Dr. Linda Siegel produced important research which helped her to illustrate that cognitive testing was not relevant to the diagnosis of dyslexia. She led the way to revisiting this finding when she edited a journal for the IDA asking for researchers to weigh in on IDA's definition of dyslexia. She's also well known for her books: Not Lazy, Not Stupid & Understanding Dyslexia and Other Learning Disabilities.

Here's a journal article she wrote: https://journals.sagepub.com/doi/abs/10.1177/002221948902200803