Cognitive impairment is one of the most common childhood health problems. Most epidemiological studies in developed countries agree to estimate their frequency at 0.7 to 0.8% of births. This pathology is badly diagnosed, ill explained to the parents and badly helped.
The term cognitive “deficit” should be preferred to “delay” because the latter term refers to the possibility of a catch-up which is not the reality.Similarly, the word “cognitive” is preferable to that of “mental” which, in relation to the whole of the activities of the mind, is broader, less precise. Within cognitive deficits, severe deficits are distinguished from those called moderate. Severe deficiencies prevent the autonomy of the child by their severity. They are usually recognized in the first year of life. The most intuitive definition of moderate cognitive deficit is the child’s inability to complete primary schooling, that is, to learn to read and write. This must of course be qualified: there are other causes of academic unfitness, but the overall cognitive deficit is by far the most frequent. Thus, the first part of the clinical process, just after recognition of the difficulty, must distinguish this global instrumental disorder from the specific disorders that are, for example, dyslexia or dysphasia, and psychoses with little deficit during which the loss is more dependent on the relationship disorder than on the instrumental deficit. However, the intricacies between these three situations are important. Global cognitive deficit is the most common pathology observed by neuropediatricians.
The role of the latter is multiple: to make the diagnosis of the type of deficit, to recognize the cause, to transmit this knowledge to the parents of the child and then to help promote the optimal development of the child. There are many medical treatment actions, even if, in most cases, there is no etiological treatment: counseling for better integration into the educational system, research and prevention of the associated handicaps, medicinal treatment in certain cases.
Recognize and characterize a child’s cognitive deficit:
Several circumstances lead to the identification of a cognitive deficit. The most frequent is a concern of the family who notices that the child behaves differently from his peers: he does not hold his head well spent 2 months, does not sit at 9 months, does not walk at 2 years, does not speak at 3 years. Motor retardation is more often the cause of initial anxiety than behavioral abnormalities.
The latter, for example, a disorderly activity, absence of organized games, absence of contact with other children, can be noticed at the crèche. Experience shows, however, that they are long tolerated and that it is often only in the nursery school, sometimes even during the preparatory course, that they are recognized as pathological. This primary concern of the family is often referred to as the “initial complaint”. The latter, like all symptoms, may have various causes; it should always be referred to at the end of the clinical analysis. Cognitive impairment may also be recognized in routine screening. Opportunities are numerous during the first years of life: signature of mandatory certificates, vaccinations, etc. The last circumstance where cognitive retardation can be identified is the systematic follow-up of a child after a serious pathology of the nervous system, particularly acute fetal distress or premature birth.If the attitude of the pediatrician in these three circumstances differs when he or she is required to transmit his / her observations to the family, the examination procedures and clinical reasoning are the same.
Explaining the techniques of neurological examination of the child during the first 3 years of life exceeds the aims of this chapter, but several general principles are important (details are given in other works):
– Cognitive assessment is always first in the course of the examination and in clinical reasoning. Whatever the initial parental complaint, this assessment must be made. This avoids major errors, the most frequent of which are, for example, to think of a muscular pathology in a child who does not sit at the usual age when it is a global mismatch of acquisitions, evoke isolated dysphasia in a 3-year-old child who does not speak while his achievements are all about 18-20 months;
– cognitive evaluation can only be done in play and pleasure.
Until the age of 3, the child is always examined on his mother’s lap, dressed, after a confidence, a phase of reciprocal seduction, between the child and the examiner. It is then necessary to install a game, always the same in order to be able to compare the children to each other (most often the manipulation of colored cubes) or to observe the child during spontaneous games if he is older;
– the most “cortical” tests take precedence over the motor tests: it is quite pathological to have no graphic and no beginning of language at 2 years even if the motor development has been accomplished at the normal rhythm;
– the age corrections related to prematurity must be used sparingly after 6 months of chronological age and refused after 9 months;
– Several scales of development exist which differ in their fineness and their maneuverability. Some, like the Denver or Brunet-Lezine test, are very handy, but are only tests for developmental disorder. Others, especially available after the age of 3, are true scales for defining levels of development and scores;
– the general examination must always follow the cognitive evaluation.
Several phases are essential: morphometric evaluation (plot of the statural, weight and cranial perimeter development curves), morphological evaluation (appearance of the face, skin, extremities, etc.), general examination. General pathologies (malabsorption by gluten intolerance, for example) may initially be due to an anomaly of cognitive development;
– the creation of a family tree is essential, but it should not be done at the first consultation because it requires a climate of confidence sufficient to be carried out optimally.
