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Saccadic oscillations (SOs) mostly occur spontaneously, but can be occasionally triggered by various stimuli. To determine clinical characteristics and underlying mechanisms of triggered SOs, we analyzed the clinical features and quantitative eye-movement recordings of six new patients and 10 patients in the literature who exhibited with triggered SOs. Eleven of the 16 patients (69%) had a lesion involving cerebellum and/or brainstem such as cerebellar degeneration, cerebellitis, or cerebellar infarction. The other causes were vestibular migraine (n = 2), multiple sclerosis (n = 1), Krabbe disease (n = 1), and idiopathic (n = 1). Vestibular stimulation was the most common trigger (n = 11, 69%), followed by removal of visual fixation (n = 4, 25%), hyperventilation (n = 1), light (n = 1), and blink (n = 1). The types of triggered SOs were varied which included ocular flutter (n = 13), opsoclonus (n = 3), vertical SOs (n = 2), and macrosaccadic oscillations (n = 1). Three patients exhibited downbeat nystagmus either before (n = 1) or after (n = 2) the onset of SOs. The frequency of triggered SOs ranged from 4 to 15 Hz, and oscillations with smaller amplitudes had higher frequencies and smaller peak velocities. SOs can be triggered by the modulation of unstable saccadic neural networks through vestibular and visual inputs in lesions of the brainstem and cerebellum. [ABSTRACT FROM AUTHOR]

BACKGROUND: Previous case-control investigations of type I Chiari malformation (CMI) have reported cognitive deficits and microstructural white matter abnormalities, as measured by diffusion tensor imaging (DTI). CMI is also typically associated with pain, including occipital headache, but the relationship between pain symptoms and microstructure is not known. METHODS: Eighteen CMI patients and 18 adult age- and education-matched control participants underwent DTI, were tested using digit symbol coding and digit span tasks, and completed a self-report measure of chronic pain. Tissue microstructure indices were used to examine microstructural abnormalities in CMI as compared with healthy controls. Group differences in DTI parameters were then reassessed after controlling for self-reported pain. Finally, DTI parameters were correlated with performance on the digit symbol coding and digit span tasks within each group. RESULTS: CMI patients exhibited greater fractional anisotropy (FA), lower radial diffusivity, and lower mean diffusivity in multiple brain regions compared with controls in diffuse white matter regions. Group differences no longer existed after controlling for self-reported pain. A significant correlation between FA and the Repeatable Battery for the Assessment of Neuropsychological Status coding performance was observed for controls but not for the CMI group. CONCLUSIONS: Diffuse microstructural abnormalities appear to be a feature of CMI, manifesting predominantly as greater FA and less diffusivity on DTI sequences. These white matter changes are associated with the subjective pain experience of CMI patients and may reflect reactivity to neuroinflammatory responses. However, this hypothesis will require further deliberate testing in future studies.

BackgroundPrevious case-control investigations of type I Chiari malformation (CMI) have reported cognitive deficits and microstructural white matter abnormalities, as measured by diffusion tensor imaging (DTI). CMI is also typically associated with pain, including occipital headache, but the relationship between pain symptoms and microstructure is not known.MethodsEighteen CMI patients and 18 adult age- and education-matched control participants underwent DTI, were tested using digit symbol coding and digit span tasks, and completed a self-report measure of chronic pain. Tissue microstructure indices were used to examine microstructural abnormalities in CMI as compared with healthy controls. Group differences in DTI parameters were then reassessed after controlling for self-reported pain. Finally, DTI parameters were correlated with performance on the digit symbol coding and digit span tasks within each group.ResultsCMI patients exhibited greater fractional anisotropy (FA), lower radial diffusivity, and lower mean diffusivity in multiple brain regions compared with controls in diffuse white matter regions. Group differences no longer existed after controlling for self-reported pain. A significant correlation between FA and the Repeatable Battery for the Assessment of Neuropsychological Status coding performance was observed for controls but not for the CMI group.ConclusionsDiffuse microstructural abnormalities appear to be a feature of CMI, manifesting predominantly as greater FA and less diffusivity on DTI sequences. These white matter changes are associated with the subjective pain experience of CMI patients and may reflect reactivity to neuroinflammatory responses. However, this hypothesis will require further deliberate testing in future studies.

