Effects Of Motor Imagery Training Research Articles

Effects of motor imagery training on balance and gait abilities in post-stroke patients: a randomized controlled trial

Objectives: To investigate the effects of motor imagery training on the balance and gait abilities of post-stroke patients. Design: Randomized controlled trial. Setting: Outpatient rehabilitation centre. Subjects: Twenty-eight individuals with chronic stroke. Interventions: The experimental group (n = 15) performed motor imagery training involving imagining normal gait movement for 15 minutes embedded in gait training for 30 minutes (45 minutes/day, 3 times/week); the control group (n = 13) performed gait training only (30 minutes/day, 3 times/week). Main measures: Balance and gait abilities were measured by the Functional Reach Test, Timed Up-and-Go Test, 10-m Walk Test and Fugl-Meyer assessment before and after interventions. Results: All measurements improved significantly compared with baseline values in the experimental group. In the control group, there were significant improvements in all parameters except the Fugl-Meyer assessment. All parameters of the experimental group increased significantly compared to those of the control group as follows: Functional Reach Test (control vs. experimental: 28.1 ± 3.1 vs. 37.51 ± 3.0), Timed Up-and-Go Test (20.7 ± 4.0 vs. 13.2 ± 2.2), 10-m Walk Test (17.4 ± 4.6 vs. 16.0 ± 2.7) and Fugl-Meyer assessment (12.0 ± 2.9 vs. 17.6 ± 1.3). Conclusions: Gait training with motor imagery training improves the balance and gait abilities of chronic stroke patients significantly better than gait training alone.

Behavioral improvements and brain functional alterations by motor imagery training

Motor imagery training is considered as an effective training strategy for motor skill learning and motor function rehabilitation. However, compared with studies of the neural mechanism underlying motor imagery, neuroimaging examinations of motor imagery training are comparatively few. Using functional magnetic resonance imaging, we designed a 2-week motor imagery training experiment, including execution and imagery tasks, to investigate the effectiveness of motor imagery training on the improvement of motor performance, as well as the neural mechanism associated with motor imagery training. Here, we examined the motor behavior, brain activation, and correlation between the behavior of the motor execution task and the brain activation across task-related region of interests (ROIs) in both pre- and post-test phases. Our results demonstrated that motor imagery training could improve motor performance. More importantly, the brain functional alterations induced by training were found in the fusiform gyrus for both tasks. These findings provide new insights into motor imagery training.

Effects of Motor Imagery Training on Gait Ability of Patients with Chronic Stroke

[Purpose] The purpose of this study was to investigate the effects of motor imagery training on improvement of gait ability of patients with chronic stroke. The motor imagery training was performed using imagination of normal gait movement. [Subjects] Participants were randomly allocated to two groups: a motor imagery training group (n=13) and a control group (n=11). [Methods] Both groups received treadmill training for 3 session 30 minutes per week for 6 weeks. The motor imagery training group practiced additional motor imagery training. Measures were evaluated by gait ability. [Results] The outcomes significantly improved by motor imagery training were gait speed, step length of paretic side, step length of non-paretic side, stride length of paretic side, stride length of non-paretic side, single limb support period of paretic side, and double limb support period of both sides. [Conclusion] The motor imagery training improved gait ability. These results suggest that motor imagery training is feasible and suitable for individuals with stroke.

Effect of motor imagery training on symmetrical use of knee extensors during sit-to-stand and stand-to-sit tasks in post-stroke hemiparesis

To investigate the effect of motor imagery training (MIT) on the symmetrical use of knee extensors during sit-to-stand and stand-to-sit tasks. We measured the electromyographic (EMG) data in the knee extensor on the affected side of 3 volunteers with post-stroke hemiparesis. We used a single-subject multiple-baseline research design across individuals. The EMG data were collected from knee extensors while performing the sit-to-stand and stand-to-sit tasks. The EMG activation and onset time ratios for the knee extensors were calculated by dividing the EMG activation and onset time of knee extensor action on the affected side by these on the unaffected side. MIT consisted of a 10-min detailed description of 5 stages: preparation, sit-to-stand tasks, weight shifting during standing, stand-to-sit tasks, and completion. During MIT, the EMG activation ratios of participants 1, 2, and 3 increased by 11.24%, 18.07%, and 26.91%, respectively, in the sit-to-stand task and by 12.11%, 14.31%, and 25.92%, respectively, in the stand-to-sit task. During MIT, the onset time of participants 1, 2, and 3 decreased by 36.09%, 24.27%, and 25.61%, respectively, in the sit-to-stand task and by 26.81%, 27.20%, and 22.83%, respectively, for the stand-to-sit task. These findings suggest that MIT has a positive effect on the symmetrical use of knee extensors during sit-to-stand and stand-to-sit tasks.

