Association between high plasma p-tau181 level and gait changes in patients with mild cognitive impairment

Previous studies on gait changes in mild cognitive impairment (MCI) are inconsistent. Alzheimer's disease (AD) plasma biomarkers, amyloid beta (Aβ) and phosphorylated-tau (p-tau), are relevant to gait disorders. This study explores gait changes in MCI and the relationship between gait performance and AD plasma biomarkers. 231 participants were recruited and stratified based on p-tau181 levels into: low p-tau181 with normal cognition (lT-NC), low p-tau181 with MCI (lT-MCI), and high p-tau181 with MCI (hT-MCI). The same cohort was subsequently stratified by Aβ42/Aβ40 levels into: high Aβ42/Aβ40 with normal cognition (hA-NC), high Aβ42/Aβ40 with MCI (hA-MCI), and low Aβ42/Aβ40 with MCI (lA-MCI). Demographic, cognitive and gait data were compared across groups. The hT-MCI and lA-MCI groups were older than the other groups. Significant differences in stride length were found between lT-NC and hT-MCI, lT-MCI and hT-MCI, but not between lT-NC and lT-MCI. Neuropsychological assessments revealed poorer performance in hT-MCI and lT-MCI groups relative to lT-NC, while global cognitive function was comparable between hT-MCI and lT-MCI groups. No such associations were observed between stride length and Aβ42/Aβ40 levels. Decreased stride length, which is generally considered to be indicative of poorer gait, was significantly associated with elevated p-tau181 levels and independent of global cognitive status. These findings highlight the potential of p-tau181 as a biomarker for tau-related motor dysfunction in MCI.