Purchase this article with an account.
Teri Lawton; Training direction discrimination rapidly remediates a wide spectrum of reading deficits. Journal of Vision 2007;7(9):521. doi: https://doi.org/10.1167/7.9.521.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
This study examined the effects of training in direction discrimination on reading performance in 7-year-old students to assess whether dyslexics are deficient in motion processing. A literacy skills test battery was administered to each participant before and after training to divide participants into groups of efficient and inefficient readers. Each of these groups was randomly split into three subgroups. Subgroup 1 (control) received no special training beyond school's reading program; subgroup 2 (control) received training in a word game; Subgroup 3 (treatment) received training in direction discrimination by judging the direction of motion (left vs. right) of vertically oriented sinusoidal gratings of varying spatial frequency. Efficient readers were initially 3–5 fold more sensitive in direction discrimination and read twice as fast as dyslexics. The direction discrimination contrast threshold was measured using a staircase procedure. Over the course of training (biweekly 10 minute sessions for 15 weeks), contrast sensitivity increased an average of 5–14 fold (depending on background structure) for dyslexics and 7 fold for efficient readers. For dyslexics, direction discrimination training improved most reading skills 1–3 grade levels, increasing reading fluency 2–4 fold, whereas dyslexic children in the control groups barely improved. Training on motion discrimination also improved a child's reading comprehension, spelling, and pronunciation. The more training, the more reading skills improved. This study suggests that the core deficiency of many poor readers is an impaired ability to discriminate the direction of motion, which may be caused by spatial and temporal sequencing problems resulting from magnocellular neural timing deficits. Sluggish magnocellular neurons would make it difficult to attend in direction discrimination tasks, since the magnocellular neurons would not signal in advance of the linked parvocellular neurons. This would cause a deficit in attentional focus, preventing the linked parvocellular neurons from isolating and sequentially processing the relevant information.
This PDF is available to Subscribers Only