At the end of the examination, the pediatrician assesses whether the cognitive deficit is real, whether it is homogeneous (ie, equal in all aspects of development), whether it is old or new, if accompanied by other clinical signs.The clinical approach that recognizes the cognitive deficit is actually linked to the one who seeks the cause, which is explained in the next chapter. As a rule, even if the delay is straightforward and the probable cause for the examiner, it is better to review the child a second time before asserting things and exchanging this information with the parents.
Search for cause of cognitive deficit:
The cause of cognitive deficits is found in 60 to 70% of cases, a percentage observed in several French and North American studies. Simultaneously, three sets of causes are found with an equivalent frequency: 20% of handicaps are acquired, 20 to 25% are certainly of genetic origin and the same percentage is linked to cerebral malformations, some of which are of genetic origin. Thus, the genetic causes of cognitive deficits are by far the most frequent; it is also in this area that progress has been most frequent in recent years.
Discovering the cause of a cognitive deficit presents an advantage for the child and for his or her family. For the child, this discovery makes it possible to stop carrying out examinations sometimes painful or painful and to anticipate the occurrence of secondary complications.
For his parents, the discovery of the cause gives a better comprehensible framework, often a name, to a cognitive deficit that appears to them under this single term as an ill-defined entity that they can not apprehend. It also allows them to eliminate the possibility of other causes and often better to fight a feeling of guilt still present, but to varying degrees. Finally, the discovery of the cause allows for possible genetic counseling not only for parents but also for their own siblings and for the siblings of the child.
The cognitive deficits acquired are half perinatal (prematurity, hypoxia-ischemia during childbirth) and half postnatal (bacterial meningitis, encephalitis, cerebral ischemia whatever its cause, trauma, etc.). The only diagnostic problem is an earlier one: not accepting too quickly a relatively moderate birth difficulty as a cause of an important cognitive deficit whereas another cause, particularly genetic, may be the true origin of cognitive deficit and complicated birth .
They are the most frequent and often the source of a homogeneous, permanent and present cognitive deficit from the first years of life. Much more rarely (about 5% of cases) induce progressive disease (ie, an initially normal child has a deterioration in cognitive abilities) and are most often referred to as metabolic diseases (the abnormal gene encodes a protein having an enzymatic activity essential to the functioning of the cell).
Different types of genetic damage:
Chromosomal abnormalities, often referred to as cytogenetics, are, for the most part, easy to diagnose when they are important.
Clinical references leading to karyotyping are the presence of frank morphological abnormalities, the association of several malformations, even the attack of several children in the family. The most frequent anomaly in this setting is trisomy 21.
However, three difficulties in the diagnosis of these chromosomal abnormalities must be known. Some balanced chromosomal rearrangements, often inversions, are common in the general population (approximately 2 ‰). Any finding of a karyotypic abnormality in a child with a cognitive deficit requires the verification of the karyotype of his parents. Some chromosomal abnormalities are not identified on lymphocytes (usually used for the production of karyotypes) whereas they are on the fibroblasts of the skin. This is the case, for example, in Ito syndrome, where cognitive deficit is associated with often linear discolored skin areas, the fibroblasts of which are derived by culturing an epidermis fragment, may have karyotypic abnormalities. Some small chromosomal abnormalities, such as microdeletions, are not visible on a standard karyotype and require special techniques (high resolution karyotype on a given region, in situ fluorescence hybridization [HISF] with a chromosomal region specific molecular probe studied).
These techniques require that the clinician make a “choice” of the region to study and the approach is similar to that of the search for gene anomalies (see below). The latter are abnormalities of a single gene which most often can only be diagnosed by molecular biology techniques. Technical advances in this area are very rapid and each progress allows the etiological diagnosis of a small additional percentage of cognitive deficits.
This is the case, for example, with techniques for studying telomeres.
Clinical approach in search of a genetic anomaly or a microdeletion:
The right choice of the region or gene to be studied is essential for successful etiological research at a lower cost and with the least physical (repetition of examinations) and psychological suffering of the child and his parents. In all cases, success depends on a logical, clinical approach, without any strictly systematic examination. This clinical approach is and remains paramount regardless of technical progress.
