Transcranial direct current stimulation in the treatment of cerebellar ataxia: A two-phase, double-blind, auto-matched, pilot study.

OBJECTIVE: To assess the impact of tDCS on posture, gait and coordination of movements in subjects with cerebellar ataxia. PATIENTS AND METHODS: This is a two-phase, double blind, auto matched, pilot study. Seven people were selected to participate in the study aged from 14 to 57. tDCS and sham-tDCS were applied at different times to all participants for 40 min over five consecutive days so that they were blind to which of the two techniques was applied at any one time. The area stimulated was the bilateral motor cortex. Subjects were evaluated before and after the interventions using the Scale for Assessment and Rating of Ataxia (SARA) and specific tests to measure posture and balance were carried out using the Wii Fit platform and CvMob software. RESULTS: The study indicates a statistically significant improvement in respect of gait parameters and the total score of the SARA scale and Wii Fit platform after tDCS when compared with data obtained from sham-tDCS trials (p: 0,03). The adverse events relating to tDCS were all self-limiting and from mild to moderate intensity. CONCLUSION: Despite the small sample size, tDCS showed positive results in some motor parameters and could be considered a valuable new option for the treatment of cerebellar ataxias.

Neurotransplantation therapy.

Neurotransplantation may be a promising approach for therapy of cerebellar diseases characterized by a substantial loss of neurons. Neurotransplantation could rescue neurons from degeneration and maintain cerebellar reserve, facilitate cerebellar compensation, or help reconstruct damaged neural circuits by cell substitution. These mechanisms of action can be of varying importance according to the type of cerebellar disease. Neurotransplantation therapy in cerebellar ataxias is still at the stage of experimental studies. There is currently little knowledge regarding cerebellar patients. Nevertheless, data provided by experiments in animal models of cerebellar degeneration and both clinical studies and experiences in patients with other neurologic diseases enable us to suggest basic principles, expectations, limitations, and future directions of neurotransplantation therapy for cerebellar diseases.

Novel homozygous GBA2 mutation in a patient with complicated spastic paraplegia.

Hereditary spastic paraplegias (HSPs) are a heterogeneous group of neurological disorders characterized primarily by a pyramidal syndrome with lower limb spasticity, which can manifest as pure HSP or associated with a number of neurological or non-neurological signs (i.e., complicated HSPs). The clinical variability of HSPs is associated with a wide genetic heterogeneity, with more than eighty causative genes known. Recently, next generation sequencing (NGS) has allowed increasing genetic definition in such a heterogeneous group of disorders. We report on a 56- year-old man affected by sporadic complicated HSP consisting of a pyramidal syndrome, cerebellar ataxia, congenital cataract, pes cavus, axonal sensory-motor peripheral neuropathy and cognitive decline. Brain MRI showed cerebellar atrophy and thin corpus callosum. By NGS we found a novel homozygous biallelic c.452-1G > C mutation in the b-glucosidase 2 gene (GBA2), known to be causative for autosomal recessive hereditary spastic paraplegia type 46 (SPG46). The rarity of this inherited form besides reporting on a novel mutation, expands the genetic and clinical spectrum of SPG46 related HSP.

Neurotransplantation Therapy and Cerebellar Reserve.

BACKGROUND & OBJECTIVE: Neurotransplantation has been recently the focus of interest as a promising therapy to substitute lost cerebellar neurons and improve cerebellar ataxias. However, since cell differentiation and synaptic formation are required to obtain a functional circuitry, highly integrated reproduction of cerebellar anatomy is not a simple process. Rather than a genuine replacement, recent studies have shown that grafted cells rescue surviving cells from neurodegeneration by exerting trophic effects, supporting mitochondrial function, modulating neuroinflammation, stimulating endogenous regenerative processes, and facilitating cerebellar compensatory properties thanks to neural plasticity. On the other hand, accumulating clinical evidence suggests that the self-recovery capacity is still preserved even if the cerebellum is affected by a diffuse and progressive pathology. We put forward the period with intact recovery capacity as "restorable stage" and the notion of reversal capacity as "cerebellar reserve". CONCLUSION: The concept of cerebellar reserve is particularly relevant, both theoretically and practically, to target recovery of cerebellar deficits by neurotransplantation. Reinforcing the cerebellar reserve and prolonging the restorable stage can be envisioned as future endpoints of neurotransplantation.

hiPSC Disease Modeling of Rare Hereditary Cerebellar Ataxias: Opportunities and Future Challenges.

