Gait variability serves as indicator of cognitive dysfunction in AD, other diseases

Gait variability — or the stride-to-stride fluctuations in distance and time when moving — served as a marker of cognitive-cortical dysfunction, according to findings published in Alzheimer’s & Dementia.

As a result, greater gait variability could be used to diagnose Alzheimer’s disease dementia, according to the researchers.

“Abnormal gait is prevalent in established dementia, and can also predict progression from normal cognition, cognitive complaints, and mild cognitive impairment (MCI) to dementia syndromes,” the researchers wrote. “Although previous studies consistently show associations between increased gait variability with virtually all neurodegenerative conditions, there is a lack of systematic comparisons across the spectrum of neurodegenerative diseases that eventually affect cognition, including pre-dementia stages.”

Frederico Pieruccini-Faria, PhD, of the Lawson Health Research Institute and the Schulich School of Medicine & Dentistry in Ontario, Canada, and colleagues examined gait and cognitive performance in 500 older adults with different neurodegenerative and cognitive conditions, including subjective cognitive impairment, Parkinson’s disease, MCI, PD MCI, AD, PD dementia, Lewy body dementia and frontotemporal dementia, in addition to a control group of adults with normal cognitive function. The study involved 11 quantitative gait parameters, from which Pieruccini-Faria and colleagues identified four independent gait domains: rhythm, pace, variability and postural control. They used these parameters for group comparisons and classification analysis.

The researchers performed gait assessments on the same day, or soon after, as clinical and cognitive assessments. Gait assessments used a 6-meter electronic walkway to calculate gait speed and stride time and length, among other parameters.

Greater gait variability correlated with dementia, especially AD dementia and PD dementia, according to the study results. While rhythm and postural control domains were also linked to dementias and MCI, only gait variability “was able to accurately discriminate and classify individuals with AD,” Pieruccini-Faria and colleagues noted. In addition, only gait variability significantly correlated with dementia and cognitive impairment compared with the other gait domains.

Among patients with PD, the researchers found that global cognitive performance was “negatively and more strongly associated with gait variability” than the Movement Disorder Society-Unified Parkinson’s Disease Rating Scale, motor section, indicating that gait variability represented a better motor marker for cognitive performance than severity of parkinsonism.

“Overall, high gait variability was significantly associated with low global cognition in AD and PD classes,” the researchers wrote.

Stride time variability identified membership in the AD group (area under the curve [AUC], 0.8; P < .0001), with a specificity of 70%, a sensitivity of 80% and a variability equal to 2.3%. Stride length variability identified AD group membership (AUC, 0.72; P < .0001), with a specificity of 54%, a sensitivity of 80% and a variability equal to 2.58%. Double support time variability identified AD group membership (AUC, 0.79; P < .0001), with a specificity of 70%, a sensitivity of 75% and a variability equal to 6.2%.

“Our study ... supports previous assumptions that cognitive performance is strongly associated with gait variability, compared with other gait parameters, independently of disease subtype,” Pieruccini-Faria and colleagues wrote. “Increased gait variability may reflect the progression of cognitive impairment in neurodegenerative diseases, and potentially with specificity for [AD] dementia, which is the archetypal cortical cognitive disorder.”