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Welzel J, Güthe M, Keil J, Hermann G, Wolke R, Maetzler W, Becktepe JS. The interplay of sensory feedback, arousal, and action tremor amplitude in essential tremor. Sci Rep 2024; 14:4301. [PMID: 38383687 PMCID: PMC10881477 DOI: 10.1038/s41598-024-54528-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2023] [Accepted: 02/13/2024] [Indexed: 02/23/2024] Open
Abstract
Essential tremor (ET) amplitude is modulated by visual feedback during target driven movements and in a grip force task. It has not been examined yet whether visual feedback exclusively modulates target force tremor amplitude or if other afferent inputs like auditory sensation has a modulatory effect on tremor amplitude as well. Also, it is unknown whether the enhanced sensory feedback causes an increase of arousal in persons with ET (p-ET). We hypothesized that (1) amplitude of tremor is modulated by variation of auditory feedback in the absence of visual feedback in a force tremor paradigm; (2) increase of tremor amplitude coincides with pupillary size as a measure of arousal. 14 p-ET and 14 matched healthy controls (HC) conducted a computer-based experiment in which they were asked to match a target force on a force sensor using their thumb and index finger. The force-induced movement was fed back to the participant visually, auditory or by a combination of both. Results showed a comparable deviation from the target force (RMSE) during the experiment during all three sensory feedback modalities. The ANOVA revealed an effect of the high vs. low feedback condition on the tremor severity (Power 4-12 Hz) for the visual- and also for the auditory feedback condition in p-ET. Pupillometry showed a significantly increased pupil diameter during the auditory involved high feedback conditions compared to the low feedback conditions in p-ET. Our findings suggest that action tremor in ET is firstly modulated not only by visual feedback but also by auditory feedback in a comparable manner. Therefore, tremor modulation seems to be modality independent. Secondly, high feedback was associated with a significant pupil dilation, possibly mirroring an increased arousal/perceived effort.
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Affiliation(s)
- Julius Welzel
- University Hospital Schleswig-Holstein, Kiel, Germany
| | - Miriam Güthe
- University Hospital Schleswig-Holstein, Kiel, Germany
| | - Julian Keil
- Department of Psychology, University of Kiel, Kiel, Germany
| | | | - Robin Wolke
- University Hospital Schleswig-Holstein, Kiel, Germany
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Bindel L, Mühlberg C, Pfeiffer V, Nitschke M, Müller A, Wegscheider M, Rumpf JJ, Zeuner KE, Becktepe JS, Welzel J, Güthe M, Classen J, Tzvi E. Visuomotor Adaptation Deficits in Patients with Essential Tremor. Cerebellum 2023; 22:925-937. [PMID: 36085397 PMCID: PMC10485096 DOI: 10.1007/s12311-022-01474-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 08/29/2022] [Indexed: 06/15/2023]
Abstract
Essential tremor (ET) is a progressive movement disorder whose pathophysiology is not fully understood. Current evidence supports the view that the cerebellum is critically involved in the genesis of the tremor in ET. However, it is still unknown whether cerebellar dysfunction affects not only the control of current movements but also the prediction of future movements through dynamic adaptation toward a changed environment. Here, we tested the capacity of 28 patients with ET to adapt in a visuomotor adaptation task known to depend on intact cerebellar function. We found specific impairments in that task compared to age-matched healthy controls. Adaptation to the visual perturbation was disrupted in ET patients, while de-adaptation, the phase after abrupt removal of the perturbation, developed similarly to control subjects. Baseline tremor-independent motor performance was as well similar to healthy controls, indicating that adaptation deficits in ET patients were not rooted in an inability to perform goal-directed movements. There was no association between clinical severity scores of ET and early visuomotor adaptation abilities. These results provide further evidence that the cerebellum is dysfunctional in ET.
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Affiliation(s)
- Laura Bindel
- Department of Neurology, Leipzig University, Liebigstraße 20, 04103, Leipzig, Germany
| | - Christoph Mühlberg
- Department of Neurology, Leipzig University, Liebigstraße 20, 04103, Leipzig, Germany
| | - Victoria Pfeiffer
- Department of Neurology, University of Lübeck, 23562, Lübeck, Germany
| | - Matthias Nitschke
- Department of Neurology, University of Lübeck, 23562, Lübeck, Germany
| | - Annekatrin Müller
- Department of Neurology, Leipzig University, Liebigstraße 20, 04103, Leipzig, Germany
| | - Mirko Wegscheider
- Department of Neurology, Leipzig University, Liebigstraße 20, 04103, Leipzig, Germany
| | - Jost-Julian Rumpf
- Department of Neurology, Leipzig University, Liebigstraße 20, 04103, Leipzig, Germany
| | | | - Jos S Becktepe
- Department of Neurology, Kiel University, 24105, Kiel, Germany
| | - Julius Welzel
- Department of Neurology, Kiel University, 24105, Kiel, Germany
| | - Miriam Güthe
- Department of Neurology, Kiel University, 24105, Kiel, Germany
| | - Joseph Classen
- Department of Neurology, Leipzig University, Liebigstraße 20, 04103, Leipzig, Germany
| | - Elinor Tzvi
- Department of Neurology, Leipzig University, Liebigstraße 20, 04103, Leipzig, Germany.
- Syte Institute, 20354, Hamburg, Germany.
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