Signs of Frozen Gait Most Evident in People Making Turns, Study Finds
Signs of frozen gait are most noticeable when people with Parkinson’s disease are turning or walking in a circle, and more noticeable when they are walking backward rather than forward, a small study reported.
Three distinct characteristics of walking — step length, walking speed, and range of joint motion — also mark the severity of frozen gait “in all walking conditions,” meaning when a person is going forward, backward, or making a turn, its researchers wrote.
Their study, “Turning reveals the characteristics of gait freezing better than walking forward and backward in Parkinson’s disease,” was published in Gait & Posture.
Freezing of gait (FoG), a major cause of falls in people with Parkinson’s, is estimated to affect between 30% and 60% of all patients. It’s often described as a person feeling their feet are suddenly stuck to the floor, and walking is arrested despite an intention to walk.
Numerous studies have looked at FoG in patients with “conflicting results,” the study noted, largely due to differences in the conditions under which walking was evaluated and whether patients were in “off” or “on” states with levodopa use.
Most of this work has also focused on walking forward, while walking backward is a more “complex task that is inevitably performed as part of activities of daily living,” that “involves turning, sitting back, and moving backward,” the researchers wrote. With turning — which “includes 20% of all steps in daily activities” — walking backward also “frequently leads to falls in older adults.”
For these reasons, “there is a need to comprehensively analyze the walking characteristics of PD [Parkinson’s disease] patients … with and without FoG,” the researchers, with Dong-A University in Busan, Korea, wrote.
Their study examined 63 Parkinson’s patients — 28 with freezing of gait and 35 without it, all on stable medication doses and able to walk independently — and 14 healthy adults as a control group. Patients’ mean age was 69.7 and their mean disease duration was 6.1 years (8.1 years for those with frozen gait and 4.5 years for those without it); healthy adults had a mean age of 67.6.
In addition to a longer time with symptoms, those with FoG had higher Mini-Mental State Examination scores (reflecting lesser cognitive impairment) and more severe disease, as measured by Hoehn and Yahr stage, than did patients without FoG.
A main study goal was to assess the walking characteristics in patients by measuring turning, and forward and backward walking using a three-dimensional motion analysis system.
These tests were monitored with cameras, with participants moving at their preferred speeds. Spatiotemporal characteristics — including walking speed, step time, step length, stride time, and stride length — were measured, as were range of motion in the hip, knees and ankle joints.
People with Parkinson’s had shorter step length, poorer toe clearance, and slower walking speed while walking forward than did controls, but no significant differences were evident between patients with and without FoG while walking forward. All patients, but especially those without frozen gait, showed differences in cadence and step time between steps, the team reported.
While walking backward, greater differences in the “kinematic characteristics” — toe clearance height and range of motion in the hip, knee and ankle joints — were evident between patients and controls. Between the two groups of patients, differences were seen while walking backward in step length and range of ankle joint motion on the body’s more affected side.
With 360-degree (circular) turning in both directions, researchers found differences between all Parkinson’s patients and healthy adults, with patients taking more steps and more time to turn, and covering a wider area while turning. Those with freezing of gait also had greater differences (asymmetry) in step lengths while turning in either direction that did patients without frozen gait, but both groups showed that such asymmetry.
“Despite the short step lengths of PD patients, they failed to perform stable turning steps, showing increased asymmetry between each step compared with the control group during natural pivot turning,” the researchers wrote, adding that asymmetry in step lengths ” could be a reliable characteristic of turning in PD patients.”
More irregular shapes while walking a 360-degree turn were also evident among Parkinson’s patients than healthy adults.
“In the present study,” the scientists concluded,” the severity of FoG was correlated with step length, walking speed, and [range of motion] of the lower limb joints in all walking conditions. These correlations were most prominent during turning, which was observed in all [range of motions] of the lower limb joints, total steps, and turning time.”
These findings suggest, they added, “that the general turning performance would better demonstrate the impact of FoG than the specific walking characteristics,” as “there was no definite difference between the steps or according to the turning direction.”
Researchers highlighted that their study’s small study size was a limitation to its findings, and they suggested that further studies with larger patient groups are needed to better capture FoG in daily life and to understand the walking and turning characteristics of people with freezing of gait.
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