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Cerebellum (London, England) Oct 2023The effectiveness of cerebellar repetitive transcranial magnetic stimulation (rTMS) on motor dysfunction in patients with neurological disorders has received increasing... (Review)
Review
The effectiveness of cerebellar repetitive transcranial magnetic stimulation (rTMS) on motor dysfunction in patients with neurological disorders has received increasing attention because of its potential for neuromodulation. However, studies on the neuromodulatory effects, parameters, and safety of rTMS implementation in the cerebellum to alleviate motor dysfunction are limited. This systematic review aimed to evaluate the effectiveness and safety of cerebellar rTMS treatment for motor dysfunction caused by neurological disorders and to review popular stimulation parameters. Five electronic databases-Medline, Web of Science, Scopus, Cochrane Library, and Embase-were searched for relevant research published from inception to July 2022. All randomized controlled trials (RCTs) that reported the effects of cerebellar rTMS combined with behavioral rating scales on motor dysfunction were eligible for enrollment. Additionally, reference lists of the enrolled studies were manually checked. Among 1156 articles screened, 21 RCTs with 666 subjects were included. rTMS conducted on the cerebellum showed an improvement in stroke (spasticity, balance, and gait), cervical dystonia, Parkinson's disease (tremor), cerebellar ataxia, and essential tremor but not in multiple sclerosis. The 8-shaped coil with a diameter of 70 mm was determined as the most common therapeutic choice. None of the studies reported severe adverse events except mild side effects in three. Therefore, rTMS appears to be a promising and safe technique for the treatment of motor dysfunction, targeting the cerebellum to induce motor behavioral improvement. Further rigorous RCTs, including more samples and longer follow-up periods, are required to precisely explore the effective stimulation parameters and possible mechanisms.
Topics: Humans; Transcranial Magnetic Stimulation; Cerebellum; Essential Tremor; Parkinson Disease; Stroke
PubMed: 36018543
DOI: 10.1007/s12311-022-01465-6 -
Cerebellum (London, England) Oct 2023The cerebellum's role in affective processing is increasingly recognized in the literature, but remains poorly understood, despite abundant clinical evidence for... (Meta-Analysis)
Meta-Analysis
The cerebellum's role in affective processing is increasingly recognized in the literature, but remains poorly understood, despite abundant clinical evidence for affective disruptions following cerebellar damage. To improve the characterization of emotion processing and investigate how attention allocation impacts this processing, we conducted a meta-analysis on task activation foci using GingerALE software. Eighty human neuroimaging studies of emotion including 2761 participants identified through Web of Science and ProQuest databases were analyzed collectively and then divided into two categories based on the focus of attention during the task: explicit or implicit emotion processing. The results examining the explicit emotion tasks identified clusters within the posterior cerebellar hemispheres (bilateral lobule VI/Crus I/II), the vermis, and left lobule V/VI that were likely to be activated across studies, while implicit tasks activated clusters including bilateral lobules VI/Crus I/II, right Crus II/lobule VIII, anterior lobule VI, and lobules I-IV/V. A direct comparison between these categories revealed five overlapping clusters in right lobules VI/Crus I/Crus II and left lobules V/VI/Crus I of the cerebellum common to both the explicit and implicit task contrasts. There were also three clusters activated significantly more for explicit emotion tasks compared to implicit tasks (right lobule VI, left lobule VI/vermis), and one cluster activated more for implicit than explicit tasks (left lobule VI). These findings support previous studies indicating affective processing activates both the lateral hemispheric lobules and the vermis of the cerebellum. The common and distinct activation of posterior cerebellar regions by tasks with explicit and implicit attention demonstrates the supportive role of this structure in recognizing, appraising, and reacting to emotional stimuli.
Topics: Humans; Cerebellum; Emotions; Cerebellar Vermis; Magnetic Resonance Imaging; Neuroimaging; Brain Mapping
PubMed: 35999332
DOI: 10.1007/s12311-022-01459-4 -
International Journal of Developmental... Dec 2022The aim of this systematic review was to explore and discuss the literature concerning the effects of hypoxia or anoxia during the perinatal period on the serotoninergic...
