Developmental Dyslexia and the Stress of Reading: A Social Stress Study of Neuroendocrine Response in Children

Dyslexia is a neurodevelopmental disorder characterized by persistently slow and effortful reading. It is associated with core cognitive deficits in decoding words, but it also presents significant challenges associated with, for example, anxiety and stress related to academic performance. We asked, thus, whether, reading out loud would be associated with elevated stress for readers with dyslexia, relative to good readers, and we investigated stress-related hormone response in these two groups. We carried out an acute psychosocial stress test (Trier Social Stress Test-Children adapted for children, TSST-C), which included a reading out loud task. We carried out a quasi-experimental study with an experimental group of participants with Developmental Dyslexia (n = 17), and a control group, with good readers (n = 18). During the stress test, we collected six saliva samples for evaluation of two stress-related hormones, cortisol, and adrenocorticotropic hormone (ACTH) levels. We found a main effect for group for ACTH and for cortisol levels. We also found significantly higher levels of ACTH in the dyslexic group at the end of the task, and during the post-task recovery period. Results are discussed in the light of the less-understood emotional impact of dyslexia, and of a recently proposed role for stress as a trigger for increased risk of development of dyslexia. Lastly, we underscore the contribution for the evidence of the emotional impact of learning disorders, especially, as is the case, from a population generally underrepresented in cognitive neuroscience research (i.e., Latin-American children).