Event-Related Desynchronization/Synchronization in Spinocerebellar Ataxia Type 3

Abstract

Introduction: Spinocerebellar ataxia type 3 (SCA3) is an autosomal dominant, cerebellar degeneration predominant disease caused by excessive CAG repeats. We examined event-related dysynchronization/synchronization (ERD/ERS) in patients with SCA3. Methods: We assessed ERD/ERS of self-paced voluntary hand movements in 15 patients with genetically proven SCA3 in comparison with healthy controls. Results: In ERS, a significant interaction effect between group, frequency, and period ( F = 1.591; p = 0.005; ρI = 0.86) was observed. The post-hoc two-tailed independent t -test showed significant differences in high beta and low beta ERS. By contrast, in ERD, no apparent differences were observed in the pattern of patients with SCA3 in comparison with healthy controls ( F = 1.01; p = 0.442). Conclusion: The study revealed a decreased ERS in patients with SCA3, especially at the frequency of 20–30 Hz. This study elucidates the significant role of cerebellum in motor control.

Altered Dynamics of Cortical Beta-Oscillations during Motor Learning in Cerebellar Ataxia

“…We then ask whether the same signal also depends on intact internal model adaptation, and how its dynamics differ in cerebellar ataxia, i.e., when internal model adaptation is disrupted. Our study thus extends a hitherto small, but growing literature that adopts a network perspective on the electrophysiology of cerebellar ataxia (Lu et al, 2008;Aoh et al, 2019;Visania et al, 2020).…”

“…Any EEG signal modulation that reflects this miscalibration, or the ensuing sensory prediction error, should therefore be in the same direction at baseline and early during adaptation. However, at baseline, the postmovement beta rebound tended to be attenuated in patients, compared to controls (see also Aoh et al, 2019), while it increased from baseline to early adaptation in patients. This pattern seems difficult to reconcile with the idea that the observed changes in the dynamics of the post-movement beta rebound in patients purely reflect abnormal encoding, or use, of sensory prediction error.…”

“…The heterogeneity in etiology may explain why patients showed only a trend for attenuated post-movement beta rebound at baseline, compared to controls. In a more homogeneous cohort of patients with spinocerebellar ataxia type 3, Aoh et al (2019) have recently reported a significant decrease in post-movement beta rebound following self-paced wrist extensions.…”

“…Symptom severity was assessed using the International Cooperative Ataxia Rating Scale (ICARS;Trouillas et al, 1997). Group sizes for both experiments were chosen to be at least as large as in previous EEG and behavioural studies into motor adaptation in healthy individuals and patients with cerebellar ataxia (Aoh et al, 2019;Tan, Wade, & Brown, 2016;Tan, Jenkinson, & Brown, 2014;Taylor, Klemfuss, & Ivry, 2010;Torrecillos, Alayrangues, Kilavik, & Malfait, 2015). All participants had normal or corrected-to-normal vision, and all gave written informed consent according to the Declaration of Helsinki.…”

“…Learning a strategy, or target error (green box), and (learning from) sensory prediction error (blue box), on the other hand, would jointly decrease the postmovement beta rebound, as in group A in Experiment 1 (blue/green box). Finally, the latent miscalibration of internal models in cerebellar ataxia (Bhanpuri et al, 2014) would result in a (slight) decrease of the post-movement beta rebound at baseline (yellow box, and Aoh et al, 2019).…”