Cognitive tasks while walking distinguish MSA, Parkinson’s: Study
The two diseases often share similar symptoms
Performing cognitive tasks while walking may help distinguish between early Parkinson’s disease and multiple system atrophy (MSA), a neurodegenerative disorder with similar symptoms, a study suggests.
MSA patients had more walking impairments alongside higher brain activity during cognitive tasks while walking than Parkinson’s patients, the research shows.
“We posit that [MSA] patients may present underlying cognitive impairments and the available cognitive resources may be insufficient to maintain optimal gait performance during complex walking,” the study’s researchers said. The study, “Differences Between Patients With Multiple System Atrophy With Predominant Parkinsonism and Parkinson’s Disease Based on fNIRS and Gait Analysis,” was published in CNS Neuroscience & Therapeutics.
MSA is a rapidly progressing neurodegenerative disease that often presents symptoms similar to those of Parkinson’s disease, making it challenging to distinguish between the two. It’s associated with poorer outcomes, with a mean survival of eight to nine years. Therefore, distinguishing it early from Parkinson’s is essential for providing individualized treatment plans that enhance patients’ survival and quality of life.
Separating MSA, Parkinson’s
Studies suggest MSA patients exhibit more variability in walking, more posture sway, and a broader base of foot support than people with Parkinson’s. Parkinson’s patients see exacerbated gait problems when engaging in cognitive tasks during walking, possibly the result of abnormal brain activity.
Researchers in China suggested “the changes in [brain] activation during complex walking can reveal the differences in the neurophysiological mechanisms of gait disorders in patients with [Parkinson’s] and MSA.” To test their hypothesis, they recruited 24 people with MSA, 20 with Parkinson’s, and 22 healthy people, who served as controls.
The participants underwent gait assessments using a portable inertial measurement system wherein wearable sensors were attached to capture motion data. At the same time, functional near-infrared spectroscopy, a noninvasive imaging device that’s worn like a hat, recorded brain activity by measuring changes in hemoglobin levels, specifically oxyhemoglobin (HbO2), which carries oxygen. Higher HbO2 changes indicated more brain activity.
The participants were randomly assigned single-task walking (STW) or cognitive dual-task walking (DTW) conditions. STW involved walking while performing the Time Up and Go (TUG) test, while DTW involved walking while subtracting 7 from a randomly generated three-digit number. A TUG test is the time it takes to rise from a chair, walk, turn, walk back, and sit down.
Analyzing walking differences
According to the analysis, the variability in the length of steps taken during walking was significantly higher among MSA patients than both Parkinson’s patients and healthy people during the DTW condition. MSA patients also showed increased step length variability during the DTW versus the STW condition. Additionally, each step was significantly shorter and the variability in cadence, the number of steps taken per minute, was greater in MSA than in Parkinson’s patients and controls.
Spectroscopy data during DTW showed that MSA patients had a significantly higher HbO2 change, or more brain activity, than Parkinson’s patients and controls in the right dorsolateral prefrontal cortex (DLPFC), a brain region implicated in Parkinson’s cognitive and motor symptoms. Parkinson’s patients showed higher HbO2 changes in this region than the healthy controls.
Both Parkinson’s and MSA patients, but not controls, had increased brain activity during DTW compared with STW.
“This suggests that MSA patients may rely on increased cortical activity to compensate for motor and cognitive deficits during complex walking tasks,” the researchers wrote. Parkinson’s patients with more severe gait disturbances also “may require additional cognitive resources to manage motor symptoms.”
When the researchers compared gait analysis data to DLPFC brain activity, higher changes in HbO2 correlated with smaller step length and step length variability during DTW. None of the other gait measurements were related to HbO2 during either condition.
Finally, a statistical analysis showed that step length variability during DTW could distinguish MSA from Parkinson’s with an accuracy of 72.1%. Meanwhile, brain activity in the right DLPFC during DTW distinguished the two conditions with 79.8% accuracy.
“This present study shows that [MSA] patients demonstrated more severe gait disturbance and increased DLPFC activity compared with [Parkinson’s] patients and [controls],” the researchers wrote. “The study provided a new way to early identification of [MSA] and [Parkinson’s] patients.”
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