A neurodegenerative disease that affects many people in their old age.
Cancer, HIV / AIDS and dementias are some of the disorders that are of greatest concern today in the western population, being some of the most frequent disorders that still do not have an effective solution or treatment.
Within the group of dementias, the best known is dementia caused by Alzheimer’s disease.
Alzheimer’s: general definition
Alzheimer’s disease is one of the most common and well-known neurodegenerative diseases. It is a chronic and currently irreversible disorder of unknown causes that acts by producing a progressive deterioration in the mental faculties of those who suffer from it. Initially it acts only at the level of the cortex, but as the deterioration progresses it ends up affecting the subcortical level as well. Insidious onset, the first lesions appear in the temporal lobe to later expand to other lobes such as the parietal and frontal.
Currently, its diagnosis is only considered completely definitive after the death of the patient and the analysis of his tissues (before death, his diagnosis is considered only probable), although as neuroimaging techniques advance, a more exact diagnosis becomes possible. The course of Alzheimer’s disease causes a homogeneous and continuous cognitive deterioration, with an average duration of between eight and ten years.
- To delve into the symptoms: “The first 11 Alzheimer’s symptoms (and their explanation)”
One of the most characteristic and well-known symptoms is memory loss, which usually occurs gradually. In the first place , recent memory is lost, and as the disease continues its course, aspects and elements increasingly distant in time are forgotten. It also decreases attention span, judgment, and the ability to learn new things.
Like most cortical dementias, Alzheimer’s disease is characterized by a progressive loss of functions that occur especially in three areas, configuring what has been called aphasic-apraxo-agnosic syndrome. In other words, throughout their deterioration, the patient loses the ability to speak (the presence of anomie or difficulty in remembering the name of things is very typical), perform sequenced actions or even recognize stimuli from outside. culminating in a state of silence and immobility. The presence of falls, sleep and eating disorders, emotional and personality disorders, and loss of smell are also common in those with Alzheimer’s.
Over time, the subject tends to become disoriented and lost, have carelessness and strange and careless behaviors, forget the value of things and even end up being unable to recognize loved ones. As the disease progresses, the subject gradually loses its autonomy, depending over time on the care and management of external agents.
Statistically, the mean age at which Alzheimer’s disease begins to appear is around 65 years of age, its prevalence increasing as age increases. It is considered early-onset or presenile if it begins before 65, and senile or late-onset if it occurs after that age. The lower the age of onset, the worse the prognosis, the symptoms progressing more quickly.
Deterioration process: phases of the disease
As we have said, Alzheimer’s disease causes a progressive deterioration of the mental functions of the patient. Said progressivity can be observed throughout the three phases in which the degeneration process has differentiated.
In addition to these phases, it must be taken into account that sometimes there may be a period of time prior to the onset of the disorder in which the individual suffers from mild cognitive impairment (generally amnesic).
First phase: Start of problems
In the early stages of the disease, the patient begins to experience small memory deficits. It is difficult for him to remember what he just did or eat, as well as to retain new information (in other words, he suffers from anterograde amnesia). Another especially typical symptom is anomie or difficulty remembering the name of things despite knowing what they are.
Judgment and the ability to solve problems are also compromised, performing less in work and daily activities. Initially, the patient is aware of the appearance of limitations, being frequent depressive and anxious symptoms such as apathy, irritability and social withdrawal. This first phase of Alzheimer’s disease can last up to four years.
Second phase: progressive loss of abilities
The second phase of Alzheimer’s disease is characterized by the appearance of aphasic-apraxo-agnosic syndrome, together with the appearance of retrograde amnesia. That is, the subject begins to have problems of understanding and emission of language beyond the anomie, as well as to have severe difficulties to carry out sequenced activities and to recognize objects, people and stimuli, in addition to beginning to have problems to remember past events ( so far memory leaks mainly refer to events that had just happened and were not retained).
The patient needs supervision and is not able to carry out instrumental activities, but can perform basic activities such as dressing or eating on his own. There is usually time-space disorientation, and it is not surprising that it is lost.
Stage Three: The Advanced Stage of Alzheimer’s Disease
During the third and final phase of the disease, the deterioration of the individual is especially intense and evident. Episodic memory loss can date back to childhood. There is also semantic memory loss. The subject stops recognizing their relatives and loved ones and is even unable to recognize themselves in an image or a mirror.
They usually have extremely severe aphasia that can lead to total mutism, as well as incoordination and gait disturbances. There is a total or almost total loss of autonomy, depending on external caregivers to survive and not being capable by themselves and the basic skills of daily life are lost, having total dependence on external caregivers. It is frequent that episodes of restlessness and personality alterations appear.
