Transcranial direct current stimulation (tDCS), is non-invasive method for stimulating the brain with low intensity electrical currents. Recent reviews speak enthusiastically to the promise of these interventions but we need to interpret the results from any trial that used 2mA tDCS (that’s the vast majority of trials in chronic pain and depression) with caution.

Living with chronic pain can be miserable. Not only are there the nagging aches and pains of every day life, but there might also be forgetfulness, anxiety, depression, or difficulty concentrating as well. Researchers don’t yet know whether these ‘cognitive deficits’ are caused by pain itself, or whether it’s naturally more forgetful, anxious, depressed or concentration-lacking people who are predisposed to developing some form of chronic pain.

Sensorimotor incongruence can generate sensations, but not pain, in healthy subjects but there is a different result in people with chronic whiplash associated disorders.

People are generally aware that pain can interact with motor performance, but pain-related motor dysfunctions are often put down to pain caused by the movement or fear of re-injury. The reality of things, however, is much more complex. In a recent review paper Mercier & Léonard discuss several examples of the complex interactions that can exist between pain and movement control.