Publications by authors named "Sheng-Han Kuo"

The cerebellum has been largely overlooked in Alzheimer's disease, despite increasing evidence implicating its cognitive capacities and functional networks, which interacts with cerebral cortex to subserve cognition. A study by Lin et al. has indicated that the cerebellum is part of the integrated network in amnestic mild cognitive impairment (aMCI), a prodromal state of Alzheimer's disease.

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Under stress, Purkinje cells (PCs) undergo a variety of reactive morphological changes. These can include swellings of neuronal processes. While axonal swellings, "torpedoes", have been well-studied, dendritic swellings (DS) have not been the centerpiece of study.

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Background: Whether low-frequency deep brain stimulation (DBS) in the caudal zona incerta (cZi) can improve cerebellar ataxia symptoms remains unexplored.

Case Report: We report a 66-year-old man initially diagnosed with essential tremor and subsequently developed cerebellar ataxia after bilateral cZi DBS implantation. We tested the effects of low-frequency DBS stimulations (sham, 10 Hz, 15 Hz, 30 Hz) on ataxia severity.

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Cross-individual variability is considered the essence of biology, preventing precise mathematical descriptions of biological motion like the physics law of motion. Here we report that the cerebellum shapes motor kinematics by encoding dynamic motor frequencies with remarkable numerical precision and cross-individual uniformity. Using in-vivo electrophysiology and optogenetics in mice, we confirmed that deep cerebellar neurons encoded frequencies via populational tuning of neuronal firing probabilities, creating cerebellar oscillations and motions with matched frequencies.

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Article Synopsis
  • The Scale for Assessment and Rating of Ataxia (SARA) is a key clinical tool for evaluating cerebellar ataxia but has received criticism regarding the relevance of its assessment items.
  • A study involving 850 patients across different types of spinocerebellar ataxias (SCA1, SCA2, SCA3, SCA6) revealed significant differences in progression rates among cohorts, particularly with the EUROSCA cohort showing the fastest rates.
  • The analysis found that not all items on the SARA scale contribute equally to measuring ataxia severity, and while some items are more sensitive to changes early or late in the disease, overall adjustments to the scale did not enhance responsiveness across different patient
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Introduction: Previous research has identified that people with cerebellar ataxia (CA) showed impaired reward-related decision-making in the Iowa Gambling Task (IGT). To investigate the mechanisms underlying this impairment, we examined CA participants' combination of performance in the IGT, which predominantly tests reward seeking, and the modified IGT (mIGT), which mainly assesses punishment avoidance.

Methods: Fifty participants with CA and one hundred controls completed the IGT and mIGT.

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Article Synopsis
  • The cerebellum plays a crucial role in regulating motor, cognitive, social, and emotional functions by interacting with other brain structures to support automatic behaviors and predictive mechanisms across various tasks, including reward-related activities.
  • It encodes important signals related to reward prediction and temporal changes, influenced by chemical changes in catecholamines, which assist in cognitive learning and complex behavior modulation.
  • Recent research highlights the cerebellum's involvement in mood disorders and addiction, as it helps manage reward sensitivity and loss aversion, while also predicting behavioral outcomes based on past experiences, which can affect social interactions and impulse control.
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Article Synopsis
  • - The study aimed to create and validate a patient-reported outcome scale (TETRAS PRO) for essential tremor, addressing a gap in existing assessments that rely on structured interviews and physical exams.
  • - The TETRAS PRO demonstrated strong correlations with established scales (TETRAS ADL, TETRAS-P, and QUEST) and showed good reliability, making it a useful tool for evaluating essential tremor impacts over time.
  • - The scale's effectiveness is influenced mainly by tremor severity and mood (specifically depression), with findings suggesting that it can detect clinically significant changes in patients' conditions.
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Essential tremor (ET) is the most prevalent movement disorder, characterized primarily by action tremor, an involuntary rhythmic movement with a specific frequency. However, the neuronal mechanism underlying the coding of tremor frequency remains unexplored. Here, we used in vivo electrophysiology, optogenetics, and simultaneous motion tracking in the mouse model to investigate whether and how neuronal activity in the olivocerebellum determines the frequency of essential tremor.

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The functional Scale for the Assessment and Rating of Ataxia (f-SARA) assesses Gait, Stance, Sitting, and Speech. It was developed as a potentially clinically meaningful measure of spinocerebellar ataxia (SCA) progression for clinical trial use. Here, we evaluated content validity of the f-SARA.

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Objective: Essential tremor is among the most prevalent neurological diseases. Diagnosis is based entirely on neurological evaluation. Historically, there were few postmortem brain studies, hindering attempts to develop pathologically based criteria to distinguish essential tremor from control brains.

