Abstract
BACKGROUND: Stroboscopic vision (SV), known for providing intermittent visual input, has been recently integrated into postural training to improve proprioceptive awareness. This research examined the impact of SV on cortico-posture coupling in older adults, along with the related changes in postural control throughout a spectrum of feedback and feedforward processes. METHODS: A total of thirty-three adults, averaging 66.1 ± 2.5 years of age, were tasked with maintaining an upright posture on a stabilometer, utilizing either complete or intermittent visual guidance. Stabilogram diffusion analysis (SDA) was employed to assess balance strategies based on postural sway, while phase-amplitude coupling (PAC) between postural fluctuations and scalp EEG provided insights into the associated neural control mechanisms. RESULTS: SV resulted in significantly increased postural sway as compared with that of full-vision feedback (p < 0.001). SDA results indicated greater critical point displacement (CD) (p < 0.001), short-term diffusion coefficients (Ds) (p < 0.001), and scaling exponents (Hs) (p = 0.014) under SV conditions. PAC analysis revealed that the coupling between the postural fluctuation phase and cortical oscillation amplitude in the theta and alpha bands of the fronto-central area was significantly greater in the SV condition than in the full-vision condition (p < 0.001). Additionally, SV led to increased beta PAC in the frontal and sensorimotor areas compared to that of full vision (p < 0.001), which negatively correlated to SV-dependent changes in open-loop gain (Hs) (p < 0.05). CONCLUSIONS: SV transitions postural sway towards an open-loop process and influences cortico-posture interactions in older adults, emphasizing a neuromotor adaptation to the uncertainty in feedforward predictions when utilizing intermittent visual feedback.