Diagnosis Of Alzheimer's Disease

Previously, the plaques and tangles that accumulate in the brain (described previously, click here to return to that discussion) with Alzheimer's disease could only be definitively identified through autopsy. In other words, there was no available test or procedure to "pull out" a small sample of the brain to determine whether someone had developed plaques or tangles while they were still alive.

Currently, scientists are working on imaging procedures (described below, procedures that provide information about the structure and function of the brain) that will allow us to use brain scans and computers to aid in diagnosis. However, because using imaging technology to diagnose AD is still relatively new, the old standard of using a battery of tests for diagnosis is still the accepted procedure. The good news is that when a qualified physician does a thorough examination - which usually takes more than one visit - Alzheimer's disease can be diagnosed while the person is still alive, and we can be over 90% sure that the diagnosis is correct.

An even better method than relying on a single physician for diagnosis - although not always available outside of metropolitan areas with large research and teaching hospitals - is to approach diagnosis and treatment with an interdisciplinary team that includes a geriatrician (i.e., a physician who specializes in working with older people), a neurologist (i.e., a physician who specializes in diseases of the nervous system), a psychologist (i.e., a doctor who specializes in mood and behavioral 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).

The goal of a diagnostic workup is to rule out any other possible condition (reversible or irreversible) that could be creating the Alzheimer's-like symptoms. Appropriate diagnosis is crucial to making treatment recommendations (particularly if the condition can be reversed) that are likely to be beneficial. There are several components in a diagnostic workup, including:

  • Medical history - This includes questions about prior illnesses, previous injuries and surgeries, and current chronic conditions in order to identify other possible causes for Alzheimer's-like symptoms. For instance, a serious head injury - even from long ago - could account for problems with memory or concentration, or heart disease could be reducing blood flow to the brain and causing forgetfulness.

  • Medication history - This includes questions about allergies, side effects from past medications, and a list of current medications and dosages. Not only will this information help guide any future prescription decisions, it also might reveal a medication interaction (when two or more medications work against or compound the effects of each other) or overdosage that accounts for confusion and other symptoms.

  • Complete physical exam - This includes an assessment of hearing, vision, blood pressure, pulse, and other basic indicators of health and disease. A current physical exam can detect acute medical conditions such as an infection that might be causing confusion and other Alzheimer's-like symptoms.

  • Laboratory tests - This may include a battery of tests, depending on the individual'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. Symptoms that came on suddenly and include severe confusion would warrant a urinalysis to rule out a urinary tract infection. Some scientists are currently refining a procedure that would allow a doctor to analyze a sample of cerebrospinal fluid (the fluid that surrounds and protects the brain and spinal cord) for the characteristic abnormal proteins that build up with Alzheimer's Disease.

  • Neurological exam - This is a specific type of exam that is used to identify problems with the brain and nervous system. The evaluation should include an examination of the motor system (i.e., movement), reflexes, gait (i.e., walking), sensory functioning, and coordination in order to detect nervous system problems that may be causing difficulties with thinking and behavior.