Side-to-side eye movement can improve stability in Parkinson’s
Moving eyes up and down didn't improve patients' body sway, however
Side-to-side eye movements can help reduce body sway and improve postural stability in people with Parkinson’s disease, even though Parkinson’s patients generally have difficulty coordinating their eye movements, a new study reports.
The study, “People with Parkinson’s Disease Are Able to Couple Eye Movements and Postural Sway to Improve Stability,” was published in Biomechanics.
People with Parkinson’s have a higher risk of falls. One of the reasons is that they tend to sway more when standing than people without the disease. This can increase the risk of them losing their balance and falling over.
It’s been proven that side-to-side and up-and-down, that is, saccadic, eye movements can help reduce body sway in adults who don’t have a neurological disease. Parkinson’s patients have a difficult time fine-tuning their eye movements, so it’s not been known if this technique could apply to them.
Here, scientists in Brazil studied 10 people with Parkinson’s and 11 similarly-aged people without the disease, and recorded how much they swayed when their gaze was fixed on one point over when they moved their eyes side to side or up and down.
Side to side, and up and down
The experiments were conducted while Parkinson’s patients were under the influence of medications to help manage their disease symptoms, but the researchers expected that eye movements would have less benefit for them than for people without the disease.
But that wasn’t the case. Side-to-side eye movements reduced body sway in the people with Parkinson’s to a similar extent as they did those without the disease, and this was true even though patients generally scored worse on measures of how well they coordinated their eye movements, which was expected.
“Individuals with [Parkinson’s] can reduce postural sway as efficiently as neurologically healthy people when performing horizontal saccades [side-to-side eye movements],” the researchers wrote.
Moving the eyes up and down didn’t improve body sway in Parkinson’s patients, however, but it did in people without the disease. The findings were consistent no matter how the participants were standing — with their feet side by side or one in front of the other.
The results suggest integrating side-to-side eye movements into postural training for Parkinson’s patients could be beneficial, said the researchers, who cautioned that their study was aimed at basic research rather than toward designing an intervention.
“It’s not an automatic strategy to avoid losing balance and falling, since routinely moving the eyes rapidly from side to side is difficult,” Fabio Barbieri, PhD, co-author of the study at São Paulo State University in Brazil, said in a university news story. “You can train horizontal saccadic eye movement, but this study was aimed at basic research rather than practical recommendations. … Our findings furnish new knowledge of the disease, and of its motor and cognitive consequences.”
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