Primitive reflexes
The primitive reflexes are a group of motor reflexes found in new-born babies. They develop in utero and share the characteristics of being present at birth in a full-term, healthy baby and are mediated or arise from the brainstem.
A reflex is an immediate involuntary response evoked by a given stimulus. All reflex responses are involuntary and are not cognitive or actively set off. A stimulus which triggers a reflex always results in the same response. Primitive reflexes are motor/movement reflexes and a specific stimuli will lead to the same pattern or sequence of movements.
A large number of reflexes are found in the brainstem – a very old area of the brain positioned between the spinal cord and the cerebral hemispheres. The first of the primitive reflexes to emerge in utero is the Moro reflex, which appears between nine – twelve weeks after conception. In the first year of life, as a child grows and matures, the primitive reflexes are integrated or absorbed and replaced by the postural reflexes. Primitive reflexes never disappear but can be activated deliberately and they might gradually re-emerge with aging. Following head injury or cerebral insult or disease, they may dramatically re-appear.
The role of primitive reflexes is two-fold: firstly, to help with survival in those delicate early months when the baby’s nervous system is not fully connected and secondly, to assist the baby to move. As previously mentioned, reflex movement is patterned, consistent and involuntary movement but this movement helps to make the baby aware of his body and his surroundings. Gradually, as the primitive reflexes retreat or are integrated, conscious voluntary movements will be established.
The primitive reflexes can be divided into three groups – the multisensory reflex, primitive reflexes of position and the primitive tactile reflexes.
The Multisensory Reflex – the Moro Reflex
The Moro reflex is the only one of the primitive reflexes which can be triggered by all the senses; that is head position (vestibular), touch, sight (visual), sound (auditory), smell (olfactory) and movement factors such as baby’s kicking or sneezing. It is the matriarch of the early reflexes – the first to develop in utero and the first to be integrated. In a normal, full-term infant this will be within the first four months of life.
When activated, the Moro reflex causes the baby to throw his arms open and away from his body (extension and abduction) and his hands open. His legs also abduct but not quite so markedly. At the same time, he takes in a sharp, sudden breath (inspiration). There is a short pause and then the limbs are drawn back into the body. He may well cry (the expiration phase) or be visibly upset.
The purpose of the Moro reflex is protective and it assists survival in a neonate whose fight/flight mechanisms are too immature to be of benefit. The arousal caused by an activated Moro reflex and the sympathetic nervous system responses of increased heart rate, rates of breathing and raising of blood pressure, together with crying will attract the mother’s attention and help.
The Moro reflex is one of the reflexes tested after birth. If it is not elicited, this may indicate that the baby is heavily sedated or that there has been a prenatal or perinatal event. It may be difficult to elicit a response in some premature babies and babies with altered tone may not show a Moro, especially those with increased tone – hypertonia. An asymmetrical response may be due to an Erb’s palsy, a fractured clavicle or humerus, or to hemiplegia.
What happens if a Moro reflex is retained?
A child with a retained Moro is likely to be hypersensitive to sensory input. By the time a child is of school age, all the primitive reflexes should be integrated and the postural reflexes present. This stage of neurological development indicates that the unconscious brainstem- triggered response to all sensory stimulation has been replaced by higher, cognitive responses. The Moro reflex is multisensory – it can be triggered by many or all of the senses – and because of this characteristic, where the Moro is retained, there can be profound motor and physiological effects in a child.
It is unlikely that a child with a retained Moro will be hypersensitive to all sensory stimulation but some may. To ‘protect’ himself from this overload, a child with a retained Moro will be constantly alert and on guard against his little body which can trip him into exaggerated reactions to certain stimuli.
Vestibular hypersensitivity may trigger responses such as motion sickness, intolerance of fairground rides, poor coordination particularly with hand/eye movements and balance insecurity (perhaps compounded by poor postural reflexes).
Hypersensitivity to touch can lead to a child who is startled by unexpected physical contact, tickling or close physical contact and ‘invasion’ of body space.
Visual hypersensitivity can lead to several issues; visual-perceptual problems such as stimulus bound effect (eyes being drawn to the edges of shapes, scenes, pictures to the detriment of understanding of the whole image), poor reaction to light (pupil responses) and tiring under florescent lighting, photosensitivity, immature eye movements and slow reaction to fast-approaching objects such as balls.