Effect of Mental Imagery on the Development of Skilled Motor Actions

To test the effect of imagery in the training of skilled movements, an experiment was designed in which athletes learned a new motor action and trained themselves for a month either by overt action or by mental imagery of the action. The experiment was carried out with 30 male karateka (M age = 35 yr., SD = 8.7; M years of practice = 6, SD = 3) instructed to perform an action (Ura-Shuto-Uchi) that they had not previously learned. The athletes were divided into three groups: Untrained (10 subjects who did not perform any training), Action Trained (10 subjects who performed Ura-Shuto-Uchi training daily for 16 minutes), and Mental Imagery (10 subjects who performed mental imagery training of Ura-Shuto-Uchi daily for 16 minutes). The subjects were tested five times, once every 7 days. During each test, they performed a series of 60 motor action trials. In Tests 1, 3, and 5, they also performed a series of 60 mental imagery trials. During the trials, an electroencephalogram (EEG), electromyography (EMG), muscle strength and power, and other physiological parameters were recorded. The results differed by group. Untrained subjects did not show significant effects. In the Action Trained group, training had an effect on reactivity and movement speed, with a reduction of EMG activation and reaction times. Moreover, muscle strength, power, and work increased significantly. The Mental Imagery group showed the same effects on muscle strength, power, and work, but changes in reactivity were not observed. In the Mental Imagery group, the study of Movement Related Brain Macropotentials indicated a progressive modification of the profile of the waves from Test 1 to Test 5 during imagery, showing significant variations of the amplitude of the waves related to the premotor and motor execution periods. Results show that motor imagery can influence muscular abilities such as strength and power and can modify Movement Related Brain Macropotentials, the profile of which potentially could be used to verify the effectiveness of motor imagery training.

Effects of imagery training on cognitive performance and use of physiological measures as an assessment tool of mental effort

The effectiveness of motor imagery training on cognitive performance was examined and the physiological mechanisms involved in the contribution of mental practice to motor learning were considered. The subject’s mental effort during motor imagery was assessed by using psychophysiological measures and particularly eye blink activity as an ‘indirect’ measurement of subjects’ attention. An electronic flight simulation program (Multiple Attribute Task Battery—MATB) was used to assess performance. Twenty healthy volunteers participated in the study divided in two groups: the control group and the imagery-training group. The subjects of the imagery group were asked for additional imagery training. The subjects of the actual performing group were asked additionally to passively observe the task in order to have equal time of exposure to the task. Performance scores and physiological parameters such as heart rate, respiratory rate, eye blinking activity and muscular activity were recorded during all sessions. The results revealed significantly higher performance level of the imagery-training group than the control group. Heart rate and respiratory rate significantly increased during imagery sessions compared to rest. A slight electromyographic activity was observed during the imagination of movement. Our findings support the notion that mental practice improves motor performance in a task where spatiotemporal or dynamic control of the action is highly required. The effects of mental practice on motor performance could be explained by the existence of a top–down mechanism based on the activation of a central representation of the movements, since the vegetative activation during motor imagery seems to be centrally controlled.

Effects of motor imagery training on service return accuracy in tennis: The role of imagery ability

This study examined how imagery ability could affect motor improvement following motor imagery training in tennis. Skilled tennis players were divided into 3 groups with regard to their MIQ scores (good imager, poor imager, and control group). During a pre‐test, participants physically performed 15 service returns toward a target. The motor imagery training period was included during physical training for 15 sessions, and each session consisted of 2 series of 15 imagined trials and 15 physical trials. Some of the participants were required to use internal visual imagery (good and poor imager groups) while others were given a reading task (control group). Finally, 48 hours after the last training session, participants were submitted to a post‐test similar to the pre‐test. Results indicated that motor imagery improved service return, and that this improvement was better in good imagers than in poor imagers. The impact of motor imagery practice on motor performance, for skilled tennis players, is discussed.

