Memory

Description Troubles Causes Symptoms Comments Medical References
Memory is an essential function of our brain, which represents only 2% of our weight, that is to say between 1100 and 1500 grams; but it uses 50% of the glucose and 20% of the blood oxygen supply. This is why the cerebral activity is strongly related to blood irrigation (gingko biloba), which unfortunately decreases with age. Memory is constantly requested: daily life, conversation, reading, examination, etc, It is thus essential, even fundamental!

Memory is the function which allows to collect, code, preserve and restore the stimulations and information that we perceive. It also puts at stake the physical structures as well as the structures of the mind. In first analysis,

There are three types of memories:

  • Sensory memory: Extremely short, it practically corresponds to the time of stimulus perception by our sensors. Sensorial visual memory (also known as iconic) persists between 300 to 500 milliseconds. Sensorial auditive memory (also known as ecoic) is hardly longer. To these visual and auditory stimuli can be added other perceptions coming from the other senses, but seem to play a less important part in the direction of the stimuli. The same goes for the tactile sensory memory (or haptic memory). It is the combination of these various perceptions which allows the information identification.
  • Short-term memory: Also known as working memory (WM), we permanently request it. It is the immediate memory which gives the capacity to remember during one to about ten seconds, up to an average of seven elements of information.
  • Long-term memory: Contrary to the preceding ones, which erase the datas immediately after their treatment, the long-term memory (LTM) stores informations for a long period of time and even over a life time. Of considerable capacity, LTM is a the trustee of our memories, our apprenticeships, our history and, to sum up, our whole life.
The informations that we perceive are not poured in bulk into a memory ‘tank’. They are organized and controled by systems which work in permanent relation. There is a distinction to make between episodic memory and semantic memory on one hand, and the procedural memory and declaratory memory on the other hand.

  • Episodical memory allows to remember events, names, dates and places that are specific to us. It is related very much connected to the emotional context;
  • Semantic memory relates to concepts, meaning of words and symbols;
  • There also exists a type of memory which is related to the form of words, their structure, their pronunciation. This is the lexical memory: the vocabulary;
  • Semantic memory and lexical memory are gathered under the term ‘verbal memory’;
  • Procedural memory corresponds to the know-how, the expertise. It is used to carry out complex operations often related to motricity, and probably also concerns the oral learning.
  • Verbal memory is that of the know-how language. It allows to evoke in a conscious way, memories in forms of words.

We now know that there is no ‘memory center’, but instead, there are several sites in the brain implied in the treatment and the storing of informations.

  • Short-term memory brings the prefrontal cortex to intervene;
  • Semantic memory uses the neocortex;
  • Striated bodies and cerebellum are very much implied in the procedural memory;
  • Verbal memory occurs in the hippocampus which is also requested by the episodical memory, at the same time as the thalamus and the prefrontal cortex.
Neurobiologists agree to confer to the hippocampus a crucial role. Located in the middle of the brain, it ensures the comparison of informations stored in different cerebral zones. Its intervention is necessary to pass short-term memory on to long-term memory.

Memory lapses occur because our brain is organized to eliminate what could unnecessarily encumber it or when the information did not undergo a suitable treatment. The organization process is essential in the work and success of recall: chances to find a specific souvenir, in the huge library that is the semantic memory, depend of the quality with which we labeled this remembrance.

Many lapses of memory also have an emotional cause. Psychoanalysts say that memory lapse is often associated with events or intentions associated with unpleasant affects or stress carriers.

More and more people are affected with Alzheimer’s disease (after 45 years of age, but especially after 65 years of age). It appears as a short-term memory loss, mental confusion and finally, by a complete physical and intellectual deterioration.

