Graded Motor Imagery

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Description

Graded Motor Imagery (GMI) is a treatment program that aims to sequentially activate the premotor and primary motor cortices through three steps:

1. Laterality recognition: left/right discrimination
2. Explicit Motor Imagery: imagined movements of the affected extremity
3. Mirror therapy: view reflected movement of the unaffected extremity

GMI was developed by Moseley et al. (NOI group) as a treatment approach to address pain and function in patients with chronic CRPS, but it has since been applied to other complex pain and movement disorders.

Mechanism of Action:

GMI is basically brain exercises aimed at addressing cortical changes associated with pain and movement dysfunction. Each component targets a different brain area/function. Researchers believe the effectiveness is related to forced attention given to the affected extremity, reduced fear of movement, increased large fibre inhibition and the reorganisation of sensorimotor incongruence.

The sequence allows for the pre-motor cortex to be activated without setting off other cortical networks involved with movement.Imagined movements utilises mirror neurons which start firing we think of movement or observe a movement.

Indication

Although GMI was originally developed to treat chronic CRPS, studies have proven its effectiveness in treating the following other conditions:

• Phantom limb pain
• Post-stroke limb pain

Contra-indications & Precautions

GMI should not be approached with caution in the following cases:

• The patient has an inability to establish ownership of the mirrored extremity
• If pain increases or movement disorders worsen during/after treatment
• Avoid explicit motor imagery if patient has experienced significant trauma or has symptoms of PTSD
• If a patient experiences pain/sweating of the affected side during MVF, the frequency/complexity of the movement needs to be reduced

Components

Each step is applied for about 2 weeks (or until the patient meets the criteria to progress) before progressing to the next step

1. Laterality Training

Left/right discrimination is the process of recognising one side of the body as district from the other and is trained by reviewing images of left and right limbs. The inability to recognise the affected limb accurately is related to disrupted sensory and motor pathways.

• Method: The patient is shown a sequence of images of the affected limb, and asked to identify each image as a right or left limb. Recognise Apps or flash cards (NOI group) or magazines can be used.
  • For the spine (neck/back) the direction of rotation/bending should be identified
• Frequency: Should practise x4 per day
• Normal responses:
  • Accuracy of 80% and above
  • The normal recognitions speed is about 1-2.1sec for necks and backs
  • The normal recognitions speed is about 1.5-2.5sec for hands and feet
  • Accuracy and response time should be more or less equal on both sides

2. Explicit Motor Imagery

Explicit motor imagery is the process of thinking about moving without actually moving. By imagining movements, similar brain areas to those involved in actual movement, are activated. Thus, imaginary movements can help train the brain towards movement. This is very useful for patients who struggle to initiate movement, or who have poor quality of movement.

• Indications: Patient reports being unsure about where the limb is, experiences pain by just thinking about moving the limb and/or pain increases with movement initiation
• Method: The patient should imagine themselves moving. Begin imagined movements on the opposite side, or same side away from the painful site and gradually move towards the painful area. Begin with small amplitude imagined movements, gradually progressing to larger movements.
  • Progress from a quiet place to busier environments
  • Add more elements to the imagined experience (eg. warmth, smells, sounds)
• Frequency: Should be practised 7 times per day

3. Mirror Visual Feedback

MVF uses movements of the unaffected body part to 'trick' the brain into thinking the affected part is moving. By putting the affected limb behind a mirror, and looking at the reflection of movements caused by the the unaffected side, the affected side is actually being 'exercised' in the brain. Although mirror therapy can be used in isolation, it's effectiveness can be enhanced by first establishing good left/right discrimination and imagined movements.

• Method: Completely conceal the affected limb, and the patient should be well supported and comfortable. Both limbs should start in the same position.
  • Start with exercises that only involve looking at the reflection (no movement)
  • Slowly start congruent movements of both limbs whilst looking at the reflection. The affected side moves only to the point where pain starts, while the unaffected side (and as a result the reflected movement) continues to full ROM.
  • Start with simple, pain free movements and progress to more complex movements
• Frequency: At least 5min, max 10min; 4-9 times daily

Do's	Dont's
Warn patient that is may feel strange and they can stop any time	Sit too far back, resulting in both arms being visible
Remove jewellery/ watch	Continue if symptoms worsen
Allow time for patient to look at the reflection until they are convinced of the illusion and feel comfortable with it	Perform unilateral/ asynchronous movements

Resources

EFIC guide to treating CRPS

NOI group website