Postural adjustments in standing and gait reflect amnestic mild cognitive impairment

Amnestic mild cognitive impairment (aMCI), a prodromal stage of Alzheimer's disease, may involve subtle motor alterations preceding overt cognitive decline. Because postural alignment integrates multisensory and executive control systems, it may reveal early motor-cognitive disruption. This study aimed to identify posture-related features associated with cognition and to determine whether individuals with aMCI exhibit distinct standing and gait kinematics.

In this cross-sectional observational study, 14 older adults with aMCI and 14 age-matched cognitively healthy controls underwent three-dimensional motion analysis during quiet standing and level walking. Segmental angles and temporospatial gait parameters were analysed. Cognitive performance was assessed using standardised neuropsychological tests. Group comparisons and exploratory partial correlation analyses adjusted for age and education were performed.

The aMCI group exhibited reduced lumbar extension (p = 0.020), pelvic anterior tilt (p = 0.012), and hip flexion (p = 0.016) during standing. While lumbopelvic deviations persisted during gait (p ≤ 0.011), hip flexion and temporospatial parameters were comparable between groups. In controls, verbal episodic memory correlated positively with lumbopelvic alignment (r = 0.67-0.80, p ≤ 0.02). In aMCI, greater hip flexion during gait was associated with poor verbal fluency (r = -0.57, p = 0.05) and visual memory (r = -0.68, p = 0.02).

Lumbopelvic alignment was closely linked to episodic memory in cognitively normal ageing, but this coupling appeared disrupted in aMCI, with motor-cognitive associations shifting toward hip-mediated compensatory or reorganised gait control. These kinematic markers were detectable despite preserved gait speed and may be more sensitive than conventional temporospatial gait measures under steady-state conditions. Longitudinal studies are warranted.