Hypersensitivity to auditory input may result in an inability to discriminate sounds or to closing out background noise. Distractibility may be profound due to auditory overload and this can lead to fatigue.
Physiological and emotional effects of a retained Moro in a child result from the constant fight/flight preparedness and, as he matures, the learnt anticipation of his body’s nasty reaction to much of life. As a result, a child may not match his peers in apparent maturity and might develop one of two coping strategies. He may be shy and fearful, poor at peer-group relationships and coping with affection and loathing of sport or he may be aggressive, excitable, unable to read the body language of his peers and be dominating. A child with a retained Moro hates change and is unable to be flexible or adaptable to situations, especially those over which he perceives he has no control.
The biochemical effects of a Moro leads to an over-production of the stress hormones, cortisol and adrenalin. This is a double hit because these hormones are designed to increase sensitivity and reactivity. Thus a Moro child is in a loop of over-reaction to stimuli and a hormonal state which is designed to heighten such a response. Also these hormones assist the body’s defence against infection and allergy but in a child with a retained Moro, there may be a lowering of the efficacy in the immune responses and so the child is more likely to suffer from allergies, to pick up every cold going at school and perhaps have food or additive sensitivities. His glucose metabolism may be fast, also resulting in sudden onset of fatigue and mood swings. All these effects compound an already challenged situation in both the classroom and the child’s academic performance.
Primitive reflexes of position
There are three primitive reflexes of position – the Tonic Labyrinthine Reflex (TLR), the Asymmetrical Tonic Neck Reflex (ATNR) and the Symmetrical Tonic Neck Reflex (STNR). These reflexes affect all four limbs. The TLR is vestibular in origin; that is, it is affected by head position and activated by the labyrinthine apparatus of the ear. The tonic neck reflexes (ATNR and STNR) are activated by cervical spine position or the position of the neck, so by default the position of the head as well.
The Tonic Labyrinthine Reflex (TLR)
The TLR has two components – the TLR forwards or into flexion and the TLR backwards or into extension. The TLRf develops in utero at about 12 weeks gestation and flexus habitus, the flexed position of a baby in the womb, is thought to be the first manifestation of this reflex. The TLR into extension is present at birth and plays an active part in a normal vaginal delivery. It is not possible in the tight space in utero for a neonate to extend his spine until he emerges from the birth canal.
The TLR in flexion and extension should be present at birth and TLRf is usually inhibited by the age of 4 months. The TLR into extension takes longer to integrate – perhaps three and a half years. This is due to the processes involved in establishing the postural reflexes and their assimilation.
To activate the TLRf, the baby’s head is brought to his chest. His arms bend into his body and his hips flex and knees bend, as his legs are drawn into his tummy. The TLR into extension is shown by letting the baby’s head drop below the level of his spine. His back will arch up, his shoulders retract and his arms straighten and move back away from his body.
The purpose of the TLR is to provide a mechanism for altering tone in the neonate. Muscle tone is also reflex in origin but it is primarily a stretch reflex. Tone is maintained and adjusted to meet the requirement of posture and movement and needs to be high enough to resist the effects of gravity but low enough to allow movement to take place – the Goldilock zone. The nervous system in a full term neonate is not yet mature enough for normal tone to be reliably established. The TLR allows switching between flexor and extensor tone depending on the position of the baby’s head.
The new-born infant is a very flexed and curled up little person but over the first few weeks of life, extension/straightening out occurs in the hips and legs. The first area to come ‘under control’ is the head and the first movement the baby will make voluntarily is lifting his head from prone (when he is on his tummy). The neck has the largest number of proprioceptors of any area in the body – these ‘sensors’ feedback information on position, movement and balance. The more that head control in extension is established, the more the TLR in flexion is integrated. By the time there is no head lag (dropping back of the head) when the baby is pulled up into sitting – at about 4 months – the TLRf should be inhibited.
