The most common form of dementia, Alzheimer's, is a disease of old age. Unfortunately, it is progressively disrupting lives with every passing decade, with 3 million patients in India. Moreover, studies indicate that this number will only double in the next 20 years.

Although these numbers are concerning, knowledge of the disease can help one cope and care. Therefore, today’s article provides an in-depth understanding of Alzheimer’s disease, also known as AD.

Let’s begin!

Many confuse Alzheimer’s disease with dementia. Therefore, before we jump into understanding AD, it is imperative to distinguish it from dementia.

When medical professionals say “dementia,” they imply a brain problem that makes it difficult for an individual to complete daily tasks without any assistance. Symptoms of dementia differ from one person to another, and may include loss of memory, mood changes, or difficulty speaking, walking, or finding their way. There are several causes for dementia, and AD is one of them.

Alzheimer’s disease is a progressive neurological disorder that brings about changes in one’s brain. It causes the human brain to shrink (atrophy), which results in the loss of brain cells. Over the course of time, a patient experiences a continuous decline in behavioural, thinking, and social skills. Down the road, it affects an individual’s ability to function independently.

Although the effects of this disease are similar, there are two main types of Alzheimer’s disease:

Early-onset Ad

This type of AD occurs to individuals who are younger than 65 years. More often than not, people are in their 40s or 50s when diagnosed with this illness. However, this form of Alzheimer’s disease is rare. In fact, only about 5% of people with AD have an early onset.

Additionally, individuals with Down syndrome tend to be more vulnerable and at a higher risk for it. Moreover, research suggests that early-onset AD differs from other forms of the disease in a few ways:

• Patients with early-onset Alzheimer’s tend to undergo more of the brain changes linked with the disease.
• The origin of this early-onset is also traced back to a defect in a particular part of one’s DNA: Chromosome 14.
• Myoclonus, which is a form of spasm and muscle twitch, is also more common in this form of Alzheimer’s disease.

Late-onset AD

This is common in individuals aged 65 years and above, and is the most common form of Alzheimer’s disease. However, medical science is yet to find concrete answers about the hows and whys of this form of AD. In fact, we still do not know for certain why it affects some individuals and not others. Additionally, researchers have not found any specific gene that causes late-onset Alzheimer’s.

Moreover, note that there is another form of AD, albeit extremely rare, called Familial Alzheimer’s disease or FAD. It makes up less than 1% of all cases of AD, making it a form of Alzheimer’s that is linked to genes.

Among the families affected by FAD, members of a minimum of two generations have this disease. Additionally, most individuals with early-onset AD also have Familial Alzheimer’s disease.

For many patients, AD starts with alterations in memory. For others, changes in language, mood, thinking, and visuospatial skills are common symptoms of Alzheimer’s disease. That being said, memory loss is a key symptom of AD. 

Early signs of Alzheimer’s include issues with remembering recent conversations or events. As this illness progresses, a patient’s memory impairments worsen and other symptoms begin to show up.

Eventually, brain changes linked with the illness results in growing trouble with various aspects and exhibits the following symptoms of advanced Alzheimer’s disease:

Memory

Most of us experience memory lapses every now and then. However, memory loss associated with AD persists and worsens, thus affecting one’s ability to function. 

An individual with AD may exhibit the following:

• Repeat questions or statements multiple times
• Cannot remember appointments, events, or conversations
• Misplace possessions or put them in illogical locations
• Gets lost in familiar places
• Forgets the names of everyday objects, sometimes even family members
• Faces difficulty in finding the right words to express thoughts or take part in conversations

Thinking and Reasoning

This disease hinders one’s thinking and concentration, especially with concepts that involve numbers. Moreover, multitasking becomes difficult for a patient with Alzheimer’s disease. It also causes a decline in his/her ability to make reasonable judgements and decisions in everyday life.

Here are some signs of decline in one’s thinking and reasoning skills due to AD:

• Managing finances is challenging
• Forgetfulness to pay bills on time
• A sudden inability to recognise and comprehend numbers
• Making uncharacteristic choices during social interactions, such as wearing clothes that are not appropriate for the weather
• Difficulty in responding to everyday problems, like unexpected driving conditions or food burning on the stove

Furthermore, as the disease progresses in an individual, they fail to undertake once-routine tasks requiring sequential steps. For instance, playing their favourite game or cooking a meal becomes a struggle. Over the course of time, individuals with advanced AD can forget how to carry out basic activities, such as bathing or dressing.

Changes in Behaviour and Personality

AD-related brain changes also affect moods and behaviours. Therefore, some symptoms of Alzheimer’s disease include the following:

• Apathy
• Social withdrawal
• Depression
• Mood swings
• Aggressiveness and/or irritability
• Severe trust issues
• Alterations or disruption in sleeping habits
• Loss of inhibitions
• Mindless wandering
• Delusions, such as a belief that something is stolen from them 

AD can also affect a person’s mood, and patients may become anxious, depressed, paranoid, or irritable. Individuals with AD gradually require constant assistance to complete their daily tasks. They may need help from others to pay their bills, shop, take medications, or remember appointments.

Later in the course of this disease, patients may need assistance with bathing and dressing. A person with AD can continue to live for many years with the disease. Moreover, research suggests that a patient may live up to 20 years or more, although this can vary from one person to another.

