Dominance of attentional focus: a comparative study on its impact on standing postural control in healthy younger and older adults.

Introduction: Attentional focus is a phenomenon in which shifting the focus of attention alters performance of standing postural control. It can be categorized as internal focus (IF), which directs attention to the body parts, or external focus (EF), which directs attention to the external environment. Although attentional focus that improves standing postural control in younger people exhibits individual dominance, the dominance of attentional focus in standing postural control in older adults remains ambiguous. Therefore, this study aimed to compare the dominance of attentional focus in standing postural control between healthy younger and older adults, a crucial step for understanding the aging process. Methods: The participants performed a standing postural control task under the IF and EF conditions. Based on the condition during which they exhibited superior performance, the participants were divided into two groups: IF-dominant and EF-dominant. The standing postural control performance in each group under the IF and EF conditions was subsequently compared. Results: The results showed that the participants, encompassing both younger and older adults, were divided into the IF-dominant and EF-dominant groups, confirming the dominance of attentional focus. The performance under the EF condition in older adults was also influenced by the dominance of attentional focus. Conclusion: These results highlight the potential importance of intervention methods based on the dominance of attentional focus, providing valuable insights into future research and clinical practice.

Effects of neurofeedback on standing postural control task with combined imagined and executed movements.

Introduction: Motor imagery (MI) is a method of imagining movement without actual movement, and its use in combination with motor execution (ME) enhances the effects of motor learning. Neurofeedback (NFB) is another method that promotes the effects of MI. This study aimed to investigate the effects of NFB on combined MI and ME (MIME) training in a standing postural control task. Methods: Sixteen participants were randomly divided into MIME and MIME + NFB groups and performed 10 trials of a postural control task on an unstable board, with nine trials of MI in between. Electroencephalogram was assessed during MI, and the MIME + NFB group received neurofeedback on the degree of MI via auditory stimulation. A postural control task using an unstable board was performed before and after the MIME task, during which postural instability was evaluated. Results: Postural instability was reduced after the MIME task in both groups. In addition, the root mean square, which indicates the sway of the unstable board, was significantly reduced in the MIME + NFB group compared to that in the MIME group. Conclusion: Our results indicate that MIME training is effective for motor learning of standing postural control. Furthermore, when MI and ME are combined, the feedback on the degree of MI enhances the learning effect.

Effects of θ High Definition-Transcranial Alternating Current Stimulation in the Anterior Cingulate Cortex on the Dominance of Attention Focus in Standing Postural Control.

Attention focus affects performance in postural control while standing, and it is divided into internal focus (IF) and external focus (EF). Each individual has a predominant attention focus, and research has revealed that the dominance of attention focus may be an acquired trait. However, the impact of non-invasive brain stimulation on attention-focus dominance remains unexplored in the current literature. Here, we examined the effect of high-definition transcranial alternating current stimulation (HD-tACS) on θ waves in the anterior cingulate cortex (ACC) on standing postural control tasks in an EF condition for IF- and EF-dominant groups. The effect of θ HD-tACS on the ACC differed between IF- and EF-dominant groups, and θ HD-tACS in the IF-dominant group decreased the performance of standing postural control under the EF condition. The forced activation of the ACC with θ HD-tACS may have conversely reduced the activity of brain regions normally activated by the IF-dominant group. Additionally, the activation of ACC prioritized visual information processing and suppressed the superficial sensory processing that is normally potentially prioritized by the IF-dominant group. These results highlight the importance of changing the type of rehabilitation and sports training tasks to account for the individual's dominance of attention focus.

Effects of neurofeedback training combined with transcranial direct current stimulation on motor imagery: A randomized controlled trial.

Introduction: Neurofeedback (NFB) training and transcranial direct current stimulation (tDCS) have been shown to individually improve motor imagery (MI) abilities. However, the effect of combining both of them with MI has not been verified. Therefore, the aim of this study was to examine the effect of applying tDCS directly before MI with NFB. Methods: Participants were divided into an NFB group (n = 10) that performed MI with NFB and an NFB + tDCS group (n = 10) that received tDCS for 10 min before MI with NFB. Both groups performed 60 MI trials with NFB. The MI task was performed 20 times without NFB before and after training, and µ-event-related desynchronization (ERD) and vividness MI were evaluated. Results: µ-ERD increased significantly in the NFB + tDCS group compared to the NFB group. MI vividness significantly increased before and after training. Discussion: Transcranial direct current stimulation and NFB modulate different processes with respect to MI ability improvement; hence, their combination might further improve MI performance. The results of this study indicate that the combination of NFB and tDCS for MI is more effective in improving MI abilities than applying them individually.