Effects of motor imagery training after chronic, complete spinal cord injury

Abnormalities in brain motor system function are present following spinal cord injury (SCI) and could reduce effectiveness of restorative interventions. Motor imagery training, which can improve motor behavior and modulate brain function, might address this concern but has not been examined in subjects with SCI. Ten subjects with SCI and complete tetra-/paraplegia plus ten healthy controls underwent assessment before and after 7 days of motor imagery training to tongue and to foot. Motor imagery training significantly improved the behavioral outcome measure, speed of movement, in non-paralyzed muscles. Training was also associated with increased fMRI activation in left putamen, an area associated with motor learning, during attempted right foot movement in both groups, despite foot movements being present in controls and absent in subjects with SCI. This fMRI change was absent in a second healthy control group serially imaged without training. In subjects with SCI, training exaggerated, rather than normalized, baseline derangement of left globus pallidus activation. The current study found that motor imagery training improves motor performance and alters brain function in subjects with complete SCI despite lack of voluntary motor control and peripheral feedback. These effects of motor imagery training on brain function have not been previously described in a neurologically impaired population, and were similar to those found in healthy controls. Motor imagery might be of value as one component of a restorative intervention.

Motor Imagery

Understanding brain plasticity after stroke is important in developing rehabilitation strategies. Active movement therapies show considerable promise but depend on motor performance, excluding many otherwise eligible patients. Motor imagery is widely used in sport to improve performance, which raises the possibility of applying it both as a rehabilitation method and to access the motor network independently of recovery. Specifically, whether the primary motor cortex (M1), considered a prime target of poststroke rehabilitation, is involved in motor imagery is unresolved. We review methodological considerations when applying motor imagery to healthy subjects and in patients with stroke, which may disrupt the motor imagery network. We then review firstly the motor imagery training literature focusing on upper-limb recovery, and secondly the functional imaging literature in healthy subjects and in patients with stroke. The review highlights the difficulty in addressing cognitive screening and compliance in motor imagery studies, particularly with regards to patients with stroke. Despite this, the literature suggests the encouraging effect of motor imagery training on motor recovery after stroke. Based on the available literature in healthy volunteers, robust activation of the nonprimary motor structures, but only weak and inconsistent activation of M1, occurs during motor imagery. In patients with stroke, the cortical activation patterns are essentially unexplored as is the underlying mechanism of motor imagery training. Provided appropriate methodology is implemented, motor imagery may provide a valuable tool to access the motor network and improve outcome after stroke.

Does motor imagery training improve hand function in chronic stroke patients? A pilot study.

To assess the efficacy of motor imagery training for arm function in chronic stroke patients. The relation between mental processes such as attentional and perceived personal control over recovery, and motor imagery was additionally investigated. Twenty patients with long-term motor impairments (mean two years post stroke), were assessed before and after four weeks of training. Ten patients mentally rehearsed movements with their affected arm. Their recovery was compared with patients who performed nonmotor imagery (n =5), or who were not engaged in mental rehearsal (n=5). Patients were recruited from the stroke database of Ninewells Hospital, Dundee. Assessment and training were performed at the patients' home. The motor imagery group was asked to practise daily imagining moving tokens with their affected arm. The nonmotor imagery group rehearsed visual imagery of previously seen pictures. All patients practised physically moving the tokens. The following variables were assessed before and after training: motor function (training task, pegboard and dynamometer), perceived locus of control, attention control and ADL independence. All patient groups improved on all motor tasks except the dynamometer. Improvement was greater for the motor imagery group on the training task only (average of 14% versus 6%). No effect of motor imagery training was found on perceived or attentional control. Motor imagery training without supervision at home may improve performance on the trained task only. The relation between movement imagery, attention and perceived personal control over recovery remained unclear.