Retinal thickness as potential biomarker in posterior cortical atrophy and typical Alzheimer’s disease

Table 1 Demographic characteristics and proposed and established biomarker data for PCA, tAD and control groups

Demographics		Posterior cortical atrophy	Typical Alzheimer’s disease	Controls	p value
Number		25	23	70
Sex (m/f)		11/14	14/9	29/41	0.26^a
Age		67.0 (±7.1)	64.5 (±6.8)	66.3 (±7.7)	0.47^b
MMSE		22.1 (±5.4)	19.8 (±5.6)	29.5 (±0.8)	< 0.001 ^c
Biomarkers		Posterior cortical atrophy	Typical Alzheimer’s disease	Controls	Linear regression models^c
					PCA		tAD
					Beta	p value	Beta	p value
OCT¹	Mean peripapillary retinal nerve fibre layer thickness (pRNFL) (μm)	98.8 (±12.2)	99.9 (±8.7)	99.6 (±10.0)	− 0.02	0.80	− 0.01	0.89
OCT¹	Mean macular retinal thickness (mRT) (μm)	266.9 (±16.3)	267.8 (±13.6)	269.3 (±13.6)	− 0.07	0.50	− 0.09	0.38
MRI subset²	AD Signature Thickness (mm)	2.5 (±0.2)	2.5 (±0.2)	2.8 (±0.1)	− 0.73	< 0.001	− 0.60	< 0.001
	Hippocampus volume (mm³)	6631.4 (±713.9)	6411.6 (±1072.1)	7847.8 (±873.5)	− 0.44	< 0.001	−0.61	< 0.001
	PCA signature thickness (mm)	1.7 (±0.2)	1.9 (±0.1)	2.1 (±0.1)	− 0.78	< 0.001	− 0.35	< 0.001
	Estimated intracranial volume (*10⁶ mm³)	1.5 (±0.1)	1.5 (±0.2)	1.5 (±0.2)	−0.14	0.21	−0.15	0.17
CSF subset³	Aβ_-1-42 (ng/L)	395.9 (±140.1)	300.1 (±133.2)	900.9 (±221.9)	− 0.70	< 0.001	− 0.90	< 0.001
	Tau₋₁₈₁ (ng/L)	573.4 (±306.4)	778.2 (±359.1)	265.1 (±119.2)	0.32	0.07	0.65	< 0.001
	Tau₋₁₈₁/Aβ_1–42 ratio	1.6 (±1.0)	3.1 (±1.8)	0.3 (±0.1)	0.22	0.18	0.68	< 0.001

Overall cohort characteristics, and proposed OCT and established biomarkers (MRI, CSF) for posterior cortical atrophy (PCA), typical Alzheimer’s disease (tAD) and control groups including between-group comparisons. MRI and CSF data were available in subset cohorts
¹OCT-imaging was available in 25 PCA cases, 23 tAD cases and 70 controls for pRNFL peripapillary ring scans and in 23 PCA cases, 22 tAD cases and 66 controls for macular scans. ²MRI was available in 18 PCA cases, 17 tAD cases and 31 controls. ³CSF was available in 14 PCA cases, 18 tAD cases and 12 controls
^aChi-square test, ^bone-way ANOVA, ^cLinear regression models assessing relationships between biomarkers (dependent) and diagnosis (independent) with controls as reference group, corrected for age, sex (and estimated intracranial volume (eTIV) for hippocampal volume). Reported betas are standardized betas. Significant results are indicated in italics.