HISTORICAL TRENDS IN BIOLOGICAL AND MEDICAL INVESTIGATIONS OF READINGDISABILITIES - 1850-1915

The theoretical roots of neuropsychological research lie in the case s tudies of reading disability completed during the late nineteenth and early twentieth centuries. This article reviews the methods, technolog ies, and operating tenets of these studies. The results suggest that t he assumptions of anatomical and functional modularity for cortical pr ocesses became guiding principles for diagnosing and correcting readin g difficulties. The advent of neuron doctrine shifted the focus of neu ropsychological explanations of reading difficulties from gross neuroa natomical studies to investigations of the microstructure of the centr al nervous system. Early definitions of reading disabilities are inter preted across the dimensions of focal lesions, autonomous cognitive pr ocesses, comorbidity with other symptoms and syndromes, etiology, and permanence.