The key to successful genetic abnormality in a child with cognitive impairment is to collect as many associated signs as possible. All these signs constitute the phenotype of the patient, which makes it possible to define a syndrome by comparison with other children already described in the literature having a similar phenotype. Once the syndrome is recognized (sometimes thanks to computer databases), it is easy to find out if the gene can be tested directly. There are many databases on the internet network, the most important in French is the Orphanet database (http://orphanet.infobiogen.fr). This clinical procedure (only the guidelines of which are set out with a few examples) seeks the associated signs along the following lines:
– analysis of the morphological phenotype: investigation of anomaly of the face, the hands, the genitals; systematic search for anomalies of the eye (study of the retina in the fundus of the eye and the lens by examination by slit lamp), skin (discolored spots and their shape, brown spots, angiomas), heart cardiac), kidneys (abdominal ultrasound), bone (by radiography evaluating morphology and bone weft); morphometric evolution of growth in weight, height and cranial perimeter; cerebral morphology (brain imaging is very often performed). One can give here as examples of syndromes that are diagnosed at this stage, Bourneville or Ito syndrome with different types of achromic cutaneous spots, Rubinstein-Taybi syndrome with a characteristic anomaly of the thumb, William syndrome associating a cardiac abnormality to a particular aspect of the face called “elf”, or FG syndrome that affects boys and associates anal and digestive anomalies with a particular implantation of the hair (spike of hair);
– behavioral phenotype analysis: in some syndromes with genetic or microdeletional abnormalities, children behave similarly: excessive joviality or, on the contrary, aggressiveness, self-mutilation, attitude stereotypies, excessive passivity, etc. However, this analysis is difficult in children with cognitive deficits, especially since no behavioral phenotype is specific. The best examples of syndromes often recognized by their behavioral phenotype are Rett syndrome with very pronounced manual stereotypes, Willi-Prader-Labhart syndrome (significant obesity and passivity after the age of 5 years), Angelman’s syndrome with bouts of laughter or Smith-Magenis with a disorderly activity;
– analysis of the evolutionary phenotype: it is essential to take up the whole history of the child and to specify the date when a particular sign was found or if signs were present and disappeared (especially during the first months of life).The two best examples are the Willi-Prader-Labhart syndrome since, in the neonatal period, there is often great hypotonia and difficulty in swallowing, which disappears afterwards, or Rett syndrome, because the girls who first phase of life of a few months where they are normal appearance followed by a phase of autistic withdrawal which finally precedes the typical phase with the manual stereotypies cited above;
– family tree. Particularly if the child with a cognitive deficiency is a boy, careful study of the mother’s collateral should be done. The syndromes in which the gene is carried by the X chromosome are numerous and the most frequent is the fragile Xq syndrome (mental retardation in several boys in the family and morphological abnormalities of the face and genitals from a certain age) .
It is only at the end of this process (which has not yet included biological examinations) that the choice of possible syndromes can be established. He leads the appropriate cytogenetics or molecular biology examinations. Several hundred different syndromes can associate with a cognitive deficit and cite all of them would be impossible, examples have been given above. One can not but emphasize the need for a great deal of know-how and therefore a specialized consultation for any child with cognitive retardation and a repetition of assessments over time, will not have been determined. Indeed, some very characteristic signs of a given syndrome may appear only after several years of life (this is the case, for example, of impuberism).
A cerebral malformation may be of genetic origin or be the consequence of a brain attack during pregnancy (viral as an infection by cytomegalovirus, ischemic, toxic, etc.). They are clinically suspected when there is: microcephaly at birth, an associated asymmetric motor abnormality, early onset epilepsy. However, cerebral imaging is almost systematic in the assessment of the cause of cognitive impairment. If a brain malformation is suspected, magnetic resonance imaging (MRI) should be done from the outset. In other cases, a computed tomography (CT) scan can be sufficient, supplemented by an MRI if it is abnormal. Conversely, an abnormal MRI can be supplemented by CT scanning, in particular for intraparenchymal calcifications that are not easily visible on MRI images. Without going into the details of the analysis of the morphological anomalies of the cerebral parenchyma, cerebral aggression during pregnancy is more often accompanied by destructive lesions, sometimes calcified with areas of normal cortices while a genetic anomaly is characterized by morphological abnormalities (cerebral coronary artery disease, posterior fossa anomaly, etc.) or abnormal cortex formation (thickened and too smooth cortex of a pachygyria, a revised cortex of a polymicrogyria, etc.). Several reviews on different types of cerebral malformations have been published. It is necessary to analyze the course of pregnancy, taking medications, handling toxic, episodes of uterine contractions and bleeding. Similarly, ultrasound examinations of pregnancy should be reviewed and, if possible, information about the condition of the placenta at the time of delivery.