Our neurons assets have so much potential and are so under-employed, that even at the end of ones lifetime, they still have preserved potentials. This undoubtedly explains the quality of mnesic performances of certain individuals sometimes very old. It is however known that with age, there is a slowing down in the intellectual capacities, the transmission of information is slower, new knowledge is more difficult to acquire, old memories exist but their recall is more complex. If there are physiological reasons with the fall of the performances, memory aging is the reason for the fall of psychic and physical activity, of intellectual capabilities, and loneliness. Memory needs to be frequently stimulated to function properly; its gymnastic must continue as late into life as possible.

One of the best methods to exert its memory and to preserve its storage capacities is through reading. Indeed, it permanently brings into play atention, visual perception, recognition, construction of mental images, organization of informations, etc., therefore, all operations which mould our memory. Sleep also has a particularly beneficial effect on the retention of acquired memories during the day before. We remember best different informations because of sufficient and regular rest, and sleep of quality, that is at least 8 hours for a teenager and a young adult. Having recourse to hypnotic sleeping pills and many other drugs does not support good memory, because they deteriorate one of the important phases of sleep: the paradoxical phase during which the process of memorization is very active.
Etiology of Attention Deficit Disorder with or without Hyperactivity (ADD/ADHD)
Since the early eighties, there has been many writings on ADD/ADHD. It was and is still the object of multiple controversies. Many researches state that this disease not only has short-term consequences on behavior and learning but also on a long-term period. Indeed, once at adulthood, the individuals presenting these dysfunctions, will be affected in their family life, at work and even in their social life.

This problem seriously handicaps academic success and individual potential. This often leads to failures in school, and even dropping out of school. It supports in particular the peripheral attention, where the secondary stimuli will have as much importance as the central stimuli, if not more, involving the scattering of interests. Sometimes, ADD/ADHD succeeds in decreasing the capacity to judgment of reality and indirectly sustains fabrication or a dreamlike life, utopian or otherwise. Sometimes, it merges entirely and participates to the behavioral difficulties as of the characteristics of opposition character.

This disorder constitutes a phenomenon of great complexity. The diagnosis is often done with school age children from pre-school and up, and could reach 3 to 5% of the population of children. The impact of ADD/ADHD on public health is so important that the Quebec Government has put in place a plan of action intended to help these individuals and their families.

Children, teenagers and adults suffering from ADD/ADHD, present with a deficit in attention as well as an abnormal impulsiveness and hyperactivity of the motor functions, for their level of development. This disorder is responsible for school and relationship difficulties. The younger the patient, the more difficult the diagnosis is to establish, because children achieve very few tasks which require concentration. Moreover, an overactive child will not necessarily develop this disease. In the majority of cases, this disorder remains stable until the beginning of adolescence and attenuates thereafter. It is estimated that one third of the children affected will present the same symptoms to adulthood and of this third, 20% will develop an antisocial personality.

This diagnostic is in clear progression and causes serious controversies, because of the unrestrained increase in the number of prescriptions of stimulants for the central nervous system, such as Ritalin (Methylphenidate), to treat children, teenagers and recently adults.

