Alzheimer’s disease: What are the warning signs?

There are more than 5.8 million people living with Alzheimer's disease in the United States. This condition results from a slow degeneration of neurons, starting in the hippocampus (a brain structure responsible for memory) and then spreading to the rest of the brain.

Alzheimer's disease is characterized by short-term memory loss, executive functions disorders and spatial disorientation. The patient gradually loses his or her cognitive faculties and independence.

What are the warning signs of the disease?

Memory loss, poor judgement, mood changes... There are many warning signs of Alzheimer's disease that can alert patients and their families.

Memory loss

Occasionally forgetting an appointment, the name of an acquaintance or a telephone number and then remembering it later is a normal phenomenon. However, a patient with Alzheimer's disease regularly forgets recent events and appointments and may never remember them.

Difficulty performing everyday tasks

We can all be distracted in our daily activities. However, a patient with Alzheimer's may not be able to cook, write or button up his or her jacket.

Language impairment

It is quite normal not to find the right word in a conversation. However, someone suffering with Alzheimer’s disease has a hard time finishing sentences and tends to replace the missing words with others that do not have the same meaning. Therefore, other people find it hard to understand the patient’s speech.

Difficulty planning or problem solving

Patients with Alzheimer's disease may experience changes in their ability to plan certain things or to set up and follow a plan. The same applies to the use of numbers. For example, they may have difficulty following a familiar recipe or handling monthly bills.

Disorientation in time and space

An Alzheimer's patient may get the season or the year wrong, or get lost in a familiar place. The patient then no longer knows how he or she got there and is not able to find his or her way home.

In addition, a person with Alzheimer's disease is more likely to misplace objects or put them away in inappropriate places.

Impaired judgement

Patients with Alzheimer's disease tend to have poor judgement leading to bad decisions. They may show poor judgement in handling money issues, thus giving away large sums of money to telemarketers, for example.

Mood or personality changes

Patients with Alzheimer's disease can change moods very quickly, from calm to angry, for no apparent reason.

Patients affected by the disease can also suffer from personality changes. An outgoing and open person may become withdrawn and suspicious.

How does Alzheimer’s disease progress?

Alzheimer's disease progresses during the next ten years following the onset of the first symptoms, and until the patient’s death. This is the consequence of the slow progression of lesions in the brain. However, it varies from person to person. The speed of cognitive decline is unique to each patient and the symptoms, as well as their order of appearance, may differ.

The latest international classification proposed by the American Psychiatric Association (DSM 5) suggests a new nomenclature for dementia, of which Alzheimer's disease is the most common cause.

The DSM 5 distinguishes between two grades that follow one another:

• Minor neurocognitive disorders: these disorders correspond to the beginning of the disease, when the symptoms have little impact on the patient's daily life. At this stage, daily activities require more effort from the patient than usual, but cognitive decline remains modest.
• Major neurocognitive disorders (corresponding to the medical term "dementia"): this is the stage where the patient's independence is compromised. At this stage, cognitive decline is significant. The patient needs help completing their daily tasks.

In addition, current classification of Alzheimer's disease distinguishes 4 main stages:

• Preclinical stage: when the very first symptoms appear. The patient experiences episodic memory loss, but it is not significant. The patient is aware of his or her difficulties and implements strategies to remedy them (e.g. sets reminders), thus remaining independent.
• Mild, early stage: dementia begins to settle in. The patient loses his or her independence. At this stage, apathy, mood disorders and depression may develop.
• Moderate stage: characterised by further increase in memory loss and decreasing independence.
• Severe stage: this is the last stage of the disease characterised by a total loss of independence. The patient no longer recognises people or places that used to be familiar. Physical abilities are progressively declining and the patient dies, most of the time, as a result of swallowing disorders or pulmonary infection.

How is Alzheimer’s disease treated?

As of today, there is no treatment capable of curing Alzheimer's disease or slowing down its progression. However, four drugs are currently on the market: Donepezil, Rivastigmine, Galantamine and Memantine.  

These treatments aim at easing the patient’s cognitive symptoms. However, they do not prevent the disease from spreading to other parts of the brain.

Donepezil, Rivastigmine and Galantamine are acetylcholinesterase inhibitors. Acetylcholinesterase is the enzyme that breaks down the neurotransmitter acetylcholine. This neurotransmitter is essential for proper functioning of the neurons. In fact, Alzheimer's disease causes a continuous loss of acetylcholine.

These treatments prevent degradation of the neurotransmitter and increase its quantity at the junction between two neurons (called “synapse”).

If taken early enough, acetylcholine is continuously replenished to make up for the deficit. However, the deficit increases and, after a certain point, the drugs are no longer sufficient.

Memantine has a similar effect on glutamate. Memantine blocks NMDA receptors. It protects these receptors against excitotoxicity that occurs in Alzheimer's disease. Excitotoxicity is a pathological process of neurotoxicity and destruction of the neurons, triggered by overactivation of the excitatory neurotransmitter glutamate which stimulates the NMDA receptor. 

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