Loss of form vision impairs spatial imagery

Valeria Occelli,Jonathan B Lin,K Sathian,Simon Lacey

doi:10.3389/fnhum.2014.00159

Valeria Occelli, Jonathan B Lin + Show 2 more

Open Access

https://doi.org/10.3389/fnhum.2014.00159

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Abstract

Previous studies have reported inconsistent results when comparing spatial imagery performance in the blind and the sighted, with some, but not all, studies demonstrating deficits in the blind. Here, we investigated the effect of visual status and individual preferences (“cognitive style”) on performance of a spatial imagery task. Participants with blindness resulting in the loss of form vision at or after age 6, and age- and gender-matched sighted participants, performed a spatial imagery task requiring memorization of a 4 × 4 lettered matrix and subsequent mental construction of shapes within the matrix from four-letter auditory cues. They also completed the Santa Barbara Sense of Direction Scale (SBSoDS) and a self-evaluation of cognitive style. The sighted participants also completed the Object-Spatial Imagery and Verbal Questionnaire (OSIVQ). Visual status affected performance on the spatial imagery task: the blind performed significantly worse than the sighted, independently of the age at which form vision was completely lost. Visual status did not affect the distribution of preferences based on self-reported cognitive style. Across all participants, self-reported verbalizer scores were significantly negatively correlated with accuracy on the spatial imagery task. There was a positive correlation between the SBSoDS score and accuracy on the spatial imagery task, across all participants, indicating that a better sense of direction is related to a more proficient spatial representation and that the imagery task indexes ecologically relevant spatial abilities. Moreover, the older the participants were, the worse their performance was, indicating a detrimental effect of age on spatial imagery performance. Thus, spatial skills represent an important target for rehabilitative approaches to visual impairment, and individual differences, which can modulate performance, should be taken into account in such approaches.

Highlights

IntroductionPrevious studies comparing spatial imagery abilities in the sighted and the blind have yielded inconsistent results (see Renzi et al, 2013 for a review), some showing little difference (Vanlierde and Wanet-Defalque, 2004; Vecchi et al, 2004; Giudice et al, 2011) but others reporting that the blind are impaired compared to the sighted (Vecchi, 1998; Aleman et al, 2001; Knauff and May, 2006; Cornoldi et al, 2009)
Since our blind participants varied quite widely in the age at which they lost vision, we examined the correlation between the age at which form vision was completely lost and accuracy on the spatial imagery task for the blind group
In the present study, we showed that the visual status of participants has an impact on performance of the spatial imagery task tested here

Summary

Introduction

Previous studies comparing spatial imagery abilities in the sighted and the blind have yielded inconsistent results (see Renzi et al, 2013 for a review), some showing little difference (Vanlierde and Wanet-Defalque, 2004; Vecchi et al, 2004; Giudice et al, 2011) but others reporting that the blind are impaired compared to the sighted (Vecchi, 1998; Aleman et al, 2001; Knauff and May, 2006; Cornoldi et al, 2009). Vecchi (1998) found that the congenitally blind were less accurate than the sighted when tested on a task that involved learning target squares and pathways on haptic matrices. Blind and sighted participants showed equivalent performance on spatial judgments from different imagined perspectives on visually and haptically learned maps, and both groups exhibited evidence for spatial updating (Giudice et al, 2011). Vanlierde and Wanet-Defalque (2004) required early-, late-blind and sighted participants to imagine shapes in a matrix, following line-by-line descriptions as to whether each square was black or white, and to make symmetry judgments. Despite the demanding nature of the encoding process, the three groups performed but employed different strategies, the late-blind and sighted using mental imagery while the early-blind used a coordinate system that was not visually based

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