How can dementia be diagnosed in the early stages of Alzheimer’s disease? What investigations are possible to gain clarity when a person with concerns about dementia or early memory impairment presents at a memory outpatient clinic or other specialized facility? In the following, possible examinations to clarify memory disorders and other cognitive deficits are presented. There are very general procedures that are always used (such as the medical history) and very specific examinations that are rarely used. Which examinations are useful and are offered to the person seeking advice is determined by the individual medical history.
In an anamnesis consultation, the doctor takes a medical history. For example, they will ask exactly why a person is worried. What complaints are perceived? How long have the symptoms been present? Have the symptoms changed? Was there a trigger? Is the person impaired in their everyday life or do they have other problems? Are there any parallel depressive symptoms? If relatives are present during the consultation, they are asked to provide information on how they experience the person’s symptoms as part of an anamnesis. They are also asked, for example, whether there were or are memory problems in the family, whether the person concerned is (still) working and whether there are other important illnesses.
The psychopathological findings are recorded as part of the medical history interview. Using a standardized system, possible signs of illness, such as memory and thinking disorders, as well as changes in mood and drive and their severity, are assessed. Based on the findings, complaints can be determined in more detail and combinations of different symptoms that are typical of certain illnesses can be identified.
The neurological diagnostic checks individual nerves, movement sequences and coordination, among other things. This examination also makes it possible to draw conclusions about typical memory disorders from certain abnormalities or their absence.
Neuropsychological testing can objectively measure functional disorders of memory and thinking that are perceived individually by those affected. In this way, the severity of disorders that can already be perceived can be determined. In addition, disorders that are still so mild that they are not yet perceived by those affected can be recorded.
Magnetic resonance imaging and computer tomography can be used to visualize the brain and the cerebrospinal fluid spaces, a system of cavities in and around the brain and spinal cord that is filled with cerebrospinal fluid. Abnormalities can thus become visible.
Differentiated blood tests can be used to search for the causes of memory disorders. For example, the blood count is analyzed and electrolytes are measured, but other values such as thyroid hormones and certain vitamins in the blood are also determined.
By examining the cerebrospinal fluid (CSF), for example, it is possible to analyze whether there is inflammation in the central nervous system (CNS – brain and spinal cord). There are also certain biomarkers, namely typical markers in the cerebrospinal fluid, which – if they are conspicuously altered – indicate the presence of Alzheimer’s disease years in advance, before the first signs of dementia appear. In the future, such biomarker tests will probably also be possible from blood samples.
Amyloid PET can be used to visualize beta-amyloid plaques, protein deposits typical of Alzheimer’s disease, in the brain before the first signs of the disease appear. The person is administered a weak radioactive substance that accumulates on the plaques and can be visualized using an imaging procedure (PET). Other nuclear medicine examinations, such as FDG-PET, can be used to examine metabolic activity in certain regions of the brain and detect typical patterns.
In certain cases, genetic testing for an increased risk of dementia may be useful. These tests are carried out after detailed consultation. The sample material is usually blood.
Numerous other diagnostics can be useful to clarify a memory disorder: These include, for example, ultrasound examinations of the blood vessels supplying the brain, examination of brain waves (EEG) and many others.
Some diagnostics can be carried out in GP practices and specialist practices (psychiatry, neurology, neurology). Other examinations are only possible at specialized centers, such as memory outpatient clinics, which focus on the examination and treatment of memory disorders.
Editors: Dr. Julia Perry and Dr. Katrin Radenbach from the University Medical Center Göttingen and Dr. Ayda Rostamzadeh from the University Hospital Cologne.