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National Institute of Health Identifies Predictive Indicators of Cognitive Decline in Parkinson's Disease Patients
Over 133,400 Patients in Korea... Early Detection and Management Are Key

A significant number of Parkinson's disease patients exhibit changes in olfactory function, such as a reduced ability to smell. Changes in the ability to distinguish or detect odors alone can serve as an indicator of cognitive decline. Since the test itself is non-invasive and simple, it is expected to play a major role in the early diagnosis of Parkinson's disease and prediction of cognitive decline in the future.

A study has shown that changes in the ability to distinguish or detect odors alone can indicate cognitive decline. Getty Images

On November 9, the Korea Disease Control and Prevention Agency (KDCA) National Institute of Health produced and distributed a card news series titled "Understanding Parkinson's Disease" to raise public awareness. The series provides information on the main symptoms of Parkinson's disease, treatment methods such as movement therapy, and self-diagnosis methods through the "Dr. Parkinson App" on its website. The Dr. Parkinson App is a customized health management application designed to help patients and their families easily record and manage changes in symptoms. It supports disease management by tracking exercise, medication, lifestyle habits, and early diagnosis.

Parkinson's disease is a chronic neurodegenerative disorder caused by the gradual loss of dopamine-producing nerve cells in the midbrain. Among those over 60, it is the second most common neurodegenerative disease after dementia. The most decisive change at onset is slowed movement and behavior. In addition to various motor symptoms such as tremors in the hands and feet, muscle rigidity, and gait disturbances, non-motor symptoms also occur, including decreased olfactory function, sleep disorders, autonomic nervous system abnormalities, and cognitive decline. Symptoms typically begin in one limb but eventually affect the opposite side as the disease progresses.

After diagnosis, it is common to start drug treatments such as levodopa, dopamine agonists, and MAO-B inhibitors. However, there is currently no treatment that can definitively stop or slow the progression of the disease. For patients who develop motor complications after long-term medication use, surgical treatments such as lesioning procedures and deep brain stimulation may be performed in addition to drug therapy, or movement therapy may be combined. The goal of these treatments is to alleviate symptoms and improve quality of life.

The number of Parkinson's disease patients in Korea increased by about 13.9%, from approximately 125,900 in 2020 to about 133,400 last year, and the number is expected to continue rising as the population ages. Accordingly, ongoing research is needed for early diagnosis, prevention, prognosis prediction, and the development of treatment technologies for Parkinson's disease.

Since 2021, the National Institute of Health has established a cohort of Parkinson's disease patients through the "BRIDGE" project (Brain Disease Research Infrastructure Establishment Project) and has been conducting long-term follow-up studies to develop technologies related to diagnosis, prevention, and prognosis prediction.

Recent studies have confirmed that changes in olfactory function can serve as a key indicator for predicting the rate of cognitive decline in Parkinson's disease patients. In a study that followed 203 early-stage Parkinson's patients for about five years, dividing them into three groups based on changes in olfactory function (normal, conversion to decreased function, persistent decrease), approximately 86% experienced a decline in olfactory function during the follow-up period. Notably, the group whose olfactory function shifted from normal to decreased showed a faster rate of cognitive decline than the other groups. This finding is expected to be highly useful for early identification of patients at high risk for cognitive impairment, such as dementia, and for establishing personalized treatment plans.

Im Seungkwan, Commissioner of the KDCA, stated, "For Parkinson's disease, early diagnosis and systematic management are of utmost importance," adding, "We will do our best to ensure that cohort and interventional studies on Parkinson's disease lead to research outcomes that patients and their families can truly experience, including identifying the causes of the disease and developing precision diagnostic technologies."