Hyperphagia and / or hypersexuality, lack of fear of aversive stimulation and episodes of anger may also appear.
The dementia produced by Alzheimer’s disease causes a series of effects in the brain that eventually cause symptoms.
In this sense , the progressive reduction in the level of acetylcholine in the brain, one of the main brain neurotransmitters involved in neuronal communication and which influences aspects such as memory and learning, stands out. This decrease in acetylcholine levels causes a progressive degradation in brain structures.
In Alzheimer’s disease, the degradation of structures begins in the temporal and parietal lobes, to go along the course of the disorder advancing towards the frontal and little by little towards the rest of the brain. Over time, neuronal density and mass are reduced, the ventricles dilating to occupy the space left by neuronal loss.
Another aspect of great relevance is the presence in the neuronal cytoplasm of neurofibrillary tangles and beta-amyloid plaques, which impede synaptic processes and cause a weakening of the synapses.
Research on this type of dementia has attempted to explain how and why Alzheimer’s disease arises. However, there is still no evidence why it appears.
At the genetic level, the participation of mutations in the APP gene, of the amyloid precursor protein, as well as in the ApoE gene, linked to the production of proteins that regulate cholesterol, is suspected.
The decrease in the level of brain acetylcholine causes the degradation of the various structures, the pharmacological treatments being based on combating said reduction. A cortical atrophy of temporoparietal onset appears that ends up generalizing over time to the rest of the nervous system.
The causes of Alzheimer’s disease remain unknown to this day. However, there are a large number of risk factors that must be taken into account when carrying out prevention tasks.
One of the factors to take into account is age. Like most dementias, that caused by Alzheimer’s disease tends to appear after the age of 65, although there are cases of even earlier onset.
The educational level or, rather, the mental activity of the individual also intervenes. And it is that the greater the mental exercise the greater the resistance and strength of the neural connections. However, this effect, although it is positive since it delays the progression of the disease, can make it difficult to identify the problem and its treatment.
Another one is the family history. Although Alzheimer’s disease is not usually transmitted genetically (except for a specific variant), it is true that almost half of individuals with this problem have a family member with this disorder.
Finally, the vital history of the patient should also be taken into account: Apparently the consumption of tobacco and diets rich in fat can favor its appearance. In the same way, a sedentary life with high levels of stress increases the probability of its appearance. The presence of some metabolic diseases such as diabetes or hypertension are facilitating elements of Alzheimer’s disease.
To this day, Alzheimer’s disease remains incurable, with treatment based on the prevention and delay of cognitive decline.
At the pharmacological level, different inhibitors of acetylcholinesterase, an enzyme that degrades brain acetylcholine, tend to be used. In this way, acetylcholine is present in the brain for a longer time, prolonging its optimal functioning.
Specifically, donepezil is used as a treatment in all stages of Alzheimer’s disease, while rivastigmine and galantamine are often prescribed in the initial stages. These drugs have been shown to slow the progression of the disease for about half a year.
At a psychological level, occupational therapy and cognitive stimulation are often used as the main strategies to slow the rate of deterioration. Likewise, psychoeducation is essential in the early stages of the disease, when the patient is still aware of the loss of faculties.
It is not uncommon for individuals who are reported to have dementia to experience episodes of the depressive or anxious type. In this way, the clinician should evaluate the effect that notification of the problem has on the subject.
It is also necessary to work with the family environment, advising them in the face of the deterioration process that the patient is going to follow, their loss of autonomy and indicating valid strategies to face the situation.
Taking into account that the causes of Alzheimer’s disease are still unknown and that its treatment is based on stopping or reducing the symptoms, it is necessary to take into account factors linked to the disorder in order to be able to carry out prevention tasks.
As we have said, a sedentary life is a risk factor for developing this disease. Physical exercise has been shown to be an excellent prevention mechanism, since it helps to strengthen both the body and the mind, being useful in a large number of disorders.
Taking into account that other risk factors include high cholesterol, diabetes and hypertension, the control of the diet becomes a preventive element of great importance. It helps to have a rich and varied diet with little saturated fat.
Another aspect to address is the level of mental activity. Exercising the brain supposes strengthening the learning capacity and neural connections, with which reading or learning new things (not necessarily technical theoretical knowledge) can help to stop the symptoms or that this does not appear.
Finally, one of the fundamental elements of prevention is the early detection of symptoms. Since memory loss without the involvement of dementia is common with age, it is not uncommon for early signs of Alzheimer’s disease to be ignored. If memory complaints are very frequent and are accompanied by other alterations in behavior and / or other faculties, it would be advisable to go to a medical center where the patient’s condition could be evaluated. We must also pay attention in cases of mild cognitive impairment, which can sometimes progress to different dementias (including that derived from Alzheimer’s disease).
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