Cerebellar dysfunction in essential tremor

Hanajima, Ritsuko; Tsutsumi, Ryosuke; Shirota, Yasuhiko; Shimizu, Takahiro; Tanaka, Nobuyuki; Ugawa, Yoshikazu

doi:10.1002/mds.26629

Cited by 36 publications

(18 citation statements)

References 27 publications

(48 reference statements)

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“…The increased volume of cerebellar GM was associated positively with longer disease duration and higher TRS scores, which also indicated a potential compensatory mechanism. Some previous pathological and physiological studies ( 54 , 55 ) reported the compensatory mechanism of cerebellum in ET. Further clinical studies can focus on it.…”

Section: Discussionmentioning

confidence: 93%

A Voxel-Wise Meta-Analysis of Gray Matter Abnormalities in Essential Tremor

2018

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Objective: To identify the consistent gray matter (GM) volume changes from the whole brain voxel-based morphometry (VBM) studies on essential tremor (ET).Methods: The whole brain VBM studies comparing ET patients and healthy controls (HCs) were systematically searched in the PubMed, Embase and Web of Science from January 2000 to December 2017. Coordinates with significant differences in regional GM volume between ET patients and HCs were extracted from included studies and the meta-analysis was performed using effect size-based signed differential mapping (ES-SDM).Results: A total of 10 studies with 241 ET patients and 213 HCs were included in the meta-analysis. The consistent GM volume reduction was detected in the left precuneus extending to the left posterior cingulate gyrus. The subgroup meta-analysis which included studies performed on a 3.0 T scanner revealed significant GM volume increases in the bilateral frontal lobes, bilateral temporal lobes, left insula, left striatum and left pons, but obvious publication biases of these findings were detected through funnel plots and Egger's tests.Conclusions: The consistent result of our meta-analysis showed a structural damage in the left precuneus extending to the left posterior cingulate gyrus, which possibly played a role in the cognitive dysfunction and depression in ET patients. It might enhance our understanding of the pathophysiological mechanisms underlying ET.

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Section: Discussionmentioning

confidence: 93%

A Voxel-Wise Meta-Analysis of Gray Matter Abnormalities in Essential Tremor

2018

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“…However, two previous CBI studies have reported conflicting outcomes. Hanajima and colleagues found CBI to be significantly reduced compared to healthy controls and therefore proposed involvement of the cerebellar efferent tract in ET . In contrast, Pinto and colleagues showed normal CBI in younger, more severely affected individuals.…”

Section: Effects Of Noninvasive Cerebellar Stimulation In Diseases Afmentioning

confidence: 99%

The Role of the Cerebellum in Degenerative Ataxias and Essential Tremor: Insights From Noninvasive Modulation of Cerebellar Activity

2019

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A BS TRACT: Over the last three decades, measuring and modulating cerebellar activity and its connectivity with other brain regions has become an emerging research topic in clinical neuroscience. The most important connection is the cerebellothalamocortical pathway, which can be functionally interrogated using a paired-pulse transcranial magnetic stimulation paradigm. Cerebellar brain inhibition reflects the magnitude of suppression of motor cortex excitability after stimulating the contralateral cerebellar hemisphere and therefore represents a neurophysiological marker of the integrity of the efferent cerebellar tract. Observations that cerebellar noninvasive stimulation techniques enhanced performance of certain motor and cognitive tasks in healthy individuals have inspired attempts to modulate cerebellar activity and connectivity in patients with cerebellar diseases in order to achieve clinical benefit. We here comprehensively explore the therapeutic potential of these techniques in two movement disorders characterized by prominent cerebellar involvement, namely the degenerative ataxias and essential tremor. The article aims to illustrate the (patho) physiological insights obtained from these studies and how these translate into clinical practice, where possible by addressing the association with cerebellar brain inhibition. Finally, possible explanations for some discordant interstudy findings, shortcomings in our current understanding, and recommendations for future research will be provided.The cerebellum is a highly complex brain region that fulfills a crucially important role in a variety of seemingly natural processes, including postural control, locomotion, and numerous cognitive functions. As an integration center receiving multimodal sensorimotor information from the spinal cord, cerebral cortex, and vestibular nuclei, it continuously compares efference copies and reafference signals and corrects for discrepancies between them to enable the execution of smooth, well-coordinated movements. Notably, given the dearth of direct connections between the cerebellum and peripheral nervous system, this intricate task is mainly accomplished by modulating the excitability of the primary motor cortex through the cerebellothalamocortical tract. 1,2 In 1995, Ugawa and colleagues demonstrated the possibility of quantifying the integrity of the cerebellothalamocortical pathway as a neurophysiological outcome measure by means of a painless paired-pulse transcranial magnetic stimulation (TMS) paradigm. 3,4 In an influential series of experiments, they showed a reduction of the motor evoked potential (MEP) amplitude when a conditioning stimulus was delivered across the contralateral skull base in a time window of 5 to 7 ms prior to a magnetic pulse over the motor cortex. 4 Given the absence of such a suppression effect in two patients with cerebellar ---

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“…The spirals of ET patients with low severity (mean = 1.4) were judged as NC, whereas the severity of ET patients mistaken for CD (mean = 2.6) was almost the same as the total ET severity (mean = 2.3). We consider the low sensitivity of ET for the following reasons: (1) slight tremors in NCs, including physiologic or senile tremor may generally be difficult to differentiate from mild ET [21], and (2) the pathophysiology of ET contains elements of cerebellar dysfunctions [22]. These problems might be solved by learning more spirals and using patients' age as a parameter in the application.…”

Section: Ai For Tremor Diagnosismentioning

confidence: 99%

Spiral drawing: Quantitative analysis and artificial-intelligence-based diagnosis using a smartphone

Ishii

Mochizuki

Shiomi

et al. 2020

Journal of the Neurological Sciences

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Background: The evaluation of neurological examination in clinical practice still remains qualitative or semiquantitative, and the results often vary depending on an examiner's skill level and are less objective. In this study, we developed a smartphone-based application to investigate quantifying neurological examinations using hand-drawn spirals and diagnose patients with tremor using artificial intelligence (AI). Methods: This study included 24 and 26 patients with essential tremor (ET) and cerebellar disease (CD), respectively, and 41 age-matched normal controls (NCs). We obtained 69, 46, and 56 hand-drawn spirals from the NC, ET, and CD groups, respectively, as image data captured by smartphones. The patients traced a printed reference spiral. The length of this spiral was compared with the reference spiral length (% of spiral length) and the total deviation area between these spirals was calculated. The server also estimates the diagnostic probability through AI. Results: The quantified spiral analysis (% of spiral length and deviation area) significantly correlated with disease severity in each disease group, and significant differences in the deviation area were observed among all groups. The AI diagnosis showed 79%, 70%, and 73% accuracies for the NC, ET, and CD groups, respectively. Conclusion: This study indicates the possibility of using a smartphone as a medical examination tool and demonstrates the application of AI in neurological examinations.

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Cerebellar dysfunction in essential tremor

Cited by 36 publications

References 27 publications

A Voxel-Wise Meta-Analysis of Gray Matter Abnormalities in Essential Tremor

A Voxel-Wise Meta-Analysis of Gray Matter Abnormalities in Essential Tremor

The Role of the Cerebellum in Degenerative Ataxias and Essential Tremor: Insights From Noninvasive Modulation of Cerebellar Activity

Spiral drawing: Quantitative analysis and artificial-intelligence-based diagnosis using a smartphone

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