Macular Ganglion Cell -Inner Plexiform Layer Thickness Is Associated with Clinical Progression in Mild Cognitive Impairment and Alzheimers Disease

Abstract

PurposeWe investigated the association of the macular ganglion cell-inner plexiform layer (GCIPL) and peripapillary retinal nerve fiber layer (RNFL) thicknesses with disease progression in mild cognitive impairment (MCI) and Alzheimer’s disease (AD).MethodsWe recruited 42 patients with AD, 26 with MCI, and 66 normal elderly controls. The thicknesses of the RNFL and GCIPL were measured via spectral-domain optic coherent tomography in all participants at baseline. The patients with MCI or AD underwent clinical and neuropsychological tests at baseline and once every year thereafter for 2 years.ResultsThe Clinical Dementia Rating scale-Sum of Boxes (CDR-SB) score exhibited significant negative relationships with the average GCIPL thickness (β = -0.15, p < 0.05) and the GCIPL thickness in the superotemporal, superonasal, and inferonasal sectors. The composite memory score exhibited significant positive associations with the average GCIPL thickness and the GCIPL thickness in the superotemporal, inferonasal, and inferotemporal sectors. The temporal RNFL thickness, the average and minimum GCIPL thicknesses, and the GCIPL thickness in the inferonasal, inferior, and inferotemporal sectors at baseline were significantly reduced in MCI patients who were converted to AD compared to stable MCI patients. The change of CDR-SB from baseline to 2 years exhibited significant negative associations with the average (β = -0.150, p = 0.006) and minimum GCIPL thicknesses as well as GCIPL thickness in the superotemporal, superior, superonasal, and inferonasal sectors at baseline.ConclusionsOur data suggest that macular GCIPL thickness represents a promising biomarker for monitoring the progression of MCI and AD.

Correlation between cognitive impairment and retinal neural loss assessed by swept‐source optical coherence tomography in patients with mild cognitive impairment

“…Although no correlation was found between OCT parameters and Pfeffer scores, both MMSE and MoCA scores yielded significant correlations with OCT measurements (both GC-IPL and GCC divided into nine ETDRS sectors), suggesting that these parameters do reflect the severity of cognitive impairment in patients with MCI. In support of our findings, Choi et al [26] found a significant correlation between FD-OCT-measured GC-IPL and cognitive deficit in patients with MCI.…”

“…Using spectral-domain-OCT, other authors have found reductions in full macular thickness in patients with MCI [30,46], but we believe the segmented inner retinal layers provide more reliable measurements. Both clinical and histopathologic studies have documented a preference for GCL impairment in AD [26,32,47,48]. Thus, segmented inner retinal layer analysis is likely to reveal similar impairment patterns in MCI and AD.…”

“…If MCI represents an early stage of AD, then one would expect AD-related optic disc and retinal changes on OCT to be present in patients with MCI to a lesser extent, but the literature is inconsistent on this point. Many authors have found pRNFL thickness to be reduced in MCI [12,13,21,26,29], whereas other groups have reported macular thinning in patients with MCI mostly based on full macular thickness measurements [12,13,17,21,[29][30][31]. Some authors have demonstrated thinning of the GC-IPL in patients with MCI [26,27,32], whereas others have failed to detect any significant difference in pRNFL, full macular, and GC-IPL thickness parameters [33,34].…”

Retinal oxygen metabolism in patients with mild cognitive impairment

“…RNFL in AD and in MCI [5][6][7][8][9]11,12,[24][25][26]. Increased venular oxygen saturation and decreased arteriovenous difference could indicate less metabolic activity in the tissue, which could be due to thinner RNFL.…”

The role of optical coherence tomography in Alzheimer’s disease

“…In nine studies TD-OCT was used and in the other fourteen, the patients were evaluated by SD-OCT. Seven studies included MCI [25, 28, 34, 35, 40–42] patients and others nine evaluated macular parameters [24–26, 31, 35, 40, 43–45]. Table 1 summarizes the demographic data and RNFL thickness measurements in Alzheimer’s disease, MCI and controls by OCT.…”