Abstract
Purpose :
Frontotemporal dementia (FTD) represents a significant proportion of the younger-age onset dementias, and is characterised by behavioural and personality changes. Cognitive decline in FTD is variable and unpredictable. The aim of this prospective cohort study was to examine the retinal neural and vascular changes in FTD, and determine if any are predictive of cognitive decline.
Methods :
30 patients with FTD and 40 matched healthy controls were recruited.
All participants were imaged with SD-OCT (Heidelberg Spectralis). Measurements included retinal nerve fibre layer (RNFL) thickness, macular ganglion cell layer volume (GCLV), subfoveal choroidal thickness (sfCT), along with retinal vessel calibre, tortuosity and fractal dimension utilising the VAMPIRE retinal vasculature analysis platform.
Cognition was measured at baseline and 6 months, using Addenbrooke’s Cognitive Examination (ACE-III) test.
Results :
FTD was associated with significantly reduced GCLV (MD=-0.11, 95% CI[-0.14, -0.07],p<0.001). RNFL thickness was not reduced in FTD when comparing means, but showed wider dispersion of values, suggesting further stratification of the FTD group may yield phenotypic subtyping. sfCT was also significantly reduced in FTD (MD=-80.1, 95% CI[-118.4, -41.7],p<0.001).
Retinal vasculature morphometry analysis revealed a reduced fractal dimension in FTD, for both arteriolar and venular trees, but no difference in vessel calibre or tortuosity.
There was no significant correlation between any retinal parameter and baseline cognitive score. However, a clear relationship emerged between RNFL thickness and cognitive change over the following six months. A regression scatterplot (Fig. 1) shows a moderate R-squared response of 48.1%. Transformation of the ACE-III data from a continuous variable to a categorical grouping (Fig. 2) demonstrates a significant difference in mean gRNFL between the groups (p<0.001), supporting this as a predictor of cognitive decline.
Conclusions :
This study shows that FTD does demonstrate some phenotypic patterns of neural and vascular change, and also supports the hypothesis that baseline RNFL thickness measurement predicts cognitive decline in FTD, with patients with thinner RNFL more likely to show moderate decline on ACE-III scoring after six months.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.