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Background: Fatigue is a prevalent and debilitating symptom in neurological disorders, including spinocerebellar ataxias (SCAs). However, the risk factors of fatigue in the SCAs as well as its impact have not been well investigated.

Objectives: To study the prevalence of fatigue in SCAs, the factors contributing to fatigue, and the influence of fatigue on quality of life.

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Purpose Of Review: Spinocerebellar ataxias (SCAs) are autosomal dominant degenerative syndromes that present with ataxia and brain stem abnormalities. This review describes the cognitive and behavioral symptoms of SCAs in the context of recent knowledge of the role of the cerebellum in higher intellectual function.

Recent Findings: Recent studies suggest that patients with spinocerebellar ataxia can display cognitive deficits even early in the disease.

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Article Synopsis
  • * The study assessed how early life events, such as maternal difficulties during pregnancy and participation in school sports, influence AAO, severity, and progression using a social determinant of health approach.
  • * Findings revealed that maternal difficulties and sports participation were linked to an earlier AAO by over 13 years, while higher education levels led to slower disease progression and less severity, highlighting the impact of non-genetic factors on SCA6 outcomes.
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RFC1 disease, caused by biallelic repeat expansion in RFC1, is clinically heterogeneous in terms of age of onset, disease progression and phenotype. We investigated the role of the repeat size in influencing clinical variables in RFC1 disease. We also assessed the presence and role of meiotic and somatic instability of the repeat.

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The Cerebellar Cognitive Affective/Schmahmann Syndrome (CCAS) manifests as impaired executive control, linguistic processing, visual spatial function, and affect regulation. The CCAS has been described in the spinocerebellar ataxias (SCAs), but its prevalence is unknown. We analyzed results of the CCAS/Schmahmann Scale (CCAS-S), developed to detect and quantify CCAS, in two natural history studies of 309 individuals Symptomatic for SCA1, SCA2, SCA3, SCA6, SCA7, or SCA8, 26 individuals Pre-symptomatic for SCA1 or SCA3, and 37 Controls.

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Objective: Postmortem examination of the essential tremor cerebellum has revealed a variety of pathological changes centered in and around Purkinje cells. Studies have predominantly focused on cerebellar neuronal connections. Bergmann glial morphology has not yet been studied in essential tremor.

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Recent findings in animals have challenged the traditional view of the cerebellum solely as the site of motor control, suggesting that the cerebellum may also be important for learning to predict reward from trial-and-error feedback. Yet, evidence for the role of the cerebellum in reward learning in humans is lacking. Moreover, open questions remain about which specific aspects of reward learning the cerebellum may contribute to.

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Cerebellar ataxias are neurological conditions with a high prevalence of aspiration pneumonia and dysphagia. Recent research shows that sensorimotor cough dysfunction is associated with airway invasion and dysphagia in other neurological conditions and may increase the risk of pneumonia. Therefore, this study aimed to characterize sensorimotor cough function and its relationship with ataxia severity.

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There are numerous forms of cerebellar disorders from sporadic to genetic diseases. The aim of this chapter is to provide an overview of the advances and emerging techniques during these last 2 decades in the neurophysiological tests useful in cerebellar patients for clinical and research purposes. Clinically, patients exhibit various combinations of a vestibulocerebellar syndrome, a cerebellar cognitive affective syndrome and a cerebellar motor syndrome which will be discussed throughout this chapter.

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Essential Tremor (ET) is a prevalent neurological disease characterized by an 8-10 Hz action tremor. Molecular mechanisms of ET remain poorly understood. Clinical data suggest the importance of the cerebellum in disease pathophysiology, and pathological studies indicate Purkinje Cells (PCs) incur damage.

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Essential tremor (ET) is a common movement disorder affecting millions of people. Studies of ET patients and perturbations in animal models have provided a foundation for the neural networks involved in its pathophysiology. However, ET encompasses a wide variability of phenotypic expression, and this may be the consequence of dysfunction in distinct subcircuits in the brain.

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With SCAview, we present a prompt and comprehensive tool that enables scientists to browse large datasets of the most common spinocerebellar ataxias intuitively and without technical effort. Basic concept is a visualization of data, with a graphical handling and filtering to select and define subgroups and their comparison. Several plot types to visualize all data points resulting from the selected attributes are provided.

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Tracking kinematic details of motor behaviors is a foundation to study the neuronal mechanism and biology of motor control. However, most of the physiological motor behaviors and movement disorders, such as gait, balance, tremor, dystonia, and myoclonus, are highly dependent on the overall momentum of the whole-body movements. Therefore, tracking the targeted movement and overall momentum simultaneously is critical for motor control research, but it remains an unmet need.

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