OBJECTIVES The damage to the cerebellum primarily results in balance-related abnormalities that may affect performance of locomotion and postural adjustments, eventually contributing to an increased risk of fall and fear of falling in patients with cerebellar disease. The purpose of the present study was to investigate the effect of a perturbation-based training that induced backward loss of balance on compensatory postural responses in patients with cerebellar disease. METHODS The participant was a 51-year-old female diagnosed with spinocerebellar ataxia and had the disease for 19 years. The perturbation-based backward balance training was performed over 8 weeks (a total of 24 training sessions) in order to facilitate the perception of postural perturbation onset and execution of rapid compensatory responses. RESULTS The patient demonstrated a noticeable reduction in the number of steps required to recover body balance after postural disturbances. The reduction of multi-step reactions in recovering balance could be attributed to improvements in the body center-of-mass displacement and trunk control during the landing of step. Besides, there were also improvements in subjective measures of functional mobility and psychological well-being after the balance training. CONCLUSION Although current research evidence of balance rehabilitation for cerebellar patients is lacking, this study offers the feasibility of adaptive training to improve postural stability through task-specific training intervention.

• Cerebellitis is a rare neurologic disease often associated with infection. • Neurosurgical consultation should be sought in all cases of cerebellitis. • Patients with cerebellitis may require ventriculostomy or surgical decompression. • Symptom severity may predict the need for neurosurgical intervention. • Cerebellitis can be devastating; many patients are dependent at follow up. The diagnostic evaluation and role of neurosurgery in the treatment of cerebellitis is unclear. We explore the diagnostic evaluation and subsequent role of neurosurgical intervention in pediatric cerebellitis in a case series, highlighting the diagnostic work up and treatments applied. A retrospective review was conducted of all pediatric patients diagnosed with cerebellitis for whom neurosurgery was consulted at a single center from June 2008 to February 2019. Nine patients, four males (44.4%) and five females (55.6%) were identified. Common presenting symptoms were headache (n = 6, 66.7%), emesis (n = 5, 55.6%), and altered mental status (n = 4, 44.4%). Six (66.7%) had associated infections. Imaging abnormalities included tonsillar ectopia (n = 8, 88.9%), bilateral cerebellar T2 hyperintensity (n = 6, 66.7%), and obstructive hydrocephalus (n = 6, 66.7%). Management included antibiotics, antivirals, corticosteroids, mannitol, and hypertonic saline. Four (44.4%) required external ventricular drain (EVD) placement for a mean 11 days (SD 6.8, range 4–20) for hydrocephalus; none required additional neurosurgical interventions. Seven patients (77.8%) required ICU care for a mean 11.7 days (SD 14.0 range 1–42). At follow-up (mean 20.8 months, SD 28.7, range 0.6–64.9), two patients (n = 2, 22.2%) recovered completely, and six (66.7%) were functionally dependent (mRS > 2); the most common residual deficit was cognitive impairment (n = 5, 55.6%). Neurosurgical consultation should be considered in pediatric patients with cerebellitis. In our experience, temporary CSF diversion via an EVD is employed nearly half of the time. The presence of hydrocephalus requiring neurosurgical intervention may be a predictor of severe disease and poor outcome. [ABSTRACT FROM AUTHOR]

Point mutations at m.8993T>C and m.8993T>G of the mtDNA ATPase 6 gene cause the neurogenic weakness, ataxia and retinitis pigmentosa (NARP) syndrome, a mitochondrial disorder characterized by retinal, central and peripheral neurodegeneration. We performed detailed neurological, neuropsychological and ophthalmological phenotyping of a mother and four daughters with NARP syndrome from the mtDNA m.8993T>C ATPase 6 mutation, including 3-T brain MRI, spectral domain optical coherence tomography (SD-OCT), adaptive optics scanning laser ophthalmoscopy (AOSLO), electromyography and nerve conduction studies (EMG-NCS) and formal neuropsychological testing. The degree of mutant heteroplasmy for the m.8993T>C mutation was evaluated by real-time allele refractory mutation system quantitative PCR of mtDNA from hair bulbs (ectoderm) and blood leukocytes (mesoderm). There were marked phenotypic differences between family members, even between individuals with the greatest degrees of ectodermal and mesodermal heteroplasmy. 3-T MRI revealed cerebellar atrophy and cystic and cavitary T2 hyperintensities in the basal ganglia. SD-OCT demonstrated similarly heterogeneous areas of neuronal and axonal loss in inner and outer retinal layers. AOSLO showed increased cone spacing due to photoreceptor loss. EMG-NCS revealed varying degrees of length-dependent sensorimotor axonal polyneuropathy. On formal neuropsychological testing, there were varying deficits in processing speed, visual-spatial functioning and verbal fluency and high rates of severe depression. Many of these cognitive deficits likely localize to cerebellar and/or basal ganglia dysfunction. High-resolution retinal and brain imaging in NARP syndrome revealed analogous patterns of tissue injury characterized by heterogeneous areas of neuronal loss.

