Why the Brain Gets Stuck
In chronic pain states, the cortical representation of the affected body part undergoes measurable reorganisation. The primary somatosensory cortex shrinks its territory for the painful limb while expanding neighbouring regions — a maladaptive plasticity that amplifies nociceptive signals and distorts body schema. This means that pain is no longer reliably tracking tissue damage; it is tracking perceived threat.
The Three Stages of GMI
- Stage 1 — Left/right discrimination: re-establishing accurate limb laterality recognition via flash-card style image recognition
- Stage 2 — Imagined movements: mentally rehearsing movements without any physical action, activating motor cortex without triggering protective responses
- Stage 3 — Mirror therapy: using a mirror box to create visual feedback of unaffected limb movement projected onto the painful side
Pain is an output of the brain designed to protect, not a measurement of tissue damage.
— Moseley, 2007
GMI is most effective when delivered in the correct sequence. Attempting mirror therapy before the patient can reliably discriminate left from right limb images typically provokes a pain flare, setting back the therapeutic relationship. Sequence integrity is not optional.
Comments(2)
The sequencing point is crucial and under-taught. In my experience, most GMI failures come from skipping stage 1 entirely because patients find L/R discrimination too basic or boring. But cortical reorganisation in CRPS can make even simple discrimination tasks genuinely difficult — and doing them wrong gives you nothing.
Do you use the Recognise app for stage 1, or printed cards? And how many daily sessions do you recommend before moving to imagined movements?
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