How do Doctors Diagnose Alzheimers Disease

Article by Jenni Baty RN

The clinical diagnosis of Alzheimer’s disease is often referred to as a diagnosis by exclusion,as there is no specific clinical test that is unique to Alzheimer’s disease. This makes diagnosing Alzheimer’s a frustrating experience for both the patient and family; they are not told that Alzheimer’s disease has been specifically diagnosed, but that other possible diagnoses have been dismissed, leaving Alzheimer’s disease as the likely diagnosis by a process of elimination.

Because of the difficulty in making an Alzheimer’s Disease diagnosis doctors have devised a number of techniques to help identify Alzheimer’s with reasonable accuracy. These techniques include:

Gathering a detailed Patient historyDoctors often begin their examination of a patient suspected of having Alzheimer’s Disease by asking questions about the patient’s history. For example, they may ask how and when symptoms developed and about the persons overall medical condition. They also may try to evaluate the patient’s emotional state. The difficulty with gathering a history is that people with dementia are often unaware of or in denial about how their disease is affecting them. Family members may also deny the existence of the disease because they do not want to accept the diagnosis and because, at least in the beginning, Alzheimer’s Disease can resemble normal aging.

Physical examinationA physical examination can help rule out treatable causes of dementia and identify signs of stroke or other disorders that can contribute to dementia. It can also identify signs of other illnesses, such as heart disease or kidney failure, which can overlap with dementia.

Neurological evaluationsDoctors will perform a neurological examination to look at balance, sensory function, reflexes, and other functions, to identify signs of other conditions that may affect the patient’s diagnosis or are treatable with medications.

Cognitive and neuropsychological testsDoctors use comprehensive tests that measure memory, language skills, math skills, and other abilities related to mental functioning to help them diagnose the patient’s condition accurately. For example, people with Alzheimer’s Disease often show changes in so-called executive functions (such as problem-solving), memory, and the ability to perform once-automatic tasks.

Doctors often use a test called the Mini-Mental State Examination (MMSE) to assess cognitive skills in people with suspected Alzheimer’s. This test examines orientation, memory, and attention, as well as the ability to name objects, follow verbal and written commands, write a sentence spontaneously, and copy a complex shape.

Brain scansDoctors may use brain scans to identify strokes, tumors, or other problems that can cause dementia. Also, cortical atrophy -degeneration of the brain’s cortex (outer layer) – is common in many forms of dementia and may be visible on a brain scan. Brain scans also can identify changes in the brain’s structure and function that may suggest Alzheimer’s Disease.

The most common types of brain scans are computed tomographic (CT) scans and magnetic resonance imaging (MRI). Doctors frequently request a CT scan of the brain when they are examining a patient with suspected Alzheimer’s Disease. These scans, which use X-rays to detect brain structures, can show evidence of brain atrophy, strokes and transient ischemic attacks (TIAs), changes to the blood vessels, and other problems such as hydrocephalus and subdural hematomas.

MRI scans can detect the same problems as CT scans but they are better for identifying certain conditions, such as brain atrophy and damage from small TIAs.

Doctors also may use electroencephalograms (EEGs) in people with suspected dementia. In an EEG, electrodes are placed on the scalp over several parts of the brain in order to detect and record patterns of electrical activity and check for abnormalities. This electrical activity can indicate cognitive dysfunction in part or all of the brain. Many patients with moderately severe to severe Alzheimer’s Disease have abnormal EEGs.

Laboratory testsDoctors may use a variety of laboratory tests to help diagnose Alzheimer’s Disease and/or rule out other conditions. Some of these tests includes a complete blood count, blood glucose test, urinalysis, drug and alcohol tests (toxicology screen), cerebrospinal fluid analysis (to rule out specific infections that can affect the brain), and analysis of thyroid and thyroid-stimulating hormone levels. Psychiatric evaluation. A psychiatric evaluation may be obtained to determine if depression or another psychiatric disorder may be causing or contributing to a person’s symptoms.

The National Institute of Neurological and Communicative Disorders and Stroke and the Alzheimer’s Association have established criteria to help physicians make a diagnose of Alzheimer’s Disease.

Alzheimer’s disease is determined when a person has: * Dementia is confirmed by clinical and neuropsychological examination * Progressive worsening of memory and other mental functioning * No disturbances of consciousness * Symptoms beginning between ages 40 and 90 * No other disorders that might account for the dementia

About the Author

Jenni Baty is a Registered Nurse with 10 years experience in Alzheimer’s Care. Your can sign up for her FREE online course Living with Alzheimers or read more about Alzheimers Disease at her website