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Terri Lewis, Louis Schmidt, Daphne Maurer; Higher-order Vision in Adults born at Extremely Low Birthweights. Journal of Vision 2014;14(10):694. doi: 10.1167/14.10.694.
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Children born very prematurely later show deficits in higher-order vision, including global form, global motion, and biological motion with four times larger deficits in perceiving global motion than in perceiving global form (e.g., Atkinson & Braddick, 2007; Taylor et al., 2009). To determine whether any deficits are permanent or merely reflect slower visual development, we tested higher-order vision in 15 adults who had been born at <32 weeks gestation with an extremely low birthweight (M age at test=32.3 yrs, range 3034 yrs; M birthweight=814 gms, range 6001,000 gms) and in 14 comparably-aged adults who had been full-term and weighed at least 2500 gms at birth. Participants all had no neurological deficits such as cerebral palsy, decreased IQ, or seizures. All had normal or corrected-to-normal visual acuity. We used staircase procedures to measure sensitivity to (a) global form using concentric Glass patterns, (b) global motion at two speeds, and (c) biological motion. Surprisingly, the two groups performed comparably on all tasks. Specifically, sensitivity to global form was normal (signal threshold=13.6% in those born prematurely and 13.3% in controls, p>0.90). Sensitivity to global motion was normal, both when tested at 18 deg/sec (coherence threshold=25.7% in those born prematurely and 19.5% in controls, p>0.10) or at 4 deg/sec (coherence threshold=37.0% in those born prematurely and 23.7% in controls, p>0.10). Sensitivity to biological motion was also normal (threshold number of noise dots tolerated=63 in those born prematurely and 69 in controls, p>0.20). Thus, deficits in the processing of global form, global motion, and biological motion evident at 5 9 years of age for children born very prematurely appear to be a consequence of slower than normal development rather than a permanent outcome of prematurity. This pattern contrasts with our findings for cataract-reversal patients, in whom the deficits found during childhood appear permanent.
Meeting abstract presented at VSS 2014
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