Cerebellar ataxias are clinically and genetically heterogeneous diseases affecting primary cerebellar cells. The lack of availability of affected tissue from cerebellar ataxias patients is the main obstacle in investigating the pathogenicity of these diseases. The landmark discovery of human-induced pluripotent stem cells (hiPSC) has permitted the derivation of patient-specific cells with an unlimited self-renewing capacity. Additionally, their potential to differentiate into virtually any cell type of the human organism allows for large amounts of affected cells to be generated in culture, converting this hiPSC technology into a revolutionary tool in the study of the mechanisms of disease, drug discovery, and gene correction. In this review, we will summarize the current studies in which hiPSC were utilized to study cerebellar ataxias. Describing the currently available 2D and 3D hiPSC-based cellular models, and due to the fact that extracerebellar cells were used to model these diseases, we will discuss whether or not they represent a faithful cellular model and whether they have contributed to a better understanding of disease mechanisms.

Expansion diverticulum of the suprapineal recess causing cerebellar ataxia. A case report.

As a result of long-standing cerebrospinal fluid (CSF) pulsation against the thinnest segments of the ventricular walls, focal enlargement of the ventricular system (diverticulum) may occur, mainly at the medial wall of the trigone of the lateral ventricles (atrial diverticula) or at the posterior wall of the third ventricle (expansion of the suprapineal recess). In the latter case, ocular signs are the most common symptoms, due to the severe deformation of the periaqueductal region. We describe a case of non-communicating hydrocephalus in a 36-year-old woman who presented a three-year history of cerebellar ataxia. Preoperative brain magnetic resonance (MR) scan showed marked supratentorial hydrocephalus with an apparently patent aqueduct of Sylvius, and an enlarged suprapineal recess causing cerebellar and tentorial dislocation. The patient was successfully treated by endoscopic third ventriculostomy and monitored by MR scans with phase-contrast sequences for assessment of CSF flow. Cerebellar ataxia is a very rare symptomatic onset for a suprapineal recess expansion diverticulum, which may cause obstructive hydrocephalus that can be effectively treated by endoscopic third ventriculostomy.

Location and restoration of function after cerebellar tumor removal-a longitudinal study of children and adolescents.

Sequelae in children following cerebellar tumor removal surgery are well defined, and predictors for poor recovery include lesions of the cerebellar nuclei and the inferior vermis. Dynamic reorganization is thought to promote functional recovery in particular within the first year after surgery. Yet, the time course and mechanisms of recovery within this critical time frame are elusive and longitudinal studies are missing. Thus, a group of children and adolescents (n = 12, range 6-17 years) were followed longitudinally after cerebellar surgery and compared to age- and gender-matched controls (n = 11). Patients were examined (1) within the first days, (2) 3 months, and (3) 1 year after surgery. Each time behavioral tests of balance and upper limb motor function, ataxia rating, and a MRI scan were performed. Data were used for subsequent lesion-symptom mapping of cerebellar function. Behavioral improvements continued beyond 3 months, but were not complete in all patients after 1 year. At that time, remaining deficits were mild. Within the first 3 months, cerebellar lesion volumes were notably reduced by vanishing edema. Reduction in edema affecting the deep cerebellar nuclei but not reduction of total cerebellar lesion volume was a major predictor of early functional recovery. Persistent impairment in balance and upper limb function was linked to permanent lesions of the inferior vermis and the deep cerebellar nuclei.

Saldino-Mainzer syndrome: nephronophthisis, retinitis pigmentosa, and cone-shaped epiphyses.

Saldino-Mainzer syndrome is part of a group disorders, the conorenal syndromes, that are characterized by cone-shaped epiphyses with chronic renal disease in childhood and are variously associated with retinitis pigmentosa, cerebral ataxia, and/or abnormalities of the proximal epiphyses and femur metaphyses. Saldino-Mainzer syndrome usually has sporadic presentation. The present report shows the unusual findings of a 23-year-old woman, affected by the Saldino-Mainzer syndrome and has undergone kidney transplantation, highlights the possible association with maxillofacial and cephalometric abnormalities.

