Diagnosis

Key points

Current assessments for dementia include:

• Cognitive status examination
• CT scan (Computerized Tomography scan) or MRI (Magnetic Resonance Imaging) or other imaging
• Blood tests
• Clinical judgment (history and physical examinations)

Introduction

Dementia is a descriptive term for a collection of symptoms including impairment of memory, language skills, perception and cognitive skills (including reasoning and judgment) that significantly affect normal activities and relationships. A number of disorders that affect the brain can cause dementia, resulting in personality changes and behavioral problems such as agitation, delusions and hallucinations.

Health professionals often diagnose dementia according to the criteria listed in the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV), currently published by the American Psychiatric Association. Cognitive status examination, CT scans and blood tests are used to determine if a person is showing symptoms of dementia and to check whether the symptoms are caused by other medical conditions. At the moment, an autopsy is required to make a definite diagnosis of dementia, according to the above criteria.

Cognitive status examination

Instruments such as the Mini mental status examination (MMSE) and the Alzheimer's disease assessment scale (ADAS-Cog) are usually used to identify a person's cognitive function. These can be used to support diagnosis.

CT scans or an MRI

The brain images of people with dementia may show no gross abnormality, or be similar to those of people suffering from other diseases. Therefore, brain images are often used to rule out other causes for the symptoms, such as brain tumors or bleeding in the brain. These can also be used to determine whether there is infarction.

Blood tests

Blood tests are often used to determine whether a person is showing symptoms due to insufficient vitamin B12. They can also help to rule out other causes for the symptoms, such as metabolic, liver and thyroid diseases.

Clinical experience

Clinical judgment is the most important factor in making a diagnosis. This is usually based on the history of the illness provided by the patient and his/her family, and physical examination of the patient. Physicians often diagnose dementia based on experience with reference to the criteria listed in DSM-V and other medical literature. Major criteria and examples are listed below:

1. Complex Attention

   • Have difficulties with concentrating in environments with multiple stimuli (TV, radio, conversation).
   • Have difficulties holding new information in mind (recalling phone numbers, or addresses just given or reporting what was just said).

2. Executive function

   • Have difficulties performing complex projects.
   • Needs to rely on others to plan instrumental activities of daily living or make decisions.

3. Learning and memory

   • Repeats self in conversation, often within the same conversation.
   • Cannot keep track of short list of items when shopping or of plans for the day.
   • Requires frequent reminders to orient task in hand.

4. Language

   • Have significant difficulties with expressive or receptive language.
   • Often uses general terms such as "that thing" and "you know what I mean".
   • With severe impairment may not even recall names of closer friends and family.

5. Perceptual-motor

   • Have significant difficulties with previously familiar activities (using tools, driving motor vehicle).
   • Have difficulties navigating in familiar environments.

6. Social cognition

   • Shows changes in behaviours with little or no insight into these changes, such as insensitivity to social.

Please read "10 Signs of Dementia" and fill out the "Informant Questionnaire on Cognitive Decline in the Elderly (IQ-CODE)" if you suspect your family member may have dementia, or contact the following professionals:

1. Private physicians
2. Memory clinic at the JCCPA
3. Memory clinics at other non-governmental organizations
4. Memory clinics, geriatrics units or psychogeriatric units at hospitals or clinics of the Hospital Authority (a referral letter signed by a general outpatient physician or private physician is needed)