Dementia & Alzheimer's Disease

Dementia is a reference to impaired memory and other cognitive deficits that accompany brain degeneration, as well as interference with normal functioning. There are more than a dozen types and causes of dementia.

Dementia is more prevalent among the elderly. However, it can occur at any point in life. In dementia, cognitive abilities are gradually lost, accompanied by brain degeneration. In people with dementia, there is an occurrence of abnormal progressive degeneration of brain tissue as a result of disease or injury.

Dementia is most common in late adulthood. The term Senile Dementia refers to dementia that begins after the age of 65. Alzheimer's Disease is the most common cause of senile dementia, but Parkinson’s Disease, Huntington Disease and Creutzfeldt-Jakob Disease are other common causes. Complications from high blood pressure and strokes may also cause it.

Scientific Studies

A large Canadian study has found an overall rate of senile dementia of around 8 percent, as well as a female-to-male ratio of about 2:1. Whereas 2 percent of 65- to 74-year-olds are estimated to have dementia, there is an increase in rate to 11 for 75- to 84-year-olds, as well as 34 percent for people who are 85 and above.

Impaired memory, in particular, for very recent events, is typically one of the first symptoms of dementia. Poor judgement, language problems and disorientation may appear gradually or sporadically, and people who develop dementia typically have distress episodes due to confusion. Their behaviour may become uninhibited, they may lose the ability to perform familiar tasks, and they may experience a significant physical decline in addition to cognitive impairments.

Comparing with adults aged 65 and older, those who are more frequently engaged in activities that stimulate cognitive functioning show a lower risk of subsequently developing Alzheimer's disease; but whether this truly reflects a causal relationship remains to be seen. However, one thing is certain: as people live longer lives, the need to find a cure for Alzheimer’s disease and other forms of senile dementia becomes a matter of urgency. Until then, many of us can expect our family members to become Alzheimer’s patients.

Caregiving

Being a caregiver for a spouse or elderly parent with dementia can, unfortunately, be a stressful and psychologically painful experience. Over half of the patients diagnosed with senile dementia show a combination of depression, anxiety, agitation, paranoid reactions, as well as disordered thinking, which may resemble schizophrenia. Ultimately, it could result in the inability to walk, talk, or recognise family members or close friends.

In-depth studies done in Finland, the United States, and Germany, have found that among adults above the age of 65 not suffering from dementia, 20 to 25 percent do have mild cognitive impairment. Combining cases of mild impairment and dementia, some experts have estimated that 79 percent of 65- to 74-year-olds; and 45 percent of people aged 85 and older, remain cognitively normal.

Though these are not pleasant statistics, they make it clear that even well into old age, cognitive impairment isn’t inevitable; and that even with the decrease of some mental abilities with age, more knowledge and wisdom could still be accumulated.        

Alzheimer's Disease (AD)

Alzheimer's disease is a progressive brain disorder which is the most common cause of dementia among adults over the age of 65, according to around 50 to 60 percent of such cases. An overall of 2 to 4 percent of the elderly is estimated to have AD.

The early symptoms AD, which worsen gradually over a period of years, include forgetfulness, poor judgement, confusion, and disorientation. Often, memory of recent events and new information is especially impaired. Forgetfulness by itself is not necessarily a sign of a person developing AD; however, memory happens to be the first psychological function that is affected, as AD initially attacks the subcortical temporal lobe regions—areas near the hippocampus, as well as the hippocampus itself—that help in the conversion of short-term memory into long-term memory.

Alzheimer's disease spreads across a person’s temporal lobes and then to the frontal lobes, as well as to other cortical regions. According to a German physician Alois Alzheimer, who first noticed the disease a century ago, patients afflicted with this disease have an abnormal amount of plaques and tangles in their brains. Plaques happen to be clumps of protein fragments which happen to build up on the outside of the neurons, whereas tangles are fibres that get twisted and wound up together within the neurons.

Neurotransmitter Systems

Neurons tend to become damaged and die, brain tissues shrink, and communication between the neurons is impaired as AD disrupts several neurotransmitter systems, especially the acetylcholine system. Acetylcholine plays a key role in synaptic transmission in several brain areas involved in memory, and drugs that help maintain acetylcholine functioning have had some temporary success in improving cognitive functioning in AD patients.

As AD progresses, working memory and long-term memory worsen. For example, if you read a list of just three words to a healthy 80-year-old and test his recall after a brief time delay, they tend to typically remember at least 2 words if not all three. On the other hand, a patient with AD will recall 1 or none.

Anterograde and retrograde amnesia become more severe and procedural, semantic, episodic, and prospective memory can all be affected. Patients may lose the ability to learn new tasks or remembering new information or experiences, as well as forget how to perform familiar tasks and have trouble recognising even close family members.

Genetic Causes

What causes AD and its characteristic plaques and tangles? According to scientific identification, several genes contribute to early-onset AD; an inherited form of the disease which develops before the age of 65 and as early as 30, but only accounts to about 5 to 10 percent of AD cases.

However, the precise cause of the more typical, late-onset AD remains elusive; but researchers have identified one genetic risk factor. This gene helps direct the production of proteins which carry cholesterol in the blood plasma, and high cholesterol and other risk factors for cardiovascular disease may likewise increase the risk of developing AD. A recent study found that even healthy elderly adults who carried this particular gene, as compared to peers that did not, performed more poorly on prospective memory tasks.

If you know anyone with AD, you are aware that it involves much more than memory loss. These patients experience language issues, disorganised thinking, and changes in mood as well as personality. Ultimately, they may lose the ability to speak and walk, and may also lose control over bladder and bowel functioning.