Summary: Following a stroke, chronic pain can alter body perception and trick the brain into believing the affected hand is a different size. This increases the risk of accidents.
Source: University of South Australia
A world-first study of stroke survivors shows how chronic pain can alter body perception, with the brain tricking patients into believing their affected hand is a different size, increasing the risk of accidents.
Australian and US researchers found there’s a strong likelihood in stroke patients with persistent pain to mistakenly believe their stroke-affected hand is either bigger or smaller than it really is.
The findings are published in a landmark paper in Brain Sciences.
Researchers, including international pain expert Professor Lorimer Moseley AO from the University of South Australia, surveyed 523 stroke survivors, finding that those living with chronic pain were almost three times as likely as pain free survivors to experience altered body perception.
The results suggest that rehabilitation to address distorted body perception in stroke survivors may improve outcomes, given that stroke is a leading cause of disability worldwide and accurate perception of hand size is critical to holding or manipulating objects.
“There are two striking findings in our study,” Professor Moseley says.
“First, that three out of five stroke sufferers are living with chronic pain, which is up to 300 percent higher than in the general population.
“Second, that those with pain are also more likely to perceive major changes in how their body feels to them. This is a potential double whammy, making daily activities more difficult and affecting quality of life,” Prof Moseley says.
Both stroke and persistent pain (lasting longer than three months) are associated with impaired cognition, more fatigue, anxiety and depression, and distortions in body perception might amplify these conditions, he says.
Distorted body perception has been reported in a range of conditions – after amputation, severe chronic pain and eating disorders – but has not previously been linked to pain after stroke.
“The next step is to identify whether body perception disturbance is contributing to pain in these patients. If it is, we need to devise treatments to address this.”
Distorted body perception was twice as likely when post-stroke pain was in the hand, which is consistent with other chronic pain populations such as knee osteoarthritis, where up to 30 percent of people believe their knee is swollen when it isn’t.
“These remarkable findings show us that we are perhaps more complex creatures than we previously thought,” Prof Moseley says.
The researchers did not find any link between chronic pain and strokes occurring on a specific side of the body.
About this body perception, pain, and stroke research news
“My hand is different”: Altered body perception in stroke survivors with chronic pain
Background: Chronic pain and body perception disturbance are common following stroke. It is possible that an interaction exists between pain and body perception disturbance, and that a change in one may influence the other. We therefore investigated the presence of body perception disturbance in individuals with stroke, aiming to determine if a perceived change in hand size contralateral to the stroke lesion is more common in those with chronic pain than in those without.
Methods: Stroke survivors (N = 523) completed an online survey that included: stroke details, pain features, and any difference in perceived hand size post-stroke.
Results: Individuals with stroke who experienced chronic pain were almost three times as likely as those without chronic pain to perceive their hand as now being a different size (OR = 2.895; 95%CI 1.844, 4.547). Further, those with chronic pain whose pain included the hand were almost twice as likely to perceive altered hand size than those whose pain did not include the hand (OR = 1.862; 95%CI 1.170, 2.962). This was not influenced by hemisphere of lesion (p = 0.190).
Conclusions: The results point to a new characteristic of chronic pain in stroke, raising the possibility of body perception disturbance being a rehabilitation target to improve function and pain-related outcomes for stroke survivors.