Investigation of the Effect of Combined Motor Imagery and Activity Observation Therapy on Strengthening the Non-Dominant Hand in Healthy Individuals

Overview

Introduction: Motor Imagery (MI) and Action Observation (AO) are well-established cognitive training techniques that activate neural networks similar to those involved in actual motor execution. MI involves the mental rehearsal of a movement without physically performing it, while AO relies on observing an action performed by others to stimulate motor-related brain areas. Recent studies suggest that when these methods are combined, they may enhance motor learning, cortical plasticity, and strength gains more effectively than when applied alone. The non-dominant hand, often less trained and weaker in performance compared to the dominant hand, provides an ideal model to examine the effects of these interventions. Strengthening the non-dominant upper limb has implications not only for improving functional balance between the limbs in healthy individuals but also for potential clinical applications in rehabilitation. Aim: The primary aim of this randomized controlled study is to investigate the combined effect of MI and AO on muscular strength and functional performance of the non-dominant hand in healthy university students. Specifically, the study seeks to compare the outcomes of three groups: (1) AO combined with MI, (2) MI only, and (3) a control group with no intervention. It is hypothesized that participants in the AO+MI group will demonstrate greater improvements in grip strength and functional outcomes compared to the other groups. Evaluation: To comprehensively measure the effects of the intervention, several standardized assessment tools will be employed. Motor imagery ability will be evaluated using the Motor Imagery Questionnaire-3 (MIQ-3). Hand dominance will be determined by the Edinburgh Handedness Inventory. Grip strength will be objectively measured using a Hand Grip Dynamometer. The Recognise App will be used to assess laterality recognition and sensorimotor integration, while overall upper limb function will be measured through the Short Musculoskeletal Function Assessment (SMMT). These evaluations will be conducted both before and after the 4-week intervention period to track changes. Treatment: The intervention will span four weeks, with participants attending 2-3 sessions per week. Training protocols will include both cognitive and physical components. In the MI group, participants will engage in guided motor imagery sessions focused on visualizing non-dominant hand exercises. The AO+MI group will observe video demonstrations of the same hand movements, followed by simultaneous motor imagery practice, thereby combining visual and cognitive engagement. Physical strengthening exercises will include dumbbell wrist flexion and handball squeeze, targeting key muscles of the non-dominant hand and forearm. The control group will not undergo any intervention during this period. By integrating AO and MI with specific strengthening exercises, the study aims to determine whether this combined approach enhances neural activation and muscular strength more effectively than MI alone.

Interventions

• Other Conservative treatment + Motor imagery program
  Participants will perform guided motor imagery of non-dominant hand strengthening exercises (dumbbell wrist flexion and handball squeeze) without video observation, 5 sessions per week for 4 weeks.
• Other Conservative treatment + Motor imagery and action observation program
  Participants will observe videos of non-dominant hand strengthening exercises (dumbbell wrist flexion and handball squeeze) and simultaneously perform guided motor imagery of the same movements, 5 sessions per week for 4 weeks.
• Other Conservative treatment via strengthening exercises
  Participants will perform only the physical strengthening exercises (dumbbell wrist flexion and handball squeeze) for the non-dominant hand, 5 sessions per week for 4 weeks, without any motor imagery or action observation.

Primary outcome measures

• Handedness was measured using the Edinburgh Handedness Inventory [Time frame: 3 minutes]
• Standardized Mini-Mental State Test [Time frame: 5 minutes]

Secondary outcome measures (3)

• Movement Imagery Questionnaire (MIQ-3) [Time frame: 10 minutes]
• Grip Strength Using a hand grip Dynamometer [Time frame: 8 minutes]
• Recognize lateralization app [Time frame: 10 minutes]

Eligibility criteria

Inclusion criteria

• Age between 18 and 65 years old
• They agreed to participate
• Having no pathology in hearing and vision
• Having no history of upper limb injury or musculoskeletal
• Having no neurologic disorders
• All subjects had no prior experience with motor imagery
• Having a Standardized Mini-Mental State Test (SMMT) score of more than 24 points

Exclusion criteria

• A score of the Movement Imagery Questionnaire (MIQ-3) was less than ≥5
• Severe cognitive deficits
• Neurological problems
• Left-handedness that was measured using the Edinburgh Handedness Inventory

Criteria are shown verbatim from the registry (in English). Final eligibility is always assessed by the study center.

Healthy volunteers: Yes

Study design

Allocation

Randomized

Model

Parallel assignment

Masking

Single blind

Primary purpose

Health services research

Study locations

Turkey (Türkiye) · 1 center

• Ammar Mahmoud Ahmed — Istanbul

Publications

• Tsukazaki I, Uehara K, Morishita T, Ninomiya M, Funase K. Effect of observation combined with motor imagery of a skilled hand-motor task on motor cortical excitability: difference between novice and expert. Neurosci Lett. 2012 Jun 19;518(2):96-100. doi: 10.1016/j.neulet.2012.04.061. Epub 2012 May 2. PMID 22580208
• Aoyama T, Kaneko F, Kohno Y. Motor imagery combined with action observation training optimized for individual motor skills further improves motor skills close to a plateau. Hum Mov Sci. 2020 Oct;73:102683. doi: 10.1016/j.humov.2020.102683. Epub 2020 Sep 16. PMID 32949991
• Marshall B, Wright DJ, Holmes PS, Wood G. Combining Action Observation and Motor Imagery Improves Eye-Hand Coordination during Novel Visuomotor Task Performance. J Mot Behav. 2020;52(3):333-341. doi: 10.1080/00222895.2019.1626337. Epub 2019 Jun 11. PMID 31185831

Identifiers

NCT: NCT07235449 · 61351342/020-1391

Primary sources (government registries)

• ClinicalTrials.gov (US NIH)

View this study on ClinicalTrials.gov ↗