Dementias are a category of neurological disorders affecting the brain that are characterized by various forms of reversible or irreversible brain degeneration, which cause symptoms such as progressive memory loss, a gradual impairment of cognitive abilities, alteration of speech and other mental functions to a degree which affects their activities of daily living.
In other words, individuals affected by a form of dementia gradually lose the mental skills and abilities they have acquired during their life due to brain degeneration that is usually permanent, but may be reversible in some cases. There are several forms of dementia, each exhibiting a specific type of brain degeneration, but most of them cause similar symptoms.
Dementias typically affect the elderly, but younger adults may also exhibit temporary dementia symptoms due to reversible causes.
Types of Dementia
*Alzheimer's disease causes dementia symptoms due to a progressive degeneration of the brain and loss of functional neurons in various brain areas. The area of the brain that is affected more prominently is the hippocampus, which is a brain region responsible for memory processing, emotions and speech. Early symptoms of Alzheimer's can be confused with anxiety, mood instability (irritability) and depression. It is difficult to diagnose Alzheimer's in its early stages unless the evaluation is performed by a mental health professional or a neurologist. In later stages, when significant brain degeneration is already present, the individual exhibits progressive symptoms like impairment of short term memory, difficulties with reasoning, difficulties with finding words and incoherent speech, and impaired social functioning, such as difficulties with recognizing people and places.
* Vascular dementia occurs as a result of damage to the blood vessels in the brain, predominantly as a result of minor strokes. The specific symptoms depend on the brain area that suffered from blood flow impairment. Vascular dementia is closely connected to cardiovascular health.
* Fronto-temporal dementia is a type of neurological disease characterized by brain generation that occurs specifically and predominantly in the frontal and temporal lobes of the brain. These brain areas are responsible for speech, clear reasoning and social communication, which is why the early symptoms of this type of dementia include social withdrawal, speech impairment and loss of the ability to reason clearly.
Prevalence of Dementias
* The prevalence of Alzheimer's diseases in the general population is slightly less than 1 percent. However, the frequency increases to 5% in people over 65 years old. About 20 percent of people aged between 75 and 84 years.
* The prevalence of vascular dementia is estimated at about 1.5 percent of the population, but it is more frequent in the elderly with a high cardiovascular risk.
* Fronto-temporal dementia is less frequent than the previous two type of dementia, which an estimated prevalence of about 20 cases per 100,000 people. However, it is quite frequent (25 percent) among early-onset dementia types, which means that it may affect individuals at a younger age.
Who gets it
Dementia usually affects the elderly, generally over 65 years old. Dementia due to Alzheimer's diseases is certainly the most frequent type, but individuals that have cardiovascular diseases (high risk for strokes) are also highly susceptible to vascular dementia. A mixed type dementia, which is a combination of both, can affect up to 10 percent of dementia sufferers. Fronto-temporar dementia is a rare form of dementia, but it is more frequent in younger individuals (early onset dementias).
All types of dementia have similar symptoms since they are caused by brain degeneration. They may include memory impairment, difficulties with spatial and temporal orientation, speech problems, deterioration or reasoning skills. Fronto-temporal dementia is specific in the sense that social withdrawal, speech and communication impairment can appear first before the other signs of dementia occur.
There are no biological tests to determine whether an individual is at a high risk or has dementia. The diagnosis is made based on memory and cognitive tests, such as the Addenbrooke's cognitive examination (ACE), which evaluates the person's memory, visual and spatial orientation skills and speech. However, there are several reversible causes that may cause temporary dementia signs that can be excluded through biological tests, such as a deficiency of vitamin B12 or folate.
* MRI or SPECT scans are used to identify the presence and the extent of brain degeneration, which is usually manifested through some degree of generalized or region-specific brain atrophy. The scans can help to distinguish the dementia sub-types. All the tests can be ordered and performed within one week at the patient’s convenience at the BMI Priory.
It is possible to delay the onset of some dementia forms through regular mental exercise (games, reading, playing chess or solving puzzles), but researchers are not sure whether dementia can be prevented since there is a significant genetic component.
* Acetylcholinesterase inhibitors (reversible and irreversible) are the only type of medication that can provide some relief for dementia symptoms. They work by increasing the amount of acetylcholine available in neuron synapses, which makes communication between neurons easier. Although these medications cannot reverse the degenerative process in Alzheimer’s disease, in about two thirds of patients it can slow the decline in cognitive functions in the mild to moderate stages.
If dementia is identified and diagnosed early, it is possible to delay its progression through medication and psychological interventions. Although currently there are no disease modifying therapies, early diagnosis and intervention can not only slow the cognitive decline in some cases, but also help to manage symptoms during disease progression through other medications, psychological and social support.