Several names are given to this disease and they include: hyperkinetic syndrome, hyperactivity, deficit of general coordination, perceptual psychomotor affection, attention disorders, minimal cerebral dysfunction, and attention deficit with or without hyperactivity.
Potential causes of Attention Deficit Disorder:
  • Heredity: The majority of children suffering from ADD/ADHD have at least one member of their family who has the disease. 1/3 of men who suffer from it will pass it on to their children. Genetics also seem to play an important role on the etiology of ADD/ADHD. More than 20 studies have suggested a relationship between ADD/ADHD and specific forms of certain genes of DAT1 and DRD4;
  • Sleep apnea : During infant period, it would seem that a reduction in levels of dopamine would be caused by a constant lack of oxygen;
  • Cerebral dysfunction: Among these patients, the cerebral zones responsible for attention, for the sense of organization and the control of movements appear less active. These patients have lower levels of dopamine than normal;
  • Exposure to certain substances during uterine life : tobacco, certain drugs, alcohol;
  • Environmental toxins : Exposure to dioxin and benzene hydrocarbons (BPC);
  • Heavy metals: Various studies have shown the role of heavy metals in ADD/ADHD. It was discovered an association between lead levels in blood plasma and the probability of being diagnosed with ADD/ADHD, as well as a synergistic effect between lead, cadmium and aluminium. In a group of children whose lead levels where particularly high, a chelating therapy intended to decrease these levels, showed a notable improvement in hyperactivity, impulsiveness, behavior problems and learning;
  • Sleep disorders;
  • Brain trauma causing latent central nervous system disorders during childhood, could cause this type of disorder later on, that is to say at adolescence and adulthood;
  • Infections of the central nervous system;
  • Dysfunctions of the thyroid gland: Thyroid hormones are important in the regulation of substances which modulate the nerve impulse in the brain, and these same substances (dopamine, serotonin and noradrenalin) and are also influenced by Ritalin®. Various studies let believe that a mild hypothyroidism of the mother during her pregnancy, may affect the intelligence of the child to be born. No less than 77 chemical substances were identified being able to cause damage to the thyroid, of which the BPC, dioxins, furans, phenols and several others, which can currently be observed in mother’s milk;
  • Problems with the intestines function may sometimes play a role in ADD/ADHD. The observation of a group of children, to which were prescribed oligosaccharides for six weeks, which are used as substrate to intestinal probiotic bacteria, showed a reduction of the ADD/ADHD symptoms;
  • Diet: A recent report entitled « Attention deficit disorder with or without hyperactivity and the use of central nervous system stimulants », published jointly by the College of doctors of Quebec and the Order of the psychologists of Quebec, regards diet as a method of intervention. Very recently, a review of 23 double blinded studies concluded that 8 studies out of 9 showed a deterioration or an improvement in ADD/ADHD according to whether food additives were added or withdrawn. Two other double blinded studies showed that, approximately 75% of children suffering from ADD/ADHD, felt an improvement of their symptoms when the subjects where aimed at eliminating possible food allergies in their diet. Similar results were obtained concerning refined sugar. Even if they do not function everytime, food strategies can make an interesting improvement in a certain number of children. Amongst possible food allergens are: dairy products, wheat, corn, yeast, soy, citrus fruits, eggs, chocolate, nuts, food additives (preservatives or stabilizing agents, food coloring, sweetening substances, etc.);
  • Dysfunction of neurotransmitters, mainly dopamine. Researches, however, could not explain why dopamine, one of the hormones involved in pleasure, functions differently in people suffering from ADD/ADHD than those who do not.

The main issue is the absence of serious evaluation when a child has inadequate behaviors at school. We must always check the total context and refuse the diagnosis of ADD/ADHD, if the behaviors are not present in all circumstances of the child’s life. A child who plays video games with attention for 30 minutes does not suffer from ADD/ADHD. A child who really suffers from ADD/ADHD has difficult behavior problems before entering school that is as early as 2 years of age. So when behaviors of ADD/ADHD appear after 5 years of age, we must first check the external cause such as intoxication, physical or psychological aggression, etc.
Attention deficit disorder with or without hyperactivity
The criteria which allow to identify attention deficit disorder with or without hyperactivity (ADD/ADHD), are established by the American Association of Psychiatry (DSM-IV-TR®, 2000) and also by the World Health Organization (ICD-10, 2003).

ADD/ADHD is a group of various symptoms which causes significant social and familial disturbances and decreased academic and/or professional performance. In fact, there are three major subgroups of ADD/ADHD. They are divided according to the predominant disorder:
  • Attention deficit: This symptom concerns people who have difficulty paying attention or concentrating on the same topic for 15 minutes or more. Their attention is easily disturbed; carrying the individuals into a daydream attitude, also, they are easily distracted by surrounding noise.
  • Hyperactivity is characterized by the difficulty remaining in place. These people constantly move their feet and/or their hands, they wriggle unceasingly and it is difficult for them to remain seated. They often rise, have difficulty to play or carry out tasks calmly. They can also show difficulty to stop talking. They are true wordy individuals. In fact, these people can even sometimes give the impression to be socially immature.
  • Impulsiveness is characterized by achieving tasks too quickly and often without thinking; their words are quicker than their thoughts. Also, they very often begin activities without having taken time to listen to or read all the instructions. They are impatient and have difficulties waiting their turn during a conversation, in play, in line, etc.
  • Those suffering from attention deficit, impulsiveness and hyperactivity at the same time. These people express symptoms of attention deficit, hyperactivity and impulsiveness at once.

