Postural control depends on early visual experience

Abstract

The present study investigated the role of early visual experience in the development of postural control (balance) and locomotion (gait). In a cross-sectional design, balance and gait were assessed in 59 participants (ages 7-43 years) with a history of (a) transient congenital blindness, (b) transient late-onset blindness, (c) permanent congenitally blindness, or (d) permanent late-onset blindness, as well as in normally sighted controls. Cataract-reversal participants who experienced a transient phase of blindness and gained sight through cataract removal surgery showed worse balance performance compared with sighted controls even when tested with eyes closed. Individuals with reversed congenital cataracts performed worse than individuals with reversed developmental (late emerging) cataracts. Balance performance in congenitally cataract-reversal participants when tested with eyes closed was not significantly different from that in permanently blind participants. In contrast, their gait parameters did not differ significantly from those of sighted controls. The present findings highlight both the need for visual calibration of proprioceptive and vestibular systems and the crossmodal adaptability of locomotor functions.

Figure 1.

Mean single-leg stance time (in seconds) for sight-recovery participants (CC and DC) and normally sighted controls (SCs), separately for the eyes-closed (EC) condition versus the eyes-open (EO) condition and for hard versus soft ground. Error bars show standard errors of the mean. Dots represent data for individual participants. Horizontal lines indicate significant pairwise group differences (p < 0.05, post hoc test).

Figure 2.

Association between visual acuity (in logMAR) and single-leg stance time (in seconds) in sight-recovery participants, collapsed across hard and soft ground. Positive logMAR values indicate the degree of vision loss; higher values denote lower visual acuity.

Figure 3.

Mean single-leg stance time (in seconds) with eyes closed, separately for congenitally cataract-reversal (CC) participants, developmental cataract-reversal (DC) participants, permanently congenitally blind (CB) participants, permanently late blind (LB) participants, and normally sighted controls (SCs) and for hard versus soft ground. Error bars show standard errors of the mean. Dots represent data for individual participants. Horizontal lines indicate significant pairwise group differences (p < 0.05, post hoc test).

Figure 4.

Mean stride length (A) and mean variability of stride length (B) for sight-recovery participants (CC and DC) and normally sighted controls (SCs), separately for the eyes-closed and eyes-open conditions. Error bars show standard errors of the mean. Dots represent data for individual participants.

Figure 5.

Mean stride time (A) and mean variability of stride time (B) for sight-recovery participants (CC and DC) and normally sighted controls (SCs), separately for the eyes-closed and eyes-open conditions. Error bars show standard errors of the mean. Dots represent data for individual participants.

Figure 6.

Mean gait speed (A) and mean variability of gait speed (B) for sight-recovery participants (CC and DC) and normally sighted controls (SCs), separately for the eyes-closed and eyes-open conditions. Error bars show standard errors of the mean. Dots represent data for individual participants.

Figure 7.

Mean stride length (A) and mean variability of stride length (B) in the eyes-closed condition, separately for congenitally cataract-reversal (CC) participants, developmental cataract-reversal (DC) participants, permanently congenitally blind (CB) participants, permanently late blind (LB) participants, and normally sighted controls (SCs). Error bars show standard errors of the mean. Dots represent data for individual participants. Horizontal lines indicate significant pairwise group differences (p < 0.05, post hoc test).

Figure 8.

Mean gait speed (A) and mean variability of gait speed (B) in the eyes-closed condition, separately for congenitally cataract-reversal (CC) participants, developmental cataract-reversal (DC) participants, permanently congenitally blind (CB) participants, permanently late blind (LB) participants, and normally sighted controls (SCs). Error bars show standard errors of the mean. Dots represent data for individual participants. Horizontal lines indicate significant pairwise group differences (p < 0.05, post hoc test).