Primitive neuroectodermal tumor arising in long-standing cerebellar atrophy.

Primitive neuroectodermal tumors (PNETs) account for one fifth of childhood brain tumors. Although little is known of the pathobiology of this tumor type, there are associations with both genetic syndromes and exposures to specific environmental agents. Progressive cerebellar atrophy predating the presentation of a primary brain tumor, in the absence of a genetic syndrome, has not been reported with PNETs. We report a case of a posterior fossa PNET occurring in association with long-standing cerebellar atrophy without evidence of a genetic syndrome. This case may represent an unrecognized paraneoplastic syndrome or a unique subtype of PNET.

Isolated cerebellar involvement in Rosai-Dorfman disease: case report.

OBJECTIVE AND IMPORTANCE: Sinus histiocytosis or Rosai-Dorfman disease (RDD) is a rare but well-recognized disorder characterized by an unusual proliferation of histiocytic cells. Intracranial localization is a rare manifestation of RDD. Only three cases of localization in the posterior fossa have been reported in the literature. The present report describes the first case, to our knowledge, of cerebellar localization of RDD. CLINICAL PRESENTATION: A 67-year-old woman was admitted to our institution with a 5-month history of cerebellar ataxia. Her medical history was unremarkable. The patient was alert and cooperative. No cranial nerve deficits were evident; Romberg positivity to the left side was recorded. No cutaneous abnormalities, lymphadenopathy, or hepatosplenomegaly were revealed by physical examination. Routine hematological and biochemical studies were normal except for the erythrocyte sedimentation rate, which was elevated. Radiologically, the lesion appeared as a well-defined and avascular mass in the right cerebellar lobe. Meningioma was considered the most likely diagnosis. TECHNIQUE: The patient underwent a suboccipital craniotomy with complete excision of the lesion. Microscopic examination of the operative specimen revealed the presence of a mixed cellular population with predominant mature histiocytes. A peculiar feature was the presence of lymphocytes and monocytes within the cytoplasm of histiocytes (emperipolesis). Immunohistochemical study of the histiocytes revealed strong positivity for S-100, CD-68 antigen, and vimentin. CONCLUSION: Involvement of the central nervous system in RDD appears to have a benign prognosis, especially in the absence of nodal diseases. Surgery is essential for diagnosis, and, when total removal is achieved, the outcome is generally good without risk of recurrence.

Cerebellar grafts partially reverse amino acid receptor changes observed in the cerebellum of mice with hereditary ataxia: quantitative autoradiographic studies.

We used quantitative autoradiography of [3H]CNQX (200 nM), [3H]muscimol (13 nM), and [3H]flunitrazepam (10 nM) binding to study the distribution of non-NMDA and GABA(A) receptors in the cerebellum of pcd mutant mice with unilateral cerebellar grafts. Nonspecific binding was determined by incubation with 1 mM Glu, 200 microM GABA, or 1 microM clonazepam, respectively. Saturation parameters were defined in wild-type and mutant cerebella. In mutants, non-NMDA receptors were reduced by 38% in the molecular layer and by 47% in the granule cell layer. The reduction of non-NMDA receptors in the pcd cerebellar cortex supports their localization on Purkinje cells. [3H]CNQX binding sites were visualized at higher density in grafts that had migrated to the cerebellar cortex of the hosts (4.1 and 11.0 pmol/mg protein, respectively, at 23 and 37 days after grafting) than in grafts arrested intraparenchymally (2.6 and 6.2 pmol/mg protein, respectively, at 23 and 37 days after grafting). The pattern of expression of non-NMDA receptors in cortical vs. parenchymal grafts suggests a possible regulation of their levels by transacting elements from host parallel fibers. GABA(A) binding levels in the grafts for both ligands used were similar to normal molecular layer. Binding was increased in the deep cerebellar nuclei of pcd mutants: the increase in [3H]muscimol binding over normal was 215% and the increase in [3H]flunitrazepam binding was 89%. Such increases in the pcd deep cerebellar nuclei may reflect a denervation-induced supersensitivity subsequent to the loss of Purkinje axon terminal innervation. In the deep nuclei of pcd mutants with unilateral cerebellar grafts, [3H]muscimol binding was 31% lower in the grafted side than in the contralateral nongrafted side at 37 days after transplantation; [3H]flunitrazepam binding was also lower in the grafted side by 15% compared to the nongrafted side. Such changes in GABA(A) receptors suggest a significant, albeit partial, normalizing trend of cerebellar grafts on the state of postsynaptic supersensitive receptors in the host cerebellar nuclei.

