Dementia is a group of clinical syndromes caused by brain pathology. Its core features include the gradual decline of memory, language, comprehension, judgment, behaviour, and daily living abilities, accompanied by changes in personality and emotions. With population ageing, dementia has become an important global public health challenge. Clinically, the presentation of symptoms varies depending on the cause, but the overall disease course shows progressive deterioration.
I. Symptoms in Cognitive Function
- Memory Decline
Memory decline is the most common and earliest symptom, especially recent memory. Patients often forget events that have just happened, repeatedly ask questions, or fail to retain new information. As the disease progresses, long-term memory is also gradually affected, and eventually patients may be unable to recognise the names of relatives or familiar environments. - Language Impairment
Language ability gradually declines. Patients may find it difficult to find suitable words, have trouble expressing themselves, or even develop aphasia. Common manifestations include word substitution, incomplete sentences, or inability to understand others’ speech. Patients with frontotemporal dementia are particularly prone to language impairment. - Decline in Comprehension and Judgment
Patients have difficulty understanding complex instructions or abstract concepts, and their judgment and decision-making ability are significantly weakened. For example, they may be unable to handle money, sign documents, or make reasonable choices. - Disorientation
Patients gradually lose the ability to recognise time, place, and people, easily get lost, or confuse dates. In the late stage, patients may even fail to recognise family members or familiar environments. - Executive Dysfunction
Executive function involves planning, organising, and completing tasks. Patients may be unable to complete familiar daily activities such as cooking, managing finances, or using transportation, gradually affecting their ability to live independently.
II. Symptoms in Behaviour and Psychology
- Personality Changes
Patients may show obvious changes in personality, such as becoming impulsive, indifferent, or unreasonable. Patients with frontotemporal dementia often show socially inappropriate behaviour or lack of empathy. - Emotional Disorders
Depression, anxiety, irritability, or emotional instability are common symptoms. Some patients may experience mood swings and react intensely to minor events. - Hallucinations and Delusions
Some patients develop visual hallucinations or delusions, such as suspecting theft or infidelity. Patients with Lewy body dementia are particularly prone to visual hallucinations. - Social Withdrawal
Patients gradually reduce participation in social activities, lose interest, leading to isolation and depression, which further accelerates disease progression.
III. Symptoms in Motor and Physical Aspects
- Motor Coordination Impairment
Patients may develop unsteady gait or reduced hand-eye coordination, increasing the risk of falls. - Parkinsonian Symptoms
Patients with Lewy body dementia often present with Parkinsonian symptoms, including rigidity, tremor, and bradykinesia. - Decline in Self-care Ability
As the disease progresses, patients gradually require assistance with dressing, eating, and toileting, eventually becoming completely dependent on care.
IV. Analysis of Symptoms by Disease Course Staging
- Early Stage (Mild)
- Memory decline, especially recent memory.
- Language difficulties, less fluent expression.
- Poor concentration, difficulty performing complex tasks.
- Still able to live independently, but requires reminders or assistance.
- Middle Stage (Moderate)
- Disorientation, confusion about time and place.
- Poor judgment, unable to handle money or daily decisions.
- Behavioural changes, hallucinations or delusions appear.
- Requires daily assistance, gradually loses independent living ability.
- Late Stage (Severe)
- Complete loss of memory and language ability.
- Unable to recognise relatives or familiar environments.
- Totally unable to live independently, requires full-time care.
- Often accompanied by swallowing difficulties, incontinence, and severe motor impairment.
V. Symptom Differences in Different Types of Dementia
- Alzheimer’s Disease: Mainly characterised by memory decline, with progressive deterioration.
- Vascular Dementia: Symptoms show “stepwise” deterioration, with functional decline after each stroke.
- Lewy Body Dementia: Symptoms fluctuate greatly, often accompanied by visual hallucinations and Parkinsonian symptoms.
- Frontotemporal Dementia: Mainly characterised by personality and language changes, with memory decline appearing later.
VI. Clinical Significance
- Early Identification is Important: Memory decline is not the only symptom. If accompanied by language, judgment, or behavioural changes, medical consultation is necessary.
- Some Symptoms are Reversible: For example, those caused by vitamin deficiency, thyroid disease, or medication side effects can improve after treatment.
- Caregiving Challenges: Symptom progression leads patients to gradually depend on care, requiring support from families and communities.
- Community Education: Enhancing public understanding of symptoms reduces stigma and promotes inclusion.
VII. Conclusion
The symptoms of dementia cover three major areas: cognitive function, behaviour and psychology, and motor and daily living abilities, and worsen progressively with the disease course. Different types of dementia show different symptom patterns, but the common feature is the gradual loss of independent living ability. Clinically, early identification and diagnosis are crucial, because some symptoms are reversible, and early intervention can slow disease progression and improve quality of life.
In an ageing society, the challenge of dementia is becoming increasingly severe. Only through professional diagnosis, multidisciplinary collaboration, and community education can we truly improve the quality of life of patients and families, and promote social understanding and acceptance of dementia.
