The goal of a diagnosis is to eliminate any other possible condition (reversible or irreversible) that could be creating dementia-like symptoms1. For instance, it is important to make a distinction between dementia and depression. Both conditions are associated with impairments of thinking ability (e.g. including memory difficulties) and with diminished interest in activities (e.g. including lack of initiative). Both in dementia and depression, the symptoms can be disruptive to daily activity performance. Moreover, depression is more common than dementia in older people. Ruling out depression is an important step in diagnosing dementia. Likewise, distinguishing dementia from the mild normal cognitive decline of advanced age is also critical.
It is generally better to approach dementia diagnosis and treatment with an interdisciplinary team rather than relying on a single physician2. However, such a team may not always be available outside of metropolitan areas with large research and teaching hospitals.
An interdisciplinary team may include a geriatrician (i.e., a physician specialised in working with older people), a neurologist (i.e., a physician specialised in diseases of the nervous system), a psychiatrist (i.e., a doctor specialised in mood and behavioural disorders), a neuropsychologist (i.e., a doctor who can perform testing to identify the nature and level of cognitive symptoms), and a social worker (i.e., a social services professional who can link individuals and families to community services).
Together, such a team can identify the appropriate diagnosis and begin making the right treatment decisions.
Components of diagnosing dementia
There are several components in a diagnostic workup. These include:
- Medical history. Questions about family history for dementia, prior illnesses, previous injuries and surgeries, and current chronic conditions. This will help to identify other possible causes for dementia-like symptoms. For instance, a heart disease could be reducing blood flow to the brain and causing forgetfulness.
- Medication history. Questions about allergies, side effects from past medications, and a list of current medications and dosages. This can help any future prescription decisions. This may also reveal a medication interaction (i.e. when two or more medications work against or compound the effects of each other) or overdosage that can account for confusion and other dementia-like symptoms.
- Complete physical exam. Assessment of hearing, vision, blood pressure, pulse, and other basic indicators of health and disease. A physical exam can detect acute or chronic medical conditions such as an infection, chronic arterial hypertension, or chronic renal failure that might be causing confusion and other dementia-like symptoms.
- Laboratory tests. Battery of tests, including blood tests, electroencephalography, or brain scans, depending on the person's medical history and current symptoms. For example, a blood glucose test might be ordered if the person is exhibiting symptoms of diabetes such as frequent urination, blurred vision, or increased thirst.
- Neurological exam. Examination of the motor system (i.e., movement), reflexes, gait (i.e., walking), sensory functioning, and coordination in order to identify problems with the brain and nervous system. This will help to detect nervous system problems that may be causing difficulties with thinking and behaviour.
- Neuropsychological tests. Assessment of cognitive functions (such as memory or language) through simple tests or questionnaires (for example, asking the person to recall words or to name objects). This will help to establish the extent of the difficulties, to track changes in the person's cognitive abilities, and to assess the person's preserved abilities (which are important for treatment)
Diagnosing Alzheimer's disease
Previously, Alzheimer's disease(AD) could only be definitively identified through autopsy. There was no available test or procedure to identify this disease while the patient was still alive.
Today, diagnosing AD is a multi-step procedure that begins with a medical history and can include imaging procedures, neuropsychological testing, and other procedures, depending on the patient's symptoms .3
The most common tool used to diagnose AD is the Mini-Mental State Examination (MMSE)4, which consists of neuropsychological tests. This involves finding out about possible problems with memory, language, planning and attention. The person is usually asked questions such as: "What is the date?" or "What city are we in?". Another example of a neuropsychological test is the Fuld Object Memory Test in which patients are shown 10 objects and then asked to memorize this list of objects and repeat it to the examiner. To be diagnosed with AD, multiple cognitive deficits must be present, one of which must be memory impairment5.
There are a number of other tests that can be used to aid the diagnosis of AD. These include laboratory tests (i.e. blood and urine samples) and various brain imaging methods, including Single Photon Emission Computed (SPEC), Computed Tomography (CT) scan, Positron Emission Tomography (PET) scan or Magnetic Resonance Imaging (MRI)6.
In patients with AD symptoms, new brain imaging technology enables physicians to diagnose probable Alzheimer's disease with almost 90% accuracy.
Unfortunately, the various diagnostic tests are only effective in diagnosing AD when a patient has already begun showing symptoms. This is problematic because the underlying causes of AD activate 10 to 20 years before any obvious symptoms of the disease appear.
Information to the patient and the relatives
Within the diagnostic framework, it is important that the patient's relatives are well informed by the physician about the possible causes of the dementia and about the test results in order to obtain a satisfactory impression about the steps which have been undertaken.
Everybody has the right to be informed about medical diagnoses, even if the diagnosis is hard to cope with. This might enable the patient to decide how to spend their time and to make their own decisions for the future. There are varied opinions in medical circles about disclosure of the diagnosis of dementia. Disclosing a diagnosis should always be followed by joint discussions about the next steps to be undertaken. The current point of view is that every patient, according to the stage of illness and to their personality, has the right to know but also the right not to know. This results in a step by step procedure for the information process. The patient is given part of the information in a way s/he can understand and s/he is asked if s/he wants to know more. Informing the relatives almost always needs prior consent of the patient.
- Waldemar G. et alii.,Access to diagnostic evaluation and treatment for dementia in Europe, Int J Geriatr Psychiatry. 2007 Jan;22 (1):47-54
- EMA Guideline on Medicinal Products for the Treatment of Alzheimer's disease and other dementias, July 2008, page 5