The TLR into extension takes longer to be absorbed because it has a role to play as each new position is mastered by the growing and developing child. The learning of these postures places a (normal) stress on a child until the new position is firm and reliable and so hints of the TLF may be present fleetingly. By the time a child is three and a half, the TLR should be integrated in both its forms.
What happens if the TLR is retained?
There are two main effects of a retained TLR – a vestibular effect and that on tone.
The vestibular effects may present as motion sickness, poor balance, visual-perception problems (the ability to correctly interpret information received through sight), issues with spatial concepts (complex cognitive skills which allows a child, for example, to know: right from left, up/down, on/in, was from saw, how to fill a sheet of paper with information). Specific visual problems may include a lack of near-point convergence and figure-ground effect (the ability to work out which is the object and which the background). The child may also have poor sequencing skills and a poor concept of time.
The effects on tone are dependent on which TLR is retained. TLR in flexion or forwards may cause hypotonus – lower than normal tone which can manifest as weakness, poor posture and slumping. A retained TLR in extension may cause hypertonus/ increased tone and presents as the lack of smooth movement or toe-walking.
The Asymmetrical Tonic Neck Reflex (ATNR)
The ATNR is a well-recognised primitive reflex and is also known as the fencing reflex. It emerges at about 18 weeks post conception. This is about the time that the mother becomes aware of the baby moving in utero. The baby uses the ATNR to reposition himself in the womb in response to the mother’s changes in position. The ATNR should be fully present at birth – in fact it is an important component in a normal vaginal delivery and the baby activates the ATNR to assist with moving down the birth canal. The ATNR is usually integrated by the age of six months.
This reflex is triggered by rotation of the head – turning the head from left to right – not flexion/extension – moving backwards and forwards. If a baby’s head is turned to the right, his right arm and leg will extend or straighten and tone will be slightly increased on this side. His left arm and leg bend or flex. Turning his head to the left elicits the same pattern but this time there is extension in the left limbs and flexion in the right.
The purpose of the ATNR is firstly to assist in the process of a normal delivery. The ATNR will also help the neonate who is prone (on his tummy) to free his mouth and nose for breathing. It makes the baby aware of homolateral movement; that is, movement on the same side of the body.
As the baby grows, it is believed that the ATNR strengthens hand-eye coordination. A new infant has a fixed gaze distance of about 6½” or 17 cm and his eyes are drawn to the periphery of objects close to him. The ATNR alerts the baby to the existence of his hand – when he turns his head to one side his hand will appear on that side and the movement will catch his eye – and it allows the baby to alternate between near point peripheral vision, when his head is centrally placed and his hands in front of his face, to focal vision when he follows his hand and focuses at arm’s length.
As full head control develops and the nervous system and cerebral cortex mature, the ATNR should be inhibited and the Symmetrical Tonic Neck Reflex will appear.
What happens if the ATNR is retained?
A child with a retained ATNR can present with one or more of several issues, most as a result of the interference caused to normal physical development and the subsequent effects on learning. An ATNR child is always being forced into the pattern of the ATNR, albeit in a slight and perhaps unobvious fashion, rather than being able to undertake voluntary movement desired. This can be frustrating for the child and compromises his full physical development.
The inability to roll over or commando crawl results because the retained ATNR prevents head rotation and flexion/bending on the same side. If you turn your head to the right, you need to be able to bend your right arm and leg to roll over to the right. Commando crawling requires the ability to have the right arm and left leg flexed/bent at the same time and then pushing through to extension/straightening of these limbs to propel oneself forwards. A retained ATNR may result in homologous movement instead – both arms are used together to pull the body forwards and the legs may just drag behind or are used together too. Crawling and creeping, important for cross-pattern development which enhances hand-eye coordination and integration of vestibular information, will be compromised with a retained ATNR.
Balance is affected – in standing a child will feel unstable and insecure unless his head is held still and in the midline. Turning his head will make his leg on the opposite, occipital side (the back of the head side) feel weak due to slight lowering of tone. In all other positions, the effect will be the same, although perhaps not so marked. When walking, the child’s gait may look strange especially if he swings his left arm forward with his left leg (rather than opposite arm and leg) in a homolateral/one sided pattern.
