. 2015 Dec 28:11:1-9.

doi: 10.1016/j.nicl.2015.12.011. eCollection 2016.

Bilateral cerebellar activation in unilaterally challenged essential tremor

Marja Broersma¹, Anna M M van der Stouwe², Arthur W G Buijink³, Bauke M de Jong⁴, Paul F C Groot⁵, Johannes D Speelman⁶, Marina A J Tijssen⁷, Anne-Fleur van Rootselaar⁸, Natasha M Maurits⁹

Affiliations

¹ Department of Neurology, University Medical Center Groningen, University of Groningen, PO Box 30001, 9700 RB Groningen, the Netherlands; Neuroimaging Center, University Medical Center Groningen, University of Groningen, PO Box 30001, 9700 RB Groningen, the Netherlands. Electronic address: m.broersma@umcg.nl.
² Department of Neurology, University Medical Center Groningen, University of Groningen, PO Box 30001, 9700 RB Groningen, the Netherlands; Neuroimaging Center, University Medical Center Groningen, University of Groningen, PO Box 30001, 9700 RB Groningen, the Netherlands. Electronic address: a.m.m.van.der.stouwe@umcg.nl.
³ Department of Neurology and Clinical Neurophysiology, Academic Medical Center, University of Amsterdam, PO Box 22660, 1100 DD Amsterdam, the Netherlands; Brain Imaging Center, Academic Medical Center, University of Amsterdam, PO Box 22660, 1100 DD Amsterdam, the Netherlands. Electronic address: a.w.buijink@amc.uva.nl.
⁴ Department of Neurology, University Medical Center Groningen, University of Groningen, PO Box 30001, 9700 RB Groningen, the Netherlands; Neuroimaging Center, University Medical Center Groningen, University of Groningen, PO Box 30001, 9700 RB Groningen, the Netherlands. Electronic address: b.m.de.jong@umcg.nl.
⁵ Brain Imaging Center, Academic Medical Center, University of Amsterdam, PO Box 22660, 1100 DD Amsterdam, the Netherlands; Department of Radiology, Academic Medical Center, University of Amsterdam, PO Box 22660, 1100 DD Amsterdam, the Netherlands. Electronic address: p.f.c.groot@amc.uva.nl.
⁶ Department of Neurology and Clinical Neurophysiology, Academic Medical Center, University of Amsterdam, PO Box 22660, 1100 DD Amsterdam, the Netherlands. Electronic address: j.d.speelman@gmail.com.
⁷ Department of Neurology, University Medical Center Groningen, University of Groningen, PO Box 30001, 9700 RB Groningen, the Netherlands; Neuroimaging Center, University Medical Center Groningen, University of Groningen, PO Box 30001, 9700 RB Groningen, the Netherlands. Electronic address: m.a.j.de.koning-tijssen@umcg.nl.
⁸ Department of Neurology and Clinical Neurophysiology, Academic Medical Center, University of Amsterdam, PO Box 22660, 1100 DD Amsterdam, the Netherlands; Brain Imaging Center, Academic Medical Center, University of Amsterdam, PO Box 22660, 1100 DD Amsterdam, the Netherlands. Electronic address: a.f.vanrootselaar@amc.uva.nl.
⁹ Department of Neurology, University Medical Center Groningen, University of Groningen, PO Box 30001, 9700 RB Groningen, the Netherlands; Neuroimaging Center, University Medical Center Groningen, University of Groningen, PO Box 30001, 9700 RB Groningen, the Netherlands. Electronic address: n.m.maurits@umcg.nl.

PMID: 26909321
PMCID: PMC4732188
DOI: 10.1016/j.nicl.2015.12.011

Bilateral cerebellar activation in unilaterally challenged essential tremor

Marja Broersma et al. Neuroimage Clin. 2015.

. 2015 Dec 28:11:1-9.

doi: 10.1016/j.nicl.2015.12.011. eCollection 2016.

Authors

Affiliations

¹ Department of Neurology, University Medical Center Groningen, University of Groningen, PO Box 30001, 9700 RB Groningen, the Netherlands; Neuroimaging Center, University Medical Center Groningen, University of Groningen, PO Box 30001, 9700 RB Groningen, the Netherlands. Electronic address: m.broersma@umcg.nl.
² Department of Neurology, University Medical Center Groningen, University of Groningen, PO Box 30001, 9700 RB Groningen, the Netherlands; Neuroimaging Center, University Medical Center Groningen, University of Groningen, PO Box 30001, 9700 RB Groningen, the Netherlands. Electronic address: a.m.m.van.der.stouwe@umcg.nl.
³ Department of Neurology and Clinical Neurophysiology, Academic Medical Center, University of Amsterdam, PO Box 22660, 1100 DD Amsterdam, the Netherlands; Brain Imaging Center, Academic Medical Center, University of Amsterdam, PO Box 22660, 1100 DD Amsterdam, the Netherlands. Electronic address: a.w.buijink@amc.uva.nl.
⁴ Department of Neurology, University Medical Center Groningen, University of Groningen, PO Box 30001, 9700 RB Groningen, the Netherlands; Neuroimaging Center, University Medical Center Groningen, University of Groningen, PO Box 30001, 9700 RB Groningen, the Netherlands. Electronic address: b.m.de.jong@umcg.nl.
⁵ Brain Imaging Center, Academic Medical Center, University of Amsterdam, PO Box 22660, 1100 DD Amsterdam, the Netherlands; Department of Radiology, Academic Medical Center, University of Amsterdam, PO Box 22660, 1100 DD Amsterdam, the Netherlands. Electronic address: p.f.c.groot@amc.uva.nl.
⁶ Department of Neurology and Clinical Neurophysiology, Academic Medical Center, University of Amsterdam, PO Box 22660, 1100 DD Amsterdam, the Netherlands. Electronic address: j.d.speelman@gmail.com.
⁷ Department of Neurology, University Medical Center Groningen, University of Groningen, PO Box 30001, 9700 RB Groningen, the Netherlands; Neuroimaging Center, University Medical Center Groningen, University of Groningen, PO Box 30001, 9700 RB Groningen, the Netherlands. Electronic address: m.a.j.de.koning-tijssen@umcg.nl.
⁸ Department of Neurology and Clinical Neurophysiology, Academic Medical Center, University of Amsterdam, PO Box 22660, 1100 DD Amsterdam, the Netherlands; Brain Imaging Center, Academic Medical Center, University of Amsterdam, PO Box 22660, 1100 DD Amsterdam, the Netherlands. Electronic address: a.f.vanrootselaar@amc.uva.nl.
⁹ Department of Neurology, University Medical Center Groningen, University of Groningen, PO Box 30001, 9700 RB Groningen, the Netherlands; Neuroimaging Center, University Medical Center Groningen, University of Groningen, PO Box 30001, 9700 RB Groningen, the Netherlands. Electronic address: n.m.maurits@umcg.nl.

