients who were ?10 years old and patients who were female had a significantly better 5-year PFS rate.     

Immunocytochemical demonstration of interphotoreceptor retinoid-binding protein in cerebellar medulloblastoma

Summary Previously, immunoreactive rod-opsin and S-antigen (arrestin), two highly characteristic markers of retinal photoreceptors and pinealocytes, were shown to be present in certain medulloblastoma cells. It, thus, has been suggested that such cells differentiate along the photoreceptor lineage. This is corroborated in the present immunocytochemical investigation using antibodies against another photoreceptor-cell marker, the interphotoreceptor retinoid-binding protein (IRBP). As shown in preparations of human retina and pineal organ, IRBP can be successfully demonstrated in formalinfixed and paraffin-embedded tissue: the IRBP immunoreaction is located to the outer and inner segments of retinal photoreceptor cells and to perikarya of certain pinealocytes. Examination of formalin-fixed, paraffinembedded biopsy specimens of 66 cerebellar medulloblastomas revealed varying numbers of IRBP-immunoreactive tumor cells in 19 cases that were formerly shown to contain rod-opsin and S-antigen immunoreaction. IRBP-immunoreactive tumor cells were also found in a retinoblastoma and a pineocytoma, but not in neuroblastoma, ganglioneuroblastoma, glioblastoma, oligodendroglioma and astrocytoma. The results indicate: (1) cerebellar medulloblastomas are heterogeneous in their differentiation potential; (2) one type of medulloblastoma displays photoreceptor characteristics; (3) this type appears to be closely related to retinoblastoma and pineal cell tumors; and (4) all three types of tumors may display additional common features to be explored in future studies.     

Plasma membrane structures of medulloblastoma and cerebellar sarcoma

Three medulloblastomas and 1 cerebellar sarcoma were studied on their plasma membrane structures. The average number of membrane particles per mum2 plasma membrane was 710 on face A and 70 on face B of medulloblastoma and 1280 on face A and 160 on face B of cerebellar sarcoma. The membrane particles were often aggregated in medulloblastoma and diffusely scattered in cerebellar sarcoma. Small gap junctions were occasionally found in cerebellar sarcoma and not evident in medulloblastoma. Round membrane protrusions, about 0.5-0.6 mu in diameter and provided with several small depressions on their foot, were often observed in region of narrow perinuclear cytoplasm of cerebellar sarcoma and different in structure from cytoplasmic processes. The present series is too limited in number to allow a definite conclusion, but indicates that the plasma membrane structures are different in medulloblastoma and cerebellar sarcoma.     

Delayed intraventricular tension pneumocephalus complicating posterior fossa surgery for cerebellar medulloblastoma

A child is described in whom intraventricular tension pneumocephalus developed 10 days after removal of a cerebellar medulloblastoma and 1 day after suture removal. The tension pneumocephalus was associated with hydrocephalus and CSF leakage from the suture line. The symptoms of the pneumocephalus were rapidly progressing loss of consciousness and hemiplegia which were promptly reversed upon aspiration of the intracranial air. A large amount of intraventricular air present in the immediate postoperative period was, however, clinically silent. The characteristics of this unusual presentation, its relation to asymptomatic pneumocephalus. hydrocephalus and the preventive and therapeutic measures required to deal with such conditions are discussed.