Dementia

Dementia is a generic term used to describe a set of irreversible neurological disorders that affect the brain and worsen over time. It is a loss of the ability to think, remember, reason or behave appropriately at levels that affect daily life.
While the most common dementia is associated with Alzheimer’s disease, other neurological diseases or brain damage are responsible for this syndrome. Dementia is one of the leading causes of addiction in the elderly, although it can occur at any age. It affects each person differently depending on the underlying causes. Diagnosis of dementia is based on a neuropsychological assessment that involves screening for cognitive impairments such as:
 

Symptoms and Diagnoses of Dementia

Only a neurologist can diagnose dementia using these tests, each of which is neither necessary nor sufficient. On the other hand, other tests such as MRI brain imaging or genetic mutation testing may support or refute the diagnosis. On the other hand, each of the cognitive abilities assessed by these tests can be diminished in the elderly person without dementia.

Biological Causes and Mechanisms of Dementia

The causes of dementia are manifold.

Alzheimer's Disease

Alzheimer's disease is often known for the memory loss experienced by patients. It is a progressive disease that usually begins with an isolated, progressive amnesiac syndrome of which the patient is generally not aware (anosognosis). Gradually, disorders of language (aphasia), writing (dysgraphy), movement (apraxia) and loss of the ability to recognize objects and faces (agnosia) are introduced.
Diagnosis is clinical and now involves high-performance diagnostic tests such as a full neuropsychological assessment of cognitive functions, imaging tests such as MRI and glucose PET that highlight areas of the brain that are suffering, and lumbar puncture that is capable of showing the biological signs of the disease, i.e. the presence of abnormal deposits of amyloid and tau proteins.

Fronto-temporal degeneration or dementia (FTD)

Fronto-temporal dementia is first suspected by relatives of the patient who report recent behavioural changes, personality changes or language difficulties.

The symptoms of FTD are caused by a dysfunction of the frontal and temporal regions of the brain in which abnormal proteins accumulate, causing neuron death and brain atrophy.

These regions are involved in functions as diverse as the control of our behaviours, especially our social behaviours, motivation and initiative, the control of emotions, and language. About 30% of fronto-temporal dementias are inherited from a genetic mutation.

Lewy body Dementia

Lewy body dementia is the second most common neurodegenerative disease after Alzheimer’s disease. It is a disease
A complex disease that borrows symptoms from Alzheimer’s disease and Parkinson’s disease, and is therefore difficult to diagnose. As in the
Parkinson’s disease, patients have slow movement and early instability, but tremors are rare.
Lewy body dementia is characterized by abnormal deposits of a protein called alpha-synuclein, the Lewy bodies, inside neurons.
Symptoms are directly related to the location of alpha-synuclein aggregates in the brain. The main symptoms of dementia are disorders of spatial and temporal orientation, attention, executive functions, but also hallucinations and sleep disturbances.
A specific characteristic of Lewy body dementia is the alternation of periods without and with symptoms, usually with a frequency of a few days to a few weeks, but sometimes during the same interview.

Vascular Dementia

Vascular dementia is the result of a stroke or several small cerebral infarctions that cause neuronal loss sufficient to reach cognitive functions. It accounts for about 10% of dementias, or about 70 000 people in France.

Early symptoms of dementia include impaired executive function, difficulty initiating actions or tasks, slowed thinking, changes in personality and mood, language problems, and later memory loss. Symptoms may vary depending on the location of the infarction.

Chronic traumatic encephalopathy

Chronic traumatic encephalopathy is a neurodegenerative disease secondary to repeated head trauma. It is mainly developed after 60 years among former sportsmen, rugbymans, boxers and American football players.

Symptoms of dementia are mainly mood disorders that develop early, followed by excessive irritability, impulsivity or even aggression, and memory problems later.

Treatments for Dementia

To date, there is no effective treatment for dementia, which remains the main cause of loss of independence in older people and strongly affects the daily lives of their caregivers.