Sensorimotor and cognitive factors associated with the age-related increase of visual field dependence: a cross-sectional study

Abstract

Reliance on the visual frame of reference for spatial orientation (or visual field dependence) has been reported to increase with age. This has implications on old adults' daily living tasks as it affects stability, attention, and adaptation capacities. However, the nature and underlying mechanisms of this increase are not well defined. We investigated sensorimotor and cognitive factors possibly associated with increased visual field dependence in old age, by considering functions that are both known to degrade with age and important for spatial orientation and sensorimotor control: reliance on the (somatosensory-based) egocentric frame of reference, visual fixation stability, and attentional processing of complex visual scenes (useful field of view, UFOV). Twenty young, 18 middle-aged, and 20 old adults completed a visual examination, three tests of visual field dependence (RFT, RDT, and GEFT), a test of egocentric dependence (subjective vertical estimation with the body erect and tilted at 70°), a visual fixation task, and a test of visual attentional processing (UFOV®). Increased visual field dependence with age was associated with reduced egocentric dependence, visual fixation stability, and visual attentional processing. In addition, visual fixation instability and reduced UFOV were correlated. Results of middle-aged adults fell between those of the young and old, revealing the progressive nature of the age effects we evaluated. We discuss results in terms of reference frame selection with respect to ageing as well as visual and non-visual information processing. Inter-individual differences amongst old adults are highlighted and discussed with respect to the functionality of increased visual field dependence.

Fig. 1

Illustration of apparatus, postural conditions and stimuli used for the subjective vertical estimation tests. Stimuli were back-projected onto a screen. A table, adjustable in height, held a black optic tube through which participants viewed the stimuli in order to reduce peripheral visual cues. For the rod-and-frame test (RFT) (a) and rod-and-disc test (RDT) (b), a head and chinrest was attached onto the table to keep the head fixed. Visual stimuli were a white tilted rod within a white tilted frame and within a disc of white dots for the two tests, respectively. The table was raised as appropriate for the rod-and-body test during the body erect (RBT BE) (c) and body tilted (RBT BT) (d) postural conditions so as the centre of the rod was centered on participants’ cyclopean eye

Fig. 2

Scores for each age group on all assessments—means with 95 % confidence intervals. a Adjustment error on the RFT and RDT, error difference between the RBT tests (BT-BE) and GEFT scores; b visual fixation bivariate contour ellipse area (BCEA) and UFOV 2 and UFOV 3. For the RFT, RDT, and GEFT scores, larger mean values indicate greater visual field dependence. For RBT data, larger mean values indicate greater egocentric dependence. For VFI and UFOV data, larger values indicate greater visual fixation instability and longer processing times (reduced UFOV), respectively

Fig. 3

Relationship of visual fixation instability (VFI) with subjective vertical estimation tests. a VFI correlation with the RFT and the RDT; b VFI correlation with the RBT (BT-BE error)

Fig. 4

Relationship of useful field of view (UFOV) subtests 2 and 3 with visual field dependence tests. a UFOV 2 and 3 correlations with the GEFT; b UFOV 2 and 3 correlations with the RFT; c UFOV 2 and 3 correlations with the RDT