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. 2022 Apr 5;8(1):e12269.
doi: 10.1002/trc2.12269. eCollection 2022.

Loss of corneal nerves and brain volume in mild cognitive impairment and dementia

Georgios Ponirakis  1 , Hanadi Al Hamad  2 , Adnan Khan  1 , Ioannis N Petropoulos  1 , Hoda Gad  1 , Mani Chandran  2 , Ahmed Elsotouhy  1   3 , Marwan Ramadan  2 , Priya V Gawhale  2 , Marwa Elorrabi  2 , Masharig Gadelseed  2 , Rhia Tosino  2 , Anjum Arasn  2 , Pravija Manikoth  2 , Yasmin H M Abdelrahim  2 , Mahmoud A Refaee  2 , Noushad Thodi  4 , Surjith Vattoth  5 , Hamad Almuhannadi  1 , Ziyad R Mahfoud  1 , Harun Bhat  1 , Ahmed Own  3 , Ashfaq Shuaib  6 , Rayaz A Malik  1   7   8
Affiliations

Loss of corneal nerves and brain volume in mild cognitive impairment and dementia

Georgios Ponirakis et al. Alzheimers Dement (N Y). .

Abstract

Introduction: This study compared the capability of corneal confocal microscopy (CCM) with magnetic resonance imaging (MRI) brain volumetry for the diagnosis of mild cognitive impairment (MCI) and dementia.

Methods: In this cross-sectional study, participants with no cognitive impairment (NCI), MCI, and dementia underwent assessment of Montreal Cognitive Assessment (MoCA), MRI brain volumetry, and CCM.

Results: Two hundred eight participants with NCI (n = 42), MCI (n = 98), and dementia (n = 68) of comparable age and gender were studied. For MCI, the area under the curve (AUC) of CCM (76% to 81%), was higher than brain volumetry (52% to 70%). For dementia, the AUC of CCM (77% to 85%), was comparable to brain volumetry (69% to 93%). Corneal nerve fiber density, length, branch density, whole brain, hippocampus, cortical gray matter, thalamus, amygdala, and ventricle volumes were associated with cognitive impairment after adjustment for confounders (All P's < .01).

Discussion: The diagnostic capability of CCM compared to brain volumetry is higher for identifying MCI and comparable for dementia, and abnormalities in both modalities are associated with cognitive impairment.

Keywords: brain volumetry; corneal confocal microscopy; dementia; mild cognitive impairment; neurodegeneration.

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Conflict of interest statement

The authors confirm that the manuscript has been read and approved by all named authors and that there are no other persons who satisfied the criteria for authorship and are not listed. They also confirm that the order of authors listed in the manuscript has been approved by all authors. Dr. Surjith Vattoth has Elsevier book author royalty, received consulting fee as an Elsevier master author consultant in head and neck imaging, and received payment for ESNR ‐ ECHNR course faculty. None of the other authors have received or anticipate receiving income, goods, or benefit from a company that will influence the design, conduct, or reporting of the study.

Figures

FIGURE 1
FIGURE 1
Corneal nerve fiber morphology in a subject with no cognitive impairment, mild cognitive impairment (MCI), and dementia. Corneal confocal microscopy (CCM) images of the sub‐basal nerve plexus from a subject with (A) no cognitive impairment, (B) MCI, and (C) dementia showing decreased corneal nerve fiber density, length, and branch density in subjects with MCI and dementia compared to subjects with no cognitive impairment
FIGURE 2
FIGURE 2
The diagnostic accuracy of corneal nerve fiber length, Montreal Cognitive Assessment (MoCA), hippocampus, and whole brain intracranial volume percentage for MCI and dementia. Receiver‐operating characteristic (ROC) curve analysis showing the area under the curve for corneal nerve fiber length, MoCA, hippocampus, and whole brain intracranial volume percentage
See this image and copyright information in PMC

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