Dyslexia studies
- 13
- Feb
Benefit of Docosahexaenoic acid supplements to dark adaptation in dyslexics
SIR-Makrides and colleagues (June 10, p 1463) provide strong evidence that docosahexaenoic acid (DHA) is an essential nutrient for the optimum neural maturation of term infants as assessed by visual evoked potential acuity. I have data indicating that DHA supplementation in adult dyslexics improves dark adaptation (scotopic vision) and thus DHA may also be a dietary essential for this condition.
We measured dark adaptation with a Friedmann Visual Field Analyser 2, set for the dark adaptation function, in ten adults with dyslexia and ten controls. Dyslexics showed poorer dark adaptation than controls, especially in the second part of the curve, which corresponds with rod dark adaptation (figure, a; repeated measures Anova p<0.05). We subsequently tested the possibility that dark adaptation might be influenced by DHA. For 1 month five dyslexics and five controls were given 480 mg of DHA daily with no additional vitamin A or vitamin D. Dark adaptation was then retested (figure, b and c). In four controls DHA had no effect on dark adaptation, although in one (a strict vegetarian) adaptation clearly improved. By contrast, in the dyslexics with poor scotopic vision DHA consistently and significantly improved dark adaptation (figure, b; paired t-test on final rod threshold, p< 0.04).
It has long been recognised that dyslexics have both retinal and central processing defects,1,2 but defective dark adaptation has to my knowledge not previously been reported. DHA is a key fatty acid in both retina and brain and is usually present in large quantities in these tissues. In these studies I show the benefit of DHA supplementation for one aspect of retinal function. I have found that DHA supplements given to dyslexics can also be associated with improvements in reading ability and behaviour. These reports are anecdotal and subjective but more formal controlled studies are in preparation.
I thank Ms. Katrina Searle, Mr. Liam Trow, and Ms. Katy Wood for technical assistance.
The author has a patent on the use of DHA for dark adaptation.
B Jacqueline Stordy
School of Biological Sciences, University of Surrey, Guildford GU2 5XH, UK
- Grosser GS, Spafford CS. Light sensitivity in peripheral retinal fields of dyslexic and proficient readers. Perceptual Motor Skills 1990; 71: 467-77.
- Galaburda A. Livingstone M. Evidence for a magnocellular defect in developmental dyslexia. Ann NY Acad Sci 1993; 682: 71-81.
Benefit of Docosahexaenoic acid supplements to dark adaptation in dyslexics
SIR-Makrides and colleagues (June 10, p 1463) provide strong evidence that docosahexaenoic acid (DHA) is an essential nutrient for the optimum neural maturation of term infants as assessed by visual evoked potential acuity. I have data indicating that DHA supplementation in adult dyslexics improves dark adaptation (scotopic vision) and thus DHA may also be a dietary essential for this condition.
We measured dark adaptation with a Friedmann Visual Field Analyser 2, set for the dark adaptation function, in ten adults with dyslexia and ten controls. Dyslexics showed poorer dark adaptation than controls, especially in the second part of the curve, which corresponds with rod dark adaptation (figure, a; repeated measures Anova p<0.05). We subsequently tested the possibility that dark adaptation might be influenced by DHA. For 1 month five dyslexics and five controls were given 480 mg of DHA daily with no additional vitamin A or vitamin D. Dark adaptation was then retested (figure, b and c). In four controls DHA had no effect on dark adaptation, although in one (a strict vegetarian) adaptation clearly improved. By contrast, in the dyslexics with poor scotopic vision DHA consistently and significantly improved dark adaptation (figure, b; paired t-test on final rod threshold, p< 0.04).
It has long been recognised that dyslexics have both retinal and central processing defects,1,2 but defective dark adaptation has to my knowledge not previously been reported. DHA is a key fatty acid in both retina and brain and is usually present in large quantities in these tissues. In these studies I show the benefit of DHA supplementation for one aspect of retinal function. I have found that DHA supplements given to dyslexics can also be associated with improvements in reading ability and behaviour. These reports are anecdotal and subjective but more formal controlled studies are in preparation.
I thank Ms. Katrina Searle, Mr. Liam Trow, and Ms. Katy Wood for technical assistance.
The author has a patent on the use of DHA for dark adaptation.
B Jacqueline Stordy
- Grosser GS, Spafford CS. Light sensitivity in peripheral retinal fields of dyslexic and proficient readers. Perceptual Motor Skills 1990; 71: 467-77.
- Galaburda A. Livingstone M. Evidence for a magnocellular defect in developmental dyslexia. Ann NY Acad Sci 1993; 682: 71-81.
Note: Signal369 contains DHA