PURPOSE
The aim of this systematic review was to explore and discuss the literature concerning the effects of hypoxia or anoxia during the perinatal period on the serotoninergic network in rodents, through mechanisms that lead to changes in serotonergic neurons, levels, segments of central nervous system affected, 5-HT transporter, and 5-HT receptor.
METHODS
Literature searches were performed in Embase, Medline (PubMed), Web of Science, and SCOPUS, from April to July 2021, with a total of 1045 published studies found. Using a predefined protocol, as registered on the CAMARADES website, 10 articles were included in this review. The PRISMA statement was used for reporting this systematic review. The internal validity was assessed using the SYRCLE's risk of bias tool.
RESULTS
Our main findings show that hypoxia in the first days of postnatal life led to a disturbance in the serotonergic system with reduced in 5-HT fibers, reduced brain levels of 5-HT and 5-HIAA, reduced SERT protein expression, and reduced receptor 5-HT . Putative mechanisms involving damage in the serotoninergic system include retrograde cell death resulting from primary damage mainly in forebrain areas, which impairs remote areas including serotonergic raphe nuclei. Other probable mechanisms associated with the serotoninergic network damage may be triggered by excitotoxic lesion and neuroinflammation.
CONCLUSION
Hypoxia at the beginning of an animal's life leads to modification of the serotonergic components associated with putative mechanisms that include cell damage and neuroinflammation.
Topics: Animals; Hypoxia; Models, Theoretical; Raphe Nuclei; Serotonergic Neurons; Serotonin
PubMed: 35996828
DOI: 10.1002/jdn.10226 -
Acta Otorrinolaringologica Espanola 2022Otolaryngology specialists must be familiar with radiological studies that allow the diagnosis of different otological pathologies. Magnetic resonance imaging is a...
Otolaryngology specialists must be familiar with radiological studies that allow the diagnosis of different otological pathologies. Magnetic resonance imaging is a complement to computed tomography, which allows a better evaluation of soft tissues and contributes to the differential diagnosis of space-occupying lesions located in the temporal bone and lateral skull base. It is also the technique of choice for the evaluation of the inner ear and the anatomical structures located in the cerebellopontine angle. In this article we present a checklist for magnetic resonance imaging of the ear with different sections that will allow a systematic review of all structures of interest in otological practice, as well as the preferred sequences for each situation.
Topics: Cerebellopontine Angle; Checklist; Ear, Inner; Humans; Magnetic Resonance Imaging; Temporal Bone
PubMed: 35397820
DOI: 10.1016/j.otoeng.2021.04.001 -
Expert Opinion on Drug Safety Jul 2022The antiseizure medication phenytoin has been associated with changes in the cerebellum, cerebellar signs, and permanent cerebellar damage. We have systematically...
INTRODUCTION
The antiseizure medication phenytoin has been associated with changes in the cerebellum, cerebellar signs, and permanent cerebellar damage. We have systematically reviewed the clinical and radiological features, and their correlation.
AREAS COVERED
We identified sixty case reports and case series of the effects of phenytoin on the cerebellum by searching Medline and Embase and relevant reference lists. The reports described 92 [median 1, range 1-5] cases, documented median age 28 [2.7-78] years. Eighty-one cases described one or more clinical sign of ataxia (present in 96%), dysarthria (63%), and nystagmus (70%). The neurological outcome (in 76 cases): 10 (13%) recovered by 12 months; 55 (72%) suffered residual disability; and 11 (14%) died. Median serum phenytoin concentration (48 cases) was 50 (interquartile range 31-66) mg/L; only three values were below 20 mg/L. The radiological findings included cerebellar atrophy in 41 of 61 patients (67%) with at least one scan.
EXPERT OPINION
Evidence mainly comes from case reports, and is inevitably biased. Most patients with cerebellar dysfunction have phenytoin concentrations above the reference range. Clinical signs of ataxia can persist without radiological evidence of cerebellar atrophy, and cerebellar atrophy is seen without any clinical evidence of cerebellar dysfunction.