PMID: 26909321
PMCID: PMC4732188
DOI: 10.1016/j.nicl.2015.12.011

Abstract
in English, Dutch

Background: Essential tremor (ET) is one of the most common hyperkinetic movement disorders. Previous research into the pathophysiology of ET suggested underlying cerebellar abnormalities.

Objective: In this study, we added electromyography as an index of tremor intensity to functional Magnetic Resonance Imaging (EMG-fMRI) to study a group of ET patients selected according to strict criteria to achieve maximal homogeneity. With this approach we expected to improve upon the localization of the bilateral cerebellar abnormalities found in earlier fMRI studies.

Methods: We included 21 propranolol sensitive patients, who were not using other tremor medication, with a definite diagnosis of ET defined by the Tremor Investigation Group. Simultaneous EMG-fMRI recordings were performed while patients were off tremor medication. Patients performed unilateral right hand and arm extension, inducing tremor, alternated with relaxation (rest). Twenty-one healthy, age- and sex-matched participants mimicked tremor during right arm extension. EMG power variability at the individual tremor frequency as a measure of tremor intensity variability was used as a regressor, mathematically independent of the block regressor, in the general linear model used for fMRI analysis, to find specific tremor-related activations.

Results: Block-related activations were found in the classical upper-limb motor network, both for ET patients and healthy participants in motor, premotor and supplementary motor areas. In ET patients, we found tremor-related activations bilaterally in the cerebellum: in left lobules V, VI, VIIb and IX and in right lobules V, VI, VIIIa and b, and in the brainstem. In healthy controls we found simulated tremor-related activations in right cerebellar lobule V.

Conclusions: Our results expand on previous findings of bilateral cerebellar involvement in ET. We have identified specific areas in the bilateral somatomotor regions of the cerebellum: lobules V, VI and VIII.

•We added EMG as an index of tremor intensity to fMRI to study essential tremor.•Block- and tremor-related activations during a unilateral motor task were separated.•Block-related activations were found in the classical motor network.•Tremor-related activations were found in bilateral cerebellar lobules V, VI and VIII.

Keywords: Cerebellum; EMG; Essential tremor; FMRI.

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Figures

**Fig. 1**
Representative EMG characteristics for one patient. A: Fast Fourier Transform during task of 3 right arm muscles (from top to bottom: ECRL, FCR, FCU). B: EMG regressor: mean EMG per scan of the 3 right arm muscles in A across the task. Higher values are associated with hand and arm extension. C: rEMG regressor as used in the fMRI model: EMG regressor in B after orthogonalization, convolving with the hrf and scaling by its SD.

**Fig. 2**
Increased cerebellar activations in essential tremor patients related to the within group comparisons for the block contrast, p < 0.001 (uncorrected, extent k = 20) (1A: block-related activations), and activations related to the within group comparisons for the r-EMG contrast, p < 0.001 (uncorrected, extent k = 20) (1B: tremor-related activations) and increased cerebellar activations in healthy controls related to the within group comparisons for the block contrast, p < 0.001 (uncorrected, extent k = 20) (2A: block-related activations), and activations related to the within group comparisons for the r-EMG contrast, p < 0.001 (uncorrected, extent k = 20) (2B: tremor-related activations). Results are projected on the SUIT-template (Diedrichsen, 2006). The color coded bars at the bottom of the figure indicate SPM T-map intensities. The z-coordinates indicate the position of the transversal planes relative to the anterior commissure–posterior commisure plane. L: left hemisphere. (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article.)

See this image and copyright information in PMC

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Bilateral cerebellar activation in unilaterally challenged essential tremor

Affiliations

Bilateral cerebellar activation in unilaterally challenged essential tremor

Authors

Affiliations

Abstract
in English, Dutch

Figures

References

Publication types

MeSH terms

LinkOut - more resources

Full Text Sources

Other Literature Sources

Medical

Abstract in English, Dutch

Figures

References

Publication types

MeSH terms

LinkOut - more resources

Full Text Sources

Other Literature Sources

Medical

Abstract
in English, Dutch