Background: Guidelines regarding recommendations for surgical treatment of spontaneous cerebellar intracerebral haemorrhage (ICH) differ. We aimed to systematically review the literature to assess treatment strategies and outcomes.Methods: We searched PubMed and Embase between 1970 and 2019 for randomised or otherwise controlled studies and observational cohort studies. We included studies according to predefined selection criteria and assessed their quality according to the Newcastle-Ottawa Scale (NOS) and risk of bias according to a predefined scale. We assessed case fatality and functional outcome in patients treated conservatively or with haematoma evacuation. Favourable functional outcome was defined as a modified Rankin Scale score of 0-2 or a Glasgow Outcome Scale score of 4-5.Results: We included 41 observational cohort studies describing 2062 patients (40% female) with spontaneous cerebellar ICH. A total of 1171 patients (57%) underwent haematoma evacuation. Ten studies described a cohort of surgically treated patients (n=533) and 31 cohorts with both surgically and conservatively treated patients (n=638 and n=891, respectively). There were no randomised clinical trials nor studies comparing outcome between the groups after adjustment for differences in baseline characteristics. The median NOS score (IQR) was 5 (4-6) out of 8 points and the bias score was 2 (1-3) out of 8, indicative of high risk of bias. Case fatality at discharge was 21% (95% CI 17% to 25%) after conservative treatment and 24% (95% CI 19% to 29%) after haematoma evacuation. At ≥6 months after conservative treatment, case fatality was 30% (95% CI 25% to 30%) and favourable functional outcome was 45% (95% CI 40% to 50%) and after haematoma evacuation, case fatality was 34% (95% CI 30% to 38%) and 42% (95% CI 37% to 47%).Conclusions: Controlled studies on the effect of neurosurgical treatment in patients with spontaneous cerebellar ICH are lacking, and the risk of bias in published series is high. Due to substantial differences in patient characteristics between conservatively and surgically treated patients, and high variability in treatment indications, a meaningful comparison in outcomes could not be made. There is no good published evidence to support treatment recommendations and controlled, preferably randomised studies are warranted in order to formulate evidence-based treatment guidelines for patients with cerebellar ICH. [ABSTRACT FROM AUTHOR]

Competing Interests: Competing interests: None declared.

Systematic perturbations in motor adaptation tasks are primarily countered by learning from sensory-prediction errors, with secondary contributions from other learning processes. Despite the availability of these additional processes, particularly the use of explicit re-aiming to counteract observed target errors, patients with cerebellar degeneration are surprisingly unable to compensate for their sensory-prediction error deficits by spontaneously switching to another learning mechanism. We hypothesized that if the nature of the task was changed-by allowing vision of the hand, which eliminates sensory-prediction errors-patients could be induced to preferentially adopt aiming strategies to solve visuomotor rotations. To test this, we first developed a novel visuomotor rotation paradigm that provides participants with vision of their hand in addition to the cursor, effectively setting the sensory-prediction error signal to zero. We demonstrated in younger healthy control subjects that this promotes a switch to strategic re-aiming based on target errors. We then showed that with vision of the hand, patients with cerebellar degeneration could also switch to an aiming strategy in response to visuomotor rotations, performing similarly to age-matched participants (older controls). Moreover, patients could retrieve their learned aiming solution after vision of the hand was removed (although they could not improve beyond what they retrieved), and retain it for at least 1 year. Both patients and older controls, however, exhibited impaired overall adaptation performance compared to younger healthy controls (age 18-33 years), likely due to age-related reductions in spatial and working memory. Patients also failed to generalize, i.e. they were unable to adopt analogous aiming strategies in response to novel rotations. Hence, there appears to be an inescapable obligatory dependence on sensory-prediction error-based learning-even when this system is impaired in patients with cerebellar disease. The persistence of sensory-prediction error-based learning effectively suppresses a switch to target error-based learning, which perhaps explains the unexpectedly poor performance by patients with cerebellar degeneration in visuomotor adaptation tasks. [ABSTRACT FROM AUTHOR]

Current techniques for quantifying human postural stability during quiet standing have several limitations. The main problem is that only two movement variables are evaluated, though a better description of complex three-dimensional (3-D) movements can be provided with the use of three variables. A single tri-axial accelerometer placed on the trunk was used to measure 3-D data.We are able to evaluate 3-D movements using a method based on the volume of confidence ellipsoid (VE) of the set of points obtained by plotting three accelerations against each other. Our method was used to identify and evaluate pathological balance control. In this study, measurements were made of patients with progressive cerebellar ataxia, and also control measurements of healthy subjects, and a statistical analysis was performed. The results show that the VEs of the neurological disorder patients are significantly larger than the VEs of the healthy subjects. It can be seen that the quantitative method based on VE is very sensitive for identifying changes in stability, and that it is able to distinguish between neurological disorder patients and healthy subjects.