Difficulty crossing the midline causes a series of issues. A child needs to learn, through movement, that both sides of the body, the page, the pathway across the carpet of his car can be traversed through the midline. There may be difficulties in: manipulating an object with both hands and passing the object between hands which may not be learnt properly: writing is compromised, as is reading, because it is necessary for the hand to go to the other side of the page and for eyes to scan and track across a page in unison: cross-laterality or mixed laterality is a consequence – the child does not have a dominant side, so has to consciously think which hand to use rather than automatically using the dominant hand. Visual-perceptual difficulties, such a symmetrical presentation of figures or symbols on a page, may be seen.
Poor visual-motor integration – hand-eye coordination – can be marked in a child with a retained ATNR because, whilst the child may be able to cope with reading by compensating for eye movements alone, writing needs both hand and eye movements to be accurate and controlled. A child may quickly learn coping strategies for reading and writing; he may sit differently with his arm out straight; he may turn the paper or book to an angle which suits him better rather than having these usually aligned; his pen grip may be very tight or unusual to override the desire for his hand to open when the head is turned towards it.
Awkwardness or a slightly different way of moving in comparison to his peers may cause the ATNR child angst. His ball skills may be below par and he might appear clumsy when catching or kicking a ball. In the swimming pool, his backstroke will be fine (his head is kept in the midline) but his front crawl may only be half right – as he turns his head to breathe, the arm on that side will want to move away from his body, not go smoothly towards his ear in line with his body. If he has not developed dominance, he may be fractionally slower than his peers in various school situations while he has to actively choose between right or left. His motor planning skills – the desired intent from a movement – and the reaction of his body will be poorly matched because the ATNR kicks in following his turning/rotation of his head before he has time to think.
Cognitive effects may be seen. The subconscious effect required to override a retained ATNR is energy-sapping. A child with an ATNR may be very capable orally in the classroom but, when writing is required or under stress, such as in an exam, he may well appear to ‘let himself down’ or perform below the level expected of him. The fluency required to think and write at the same time seems to be blocked. This is frustrating for all concerned but is a true effect of a retained ATNR and is not the child’s ‘fault’.
The Symmetrical Tonic Neck Reflex (STNR)
The STNR is difficult reflex to categorise. Strictly speaking, it is not a true primitive reflex because it is not present for any length of time at birth. Nor is it a postural reflex because it should not be retained. It is, however, a reflex of position and sequentially the last of these reflexes to appear.
Like the TLR, the STNR has two types – the STNR into flexion and the STNR into extension. Both appear between six and nine months of age and should be inhibited by the time the child reaches his first birthday.
The STNR is triggered by neck position and flexion/extension of the head. Unlike the TLR, the STNR does not cause a whole body response of flexion/extension but the reflex separates the body into two halves at the waist – two opposite patterns of movement happen to the top and bottom halves of the body. When the chin lifts, the arms go into extension/straighten and the hips and legs flex/bend; conversely, when the head goes down the arms flex/bend and the legs extend/straighten. The STNR is beautifully demonstrated by a toddler standing in his cot – his mother comes to lift him out and he looks up and raises his arms and promptly sits down because his lower limbs have gone into flexion.
The purpose of the STNR is to inhibit the TLR and allow the child to get into a position to creep or crawl. This is seen when a child raises his head and shoulders when in prone/on his tummy – his arms extend and knees and hips flex and this helps him get onto his hands and knees. The STNR is inhibited by crawling because this is a movement in which the limbs must move contra-laterally/in opposites and independently of head position. The rocking movement, used by infants as they attempt to crawl, is thought to help break down the STNR.
By the time the STNR appears, the child should be able to sit unaided; he is rolling and getting himself into sitting. The strength in his legs is improving – his legs are always behind his arms due to the cephalo-caudal (head to toe) sequence of development. Now he wants to stand. He will use the STNR to help him get up from sitting to standing. If he keeps his head down and arms bent as he pulls upwards, his legs will extend, helping him upright.
The STNR is also thought to help develop visual accommodation – the ability to maintain a clear image of an object as its distance changes. The ATNR has assisted in focusing to arm’s length. Now the STNR in flexion brings the focus back to near distance (between the knees) and, as the head is lifted and the STNR in extension established, the focus is moved to far distance.