Topics: Adult; Ataxia; Atrophy; Cerebellar Ataxia; Cerebellar Diseases; Cerebellum; Humans; Phenytoin
PubMed: 35325581
DOI: 10.1080/14740338.2022.2058487 -
BMC Neurology Mar 2022Study the cognitive profile of individuals with Friedreich ataxia (FRDA) and seek evidence for correlations between clinical, genetic and imaging characteristics and... (Meta-Analysis)
Meta-Analysis
BACKGROUND
Study the cognitive profile of individuals with Friedreich ataxia (FRDA) and seek evidence for correlations between clinical, genetic and imaging characteristics and neuropsychological impairments.
METHODS
Based on PRISMA guidelines, a meta-analysis was realized using the Pubmed and Scopus databases to identify studies (1950-2021) reporting neuropsychological test results in genetically confirmed FRDA and control participants in at least one of the following cognitive domains: attention/executive, language, memory and visuo-spatial functions as well as emotion. Studies using identical outcomes in a minimum of two studies were pooled. Pooled effect sizes were calculated with Cohen's d.
RESULTS
Eighteen studies were included. Individuals with FRDA displayed significantly lower performance than individuals without FRDA in most language, attention, executive function, memory visuospatial function, emotion regulation and social cognitive tasks. Among the included studies, thirteen studies examined the relationship between neuropsychological test results and clinical parameters and reported significant association with disease severity and six studies reviewed the relationship between neuroimaging measures and cognitive performance and mainly reported links between reduced cognitive performance and changes in cerebellar structure.
CONCLUSIONS
Individuals with FRDA display significantly lower performances in many cognitive domains compared to control participants. The spectrum of the cognitive profile alterations in FRDA and its correlation with disease severity and cerebellar structural parameters suggest a cerebellar role in the pathophysiology of FRDA cognitive impairments.
Topics: Cerebellum; Cognition; Executive Function; Friedreich Ataxia; Humans; Neuropsychological Tests
PubMed: 35300598
DOI: 10.1186/s12883-022-02615-3 -
BMC Neurology Feb 2022Intra-cranial schwannomas account for less than 8% of brain tumors, among which more than 80% arise from the vestibular nerve. Intra-cerebellar schwannomas are extremely...
BACKGROUND
Intra-cranial schwannomas account for less than 8% of brain tumors, among which more than 80% arise from the vestibular nerve. Intra-cerebellar schwannomas are extremely rare. Several cases have been previously reported but without remarkable degenerative changes on histology.
CASE PRESENTATION
A 61-year-old man presented with worsening disorientation, and an imaging study revealed a cystic lesion (6.5 cm in the largest diameter) in the left hemisphere of the cerebellum accompanied by a mural nodule (2.5 cm) located just inside the skull with enhancement and focal calcification, in addition to hydrocephalus. The lesion was more than 5 mm from the left acoustic nerve. The patient underwent gross total resection. Pathological examination revealed remarkable degenerative changes with various morphological features. Tumor cells were pleomorphic with rich cytoplasm containing numerous eosinophilic granules. Blood vessels and extracellular matrix showed remarkable hyalinization. Immunohistochemical staining revealed that the tumor cells were positive for S-100 protein and negative for Olig2. The tumor was diagnosed as a schwannoma with marked degenerative changes.
CONCLUSIONS
The present case is discussed with reference to a systematic review of previous reports of intra-cerebellar schwannoma. Intra-cerebellar schwannoma should be included in the differential diagnosis of cystic lesions with heterogeneous histopathological morphology in the cerebellum.
Topics: Brain Neoplasms; Calcinosis; Cerebellum; Diagnosis, Differential; Humans; Male; Middle Aged; Neurilemmoma
PubMed: 35209854
DOI: 10.1186/s12883-022-02596-3 -
Audiology & Neuro-otology 2022It has been suggested that vascular loops in the cerebellopontine angle and internal auditory canal are involved in the etiology of audio-vestibular symptoms. Several...
