How is the diagnosis established?
Consulting a doctor to obtain a diagnosis at an early stage is critical. A complete medical and psychological assessment may identify a treatable condition. A number of conditions exist that produce symptoms similar to dementia. These include vitamin and hormone deficiencies, depression, overmedication, infections and brain tumours. If the symptoms are caused by dementia, an early diagnosis will mean early access to support, information, and medication.
It is important that anyone with suspected dementia has a thorough assessment by a neurologist, geriatrician or psychiatrist with a special interest in dementia to establish the diagnosis. Another option is to attend a memory clinic. A referral can be obtained from a general practitioner. A typical work-up is likely to include the following:
- Detailed medical history. If possible, this history ought to be provided by the person with the symptoms and a close relative or friend. Medical history helps establish the onset (sudden or insidious) and progression of the symptoms (fast or slow). Often, behavioural changes are more apparent to family and friends than to the person with dementia.
- Thorough physical and neurological examination. Usually this examination includes tests of the senses and movements to rule out other diseases and to identify medical conditions which may worsen confusion associated with dementia.
- Laboratory tests. These blood and urine tests are sometimes called a ‘dementia screen’. They test for a variety of possible illnesses which could be responsible for the symptoms such as an under-active thyroid gland or vitamin B12 deficiency.
- Brain imaging. Imaging of the brain is mandatory in all younger adults with suspected dementia to rule out reversible causes such as a benign brain tumour or hydrocephalus (fluid on the brain) and to look for patterns of brain changes associated with the specific types of younger onset dementia, such as local shrinkage (atrophy) of the frontal lobes in frontotemporal dementia. Computerised Tomography (CT) and Magnetic Resonance Imaging (MRI) are forms of structural imaging methods that are widely available. In some specialist centres, structural imaging may be supplemented by functional imaging (SPECT or PET), which show how the brain is working.
- Psychiatric assessment. This investigation helps identify treatable disorders such as depression, which can mimic dementia. It also helps to identify and manage symptoms such as anxiety or delusions which may occur in conjunction with dementia.
- Neuropsychological assessment. Tests of cognition are administered to identify retainedabilities and specific problems in areas such as memory, comprehension, visual abilities, problem solving and numerical skills. These results can help with determining the diagnosis.
