Pulsed lighting for adults with Dyslexia: very limited impact, confined to individuals with severe reading deficits

The goal of this study is to evaluate the impact of pulsed lighting on the reading performance of young adults with dyslexia. A total of 42 participants were recruited, including individuals diagnosed with developmental dyslexia and adults without reported reading difficulties. The severity of each participant's reading deficit was assessed on a continuous scale using a reading impairment score, derived from four reading tests: an isolated-word reading test, a pseudoword reading test, and two reading fluency tests. The impairment score ranged from 0 (no impairment) to 4 (severe impairment across all tests). To examine the potential effect of pulsed lighting, we measured (1) sentence reading speed, expressed as a reading accessibility index (ACC), and (2) text comprehension, expressed as a comprehension score. These measures were taken under three lighting conditions: standard lighting, pulsed lighting, and a combination of the two. Linear mixed-effects models were applied to assess the effects of lighting on ACC and comprehension, controlling for the reading impairment score. We found no effect of lighting conditions on either ACC or comprehension, except in the most impaired readers, who showed a small but significant increase of 7% in ACC. However, even with pulsed lighting, impaired readers did not reach the performance level of skilled adult readers. In conclusion, the study did not demonstrate a clear positive impact of pulsed lighting on the reading skills of adults with dyslexia.