1) Background of research
Alzheimer's disease-induced dementia (AD) involves various brain areas that govern sensory and cognitive functions, and displays various clinical patterns, making early diagnosis difficult and often missing the right time to intervene in treatment. In order to delay or prevent symptoms of dementia, it is essential to develop biomarkers to determine the early screening and severity of AD.
Visual stimuli are detected through three types of cones in the eye retina, and their perfusion and interaction take place in the primary, secondary, and oligocentric visual cortical areas of the brain via ophthalmic neve.
Previous studies have shown that various visual dysfunction begins in the early stages of degenerative brain diseases, including Alzheimer's, Parkinson's and multiple sclerosis. Among them, it has been reported that the threshold for yellow and blue recognition is higher, i.e., the sensitivity of color perception is less, which is thought to be the main cause of color recognition by red cone cells in the retina due to defects in the signaling process of green and blue cone cells that are responsible for wavelength recognition shorter than red. Color vision impact in Alzheimer's dementia has been reported since the early 2000s, and more specifically in the late 2000s, studies have been conducted on structural changes in the retina, such as RNFL thinning, and the correling of neurodegenation of visual pathways.
However, this study is meaningful in that it wants to see the correlation between changes in sensitivity to a particular color and the retinal nerve fiber layer (RNFL) thinning, and the severity of dementia symptoms and the structural changes in the visual cortex on the Brain MRI. Systematization of this is expected to predict the progress of dementia and even the findings of Brain MRI before multiple tests are conducted by measuring the sensitivity changes to a particular color.

2) Research hypothesis and purpose
As cognitive degradation progresses in Alzheimer's dementia patients, cones cell degeneration of the retina will be reflected in increasing sensitivity to red. This increase in sensitivity will be correlated with a decrease in RNFL. In addition, the RNFL reduction would be related to the atrophy of the Brain Region (primary, secondary, oligopolical specific areas) associated with the color vision on the Brain MRI.

Cohort/Group Label

cognitive decline group

Cohort/Group Description

As cognitive degradation progresses in Alzheimer's dementia patients, cones cell degeneration of the retina will be reflected in increasing sensitivity to red. This increase in sensitivity will be correlated with a decrease in RNFL. In addition, the RNFL reduction would be related to the atrophy of the Brain Region (primary, secondary, oligopolical specific areas) associated with the color vision on the Brain MRI.
MMSE and CDR score will be used to observe cognitive decline and OCT, Ishihara 24 plate test will be conducted to measure RNFL thinning and color vision changes. We will also use Brain MRI to see the changes in the related Brain region.

Not collect nor Archive

Patients who visit the psychiatry outpatient clinic with chief complaint of cognitive decline

Among the patients who visit the psychiatry outpatient clinic with chief complaint of cognitive decline, a person who is suspected of Alzheimer's dementia and deemed necessary to evaluate MMSE-K and Brain MRI by a psychiatrist will be included. Non-probability sampling is used.

Gender

Age

Description

(1) A person who is suspected of Alzheimer's dementia in the opinion of a psychiatrist among patients who visit the psychiatry outpatient clinic with chief complaint of cognitive decline, and is deemed necessary to evaluate MME-K and Brain MRI.
(2) the age of 65 or older

(1) Major mental disorders, such as bipolar disorder and schizophrenia;
(2) Major degenerative diseases other than Alzheimer's (Parkinson's disease, vascular dementia, frontal lobe dementia, multiple sclerosis, etc.)
(3) Patients with color blindness
(4) A person with a past history of convulsions, head trauma, or substrate brain disease;

Mini-Mental State Exam-Korea (MMSE-K), Clinical Dementia Rating (CDR), Geriatric Depression Scale (GDS), Ishihara 24 plate test

baseline

Optical Coherence Tomography (OCT), Brain MRI

within 6 months of baseline