Corneal Nerve and Brain Imaging in Mild Cognitive Impairment and Dementia.

Abstract

BACKGROUND:

Visual rating of medial temporal lobe atrophy (MTA) is an accepted structural neuroimaging marker of Alzheimer's disease. Corneal confocal microscopy (CCM) is a non-invasive ophthalmic technique that detects neuronal loss in peripheral and central neurodegenerative disorders.

OBJECTIVE:

To determine the diagnostic accuracy of CCM for mild cognitive impairment (MCI) and dementia compared to medial temporal lobe atrophy (MTA) rating on MRI.

METHODS:

Subjects aged 60-85 with no cognitive impairment (NCI), MCI, and dementia based on the ICD-10 criteria were recruited. Subjects underwent cognitive screening, CCM, and MTA rating on MRI.

RESULTS:

182 subjects with NCI (n = 36), MCI (n = 80), and dementia (n = 66), including AD (n = 19, 28.8%), VaD (n = 13, 19.7%), and mixed AD (n = 34, 51.5%) were studied. CCM showed a progressive reduction in corneal nerve fiber density (CNFD, fibers/mm2) (32.0±7.5 versus 24.5±9.6 and 20.8±9.3, p < 0.0001), branch density (CNBD, branches/mm2) (90.9±46.5 versus 59.3±35.7 and 53.9±38.7, p < 0.0001), and fiber length (CNFL, mm/mm2) (22.9±6.1 versus 17.2±6.5 and 15.8±7.4, p < 0.0001) in subjects with MCI and dementia compared to NCI. The area under the ROC curve (95% CI) for the diagnostic accuracy of CNFD, CNBD, CNFL compared to MTA-right and MTA-left for MCI was 78% (67-90%), 82% (72-92%), 86% (77-95%) versus 53% (36-69%) and 40% (25-55%), respectively, and for dementia it was 85% (76-94%), 84% (75-93%), 85% (76-94%) versus 86% (76-96%) and 82% (72-92%), respectively.

CONCLUSION:

The diagnostic accuracy of CCM, a non-invasive ophthalmic biomarker of neurodegeneration, was high and comparable with MTA rating for dementia but was superior to MTA rating for MCI.

• Authors: Eiman Al-Janahi, Georgios Ponirakis, Hanadi Al Hamad, Surjith Vattoth, Ahmed Elsotouhy, Ioannis N Petropoulos, Adnan Khan, Hoda Gad, Mani Chandran, Anoop Sankaranarayanan, Marwan Ramadan, Marwa Elorrabi, Masharig Gadelseed, Rhia Tosino, Priya V Gawhale, Anjum Arasn, Maryam Alobaidi, Shafi Khan, Pravija Manikoth, Yasmin Hamdi, Susan Osman, Navas Nadukkandiyil, Essa AlSulaiti, Noushad Thodi, Hamad Almuhannadi, Ziyad R Mahfoud, Ahmed Own, Ashfaq Shuaib, Rayaz A Malik
• Journal: Journal of Alzheimer's disease : JAD (J Alzheimers Dis) Vol. 77 Issue 4 Pg. 1533-1543 ( 2020) ISSN: 1875-8908 [Electronic] Netherlands
• PMID: 32925064 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Topics

• Aged
• Aged, 80 and over
• Brain (diagnostic imaging)
• Cognitive Dysfunction (diagnostic imaging, psychology)
• Cornea (diagnostic imaging, innervation)
• Dementia (diagnostic imaging, psychology)
• Female
• Humans
• Magnetic Resonance Imaging (methods)
• Male
• Microscopy, Confocal (methods)
• Middle Aged
• Ophthalmic Nerve (diagnostic imaging)