The effectiveness of graded motor imagery training on pain and functionality

Key points

1. 01GMI group achieved clinically significant pain reduction (MCID on VAS) 2-6 sessions earlier than the control group
2. 02DASH disability score improved by 41.43 points in the GMI group versus 20.17 points in the control group after 6 weeks, both exceeding the MCID of 10.83
3. 03Shoulder abduction and external rotation range of motion improved significantly more in the GMI group (large effect sizes, ηp2 = 0.185 and 0.189)
4. 04Lateralization accuracy and motor imagery ability improved only in the GMI group; control group showed no significant lateralization change
5. 0590.5% of GMI participants reported significant improvement versus 57.1% in the control group (p = 0.014)

How it was conducted

Design

Prospective, single-blind, parallel-group randomized controlled trial

Participants

42 adults (aged 25-65) with chronic subacromial pain syndrome confirmed by clinical tests and MRI, randomly assigned 21 per group

Intervention

GMI group received graded motor imagery (lateralization training weeks 1-2, motor imagery weeks 2-3, mirror therapy weeks 3-6) plus conventional physiotherapy, 3 sessions/week for 6 weeks

Control

Conventional physiotherapy only (TENS, cold pack, progressive ROM and strengthening exercises), 3 sessions/week for 6 weeks, followed by 6-week home exercise program in both groups

Primary outcomes

Pain intensity (VAS 0-10) and upper-limb disability (DASH questionnaire 0-100)

Follow-up

Assessments at baseline, 6 weeks (end of treatment), and 12 weeks (end of follow-up)

What they found

• VAS-activity: GMI improved by 7.43 cm vs control 5.24 cm (T0-T1); group-by-time interaction F = 37.88, p < 0.001, ηp2 = 0.486
• VAS-rest: GMI improved by 5.81 cm vs control 3.71 cm (T0-T1); F = 14.60, p < 0.001, ηp2 = 0.267
• VAS-night: GMI improved by 7.38 cm vs control 5.10 cm (T0-T1); F = 14.53, p < 0.001, ηp2 = 0.267
• GMI group reached MCID for VAS-night at session 5, VAS-activity at session 6, VAS-rest at session 7; control group reached MCID at sessions 8 and 11
• DASH score improved by 41.43 points (GMI) vs 20.17 points (control) at 6 weeks; F = 15.45, p < 0.001, ηp2 = 0.279
• Shoulder abduction AROM: GMI +49.76 degrees vs control +32.74 degrees (T0-T1); F = 9.10, p = 0.004, ηp2 = 0.185
• Shoulder ER AROM: GMI +22.25 degrees vs control +9.40 degrees (T0-T1); F = 8.89, p = 0.005, ηp2 = 0.189
• Abduction isometric strength: GMI +6.66 kg vs control +1.85 kg (T0-T1); F = 11.36, p = 0.002, ηp2 = 0.221
• Shoulder lateralization accuracy (affected side): GMI +12.44% vs control +1.25% (T0-T1); F = 147.12, p < 0.001, ηp2 = 0.786
• KVIQ total score: GMI +34.05 vs control +1.33 (T0-T1); F = 98.09, p < 0.001, ηp2 = 0.710

Limitations

• No third group receiving GMI alone, so the independent contribution of GMI versus conventional physiotherapy cannot be isolated
• Single-blind design only (patient-blinded); therapist and assessor blinding was not fully described
• Short and mid-term follow-up only (12 weeks total); long-term durability of benefits is unknown
• Neuroplastic mechanisms were not directly measured due to cost of functional imaging (fMRI), leaving proposed cortical reorganization unconfirmed

Why it matters

For patients

People with persistent shoulder pain from subacromial syndrome may recover faster and regain more shoulder movement by combining mental imagery exercises with their usual physiotherapy program.

For clinicians

Adding the full three-stage GMI protocol (lateralization, motor imagery, mirror therapy) to a standard physiotherapy program produces large, clinically meaningful gains in pain, disability, and range of motion, and is feasible in an outpatient setting.

For readers

This is the first RCT testing all three GMI components together in subacromial pain syndrome, providing a structured protocol and session-level pain tracking that prior shoulder GMI studies lacked.