Additionally, a patient with Alzheimer’s disease may have some key skills preserved even while their symptoms worsen. Here, preserved skills can include reading books, listening to music, singing, dancing, and telling stories, etc. However, these are preserved for longer periods as they are controlled by areas of the brain affected later during the disease.

Now that we have a fundamental idea of this illness, let’s delve into the causes and prevention of Alzheimer’s disease.

Unfortunately, medical science is yet to identify the causes of Alzheimer’s disease. So, at the moment, there are no concrete answers as to what causes Alzheimer’s disease.

That being said, research traces its causes to a combination of age-related brain changes, alongside genetic, lifestyle, and environmental factors. Here, changes in the brain refer to an abnormal build-up of proteins in and around one’s brain cells. These proteins include amyloid and tau, deposits of which form plaques and tangles, respectively.

Although the cause of this process is unknown, scientists suggest that it begins several years before symptoms of Alzheimer’s disease appear. Over time, various parts of one’s brain shrink, among which the areas to usually get affected first are linked with memories.

As mentioned earlier, the exact triggers of AD remain unknown. However, several factors are known to increase one’s risk of developing this disease. These risk factors linked to Alzheimer’s disease include the following:

Age

For AD, age is the single most critical factor. In fact, the likelihood of developing this condition doubles every 5 years after one reaches the age of 65 years. But it does not affect only older individuals; 1 in 20 patients of AD tend to be under 65 years of age. Moreover, early-onset affects individuals aged close to 40 years.

Down’s syndrome

The genetic fault that causes this syndrome also causes the build-up of amyloid plaques around brain cells, which can eventually lead to AD. As a result, individuals with Down’s syndrome are more vulnerable to this disease.

In fact, as per the National Down Syndrome Society, nearly 30% of down syndrome patients aged close to 50 years have Alzheimer’s [1]

Cardiovascular Disease

Research points towards numerous lifestyle factors associated with cardiovascular diseases, which can increase the risk of AD. These factors include the following:

• Smoking
• Diabetes
• Obesity
• High cholesterol
• High blood pressure

Genetics

Figures suggest that Alzheimer’s disease can be caused by inheriting a single gene, while the risk of developing the disease gets higher with age.

So, if several members of your family have experienced dementia over generations, especially at a younger age, it is advised that you take genetic counselling.

Other Risks

The latest research also suggests that several other factors can lead to AD, although they are not directly responsible for causing it. These include:

• A sedentary lifestyle
• Loss of hearing
• Undiagnosed and untreated depression
• Social isolation or loneliness

Alzheimer’s Disease Tests and Diagnosis

When it comes to diagnosis, an important factor is to explain one’s symptoms and their impact on daily life. In addition, a diagnosis of AD is premised upon tests conducted by a doctor to assess one’s thinking skills and memory.

Here, a diagnostic work up is likely to comprise these tests:

• Physical and Neurological Evaluation: It includes testing a patient’s neurological health by examining their reflexes, coordination, muscle tone, strength, balance, sense of sight, hearing, etc.
• Labs Tests: Blood tests help a doctor rule out other causes of memory loss, such as vitamin deficiencies and thyroid disorders.
• Neuropsychological Testing: It contains a brief test of one’s mental status to assess thinking skills and memory. Additionally, these tests serve as a starting point for tracking the progression of the disease.
• Brain Imaging: Images of a brain can reveal visible abnormalities related to AD that may be causing cognitive changes. It includes computerized tomography (CT), magnetic resonance imaging (MRI), and positron emission tomography (PET).
• Genetic Testing: Generally, genetic testing is prescribed for patients with a known family history of early-onset AD.

Differential Diagnosis of Alzheimer’s Disease

Alzheimer’s accounts for about 80% of dementia cases. Besides, its diagnosis can be complex as the disease shares symptoms and pathologies with other forms of dementia.

Therefore, an understanding of critical characteristics of various kinds of dementia can lead to accurate diagnosis of AD.

The table below highlights some of the clinical differences between various major dementias:

Given the complexity of the disease, it is unlikely that a specific drug or intervention can effectively treat it. Moreover, there is no cure for Alzheimer’s. On the bright side, however, there are several approaches to help patients manage behavioural symptoms and mental function, thereby slowing down the progression of this disease.

Therefore, doctors recommend a number of prescription drugs to patients diagnosed with AD. Moreover, medication works best during the early stages for the treatment of mild Alzheimer’s disease. For instance, drugs can reduce the pace of memory loss in patients and control behavioural changes.

As the exact cause of AD is unknown, there are no certain ways to prevent Alzheimer’s disease. However, you can reduce the risk of AD by way of a healthy lifestyle.

• Be Watchful of the Heart-head Connection: Cardiovascular diseases like high blood pressure, diabetes, and high cholesterol can increase the risk of AD.
• Participate in Social Activities: Studies indicate that maintaining solid social connections as you age keeps you mentally active and lowers cognitive decline.
• Avoid Head Trauma: Serious head trauma can lead to Alzheimer’s disease in old age.
• Workout Regularly: Exercise increases the flow of oxygen and blood in the brain, which can lower the risk of AD.
• Eat Right: Although there are no foods to prevent Alzheimer’s disease, eating healthy can protect the brain. Therefore, you can take these steps:
  • Limit your intake of saturated fats and sugar
  • Eat plenty of fruits, vegetables, and whole grains.
  • Try a DASH or Mediterranean diet, both of which are beneficial to lower the risk of AD. However, consult your doctor before switching up your diet.