Mental imagery (the mental rehearsal of a movement without any actual movement – ‘MI’) has been used to improve sports performance for many years, but can MI help us in our work to improve impairment and function in individuals in pain?
Here’s a look at three reasons to consider using mental imagery in your clinical practice.
Reason 1: mental imagery appears to have a positive effect on muscle performance.
An elegant study involving complete immobilisation of healthy wrists in a brace for four weeks (Clarke et al 2014) – you’ve got to love an immobilising-the-limbs-of-healthy-people study! – demonstrated 50% less muscle strength loss in the immobilisation and MI group compared to a group who were immobilised but performed no MI, at four weeks.
The MI group undertook five times per day mental rehearsal of forearm / hand exercises with EMG monitoring of the forearm muscles during the MI intervention to confirm absence of muscle contraction. The authors concluded that ‘neurological factors are critical contributors to weakness.’
A very interesting recent systematic review on the use of MI in asymptomatic individuals (Scholefield et al 2015) concluded there were ‘promising clinical implications for the use of MI for improvements or maintenance of strength within a patient group unable to actively strengthen due to pain or immobilisation.’ There was also a suggestion from this review that MI may be more effective for muscle groups with a larger motor cortex representation e.g. the hand, which is probably not surprising.
50% less muscle strength loss in the mental imagery group compared to a control group who performed no mental imagery
(Clark et al 2014)
The effects are not just restricted to strength gains however; two randomised controlled trials have demonstrated improved proprioception in individuals with neck pain who undertook MI (Beinert 2015) and a greater degree of improvement in sensorimotor function of the neck following a ‘motor control exercise program’ that included MI in asymptomatic subjects, compared to a group that did not perform MI (Hidalgo-Perez et al 2015).
Clearly MI has potential to improve motor performance from both a ‘strength’ and ‘sensorimotor’ perspective. Let’s look at another reason to use MI.
Reason 2: mental imagery appears to improve psychological aspects of pain and disability.
It is here I think where MI’s true potential lies. In a wonderful study, Robinson et al (2013) utilised mental imagery as part of a package that included in vivo desensitisation (i.e. physical exposure to feared movements) in a cohort of whiplash injured individuals – as a means of ‘preparing the way’ for physically carrying out those same feared movements / activities.
Following three sessions of exposure therapy, subjects demonstrated significant improvements in fear of movement, pain, disability and confidence / self-efficacy, compared to a group receiving an informational booklet only. Interestingly, the authors suggested that the reductions in fear had mediated the improvements seen in the reported pain and disability levels.
So, MI also appears to have a role to play in introducing feared or anxiety provoking movements, prior to physically carrying out those same movements.
Reason 3: Mental imagery is incredibly straightforward to use in a clinical setting and also dovetails very well with relaxation / diaphragmatic breathing approaches. What is there not to like about MI?
My usual approach is to suggest imagined performance of exercises prior to physically carrying out the movements and as I have mentioned, I usually combine this with diaphragmatic breathing / relaxation.
This can be as simple as suggesting a few deep breaths whilst imagining specific movements. If fear is an issue then it might be worth considering starting out with activities that individuals rate as less fearful before moving on to activities that are rated as ‘high fear’. If high levels of avoidance, anxiety and fear are present then this may necessitate longer periods of MI.
So much of what we do with individuals experiencing pain involves decreasing fear and increasing confidence to move. It appears mental imagery has potential to not only reduce muscle strength loss due to immobilisation or pain, but to enable confident, fearless movement where there is pain, loss of confidence and fear.