This work focuses on the novelty of applying a 3-D postural analysis on the cerebellar disorders diagnosis and on introduction of an alternative to recent methods of quantifying the human postural stability during quiet stance, which uses a three-axis accelerometer. It introduces an advantage in the form of an ability to evaluate a complex three-dimensional (3-D) movement, as opposed to a major limitation of todaýs alternatives that evaluate only two coordinates in space. 3-D data (anterior-posterior, superior-inferior, and medio-lateral accelerations of a patient́s trunk) were obtained using a three-axis accelerometer (Xsens Mtx), enabling us to evaluate 3-D translational body movements on the basis of the average velocity (AV) of the point and the total length (TL) of the 3-dimensional trajectory. Then a pathological balance control has been identified from the 3-D plot of the three trajectories. The data were obtained from patients suffering from the progressive cerebellar ataxia as well as from healthy participants and were analyzed statistically. The analysis revealed several significant differences between the AVs and TLs of the patients versus the healthy participants. [ABSTRACT FROM AUTHOR]

Tandem gait testing is an integral part of the neurological exam. It is informative in a wide variety of disorders ranging from cerebellar disease to vestibular and peripheral neuropathies, parkinsonism, and other neurodegenerative conditions. We discuss the history and development of tandem gait testing as well as its technique, utility, and limitations in the assessment of neurological conditions. Tandem gait has emerged as a tool in the assessment of cerebellar disease, Huntington disease, idiopathic Parkinson's disease, atypical parkinsonism, peripheral neuropathies, and vestibulopathies. Its origin can be deduced from experimental observation and clinical experience as far back as the early nineteenth century. Despite the long history and ubiquitous performance of tandem gait testing, there is no standardized, guideline-based protocol to model for more homogenous research and clinical practices. Such a protocol should be developed using historical texts and manuscripts as well as the consensus of the medical research community. With standard protocols, further studies could define the sensitivity of abnormal tandem gait testing in cerebellar disorders, more diffuse neurodegeneration, and peripheral pathologies. Tandem gait can be a useful marker of dysfunction in neurologic conditions whose pathologies extend beyond the vermis or vestibulocerebellar module to include interconnected networks throughout the nervous system. [ABSTRACT FROM AUTHOR]

The current paper reports on a patient with recurrent rotational vertigo and persistent dizziness and imbalance lasting several weeks, who underwent extensive neuro-otological and radiological examinations. Pathological findings initially included right-sided benign paroxysmal positional vertigo (BPPV), persistent horizontal spontaneous nystagmus (SPN) to the left, and a pathological bedside and video head impulse test (HIT) on the left. The pathological HIT on the left and the SPN to the left indicated a central origin. Therefore, cranial magnetic resonance imaging was performed which revealed a left-sided ischemic stroke in the territory of the medial branch of the posterior inferior cerebellar artery (mPICA). [ABSTRACT FROM AUTHOR]

The main tools for measuring postural instability of the body during quiet stance are stabilometric platforms. Frequency domain analysis of center of pressure excursions is used for detecting and quantifying specific diseases. The disadvantage of such platforms is their higher price and large dimensions. The main aim of this work was to identify the applicability of the frequency domain analysis of the trunk acceleration measured by one-axis accelerometer. In order to test the new technique, 10 patients with degenerative cerebellar ataxia and 11 healthy subjects were chosen to participate. The trunk acceleration of each subject with opened/closed eyes was measured during quiet stance on a firm/foam surface. The distribution of the power spectral density in the frequency spectrum of acceleration in the anterior–posterior direction is a suitable tool for quantifying postural instability. The percentages of the area under the power spectral density curve of middle frequency range (2.4–3.5 Hz) of acceleration in patients and healthy subjects were compared, and significant differences were found. The finding of our research is that a single cheap one-axis accelerometer placed on trunk to measure the acceleration in AP direction, together with the method based on the power spectral density of acceleration, could be a new tool for examinations of body instability. [ABSTRACT FROM PUBLISHER]