It has been suggested that vascular loops in the cerebellopontine angle and internal auditory canal are involved in the etiology of audio-vestibular symptoms. Several studies have focused on the compression of the eighth cranial nerve by vascular loops but have yielded contradictory results regarding their clinical significance. The aim of this study was to investigate whether vascular loops in this region correlate with audio-vestibular symptoms and which loop features - if any - can potentially lead to symptom manifestation. This systematic review was conducted according to the PRISMA guidelines. We performed on PubMed a literature search from November 2005 to October 2020. The search strategy included the following keywords ("vascular loops" OR "AICA loops" OR "vascular compression syndrome") AND ("hearing loss" OR "tinnitus" OR "vertigo"). Fifteen studies were eligible and included in the analysis. Overall, the studies encompassed a total of 11,788 patients included in this review. The significantly larger group of patients (70%), in which no correlation of symptoms with vascular loops was found, suggests that vascular loops are probably anatomic variations in a substantial majority of cases with an uncommon subset causing some audio-vestibular symptoms. Even within the papers claiming a correlation, there is a multitude of symptoms that did not correlate with vascular loops. It has been suggested by most authors that magnetic resonance imaging should be performed to exclude the role of a vascular loop in the etiology of audio-vestibular symptoms only when vascular compression syndrome is suspected based on clinical indications and not routinely. Further studies would be useful in order to detail the relationship between the vascular structures and the nervous system.
Topics: Cerebellopontine Angle; Humans; Magnetic Resonance Imaging; Tinnitus; Vertigo; Vestibule, Labyrinth; Vestibulocochlear Nerve
PubMed: 35176744
DOI: 10.1159/000521792 -
International Journal of Environmental... Oct 2021Cerebellar transcranial direct current stimulation (cerebellar tDCS) is a promising therapy for cerebellar ataxias and has attracted increasing attention from... (Review)
Review
Cerebellar transcranial direct current stimulation (cerebellar tDCS) is a promising therapy for cerebellar ataxias and has attracted increasing attention from researchers and clinicians. A timely systematic review focusing on randomized sham-controlled trials and repeated measures studies is warranted. This study was to systematically review existing evidence regarding effects of anodal cerebellar tDCS on movements in patients with cerebellar ataxias. The searched databases included Web of Science, MEDLINE, PsycINFO, CINAHL, EMBASE, Cochrane Library, and EBSCOhost. Methodological quality of the selected studies was assessed using the Physiotherapy Evidence Database scale. Five studies with 86 patients were identified. Among these, four studies showed positive effects of anodal cerebellar tDCS. Specifically, anodal cerebellar tDCS decreased disease severity and improved finger dexterity and quality of life in patients, but showed incongruent effects on gait control and balance, which may be due to heterogeneity of research participants and choices of measures. The protocols of anodal cerebellar tDCS that improved movements in patients commonly placed the anode over the whole cerebellum and provided ten 2-mA 20-min stimulation sessions. The results may show preliminary evidence that anodal cerebellar tDCS is beneficial to reducing disease severity and improving finger dexterity and quality of life in patients, which lays the groundwork for future studies further examining responses in the cerebello-thalamo-cortical pathway. An increase in sample size, the use of homogeneous patient groups, exploration of the optimal stimulation protocol, and investigation of detailed neural mechanisms are clearly needed in future studies.
Topics: Cerebellar Ataxia; Cerebellum; Electrodes; Fingers; Humans; Motor Skills; Quality of Life; Transcranial Direct Current Stimulation
PubMed: 34682435
DOI: 10.3390/ijerph182010690 -
Cerebellum (London, England) Dec 2022Essential tremor (ET) is one of the most common movement disorders. Over the last 10 years, magnetic resonance imaging (MRI) has shed light on the structural and... (Review)
Review
Essential tremor (ET) is one of the most common movement disorders. Over the last 10 years, magnetic resonance imaging (MRI) has shed light on the structural and functional abnormalities possibly involved in ET pathophysiology. In this systematic review, we aimed to identify the cortical and subcortical structures involved and the role that different brain areas play in the pathophysiology of motor and non-motor ET features. We found that structural (grey and white matter) cerebellar damage and connectivity alterations between the cerebellum and various cortical areas play a role in both motor and non-motor symptoms of ET. In particular, many studies found an association between MRI findings and non-motor symptoms.
Topics: Humans; Essential Tremor; Neuroimaging; Magnetic Resonance Imaging; Brain; Cerebellum
PubMed: 34657271
DOI: 10.1007/s12311-021-01335-7