Carpal tunnel syndrome in amyotrophic lateral sclerosis and late onset cerebellar ataxia.

We report on clinical and electrophysiological findings and management in nine patients who developed carpal tunnel syndrome during the course of amyotrophic lateral sclerosis and late onset cerebellar ataxia, two neurodegenerative diseases. The patients were treated with surgical decompression (five cases) and local steroid injections (four cases). Only one showed lasting relief of symptoms and significantly improved distal conduction in the median nerve at follow-up after 2 to 3 months. The symptoms and conduction data remained unchanged in three patients who could be followed for more than 1 year. We think that axonal neuropathy plays an important role in the development of carpal tunnel syndrome in these patients and accounts for the failure of the standard treatments.

[Paraneoplastic cerebellar degeneration: case report of a patient with breast carcinoma]. / Paraneoplastische zerebelläre Degeneration: Fallbeobachtung einer Patientin mit Mammakarzinom.

Case Report on a Breast Cancer Patient: A description of medical history, diagnosis and therapy of a patient with breast cancer is presented. The patient showed primary symptoms of vertigo and truncal and gait ataxia. The cause of this cerebellar disorder was a paraneoplastic cerebellar degeneration (PCD) characterized by anti-Purkinje cell antibodies (anti-Yo) directed against specific epitops shared by Purkinje and tumour cells. The presence of these antibodies in some patients suggests an autoimmune mechanism, although their role in pathogenesis has not been established. Usually malignancies of the breast and the ovaries are associated with anti-Yo positive PCD. The intensive search for the underlying neoplasma led to the identification of a malignant tumour of the right breast. Tumour excision of subsequent immunosuppressive treatment resulted in a progression of PCD. Antibody titers remained nearly unchanged during the course of the disease.

Paraneoplastic cerebellar degeneration: successful early detection and treatment of cancer through characterization of the anti-Purkinje cell antibody.

Paraneoplastic cerebellar degeneration (PCD) is thought to be caused by an autoantibody against both tumor and neuronal tissue. Such autoantibodies are most frequently detected in patients with gynecological or breast cancer, and are designated as anti-Yo. We report here a patient with PCD whose underlying cancer could not be detected despite extensive tumor survey. IgG in her serum and cerebrospinal fluid reacted with the cytoplasm of cerebellar Purkinje cells immunohistochemically. On immunoelectron microscopy, the endoplasmic reticulum and Golgi complex were stained. Her IgG bound to the 58 kD band on immunoblots of cerebellar proteins. A reaction was also observed with the recombinant proteins deduced from the complementary DNA clone encoding a neuronal cell antigen reported by Sakai et al (Ann Neurol 28: 692, 1990). Based on these results, successful early resection of fallopian tube adenocarcinoma was performed. It is crucially important to characterize these PCD related autoantibodies for the early treatment of underlying malignant tumors.

Fetal tissue grafts for cerebellar atrophy.

It has been shown in a rat model that surgical injury to the right cerebellum with resultant ataxia can be corrected by implantation of embryonic cerebellar tissue into the injured cerebellum. Histological examinations of the cerebellar tissue revealed that mitoses of Purkinje cells of the implanted group were increased substantially over the control group's. The surgically induced ataxia resolved more rapidly in the cerebellar implant group than the control group. Based on this experimental data, a similar technique was applied in 6 patients with severe hereditary cerebellar degenerative ataxia. The preliminary results in these 6 surgically implanted patients with heredity degenerative cerebellar disease show 2 with marked improvement, 3 with moderate improvement and 1 with improvement for 2 months followed by mild deterioration but still better than presurgery. We also studied immunological markers in the blood and CSF in an attempt to determine whether rejection of implanted tissue occurs.