Many disorders, such as nervous system disorders, can affect orientation of the body segments in 3D space negatively. Patients with these disorders often show body segments instability during stance tasks. Nowadays, 3-axis gyroscopes are about to be used to measure postural stability. The main objective of the paper is to describe a method which would be suitable for quantifying postural stability and 3D movement as a whole using a cheap 3-axis gyroscope. New method based on the volume of a 3D convex hull (CH) obtained by plotting pitch, roll and yaw angles versus each other was proposed for quantitative evaluation of 3D trunk sway. The sway was measured while patients with degenerative cerebellar disorder (Pts) and eleven healthy subjects (HSs) performed quiet stance on a firm surface (FiS) and foam surface (FoS) with open eyes (OE) and closed eyes (CE). The CH was used to identify differences in balance control, and there were significant differences found between the two groups. The median (Mdn) of the volume of Pts with OE on FiS is four times larger than the Mdn of the volume of HS with OE on FiS. The Mdn of the volume of Pts with CE on FoS is 80 times larger than the Mdn of the volume of HS with CE on FoS. It was therefore found that the volume of CH is suitable for quantifying postural sway and identifying differences in balance control. [ABSTRACT FROM AUTHOR]

The article focuses on a non-invasive method of quantifying human postural stability. Recent alternatives to quantify human postural stability have several limitations – the major one being the evaluation of only two physical quantities of body movement in 3D space – however, a complex movement pattern can be described better using three physical quantities. A cheap 3DOF orientation tracker (Xsens MTx unit) placed on patient's trunk was used to measure roll, pitch and yaw. Using a novel method based on the total length of the 3-D trajectory of body sway angles, we are able to evaluate 3-D movements of the trunk. The trajectory length obtained by plotting roll, yaw and pitch vs. each other (i.e. curve in the 3-D plot) was used to identify a pathological balance control. In this study, ten patients with progressive cerebellar ataxia and eleven healthy subjects were measured and a statistical analysis was performed. The results yielded by new method show that the total trajectory lengths of patients with cerebellar disease are significantly larger than the total trajectory lengths of healthy subjects. It is evident from the median of the total trajectory lengths that the method based on the data obtained by an inexpensive orientation tracker may be used to quantify human postural stability and enables for studying body sway in 3-D space. For example, the 3-D deviations of the trunk angles in a time period that are caused by a tremor in 3-dimensional space can be studied accordingly by the method. [ABSTRACT FROM AUTHOR]

Summary This study examines a relatively new method of studying and quantifying human postural stability in patients with degenerative cerebellar disease. Trunk sway and feet sway were measured during quiet stance. To test the method, ten patients and eleven healthy subjects performed two different stance tasks: standing with eyes open on a firm surface and standing with eyes closed on a foam support surface. Data were recorded using three body-worn gyroscopes (Xsens Technologies B.V.) to measure roll and pitch angular movements of the lower trunk, and left and right foot. The pitch versus roll plots of the trunk and feet were created, and the areas of the convex hull shapes were calculated. It was found that the area of the convex hull of the pitch versus roll plots is suitable for the identification of postural instability disorders caused by degenerative cerebellar disease. [ABSTRACT FROM AUTHOR]

The article investigates the feasibility of a randomized controlled trial of a training balance with opto-kinetic stimuli in the home people with cerebellar ataxia. The patients are randomized into a therapy or control group. In outcome measures evaluating balance at impairment and activity levels, test-retest reliability is noted strong. The home-based balance intervention for the patients is found feasible and the reliability of the outcome measures employed is noted.

Given its anatomical proximity to the brainstem and the ventricular system, cerebellar haemorrhage may lead to immediate life-threatening complications such as brainstem compression and hydrocephalus, or to herniation through the foramen magnum or the tentorium. This situation mandates fast diagnosis and precise emergency treatment strategies. However, the treatment protocols in current use are based on little evidence and the indication criteria for surgical intervention are unclear. Early suboccipital decompressive surgery may be life-saving, but the potential risk involved is unnecessary if the haemorrhage is benign and can be managed conservatively or with insertion of an external ventricular drain. Deterioration of the patients' state of consciousness has often been used as an indication for surgery, but clinical decline can be a fulminant process leading to death within a short time. Research on cerebellar haemorrhage so far has focused on identifying outcome predictors from which treatment algorithms can be derived. Large randomised controlled trials (RCTs) are lacking. However, RCTs are urgently needed, in order to improve the level of evidence, treatment decisions may be based on. Here, we review the available literature on complications, treatment and outcome of primary cerebellar haemorrhage (PCH). Finally we propose the design of a potential RCT. [ABSTRACT FROM AUTHOR]

