Links Between Eye Measurements and Brain Function in People with Multiple Sclerosis Point to Possible Biomarker for Cognitive Performance
A recent study led by BNAC Clinical Research Unit Director Dejan Jakimovski MD, Ph.D., investigated the relationship between optical coherence tomography (OCT) measurements of the eye and cognitive performance in individuals with multiple sclerosis (MS). The findings suggest that retinal nerve fiber thickness could serve as a potential biomarker for cognitive impairment in people with MS, possibly predicting future cognitive decline.
OCT is a non-invasive technique that uses infrared light waves to take cross-sectional images of the retina. The study, which entailed a systematic review and in-depth meta-analysis of existing research, found that reduced retinal nerve fiber layer (RNFL) thickness was significantly associated with cognitive abilities in multiple domains such as processing speed, memory, and verbal fluency in people with MS.
The RNFL is a thin layer of nerve fibers in the retina, which is the light-sensitive tissue at the back of the eye. These nerve fibers originate from the cells in the innermost layer of the retina called ganglion cells.
A common manifestation of MS is cognitive impairment, or a decline in memory, attention, processing speed, and other cognitive functions. Identifying reliable biomarkers to assess current or even future cognitive performance in people with MS is essential for effective diagnosis and management of the condition.
OCT has emerged as a potential tool for evaluating neurodegeneration in MS. Dr. Jakimovski and his team conducted a comprehensive analysis of relevant studies on OCT measurements as well as studies of cognitive performance in people with MS. They applied strict inclusion criteria and followed established guidelines for systematic reviews and meta-analyses. They performed a meta-analysis to examine the overall association between RNFL thickness measured by OCT and various widely-accepted cognitive tests used in MS disease management and research, such as Symbol Digit Modalities Test (SDMT).
This analysis builds upon the continued BNAC research regarding OCT utility and relevance in the care of people with MS. Related studies* conducted by the BNAC team explore various aspects of OCT imaging and its correlation with MS progression and associated visual and cognitive impairments.
Together, these studies show that OCT can help us understand how MS affects the body. It helps us see the effects of inflammation of the optic nerve and changes in blood vessels in the eyes. These changes are linked to thinning of certain parts of the brain's outer layer, which can lead to problems with thinking and memory. The studies also suggest that these changes in the eyes can give us clues about how MS may progress and cause disability over time.
This latest study highlights the utility of OCT measurements of the eye to assess cognitive function in individuals with MS. OCT offers several advantages over alternative methods, such as magnetic resonance imaging (MRI), including shorter scanning time, reduced costs, and compatibility with patients who cannot undergo MRI scans. Using OCT as a routine screening tool could help healthcare professionals monitor cognitive impairment in MS patients more conveniently and efficiently.
*Read the related OCT manuscripts here:
Multiple sclerosis optic neuritis and trans-synaptic pathology on cortical thinning in people with multiple sclerosis - PubMed (nih.gov)
