Mai Ikuta1, Takashi Iida2, Mohit Kothari3, Akiko Shimada4, Osamu Komiyama5, Peter Svensson6. 1. Division of Oral Function and Rehabilitation, Department of Oral Health Science, Nihon University School of Dentistry at Matsudo, Matsudo, Japan; Section of Orofacial Pain and Jaw Function, Aarhus University, Department of Dentistry, Aarhus, Denmark. 2. Division of Oral Function and Rehabilitation, Department of Oral Health Science, Nihon University School of Dentistry at Matsudo, Matsudo, Japan. Electronic address: iida.takashi96@nihon-u.ac.jp. 3. Hammel Neurorehabilitation Centre and University Research Clinic, Hammel, Denmark; Department of Clinic Medicine, Aarhus University, Aarhus, Denmark. 4. Section of Orofacial Pain and Jaw Function, Aarhus University, Department of Dentistry, Aarhus, Denmark; Osaka Dental University Hospital, Osaka, Japan. 5. Division of Oral Function and Rehabilitation, Department of Oral Health Science, Nihon University School of Dentistry at Matsudo, Matsudo, Japan. 6. Section of Orofacial Pain and Jaw Function, Aarhus University, Department of Dentistry, Aarhus, Denmark; Scandinavian Center for Orofacial Neurosciences (SCON), Aarhus, Denmark; Department of Dental Medicine, Karolinska Institutet, Huddinge, Sweden.
Abstract
PURPOSE: To investigate if sleep bruxism (SB) influences training-induced cortical plasticity and performance in terms of accuracy and precision of a tooth-clenching task (TCT). METHODS: Thirty-eight participants were allocated into SB group (N=19) and control group (N=19) according to presence of SB based on a 2-week screening. The participants were instructed to perform a standardized TCT for 58min at three different force levels (10%, 20% and 40% of maximum voluntary contraction; MVC) in three series (first and third without visual-feedback and second with visual-feedback). Accuracy and precision of the TCT were calculated from actual bite force values. Transcranial magnetic stimulation was applied to elicit motor evoked potentials (MEPs) from the masseter and first dorsal interosseous muscle (FDI) before the TCT (pre-TCT-session) and 5-min after the TCT (post-TCT-session). RESULTS: Accuracy was significantly dependent on the series and target force level (P<0.001), however, there was a significant decrease only in the control group at 10% MVC from first to third session (P<0.001). No significant differences between groups were observed for the precision of the TCT. Masseter MEPs in the SB group in the pre-TCT-session at 120% and 160% motor threshold were significantly lower than in the control group (P<0.05). Masseter MEPs of the control group in the post-TCT-session were significantly higher than the pre-TCT-session (P<0.05) but not SB. FDI MEPs were only dependent on stimulus intensity (P<0.001). CONCLUSIONS: SB is associated with significant changes not only in excitability of corticomotor control but also motor learning of jaw movements and force control.
PURPOSE: To investigate if sleep bruxism (SB) influences training-induced cortical plasticity and performance in terms of accuracy and precision of a tooth-clenching task (TCT). METHODS: Thirty-eight participants were allocated into SB group (N=19) and control group (N=19) according to presence of SB based on a 2-week screening. The participants were instructed to perform a standardized TCT for 58min at three different force levels (10%, 20% and 40% of maximum voluntary contraction; MVC) in three series (first and third without visual-feedback and second with visual-feedback). Accuracy and precision of the TCT were calculated from actual bite force values. Transcranial magnetic stimulation was applied to elicit motor evoked potentials (MEPs) from the masseter and first dorsal interosseous muscle (FDI) before the TCT (pre-TCT-session) and 5-min after the TCT (post-TCT-session). RESULTS: Accuracy was significantly dependent on the series and target force level (P<0.001), however, there was a significant decrease only in the control group at 10% MVC from first to third session (P<0.001). No significant differences between groups were observed for the precision of the TCT. Masseter MEPs in the SB group in the pre-TCT-session at 120% and 160% motor threshold were significantly lower than in the control group (P<0.05). Masseter MEPs of the control group in the post-TCT-session were significantly higher than the pre-TCT-session (P<0.05) but not SB. FDI MEPs were only dependent on stimulus intensity (P<0.001). CONCLUSIONS: SB is associated with significant changes not only in excitability of corticomotor control but also motor learning of jaw movements and force control.
Authors: Noéli Boscato; Fernando Exposto; Gustavo G Nascimento; Peter Svensson; Yuri M Costa Journal: Brain Imaging Behav Date: 2022-01-28 Impact factor: 3.224