Abstract: Background: Detection of 14-3-3 proteins in cerebrospinal fluid (CSF) is a powerful tool for elucidating the mechanisms of neurological disorders. There have been useful studies on 14-3-3 CSF protein detection in Creutzfeldt–Jakob disease and other neurological disorders, but none on cerebellar diseases. Objective: To elucidate whether 14-3-3 CSF proteins are a sensitive biomarker of cerebellar disruption in children. Materials and Methods: We examined 14-3-3 CSF proteins by immunoblotting in seven patients with cerebellar disorders: two with acute cerebellitis, two with acute cerebellar ataxia, and three with cerebellar atrophy. We also investigated 14-3-3 CSF proteins in four cases of febrile seizure and three of influenza-related encephalopathy. Isoforms of 14-3-3 proteins were also identified using isoform-specific antibodies. Results: 14-3-3 proteins were detected in CSF of six patients with cerebellar disorders, the exception being one with acute cerebellar ataxia caused by viral infection. Interestingly, only the 14-3-3 ε isoform was detected in two tested patients with cerebellar involvement. Moreover, longitudinal analysis of 14-3-3 CSF proteins in one patient with infantile neuroaxonal dystrophy showed that the 14-3-3 band density proportionally decreased when the cerebellar atrophy gradually progressed. Another CSF derived from a case of febrile seizure showed no 14-3-3 proteins, whereas all those derived from influenza-related encephalopathy demonstrated 14-3-3 CSF proteins with six isoforms. Conclusions: This is the first report on 14-3-3 CSF proteins as a significant biomarker of cerebellar disruption, as well as other brain diseases. Since 14-3-3 ε is localized in the molecular layer of cerebellum, the unique detection of 14-3-3 ε may indicate cerebellar involvement in the brain. [Copyright &y& Elsevier]

Introduction: We aim to present and discuss clinical outcomes of preoperative liquid embolization of hemangioblastomas (HB) using N-butyl cyanoacrylate (NBCA). Methods: From 1999 through 2010, 19 patients presenting with symptoms of vertigo and/or headaches were diagnosed with HB based on preoperative magnetic resonance imaging and cerebral angiographic findings at our institution. Preoperative embolization with NBCA was performed on tumors in 10 of 21 operations for 19 patients. For each of these patients, the lesion was pathologically confirmed as HB. Results: Embolization had a favorable outcome in all patients. No permanent neurological complications were observed after preoperative embolization using NBCA. However, thalamic infarction and minor hemorrhage were observed in two patients with cerebellar HB. Conclusion: The authors recommend NBCA as an embolization material for large cerebellar HB. [ABSTRACT FROM AUTHOR]

Early after stroke, there is loss of intracortical facilitation (ICF) and increase in short-interval intracortical inhibition (SICI) in the primary motor cortex (M1) contralateral to a cerebellar infarct. Our goal was to investigate intracortical M1 function in the chronic stage following cerebellar infarcts (>4 months). We measured resting motor threshold (rMT), SICI, ICF, and ratios between motor-evoked potential amplitudes (MEP) and supramaximal M response amplitudes (MEP/M; %), after transcranial magnetic stimulation was applied to the M1 contralateral (M1) and ipsilateral (M1) to the cerebellar infarct in patients and to both M1s of healthy age-matched volunteers. SICI was decreased in M1 compared to M1 in the patient group in the absence of side-to-side differences in controls. There were no significant interhemispheric or between-group differences in rMT, ICF, or MEP/M (%). Our results document disinhibition of M1 in the chronic phase after cerebellar stroke. [ABSTRACT FROM AUTHOR]

Abstract: Background context: There have been only five reported cases with cerebellar hemorrhagic infarction after spinal surgery, and the underlying pathomechanism remains obscure. Purpose: To describe a case with multiple cerebellar hemorrhagic infarctions after surgery for a huge atlantoaxial neurinoma. Study design/setting: Case report Methods: A 36-year-old man underwent uneventful surgery for a huge atlantoaxial neurinoma. After surgery, the patient was lethargic with slurred speech and subsequently developed cerebellar symptoms, although preoperative myelopathic symptoms did not worsen. The clinical and radiological findings are presented, and possible causes of the hemorrhages are discussed. Results: Magnetic resonance imaging of the brain after surgery showed multiple cerebellar hemorrhagic infarctions. However, magnetic resonance angiography revealed no occlusion or stenosis in the vertebrobasilar system, and a duplex scan of the neck vessels confirmed normal flow in the vertebral arteries after surgery. In response to the conservative treatment, the patient exhibited neurological recovery with disappearance of cerebellar symptoms. Conclusions: In the present case with multiple cerebellar hemorrhagic infarctions, venous infarction appears more likely to be the cause of cerebellar hemorrhagic infarction than arterial infarction. The most likely underlying pathomechanism is a cerebellar venous disturbance precipitated by loss of a large amount of cerebrospinal fluid, although the exact etiology remains elusive. [Copyright &y& Elsevier]

