Lecture 11. The concept of deviation development.

It has long been known that children's mental and physical development proceeds in an orderly fashion. Events such as smiling, sitting, walking, and speaking occur in normal children at such precise ages that they are often called the milestones of development. Study of these development stages is of great importance from the point of view of differential, or better, developmental diagnosis, as deviation from the normal may have some significance and indicate mental retardation, deafness or other illness. This can only be appreciated if the normal sequence of events is known and understood. REFLEXES There are four important reflexes which should all be present in normal full-term babies. They are poorly developed in premature babies and may be absent in babies who are acutely or chronically ill. Their significance lies not only in the fact of their presence, but also in the age at which they disappear. If any of these reflexes can be elicited after the age of three months it is possible that some neurological abnormality is present. The Moro or staitle reflex. This is best elicited by lifting the baby with one hand under the back and another under the head. If the head is suddenly allowed to fall backward the Moro reflex should occur. This reflex consists of a sudden throwing out of the arms which are then brought together again as in an embrace. The grasp reflex. If the examiner's finger is rubbed across the baby's palm, he will grip the finger so hard that it is possible to lift him off the couch by this means. The tonic neck reflex. When a baby's head is turned to one side he extends the arm on that side and flexes the arm of the opposite side in the position of a fencer taking up guard. The walk i eflex. This reflex is less important than the above. If the foot of a newborn baby is placed flat on a table and the baby moved forward and from side to side he will bring up each foot as in walking. He does not, of course, bear any weight. CLASSIFICATION OF STAGES OF DEVELOPMENT All classifications are based on the original work of Gesell and Amatruda (1947). A modified version of the classification of Sheridan (1960) is used here. Gross Motor Development Gross motor development is assessed by placing the baby in various positions. Prone position. In the newborn, the pelvis is high and the knees are drawn up under the abdomen. Later the legs extend at the hips and knees and the pelvis rests flat on the couch. At first the baby cannot raise his head, but at the age of six weeks he can lift it momentarily from the couch. With advancing age this power develops until the child is able to hold the head up well and support himself, at first on his elbows and later on his straight arms. Ventral suspension. When a newborn baby is held in the air with a hand under the abdomen supporting the body, his head hangs down, but the arms, and to a lesser extent the legs, are flexed. Within a few weeks the baby is able to lift his head progressively until it reaches 180° or above. The legs extend at the hips and knees. Lying supine. If the baby is laid on his back and is then pulled by his arms into the sitting position, his head at first flops backward. The older child voluntarily raises his head at the same time. Sitting. When sitting, the baby's back is uniformly rounded and the head is facing downwards. With the older child, the head for a time still wobbles from side to side if the baby is shaken, but the back is straighter. By the age of 6 | months he should be able to sit momentarily with his hands forward for support. Gradually the baby becomes more steady in the sitting position and by 11 months he can twist around to pick up an object from behind. When testing for sitting, see that the baby is unsupported and on a hard surface, otherwise he will appear to be more advanced than he is. Standing and walking. When held in the standing position the infant is able to bear progressively more weight on his legs. By seven months he can bear all his weight and soon after this will start to pull himself up to the standing position. A few weeks later he momentarily lets go of his support and stands alone. The next stage, when he learns to walk around the playpen or furniture, is called "cruising". By the age of about 14 months the child can walk unsupported. At first he still has a wide base and falls frequently, but gradually the walk becomes more mature. Fine Motor Development and Vision Fine movements are mainly performed by the upper arms, particularly the hands. A child obviously will not touch and pick up small objects unless he can see them. It should be possible to tell that a child is blind before the age of two to three months. By this time the normal child follows with his eyes the movements of an adult near his cot. He is also starting to take notice and play with his own hands. A child usually smiles at a face. The blind child cannot see the face and so does not smile when an adult looks at him, but will do so immediately if the adult speaks or tickles him. By the age of nine months the baby is playing well with small objects which he picks up, transfers from one hand to the other and frequently ends by putting in his mouth. At 15 months he is ready for constructive play and will build a tower of two or three bricks. Hearing and Speech Even at} the age of one month a baby may be startled by a loud noise. By three months he may be quietened by a voice talking to him and when happy will vocalize when he smiles. By six months there should be no doubt as to whether the infant can hear as he will turn immediately toward his mother's voice. Speech develops more slowly. A baby makes "da-da", "ma-ma", "ba-ba" noises from the age of nine months and these are often confused with speech. When questioning the mother therefore it is essential to discover whether the words used are "with meaning". That is to say "da-da" is said in the father's presence only. By 15 months the child is able to say two to three words well, and by two years should be putting a few words together in recognizable sentences. Social Behaviour and Play The neonate spends most of his time sleeping or sucking. When not doing either of these he is usually crying. The time spent on the latter exercise gradually increases until by the age