Poly-unsaturated Fatty Acids and Developmental Dyslexia

Overview

Poly-unsaturated fatty acids (PUFAs) represent a component of lipids that covers a relevant role in human diet and biological functions such as provision of energy, functionality of cell membranes and tissue metabolism. Fatty acids carbon chains can be saturated (with no presence of double bonds) or unsaturated (with one or more double bonds). PUFAs fall into the unsaturated group, and they can be divided into two classes: omega-3 (n-3) and omega-6 (n-6) fatty acids (FAs). PUFAs are relevant components of cellular membranes, phospholipids, and precursors of eicosanoids, which influence neuronal development and functioning, docosahexaenoic acid (DHA) and arachidonic acid (AA) in fact are involved in cell growth, neural signaling, and gene expression. The main natural dietary source for Eicosapentaenoic acid (EPA) and DHA is fish oil. It has also been shown how the Magnocellular system, which includes the retinal ganglion cells, the lateral geniculate nucleus (for the visual system, while the medial geniculate nucleus would be involved for the auditory system) of the thalamus, the posterior parietal cortex, various areas visual of the cortex and part of the cerebellum, is sensitive to the contribution of fatty acids through nutrition. A deficit related to the Magnocellular system, specialized in the processing of stimuli with high temporal frequencies and low spatial frequencies, in both the visual and auditory modalities, has been proposed as one of the causes of Developmental Dyslexia (DD). According to this hypothesis, an alteration at the magnocellular level would affect reading by hampering temporal processing of the visual signal and would reduce the quality of the phonological representations due to imperfect acoustic analysis of the incoming phonemes. It is therefore possible to hypothesize that supplementation of PUFA in dyslexic children would improve the functions of the M-system and thus create better conditions to the remediation of reading difficulties, especially through remediation programs specifically tapping visual attention and rapid processing of visual stimuli. The remediation program currently used at Scientific Institute (IRCCS) Medea, "Tachidino", based on tachistoscopic, hemisphere-specific stimulation and on training of selective visual-spatial attention, has exactly these characteristics. Hence, the present study aims to test the efficacy of PUFA supplementation before and during treatment with Tachidino.