Abstract: It is widely accepted that the cerebellar and basal ganglia control circuits contribute to the programming of movement. Converging evidence from neuroimaging, limb control, and neuropsychological studies suggests that (1) people with cerebellar disease have reduced ability to program movement sequences in advance of movement onset and (2) people with Parkinson’s disease are unable to maintain a programmed response or to rapidly switch between responses. Despite a substantial supporting literature, no studies have addressed these potential areas of speech programming disruption for speakers with ataxic and hypokinetic dysarthria. Control participants and adults with dysarthria completed speech reaction time protocols designed to capture these aspects of utterance preparation. Results provided initial support for processing deficits in speakers with ataxic and hypokinetic dysarthria that are separable from motor execution impairments. [Copyright &y& Elsevier]

Responses to pitch head impulses were measured in 15 patients with cerebellar degeneration and downbeat nystagmus and in 5 control subjects, using three-axis search coils. For each subject, response gains were calculated as (1) the ratio of instantaneous vertical eye velocity to pitch head velocity (at 30 ms and at 70 ms into the response), and (2) the ratio of peak eye velocity to peak head velocity. Gains varied more widely among patients. When calculated at 70 ms and using peak values, patients had higher gains for downward pitch, and normal subjects had symmetric gains. At 30 ms, gains were more symmetric in patients, but at that point control subjects actually had lower gains for downward pitch. Thus, the pitch gain ratio (ratio of downward gain to upward gain) was consistently greater in patients than in normal subjects. Because downward impulses were generally faster, eye velocities during downward and upward pitch for equivalent head speeds were also compared. Again, patients had higher gains for downward pitch. These results are consistent with the authors' hypothesis that cerebellar disease results in a higher sensitivity of anterior than posterior semicircular canal pathways, perhaps through loss of inhibition from the flocculus/paraflocculus complex on anterior canal secondary neurons in the vestibular nuclei. The pitch gain asymmetry was larger than, and did not correlate with, the velocity of spontaneous upward drift. This supports the notion that other mechanisms are likely to contribute to downbeat nystagmus in these patients. [ABSTRACT FROM AUTHOR]

Force control on the basis of prediction avoids time delays from sensory feedback during motor performance. Thus, self-produced loads arising from gravitational and inertial forces during object manipulation can be compensated for by simultaneous anticipatory changes in grip force. It has been suggested that internal forward models predict the consequences of our movements, so that grip force can be programmed in anticipation of movement-induced loads. The cerebellum has been proposed as the anatomical correlate of such internal models. Here, we present behavioural data from patients with cerebellar damage and data from brain imaging in healthy subjects further elucidating the role of the cerebellum in predictive force control. Patients with cerebellar damage exhibited clear deficits in the coupling between grip force and load. A positron-emission-tomography (PET) paradigm that separated the process of the grip force/load coupling from the isolated production of similar grip forces and loads was developed. Interaction and conjunction analyses revealed a strong activation peak in the ipsilateral posterior cerebellum particularly devoted to the predictive coupling between grip force and load. Both approaches clearly demonstrate that the cerebellum plays a major role in force prediction that cannot be compensated for by other sensorimotor structures in case of cerebellar disease. However, evidence suggests that also extra-cerebellar structures may significantly contribute to predictive force control: (1) grip force/load coupling may also be impaired after cerebral and peripheral sensorimotor lesions, (2) a coupling-related activation outside the cerebellum was observed in our PET study, and (3) the scaling of the grip force level and the dynamic grip force coupling are dissociable aspects of grip force control. [ABSTRACT FROM AUTHOR]

Congenital cerebellar disorders can be caused by in utero or neonatal infections, genetic aberrations causing malformations, and neurodegenerative processes. Most congenital cerebellar disorders are diagnosed definitively with histopathology. However, antemortem diagnosis of cerebellar malformations can be made by imaging the brain. This paper describes the antemortem appearance of a congenital cerebellar malformation in a Boston Terrier puppy on ultrasound images. This appearance was compared with the postmortem findings that were comparable to Dandy Walker Syndrome in humans. A previous report of this syndrome in Boston Terriers suggests the problem may be inherited in this breed. [ABSTRACT FROM AUTHOR]

