BACKGROUND: Visual input significantly influences cerebral activity related to locomotor navigation, although the underlying mechanism remains unclear. This study aimed to analyze the effects of chronic visual impairment and its rehabilitation on sensorimotor integration during level walking in patients with age-related cataract. METHODS: This prospective case series enrolled 14 female patients (68.4 ± 4.7 years) with age-related cataract, scheduled for consecutive cataract surgeries at the Department of Ophthalmology in Peking University Third Hospital from June 2019 to June 2020. Electroencephalogram (EEG) signals during level walking were recorded using a portable EEG system before and 4 weeks after visual restoration. Walking speed was assessed using the Footscan system. Spectral power of the theta and alpha bands was analyzed with repeated-measures analysis of variance, with Assignment (rest and walking), Phase (preoperative and postoperative), and Electrode sites (F3, Fz, F4, O1, and O2) as within-subject factors. RESULTS: Compared to the visual impairment state, theta band power significantly decreased after visual restoration (13.16 ± 1.58 μV 2vs. 23.65 ± 3.48 μV 2 , P = 0.018). Theta activity was notably reduced during walking (17.24 ± 2.43 μV 2vs. 37.86 ± 6.62 μV 2 , P = 0.017), while theta power at rest was not significantly different between the two phases (9.44 ± 1.24 μV 2vs. 9.08 ± 1.74 μV 2 , P = 0.864). Changes in walking speed were correlated with alterations in theta power at electrode sites of O1 ( r = -0.574, P = 0.032) and O2 ( r = -0.648, P = 0.012). Alpha band power remained stable during walking and was unaffected by visual status. CONCLUSIONS Chronic visual impairment from age-related cataract triggers enhanced cerebral activation of sensorimotor integration to compensate for visual decline during locomotion. This cerebral over-activation is effectively alleviated by visual restoration.
Humans ; Female ; Walking/physiology* ; Aged ; Electroencephalography/methods* ; Prospective Studies ; Middle Aged ; Cataract/physiopathology* ; Vision Disorders/physiopathology*

Background::Visual inputs are critical for locomotor navigation and sensorimotor integration in the elderly; however, the mechanism needs to be explored intensively. The present study assessed the gait pattern after cataract surgery to investigate the effects of visual restoration on locomotion.Methods::The prospective study recruited 32 patients (70.1 ± 5.2 years) with bilateral age-related cataracts in the Department of Ophthalmology at Peking University Third Hospital from October 2016 to December 2019. The temporal-spatial gait parameters and kinematic parameters were measured by the Footscan system and inertial measurement units. Paired t-test was employed to compare data normally distributed and Wilcoxon rank-sum test for non-normally distributed. Results::After visual restoration, the walking speed increased by 9.3% (1.19 ± 0.40 m/s vs. 1.09 ± 0.34 m/s, P=0.008) and exhibited an efficient gait pattern with significant decrease in gait cycle (1.02 ± 0.08 s vs. 1.04 ± 0.07 s, P=0.012), stance time (0.66 ± 0.06 s vs. 0.68 ± 0.06 s, P=0.045), and single support time (0.36 ± 0.03 s vs. 0.37 ± 0.02 s, P=0.011). High amplitude of joint motion was detected in the sagittal plane in the left hip (37.6° ± 5.3° vs. 35.5° ± 6.2°, P=0.014), left thigh (38.0° ± 5.2° vs. 36.4° ± 5.8°, P=0.026), left shank (71.9° ± 5.7° vs. 70.1° ± 5.6°, P=0.031), and right knee (59.1° ± 4.8° vs. 56.4° ± 4.8°, P=0.001). The motor symmetry of thigh improved from 8.35 ± 5.30% to 6.30 ± 4.73% ( P=0.042). Conclusions::The accelerated gait in response to visual restoration is characterized by decreased stance time and increased range of joint motion. Training programs for improving muscle strength of lower extremities might be helpful to facilitate the adaptation to these changes in gait.

Amblyopia is a developmental visual disorder,which is accompanied by physiological changes in the visual cortex.Many studies that focused on the treatments of amblyopia and improvment of therapeutic effects in teenagers and adults have been paid more and more attention.Recent studies reveal that a threshold level of neurotransmitters,such as γ-aminobutyric acid (GABA),norepinephrine (NE),acetylcholine,5-hydroxytryptamine (5-HT) and dopamine,is required to open the critical period.Meanwhile,the content of specific extracellular matrix,such as extracellular protease tissue plasminogen activator (tPA) and cross-linked chondroitin sulphate proteoglycans (CSPGs),exhibits dynamic changes over the time course of the critical period,which plays a key role in synaptic modifications.Clinical studies show that suppression and deficits in visual attention towards signal from the amblyopia eye may be important factors in physiological mechanism of amblyopia,which support a basis for non-invasive brain stimulation and perceptual learning as new effective treatments.This paper described the recent advances in plasticity of visual cortex and binocular vision in the field of amplyopia treatment,especially in teenagers and adults.