Left right discrimination is the process of recognising one side of the body as distinct from the other. this ability for left/right discrimination can be trained by reviewing images of left and right limbs.
Aim of treatment:
Research has shown that people with CRPS often lose the ability to correctly identify left or right images of their painful body part(s). This inability to recognise the affected limb accurately is thought to be a consequence of disruption to the sensory and motor pathways which one needs to subconsciously plan and initiate movement. Left/ right laterality treatment aims to retrain the brain to be able to correctly recognise the affected limb.
This training appears to help patients to
The treatment involves exposing patients to series of images of limbs in different positions, and advising patients to make a judgement whether the image represents a right or left limb.
The aim is to achieve a normal recognition speed that is about equal for both sides and stable (e.g. not fading with stress) for at least a week.
A normal value for hand/foot recognition speed is about 2 seconds +/- 0.5 seconds, based on research conducted by the NOI research group.
Some useful tools for training left/right discrimination are the online Recognise™ software, Recognise™Apps, Recognise™ Flash Cards produced by the NOI group. Alternatively other readily available tools include magazines (with people pictures), Google images, Facebook photos, photo albums
When to consider:
Left/ right laterality training can be considered when patients have marked neglect or have strong emotional distain for their limb.
This is often a good introduction exercise when patients struggle to tolerate touch or movement of the affected limb.
When not to consider:
Training requires regular practice and patients should not use this technique if they are not prepared to commit to practicing at least 4 or more times a day.
When a subject’s ability to perform left/ right discrimination falls within what are considered normal ranges.
Top tips:
Progress with accuracy scores and reaction times is commonly being measured. Accuracy is measured as a percentage reflecting the subject’s ability to accurately recognise left/ right images. Reaction time refers to the time taken for a subject to recognise whether an image represents a left or right limb.
When subjects score within normal ranges treatment can be either discontinued or progressed.
Treatment progression can involve the use of more abstract images which further challenge the person’s ability to mentally orientate to whether the image is left or right. For example images in different environments are often used such as a foot walking on sand, or a foot print.
Treatment progression can also involve performing training in a more challenging environment such as a noisy room.
Results should be stable (e.g. they don’t fade out with stress) and be consistent for at least a week before treatment is progressed.
Change in performance should be evaluated on an individual level and within the context of the person performing the task. For example, minor left/right discrimination changes may not be so relevant in a person who has severe pain related incapacity, whereas they may be more relevant in a person with a much more minor problem.
The normal ranges are based on studies of hundreds of people and act as a guide only. There may be independent reasons why people don’t achieve normal ranges. Patients should always feel treatment is progressing and therefore treatment should not be continued for extended periods with no to little progress.
The exercises should always involve patients mentally orientating their affected limb to evaluate whether the pictured image is left or right; people should be discouraged from shortcutting this process. For example some people will try and use a visual anchor such as thumb position or presence of a watch to quickly determine left and right rather than mentally orientating the whole limb.