Eagle-Eyed Visual Acuity: An Experimental Investigation of Enhanced Perception in Autism

Autism Research Centre, Department of Psychiatry, University of Cambridge, Douglas House, Cambridge, United Kingdom.
Biological psychiatry (Impact Factor: 10.26). 01/2009; 65(1):17-21. DOI: 10.1016/j.biopsych.2008.06.012
Source: PubMed


Anecdotal accounts of sensory hypersensitivity in individuals with autism spectrum conditions (ASC) have been noted since the first reports of the condition. Over time, empirical evidence has supported the notion that those with ASC have superior visual abilities compared with control subjects. However, it remains unclear whether these abilities are specifically the result of differences in sensory thresholds (low-level processing), rather than higher-level cognitive processes.
This study investigates visual threshold in n = 15 individuals with ASC and n = 15 individuals without ASC, using a standardized optometric test, the Freiburg Visual Acuity and Contrast Test, to investigate basic low-level visual acuity.
Individuals with ASC have significantly better visual acuity (20:7) compared with control subjects (20:13)-acuity so superior that it lies in the region reported for birds of prey.
The results of this study suggest that inclusion of sensory hypersensitivity in the diagnostic criteria for ASC may be warranted and that basic standardized tests of sensory thresholds may inform causal theories of ASC.

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    • "Bölte et al. (2012) found no significant difference in visual acuity between the three groups. Tavassoli et al. (2011) also sought to clarify Ashwin et al.'s (2009) work by assessing best corrected visual acuity (BCVA) using both the FrACT and another robust clinical vision test, with a standardised log- MAR scoring design, the Early Treatment Diabetic Retinopathy Study (ETDRS) eye chart. Participants were adults with and without ASD (n = 20 each group, mean age 30.4 ± 10.0 and 30.7 ± 10.1 years, respectively) assessed following full correction of refractive error. "
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    Journal of Autism and Developmental Disorders 04/2015; 45(9). DOI:10.1007/s10803-015-2431-8 · 3.06 Impact Factor
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    • "Systematic review of the literature indicates that rates of sensory processing dysfunction may be as high as 90 % in individuals with ASD (Baker et al. 2008; Blakemore et al. 2006; Leekam et al. 2007; Tomchek and Dunn 2007), and indeed, sensory sensitivities are now included in DSM-5 criteria for ASD (American Psychiatric Association 2013). Abnormal responses to stimuli seem to affect all sensory modalities and not only include enhanced perceptual function such as visual hyperacuity (Ashwin et al. 2009), hyperacusis (Khalfa et al. 2004) and acute tactile sensitivity (Blakemore et al. 2006), but also hyporeactivity to sensory stimuli which has been extensively reported in all sensory modes (Ben- Sasson et al. 2009; Reynolds and Lane 2008). The emergence of some autistic behaviour may stem from these sensory impairments (see for comprehensive review, Gerrard and Rugg 2009) and might be unintentionally triggered by stimuli used in the experiments. "
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    12/2014; 1(4):373-386. DOI:10.1007/s40489-014-0034-5
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    • "Resistance to change may also occur at the sensory level; individuals with ASD clinically display unusual behaviors in response to changes in all sensory modalities stimuli (Boyd et al., 2010). Moreover, several behavioral studies and results from questionnaires have revealed unusual sensory responses such as hyper-reactivity or hypo-reactivity in all sensory modalities (Khalfa et al., 2004; Leekam et al., 2007; Reynolds and Lane, 2008; Ashwin et al., 2009; Ben-Sasson et al., 2009), both sometimes occurring in the same subject. Such paradoxical responses to sensory stimuli have led to a lack of consensus on the exact nature of the underlying sensory dysfunction, but have been hypothesized to contribute to stereotyped behaviors and quest for sameness (Gerrard and Rugg, 2009). "
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