Repetitive Peripheral Magnetic Stimulation Combined with Motor Imagery Changes Resting-State EEG Activity: A Randomized Controlled Trial.

Repetitive peripheral magnetic stimulation is a novel non-invasive technique for applying repetitive magnetic stimulation to the peripheral nerves and muscles. Contrarily, a person imagines that he/she is exercising during motor imagery. Resting-state electroencephalography can evaluate the ability of motor imagery; however, the effects of motor imagery and repetitive peripheral magnetic stimulation on resting-state electroencephalography are unknown. We examined the effects of motor imagery and repetitive peripheral magnetic stimulation on the vividness of motor imagery and resting-state electroencephalography. The participants were divided into a motor imagery group and motor imagery and repetitive peripheral magnetic stimulation group. They performed 60 motor imagery tasks involving wrist dorsiflexion movement. In the motor imagery and repetitive peripheral magnetic stimulation group, we applied repetitive peripheral magnetic stimulation to the extensor carpi radialis longus muscle during motor imagery. We measured the vividness of motor imagery and resting-state electroencephalography before and after the task. Both groups displayed a significant increase in the vividness of motor imagery. The motor imagery and repetitive peripheral magnetic stimulation group exhibited increased ß activity in the anterior cingulate cortex by source localization for electroencephalography. Hence, combined motor imagery and repetitive peripheral magnetic stimulation changes the resting-state electroencephalography activity and may promote motor imagery.

Reliability and validity of the Japanese movement imagery questionnaire-revised second version.

OBJECTIVE: Developing a Japanese version of the Movement Imagery Questionnaire-Revised Second Version (MIQ-RS) is essential for widespread evaluation and treatment based on motor imagery in physically disabled persons and patients in rehabilitation. This study aimed to investigate the reliability and validity of the Movement Imagery Questionnaire-Revised Second Version (MIQ-RS), which assesses motor imagery ability, by translating it into Japanese. RESULTS: This study enrolled twenty healthy participants (10 men and 10 women, mean age 21.17 ± 1.10 years). Reliability was examined for internal consistency using Cronbach's alpha coefficient. Spearman's rank correlation coefficient was used to examine the criterion-related validity of the MIQ-RS and the Kinesthetic and Visual Imagery Questionnaire (KVIQ-20). Results showed that Cronbach's alpha coefficients for the MIQ-RS were 0.81 and 0.82 for visual and kinesthetic imagery, respectively. Significant positive correlations were found between each visual and kinesthetic imagery score, and each total on the MIQ-RS and KVIQ-20 scores (r = 0.73, p < 0.01; r = 0.84, p < 0.01; r = 0.80, p < 0.01, respectively). This study suggests that the Japanese version of the MIQ-RS is a reliable and valid method of assessing motor imagery ability.

Dominance of Attention Focus and Its Electroencephalogram Activity in Standing Postural Control in Healthy Young Adults.

Attention focus changes performance, and external focus (EF) improves performance compared to internal focus (IF). However, recently, the dominance of attention focus, rather than the effectiveness of unilateral EF, has been examined. Although the positive effects of EF on standing postural control have been reported, the dominance of attention focus has not yet been examined. Therefore, the purpose of this study was to examine the dominance of attention focus and its neural mechanism in standing postural control using electroencephalography (EEG). A standing postural control task under IF and EF conditions was performed on healthy young men. Gravity center sway and cortical activity simultaneously using a stabilometer and an EEG were measured. Participants were classified into IF-dominant and EF-dominant groups according to their index of postural stability. The EEG was analyzed, and cortical activity in the theta-wave band was compared between the IF-dominant and EF-dominant groups. Significant neural activity was observed in the left parietal lobe of the IF-dominant group in the IF condition, and in the left frontal lobe of the EF-dominant group in the EF condition (p < 0.05). Differences in EEG activity between IF-dominant and EF-dominant groups, in standing postural control, were detected. This contributes to the development of training methods that consider attentional focus dominance in postural control.