Everyone knows the difficulty and everything has been said and written about what should not be done. It is usually the neuropediatrician who is obliged to transmit this information to the parents. Not all situations are equivalent. Thus, announcing the discovery of a trisomy 21 at birth poses very different problems from the announcement of the evidence of a delay in acquisition at, for example, 18 months. Even if this is the case, the dialogue with the parents is totally different if they themselves have noticed something and are worried or if, on the contrary, only the nursery staff or a doctor are sensitive to the variation of development of the child. It is evident that no systematic conduct can be given; only a few rules can be mentioned:
– the delay must be announced one day. There is no chance that this will happen “alone”. The best time in the child’s life is probably between 6 and 18 months with nuances depending on the severity of the disability. A very early announcement can hamper the establishment of links between parents and children. An announcement too late will be a source of greater difficulty for the parents for whom the dissociation between imaginary and reality will be too strong;
– this moment which will be considered by the parents as the founder of a new time can not be placed safely at the first interview. It is necessary that the doctor and parents have already established a certain common rhythm, a common evaluation of the development of the child. It is also necessary that a certain expectation has arisen among the parents with anxiety as to the rules of conduct with respect to their child. This propitious moment is thus often found during the second or third interview, separated from the first by 1 or 2 months;
– it is necessary to explain data that seem obvious to the physician but are not (or are no longer in this paroxysmal circumstance) parents. It is thus necessary to say the role of the brain in the development of the child and the different aspects (motor, cognitive, relational) of the latter. Naming the syndrome should be done with finesse. The information must obviously be transmitted as soon as it is available but it is not necessary to insist too much or too early in the initial interview (it will be necessary to return to it precisely later). The level of information in biology of the general population is low: the words chromosome, gene, even nucleus and cell, are often unclear spontaneously;
– the announcement of difficulties must be accompanied by practical measures to be taken: an immediate role must be given to the parents so that they can “reappropriate” their child’s development and its own rhythm (activities of awakening, psychomotor, physiotherapy). On the other hand, it is necessary to avoid projecting too far into the future, which is a very frequent request from parents;
– a follow-up consultation is essential in all cases. At times there is a denial that can be perfectly respected if the difficulties have been clearly stated before. The role of associations, host structures, financial aid are exposed at this time;
– the need for empathy is evident. There is no chance that this bad news will be given and, even less, received with ease. The doctor hurts in every sense of the word. It is appropriate, especially in subsequent consultations, to make it clear that the cost of the child’s disability, the psychological cost, but also the practical organization and daily life of the family is known;
– the announcement of disability is thus a medical act of great difficulty and of great technicality, if this term can be applied to a know-how in the field of the transmission of a knowledge.
In the vast majority of cases, no treatment can eliminate cognitive deficit (the only exceptions are cognitive deficits secondary to a general disease or rare endocrine and metabolic diseases, where the medical action aims rather to prevent the deficit). The role of the neuropediatrician is to accompany the family, to prevent complications or to treat them, to help remediation, that is to say to a series of palliative actions.
ACTIONS TO PROMOTE CHILD DEVELOPMENT:
These educational aids vary according to the age of the child, but are still indispensable. They consist most often of a combination of physiotherapy, psychomotricity or specialized education that is best performed within a team, either as part of a home care service or as part of a Center for Early Medico-Social Action (CAMSP). The range widens at school age and then uses the institutes medico-educational. A child-specific educational program must be designed, in all cases, to increase autonomy, communication and verticalization (for non-walker children).
TREATMENTS OF COMPLICATIONS:
These are numerous and can be grouped into four areas:
– complications of everyday life. Constipation is frequent and is controlled by adequate water supply (at least 1 L, possibly in the form of gelled water), adequate physical activity and verticalization, and finally by medicines such as Lansoy¨ t jelly, or even of the Forlax t . The disturbance of the sleep-wake rhythm induces awkward nighttime awakening, which can be improved by limiting diurnal sleep (naps are often too long), increasing physical activity and exposure to daylight and sometimes by drugs (melatonin, benzodiazepines). Conditions of agitation are another daily discomfort that are often improved by neuroleptics (especially Nozinan t ) and most often aggravated by benzodiazepines. The existence of epilepsy obviously requires additional medications and many epilepsies in this setting are quite resistant to treatment;
– feeding difficulties and breathing difficulties. Swallowing disorders and permanent dribbling can be controlled by special rehabilitation of the mouth. Frequent false roads during meals, weight loss can lead to the realization of a gastrostomy;
– Orthopedic complications. They are prevented by the construction of a seat and an adequate system of verticalization;
– Associated deficits of sense organs. Hearing impairment should be sought easily.
The complications cited here are only examples, knowledge of the etiology and clinical experience in specialized consultation make it possible to refine their detection.
Disability is a source of substantial direct costs (material for the child) and indirect costs (displacement, development of the home, limitation of the professional development of one or both parents). Several types of financial aid can be obtained: 100% hospital, special education allowances of which there are three categories, disability card, allocations specific to certain departments or companies. Any family with children with cognitive deficits must be able to meet with a specialized social worker, which again emphasizes the need for specialist hospitals and health care facilities.
The role of the neuropediatrician is essential to a child’s cognitive developmental disorder. It must, however, exercise this role in a network: with other medical personnel, in particular geneticists and child psychiatrists, with other health workers, in particular rehabilitation or special education.