To confirm the diagnosis, the symptoms must appear in at least two different environnements from daily life: at home, at school or at work, for example. Moreover, one has to make sure that symptoms were present before seven years of age, and that they are not caused by intellectual retardation, psychiatric or emotional disorders. Nevertheless, it is important to note that an emotional or psychiatric disorder can coexist with ADD/ADHD.

Since ADD/ADHD belongs to the class of mental disorders, the diagnosis must be very precise and many various criteria are to be considered.

The American Association of psychiatry notes the criteria of diagnosis for this disorder in the Diagnostic Handbook and Statistics of Mental Disorders, the DSM-IV (1994)1.

There are no medical tests to diagnose Attention Deficit Disorder. However, to establish a positive diagnosis, five precise criteria must be present:
Expert suggestions intended towards parents or teachers of children suffering from ADD/ADHD.

  • Urge the child to practice sports;
  • Parents must be firm and impose a limit on activities which excite their child. A specialist has writen: “Television, radio, video games, are stimulants that hinder the power of concentration and relaxation.” (Jefferson, 2002);
  • Parents should assign specific tasks to their child. For instance: Empty the trashcans rather than asking them to take out the trashcans;
  • With the assistance of ‘behavior modification therapy’, teach the child organizational techniques and time management skills, using a daily planner (diary) or an electric organizer (electronic diary) (Karlak, 2001);
  • Create strict routines by taking time for physical exercise in order to minimize the symptoms of ADD/ADHD (Weinsteinl, 1994);
  • Divide large tasks into several stages, this will allow to considerably reduce anxiety (Weinstein, 1994);
  • Avoid sitting the child close to windows, a corridor or in an agitated place, to study or carry out tasks which require attention;
  • If you must write a lot of information on a blackboard, it is important to use different color chalks to emphasize important information;
  • Avoid dividing his attention, by asking the child to write while speaking, for instance;
  • Use the child’s first names in examples, supporting this way his participation;
  • Clear and short instructions with simple vocabulary. Avoid giving more than one instruction at once. Restate the instructions when necessary. Visual aids should be used, such as pictograms, illustrations of the instructions, charts, etc.
  • Call upon all the senses when presenting a schoolwork, and limit questions to those only pertaining to that schoolwork.
  • Encourage mental imaging (example: show the child how the visualize a story already heard, by imagining it in his head);
  • Use the computer to present teaching material;
  • Use the child as a help, by giving him responsibilities;
  • Reward the child for his even tiny progress: words of encouragement, stickers;
  • Adjust the schoolwork according to his learning rhythm;
  • Make sure that the child sleeps sufficiently; that is a minimum of eight to nine hours of sleep daily;
  • By undergoing constant reprimands, hyperactive children are more likely to develop serious problems of self-confidence; this will only amplify the problem. Motivation and encouragements give the best results;
  • A hyperactive child does not have the notion of danger. He must benefit from an increased vigilance;
  • When the child is out of control, it is better to ask him to go to his room for a few minutes;
  • According to the Tomatis approach, ADD/ADHD would be attributed to a bad sensory integration. Initially, this approach consists in improving the capacity of listening in the young patient, by stimulating his brain and by helping him to concentrate on sounds without being distracted. To do so, the patient uses special earphones with which he listens to specially designed cassettes containing Mozart’s music, Gregorian chants or even the voice of his mother.
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