SEMG investigation protocols are described within the neurological framework. A neuro- anatomic pathway is utilized including muscular disease, neuromuscular junction conditions, peripheral neuropathy, radiculopahy, myleopathy, brainstem disorders, cerebellar disorders, subcortical and cortical disease. SEMG findings within the clinical presentation of those pathologies are aimed at improving the diagnostic process and serve to focus the SEMG neuromuscular reeducation (biofeedback) component of the overall treatment plan. [ABSTRACT FROM AUTHOR]

We examined the stability and strategies used by balance impaired (vestibular hypofunction, VH: n=25; cerebellar damage, CB: n=20) patients and healthy (HE: n=52) controls during planned gait termination. Upper body strategies (during final stride and final step) were investigated using peak positive kinetic power (KP(+): kinetic energy increasing), and peak negative kinetic power (KP(−): kinetic energy decreasing) of the head–arms–trunk segment. Compared to HE controls (P<0.05): CB patients'' medio-lateral KP(+) and KP(−) and were 53 and 71% higher during final stride, respectively; VH patients medio-lateral KP(+) and KP(−) was 78 and 57% higher during final step, respectively, and; during the final, standing stage VH patients were 32% less stable (from phase plane analysis) in the frontal plane. The excessive energy transfers in final stride for CB patients was likely due to poor eccentric muscle control when preparing for the stop. VH patients had difficulty controlling lateral stability during final step and once they had stopped walking, probably due to the lack of vestibular feedback regarding forward velocity changes. A better understanding of these abnormal movement patterns or compensatory strategies may assist in rehabilitation of patients with balance dysfunction. [Copyright &y& Elsevier]

Objective attempts to characterize postural control in subjects with cerebellar (Cb) pathology have focused primarily on sagittal plane responses to static standing, semi-dynamic standing, and platform perturbation. Repeated, dynamic, functional movement may provide a better opportunity to study the effects of ataxia on frontal plane postural stability. The purpose of this investigation was to quantify lateral stability using center of gravity (CG) and center of pressure (CP) movement analysis, and to examine motor responses necessary to complete a repetitive stepping task. Whole body kinematic and kinetic data were collected as patients with Cb degeneration and non-disabled volunteers repeatedly ascended forward and descended backward from a 7.6-cm step to the beat of a metronome. Cb subjects demonstrated significantly greater lateral CG instability, consistent with increased CG velocity and displacement variability in the frontal plane compared to non-disabled subjects. Significantly greater lateral CP displacement was found in subjects with Cb degeneration. Phase plot patterns from patients with Cb degeneration showed poor movement quality, indicated by abruptly changing CG phase plot patterns and abnormal CG acceleration and deceleration phases. Ataxic postural reactions were observed consistently during lateral weight shifting phases toward the stance limb. We hypothesized that lateral postural instability in Cb subjects stems from altered lower extremity intersegmental coordination and inadequate lateral CG velocity control. Frontal plane CG instability may necessitate a wide-based gait. Despite the varied neuroanatomic sites of degenerative Cb pathology, subjects with Cb pathology demonstrated similar CG movement patterns and altered motor strategies to avoid destabilization. Dynamic assessment provides important information regarding frontal plane instability not revealed by static assessment methods. These findings suggest that a dynamic, constrained stepping task effectively differentiates Cb and non-disabled volunteers, contributing to our knowledge of the effect of ataxic movement disturbances on frontal plane postural stability and lower limb coordination. [ABSTRACT FROM AUTHOR]

Automatic postural responses of leg muscles to the sudden displacement of standing support were investigated under four different conditions of information given to subjects in advance. Results from three groups of subjects were compared: 6 normal subjects, 10 patients with cerebellar disease, and 9 patients with Parkinson's disease. Specifically, each subject was provided with visual information about the direction and/or the amplitude of an upcoming platform tilt. For the control situation no advance information on the characteristics of platform tilt was provided. Neither the latencies nor the integrals of postural EMG-responses showed alterations with advance information. In contrast, in a control experiment in which 3 normal subjects had to perform large or small forward or backward voluntary movements of the body around the ankle joint, shorter onset-latencies of leg muscle EMG responses were observed with increasing complexity of the advance information. These results suggest that, unlike voluntary movements, postural responses to rapid surface tilts do not benefit from advance visual information on direction or amplitude of a postural disturbance. [ABSTRACT FROM AUTHOR]