Definition and Overview
Dementia is a clinical syndrome in which the normally mature brain is damaged due to acquired causes, resulting in deterioration of various cognitive areas such as memory, language, visuospatial ability, judgment, and executive function, making independent daily life and social activities difficult. In recent diagnostic systems, it is classified as a major neurocognitive disorder.
Dementia is not a single disease, but a common result of several diseases. Therefore, the core of diagnosis consists of two steps: confirming the presence of cognitive decline and identifying the cause of the disease.
In ICD-10, dementia itself is classified as F03 (dementia of unspecified condition), and dementia caused by Alzheimer's disease is classified into G30 and F00 series.
Main cause disease
Alzheimer's disease
Alzheimer's disease is the most common cause, accounting for 60-70% of all dementia cases. Nerve cells are lost due to abnormal accumulation of amyloid beta and tau proteins, and recent memory slowly begins to deteriorate.
vascular dementia
Vascular dementia is caused by damage to brain tissue due to stroke or chronic cerebrovascular disease and is the second most common cause. It is characterized by progressive worsening and focal neurological signs.
Lewy body dementia
Dementia with Lewy bodies is caused by deposition of alpha-synuclein protein and is accompanied by cognitive fluctuations, visual hallucinations, Parkinson's symptoms, and REM sleep behavior disorder.
frontotemporal dementia
Frontotemporal dementia occurs at a relatively young age, and personality changes, behavioral abnormalities, and language disorders appear before memory.
Other causes include Parkinson's disease dementia, alcoholic dementia, normal pressure hydrocephalus, hypothyroidism, and vitamin B12 deficiency. In fact, mixed dementia, in which both Alzheimer's pathology and vascular pathology exist together, is common in elderly patients.
progress stage
Dementia generally progresses through the following stages:
- Mild: Deterioration of recent memory, mild disruption of occupational and social activities. Independent living is generally possible.
- Moderate: Help is needed to perform daily activities, navigation difficulties, speech and judgment decline, and behavioral changes become evident.
- Severe: Full assistance is required for all aspects of daily life, communication is difficult, and basic functions such as walking and swallowing are impaired.
The speed of progression varies depending on the causative disease and individual, and even for the same Alzheimer's disease, there is a large difference in the course of the disease.
diagnosis
Diagnosis aims to objectively confirm and identify the cause of cognitive decline.
- History taking: Confirmation of onset time, progression pattern, and accompanying symptoms through guardian
- Neuropsychological test: Evaluation of cognitive areas such as memory, language, visuospatial, and executive function
- Brain imaging: MRI confirms atrophy, vascular lesions, normal pressure hydrocephalus, etc.
- Blood test: exclude correctable causes such as thyroid function, vitamin B12, electrolytes, etc.
- Biomarker: Amyloid PET, cerebrospinal fluid amyloid and tau test to confirm Alzheimer's pathology
If you accurately identify the cause early, you can avoid missing out on correctable dementia and develop an appropriate drug and non-drug treatment plan.
treatment
medication
In Alzheimer's disease and some dementias, cholinesterase inhibitors (donepezil, rivastigmine, galantamine) and NMDA receptor antagonists (memantine) are used to relieve cognitive symptoms. Recently, anti-amyloid antibodies (such as lecanemab), which directly remove amyloid, were introduced to suppress the progression of early Alzheimer's disease.
Non-drug treatment
Cognitive stimulation training, regular exercise, social activities, and lifestyle management contribute to maintaining cognitive function. For behavioral and psychological symptoms, environmental adjustments and non-pharmacological approaches are given priority.
Risk Factor Management
High blood pressure, diabetes, dyslipidemia, smoking, obesity, lack of exercise, hearing loss, depression, and social isolation are correctable risk factors. It is analyzed that managing these can theoretically prevent or delay about 40% of dementia.