We may have often heard of the word dementia being used, especially in relation to the older adults and memory issues. Dementia is a disease entity and contrary to what many people believe, it is not a sign of aging or normal in aging, rather it is a disease that occurs more in the elderly population.
Dementia is the loss of cognitive functioning (ability to process thoughts), that is thinking, remembering, and reasoning to such an extent that it interferes with a person’s daily life and activities. It can be associated with poor control of emotions, and personality changes. It affects the memory, thinking, orientation, comprehension, calculation, learning capacity, language, and judgement of an individual but the consciousness is not affected. Dementia ranges in severity from the mildest stage, when it is just beginning to affect a person’s functioning, to the most severe stage, when the person must depend completely on others for basic activities of living.
Currently more than 55 million people live with dementia worldwide, and there are nearly 10 million new cases every year. It is currently the seventh leading cause of death among all diseases and one of the major causes of disability and dependency among older people globally.
Dementia has physical, psychological, social and economic impacts, not only for people living with dementia, but also for their careers, families and society at large. There is often a lack of awareness and understanding of dementia, resulting in stigmatization and barriers to diagnosis and care.
People younger than 65 years old can also have dementia, although this is not common. Such people are described to have ‘early onset dementia’.
What causes dementia?
There are over a 100 diseases that cause dementia. These diseases have different causes and pathways but all have the loss of memory and cognitive function in common. The commonest ones are Alzheimer’s disease, vascular dementia and dementia with Lewy bodies.
Alzheimer’s disease is the commonest cause of dementia. About 60 to 80% of people with dementia suffer from Alzheimer’s disease. This disease is associated with interruption of signals between brain cells and normal transport of food and energy to the brain, leading to the death of the brain cells and shrinking of the brain. This process is responsible for the dementia and other symptoms seen in Alzheimer’s disease.
Vascular dementia is another form of dementia associated with problems with blood circulation to the brain. There are several types of vascular dementia. A stroke is a very strong risk factor for vascular dementia. Some other risk factors like high blood pressure, smoking, diabetes, high cholesterol, and arterial wall diseases also predispose people to having the disease.
Lewy Body disease is another important cause of dementia. It is caused by the degeneration and death of nerve cells in the brain. There is development of abnormal structures called ‘lewy bodies’ inside the nerve cells of the brain. This is thought to lead to the death of the brain cells, causing dementia.
Other types and causes of dementia include: Frontotemporal dementia, Alcohol related dementia, Down syndrome /Alzheimer’s disease, HIV associated dementia, Creutzfeldt-Jakob disease, Huntington’s disease, and Chronic Traumatic Encephalopathy (CTE) dementia.
Often, more than one type of dementia may occur in an individual.
Symptoms of dementia
The symptoms of dementia include: memory loss starting from recent memory like recent events, to long term memory loss; poor judgment, and confusion; difficulty in speaking, understanding and expressing thoughts; wandering and getting lost familiar places, trouble with handling money responsibly and paying bills; repeating questions; acting impulsively and sometimes callously; loss of interest in normal activities, hallucinations, delusions and paranoia.
These symptoms often led to a personality change of the sufferer and have a very heavy negative impact on the care givers and family of the sufferers as they painfully watch their loved ones change into unpleasant versions of themselves.
Is dementia hereditary?
Because of the different causes and types of dementia, one answer does not fit all in answering this question.
Concerning, the commonest cause of dementia, the Alzheimer’s, disease strictly speaking, it is not a genetic disorder, although genetic factors play an important role. The most important genetic risk factor for Alzheimer’s, which may be inherited is a substance called the Apolipoprotein E (ApoE4). The presence of this ApoE does not guarantee the occurrence of AD as some people with it do not develop the disease while others without it do. Individuals who have a parent or sibling with Alzheimer’s are more likely to develop the disease than those who do not have a first-degree relative with Alzheimer’s.
There is however, another rare type of Alzheimer’s disease, the Familial Alzheimer’s disease (FAD). This is hereditary and occurs in every generation. If a parent has a mutated gene that causes FAD, each child has a 50% chance of inheriting it. The presence of the gene means that the person will eventually develop Alzheimer’s disease, mostly in their 40s or 50s.
Most dementia with Lewy bodies are not hereditary, although a there are few rare cases of hereditary dementia with lewy bodies that occur in families. The same also applies to some cases of dementia caused by the Creutzfeldt-Jakob disease.
Another rare cause of dementia, Frontotemporal lobar degeneration is also largely regarded as hereditary. Almost 50% of persons afflicted with this have a positive family history of the disease and in roughly 10-20% of cases, each child of a sufferer has a 50% chance of having the disease.
Huntington’s disease is also another rare cause of dementia that is hereditary, and occurs in a dominant form of 50% of every generation of sufferers.
Support for dementia
It is reassuring that hereditary dementias are rare and occur in a small percentage of the population. However, if you are worried about your chances of inheriting dementia, or struggling with caring for loved one with dementia, do reach out to the different support groups available online and in your area. They include the : Alzheimer’s Association, Lewy Body Dementia Association (LBDA) Family Caregiver Alliance, American Parkinson’s Disease Association (APDA), Dementia Mentors, Dementia Australia, among very many other support groups.