Some degree of memory loss occurs naturally as we age, sometimes making a diagnosis of dementia difficult. The severity of memory loss must be considered, along with other symptoms of dementia, such as anxiety, depression, and paranoia.
A dementia diagnosis is based on medical history, observations of patient behavior, identification of existing symptoms and blood tests. Neuroimaging tools, such as PET scans and computed tomography scans, are used to check the brain for structural changes associated with dementia.
Memory Loss, Paranoia, and Other Dementia Symptoms
A diagnosis begins with the doctor taking a detailed medical history, including investigating any medications that may cause dementia as a side effect. The diagnosing physician will ask for a list of possible dementia symptoms. People with dementia often downplay the severity of their own symptoms, especially if they are suffering from paranoia or depression. To compile an accurate list of dementia symptoms, the doctor may even interview family members.
A dementia diagnosis is based on the presence of some or all of the following symptoms:
- memory loss
- difficulty with daily tasks
- loss of motivation
- personality changes
- social withdrawal.
The Mini-Mental State Exam
Tests that indicate the severity of memory loss and dementia are available. Although these dementia tests cannot diagnose dementia by themselves, they are a useful aid to diagnosis.
The Mini-Mental State Examination (MMSE) is the most commonly used dementia test. The MMSE is used to rate abilities that are often impaired by dementia, including:
- ability to name objects
- memory and memory loss
- spatial skills.
Computed Tomography, PET Scans and Neuroimaging
PET scans and computed tomography scans (CT scans) are neuroimaging tools used during the diagnostic process to examine the structure of the brain. Both PET scans and computed tomography can reveal evidence of strokes, blood clots in the brain, tumors, and head injuries, all of which can cause dementia.
Computed tomography uses multiple x-rays to construct images of the brain. Each x-ray displays a sectional “slice” of the brain. When the x-rays are taken as a whole, a computed tomography reveals a comprehensive picture of brain structure.
While a CT scan displays the structure of the brain, a PET scan shows how the brain functions. A PET scan is combined with the intravenous injection of tiny amounts of radioactive substances that are taken up by the brain tissue.
An EEG (electroencephalogram) measures brain wave activity. EEG may also be used as an aid in the diagnosis of dementia. The presence of Alzheimer’s disease often results in slower than normal brain waves.
Blood Tests and Dementia
Blood tests can aid diagnosis by ruling out (or confirming) a number of physical causes of dementia. Blood tests may check hormone levels, as well as check for vitamin deficiencies and electrolyte imbalances. Blood tests can also provide a complete blood count, and may indicate liver or kidney disorders.
A spinal tap is occasionally performed during dementia diagnosis. The presence of specific proteins in the spinal tap sample may be associated with an increased risk for developing Alzheimer’s disease. A spinal tap is also useful for ruling out meningitis and brain hemorrhage.