of eight weeks most normal babies cry for about two hours out of the 24. At three months the baby shows obvious pleasure when someone plays with him. By six months he can grasp and play with toys and takes pleasure in playing with his feet. He is friendly with strangers but at nine months may turn from them to bury his face in his mother's shoulder. He should drink well from a cup and likes to hold a spoon although he cannot yet feed himself. Grasping comes long before letting go. A child can hold on to the playpen when standing, or can show a toy to an adult, but he cannot let go in order to sit down nor can he give the toy to the adult. By 12 months, however, he has acquired the act of letting go and practises it by frequently throwing objects to the floor and watching them fall. At the age of 12 months the baby will hold out his arm to assist his mother to put his coat on. DEVELOPMENTAL DIAGNOSIS It is not possible to give an accurate estimate of what a child's intelligence will be like in later years from a developmental examination at six months, but it is usually possible to prognosticate into which of four main intelligence groups the child will fall: an I.Q. of 100 or above, an LQ. between 75 and 100, an LQ. between 50 and 75 or an I.Q. below 50. If all aspects of development are delayed, the most probable reason is that the child is mentally retarded. Three other conditions may also cause general retardation of development: Prematurity. If a baby has been born a month prematurely, he cannot be expected, at the age of three months, to do the things that a full-term baby of three months should do. This factor of prematurity becomes of less importance as the child grows older. Severe illness. A baby who has been severely ill with, for instance an intestinal obstruction, may be too weak to sit at the expected age and too unhappy to smile or vocalize. He may, therefore, appear to be mentally retarded, but as he recovers it will be found that not only does he improve physically, but also developmentally. In time he will catch up with other children of the same chronological age. The deprived child. However well a baby is looked after physically, if he is deprived of the love of his mother, he is liable to become retarded in development. The baby is particularly vulnerable between the ages of seven months and five years, and at this age should never be taken away from his mother if it can be avoided. The deprived child looks very like a mentally retarded child, in fact, it may not be possible to distinguish between them. The best way to make the diagnosis is to send the baby home to his mother and watch the remarkable transformation which takes place in the next few weeks. The baby who previously lay apathetically in his cot is now sitting up and playing. Very often he is feeding better, too, and for this reason has put on weight. The differentiation between mental retardation, prematurity, severe illness and the deprivation syndrome may be made more difficult because two or more of these conditions may be operative at the same time. It is essential that the correct diagnosis be made, however, as the management of the case varies with the cause. Isolated Developmental Delay Sometimes a child's development is delayed in one aspect only, for instance, speech. If there are no other abnormal features a child may not start to speak until two or three years of age and yet be quite normal. Isolated delay in motor development, however, is more likely to indicate some abnormality. For instance, a child might present with lateness in sitting. If other fields of development were normal this could be due to a local lesion such as a congenital dislocation of the hip or a paraplegia. Mutiple Handicaps The greatest difficulty with developmental diagnosis arises with multiple handicaps. Probably the commonest example of this is the combination of cerebral palsy and mental retardation. In the past this led to many misdiagnoses: in particular, severely athetoid children were thought to be mentally retarded when in fact their intelligence was normal, It is important in these cases that all fields of development should be considered and undue emphasis must not be placed on gross motor development. Children with athetosis do not usually show the characteristic movements until after the age of one year. Before this they may show hypotonia which causes retardation of motor development. Other fields of development — speech, vision and social — should be normal, thus showing that the child is not mentally retarded. Considerable difficulty sometimes occurs if there is a combination of athetosis and deafness. Here two different developmental fields are abnormal, and such a child might well be considered to be mentally retarded. It is particularly in the treatment of cerebral palsy that accurate developmental diagnosis is essential. Every effort must be made to discover the probable level of intelligence of the child. At one time all children with cerebral palsy, or Little's disease as it was then called, were considered to be mentally retarded. Then the pendulum swung in the opposite direction and sometimes spastic children were credited with too high an intelligence and it was thought that most if not all could be greatly helped by treatment. It is now realized that only those who have sufficient intelligence to respond to and benefit by their training are worth treating. It is in this sphere that developmental diagnosis can be of particular value. SUMMARY The development of a child proceeds in a precise and regular manner. Knowledge of normal development enables the examiner to appreciate when development is abnormal. Generalized developmental retardation occurs mainly in mental deficiency, prematurity, severe physical illness and the deprived child. Multiple handicaps may mimic mental retardation if several spheres of development are affected such as the motor and hearing spheres in an athetoid child with deafness. It is important, but often difficult, to recognize the degree of mental retardation in a child with cerebral palsy. The success of treatment depends largely on the intelligence of the child. A knowledge of developmental diagnosis is of value in deciding how much of the child's handicap is due to the cerebral palsy and how much to mental retardation.