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Retinal vascular fractal dimension, childhood IQ, and cognitive ability in old age: the Lothian Birth Cohort Study 1936.

Taylor AM, MacGillivray TJ, Henderson RD, Ilzina L, Dhillon B, Starr JM, Deary IJ - PLoS ONE (2015)

Bottom Line: Cerebral microvascular disease is associated with dementia.Only three out of 24 comparisons (two eyes × four Df parameters × three cognitive measures) were found to be significant.No single association was verified by an equivalent association in the contralateral eye.

View Article: PubMed Central - PubMed

Affiliation: Department of Psychology, University of Edinburgh, Edinburgh, United Kingdom.

ABSTRACT

Purpose: Cerebral microvascular disease is associated with dementia. Differences in the topography of the retinal vascular network may be a marker for cerebrovascular disease. The association between cerebral microvascular state and non-pathological cognitive ageing is less clear, particularly because studies are rarely able to adjust for pre-morbid cognitive ability level. We measured retinal vascular fractal dimension (Df) as a potential marker of cerebral microvascular disease. We examined the extent to which it contributes to differences in non-pathological cognitive ability in old age, after adjusting for childhood mental ability.

Methods: Participants from the Lothian Birth Cohort 1936 Study (LBC1936) had cognitive ability assessments and retinal photographs taken of both eyes aged around 73 years (n = 648). IQ scores were available from childhood. Retinal vascular Df was calculated with monofractal and multifractal analysis, performed on custom-written software. Multiple regression models were applied to determine associations between retinal vascular Df and general cognitive ability (g), processing speed, and memory.

Results: Only three out of 24 comparisons (two eyes × four Df parameters × three cognitive measures) were found to be significant. This is little more than would be expected by chance. No single association was verified by an equivalent association in the contralateral eye.

Conclusions: The results show little evidence that fractal measures of retinal vascular differences are associated with non-pathological cognitive ageing.

No MeSH data available.


Related in: MedlinePlus

Colour retinal image acquired by fundus photography and retinal blood vessels segmented by computerized procedure.
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pone.0121119.g002: Colour retinal image acquired by fundus photography and retinal blood vessels segmented by computerized procedure.

Mentions: Retinal images from both eyes were captured with a nonmydriatic camera at 45o FOV (CRDGi; Canon USA Inc., Lake Success, NY) and stored with 8 bits per colour plane, at 2048 × 3072 pixels and in TIFF format. Images were down-sampled to 685 x 584 pixels prior to processing and analysed by an expert retinal image analyst (TM) using custom software built in MATLAB (The MathWorks, Natwick, MA) [49]. Automatic segmentation of the retinal microvascular network (arterioles and venules) was performed using an algorithm described previously [50] which classifies each pixel of a fundus image as vessel or non-vessel to produce a segmented map of the retinal vasculature (see Fig. 2). Prior to fractal analysis computationally segmented images were inspected and obvious artefacts, such as areas of low contrast noise or “ring” artefacts caused by dust on the camera, were corrected or removed. Fractal analysis may be more sensitive to changes in vascular patterns when skeletons rather than images containing vessel width information are considered [51]. Therefore all images were skeletonised by iterative deletion of pixels [52]. Finally, monofractal and multifractal analysis was applied.


Retinal vascular fractal dimension, childhood IQ, and cognitive ability in old age: the Lothian Birth Cohort Study 1936.

Taylor AM, MacGillivray TJ, Henderson RD, Ilzina L, Dhillon B, Starr JM, Deary IJ - PLoS ONE (2015)

Colour retinal image acquired by fundus photography and retinal blood vessels segmented by computerized procedure.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4376388&req=5

pone.0121119.g002: Colour retinal image acquired by fundus photography and retinal blood vessels segmented by computerized procedure.
Mentions: Retinal images from both eyes were captured with a nonmydriatic camera at 45o FOV (CRDGi; Canon USA Inc., Lake Success, NY) and stored with 8 bits per colour plane, at 2048 × 3072 pixels and in TIFF format. Images were down-sampled to 685 x 584 pixels prior to processing and analysed by an expert retinal image analyst (TM) using custom software built in MATLAB (The MathWorks, Natwick, MA) [49]. Automatic segmentation of the retinal microvascular network (arterioles and venules) was performed using an algorithm described previously [50] which classifies each pixel of a fundus image as vessel or non-vessel to produce a segmented map of the retinal vasculature (see Fig. 2). Prior to fractal analysis computationally segmented images were inspected and obvious artefacts, such as areas of low contrast noise or “ring” artefacts caused by dust on the camera, were corrected or removed. Fractal analysis may be more sensitive to changes in vascular patterns when skeletons rather than images containing vessel width information are considered [51]. Therefore all images were skeletonised by iterative deletion of pixels [52]. Finally, monofractal and multifractal analysis was applied.

Bottom Line: Cerebral microvascular disease is associated with dementia.Only three out of 24 comparisons (two eyes × four Df parameters × three cognitive measures) were found to be significant.No single association was verified by an equivalent association in the contralateral eye.

View Article: PubMed Central - PubMed

Affiliation: Department of Psychology, University of Edinburgh, Edinburgh, United Kingdom.

ABSTRACT

Purpose: Cerebral microvascular disease is associated with dementia. Differences in the topography of the retinal vascular network may be a marker for cerebrovascular disease. The association between cerebral microvascular state and non-pathological cognitive ageing is less clear, particularly because studies are rarely able to adjust for pre-morbid cognitive ability level. We measured retinal vascular fractal dimension (Df) as a potential marker of cerebral microvascular disease. We examined the extent to which it contributes to differences in non-pathological cognitive ability in old age, after adjusting for childhood mental ability.

Methods: Participants from the Lothian Birth Cohort 1936 Study (LBC1936) had cognitive ability assessments and retinal photographs taken of both eyes aged around 73 years (n = 648). IQ scores were available from childhood. Retinal vascular Df was calculated with monofractal and multifractal analysis, performed on custom-written software. Multiple regression models were applied to determine associations between retinal vascular Df and general cognitive ability (g), processing speed, and memory.

Results: Only three out of 24 comparisons (two eyes × four Df parameters × three cognitive measures) were found to be significant. This is little more than would be expected by chance. No single association was verified by an equivalent association in the contralateral eye.

Conclusions: The results show little evidence that fractal measures of retinal vascular differences are associated with non-pathological cognitive ageing.

No MeSH data available.


Related in: MedlinePlus