Alzheimer's disease

What is it?

Alzheimer's disease is a neurodegenerative disorder which was discovered by Aloïs Alzheimer in 1906. It causes a gradual loss of neurons, which are the brain's basic functional units used to programme various actions such as memory, language and reasoning.

Neuron deterioration causes problems relating to memory, cognitive functions and behaviour. The onset of symptoms is generally slow with symptoms becoming more severe over time. As a result, people affected by the disease gradually lose their independence.

Although Alzheimer's disease is more common among elderly people, it is not a normal consequence of ageing.

No treatment has yet been developed to tackle the cellular mechanisms of the disease. Current treatments are not curative and do not impede neuron degeneration and death, although they can slow symptom progression.

Four such drugs are currently marketed. Their molecules act by preventing the destruction of neurotransmitters which enable information to be transmitted between neurons in certain parts of the brain.

Controlled trials have shown moderate yet significant improvements in cognitive functions, everyday activities and general judgement in patients as reported by their families and physicians.

Brain

a) Healthy brain     b) Brain in the advanced stage of the disease

          c) The two brains overlaid

 Neurons

Source: www.alz.org

Illustration: Jannis Productions. Rebekah Fredenburg, computer animation; Stacy Jannis, illustration/artistic direction.

The disease in figures (France)

  • 850,000 sufferers
  • 3,000,000 people affected - patients and families/friends - in France and its overseas territories
  • Potentially 1,275,000 sufferers in 2020, or one in every four French people over the age of 65
  • 1 in every 2 patients are unaware that they are suffering from Alzheimer's disease
  • The average time between the onset of the first symptoms and diagnosis is 24 months in France
  • 0 curative or preventive treatment
  • Up to 5% of people suffering from Alzheimer's disease contract it early, often from the age of 40 or 50

Risk factors

Ninety percent of what we know about Alzheimer's disease has been discovered over the past two decades.Although researchers have shed light on the mechanisms that cause the lesions to form, they have not yet explained why they occur. The exact cause of the disease is therefore still not known.

However, certain risk factors have been identified:

  • Age: elderly people are most commonly affected
  • Gender: women aged over 80 years are most at risk of contracting the disease
  • Vascular risk factors
  • Diabetes, lipid disorders, high blood pressure and smoking
  • Family history: however, so-called 'familial' forms of the disease only affect approximately 1% of all sufferers.

10 signs and symptoms of Alzheimer's disease

It is completely normal to occasionally forget appointments, a colleague's name or a telephone number. However, if several disorders combine to impact significantly on a person's life, this should prompt both the individual and their family to consider the possibility of Alzheimer's disease.

The disorders associated with Alzheimer's disease are:

  • Memory loss that impacts on everyday life
  • Difficulty planning or solving problems
  • Difficulty performing familiar tasks at home, work or as part of leisure pursuits
  • Confusion with regard to time and place
  • Difficulty understanding images and spatial relationships
  • Recent problems with verbal or written expression
  • Losing objects and a diminished ability to retrace steps
  • Impaired judgement
  • Withdrawal from work or social activities
  • Mood swings and personality changes

Do not ignore these signs. Go and see a physician to determine the cause.

Potential preventive strategies

Although no preventive treatment has been developed for the disease, researchers are examining various potential strategies for protecting against it and slowing its progress.

Food

Various studies have examined the impact of specific diets on Alzheimer's prevention. In particular, several observations have been made regarding the Mediterranean diet which largely consists of fish, fruit, vegetables and olive oil. For example, it has been noted that subjects who eat fish twice or three times a week reduce their risk of declining cognitive function. Although this is a promising potential preventive strategy, it needs to be backed up by more robust long-term studies.

Physical and mental activity

Physical rather than sporting activity is cited as a potential preventive strategy. Naturally, physical exercise is recommended for people of all ages, whether by taking walks or using the stairs instead of taking the lift. Although this constitutes a good preventive strategy, it is not unique to Alzheimer's disease.

As regards mental activities, there is evidence to suggest that risk is reduced by engaging in exercises that stimulate memory, logic or thought. However, this theory is also still being scientifically tested.

Protective factors

There are two prevailing assumptions regarding protective factors – one relating to cognitive reserve (whereby the more neuron networks are developed, the longer the onset of symptoms is delayed) and the other to vascular lesion prevention.

In terms of cognitive reserve, increased brain activity is recommended.

In terms of vascular lesions, people are advised to control their blood sugar, blood pressure and cholesterol.

Hopes for research

To date, studies have identified the most critical factors in Alzheimer's disease, namely patients' level of education, diabetes, fruit and vegetable intake and genetic aspects. However, it is too early to confirm a causal link with these factors. This remains to be proven by epidemiological and clinical trials. Although work is under way,it is likely that we will have to wait five to ten years before more tailored prevention can be offeredand specific recommendations made.

Sources: www.francealzheimer.org and www.alz.org