What happens if the STNR is retained?
One of the more obvious signs of a retained STNR is seen in the posture, both active and static. If the STNR pattern has not been inhibited, head position will still affect the tone of the upper and lower body differently. When walking, the gait may have simian/monkey-like quality. In standing, the posture is slouched with shoulders rounded and the chin forward. In sitting on the floor, a child may adopt a ‘W’ position. Sitting cross-legged on the floor is almost impossible if the STNR is strong because, with the head flexed/bent, the legs want to be extended/straight. Sitting on a chair at a desk also causes problems because again, if the arms are flexed/bent and the chin down, the legs want to be straight. The child may end up lying on his desk when writing. He may also tuck his feet under his bottom or hook his feet round the legs of the chair to lock his legs and keep them ‘under control’.
As a result of the issues caused by posture, a STNR child may have problems with concentration and attention. He may appear to be fidgety and unable to sit still, all because it is too uncomfortable to be so.
A retained STNR will have affects on vision – on accommodation and also on vertical tracking. The child may find actions like catching a ball difficult, as his ability to focus correctly on a moving object (especially one moving towards him) may be compromised. He will also find it awkward to copy from a blackboard or white board as switching from far to near vision quickly will be slower for him than that of his peer group. Vertical tracking, where the eyes move from top to bottom, has been shown to be impaired in STNR children. This affects tasks such as lining up information or numbers in columns and can lead to trouble assessing height, such as walking onto a descending escalator or when standing on the edge of a diving board or cliff.
A child with a retained STNR may be a messy eater and end up wearing his food rather than getting it into his mouth. He may also find swimming a challenge – whenever he raises his head above the water his lower limbs will bend, so this is a child who likes to swim under water.
Primitive tactile reflexes
There are many primitive tactile reflexes and, as their name suggests, these reflexes are triggered by touch. They are also classified as grasp reflexes. Six will be discussed here. In order of their appearance, these are the palmar, plantar, Spinal Gallant, rooting, suck and swallow, and Babinski reflexes.
The palmar grasp reflex
The palmar reflex emerges at 11 weeks in utero and should be present at birth. It is a reflex of two parts – the grasp and the response to traction or the effect of pulling. If an object such as a finger is placed in the palm, the fingers close round the object (the grasp). If the fingers are then drawn gently upwards, the grip is reinforced (the traction effect) and it would appear that the baby could support its own weight if so suspended. If the baby’s head is not in the midline, the grasp will be strongest on the occiput side/the side nearest the back of the head.
The purpose of the palmar reflex is deep-rooted; it helps the neonate cling to his mother for safety. In the first post-natal months, there is a connection between the palmar reflex and sucking and vice versa, such that there is reciprocal elicitation of these reflexes.
This specific link is known as the Babkin reflex – the palmar-mandibular response. When pressure is applied to the palms, the neonate may flex and/or rotate his head and open his mouth. The Babkin response demonstrates the hand-mouth sensorimotor links which are present in the early months.
An exceptionally strong palmar reflex may be found in an infant with kernicterus and hypertonic cerebral palsy. It will be unilateral in hemiplegia.
The palmar reflex should be inhibited in the first three to six months of life. A baby losing his palmar reflex will drive his parents mad by his incessant dropping of an object and the resultant demands that this is retrieved and handed back – only for it to be dropped again. The child is learning to ‘let go’ of an object previously held in an uncontrolled fashion because the reflex dictated it be so. Once he learns to release the object, a child can start to develop more mature hand movements, the most important and useful of which is opposition.
What happens if the palmar reflex is retained?
If a child has not learnt how to release objects, his manual dexterity and fine motor use of his hand will be compromised. He will use a pencil, feeding tools and items such as scissors inappropriately. This leads to the need for increased effort to perform tasks and the likelihood that these tasks are performed inefficiently and with reduced accuracy.
There may be overflow and lack of separation of hand/mouth movements so that the child uses his mouth when he writes or overuses his arms and hands when he talks. In severe cases, the development of speech may be affected because articulation is affected by a continuing Babkin response.
Hypersensitivity in the palm of the hand and intense dislike of touch in the hand is a nuisance and can prevent correct use of implements.
The plantar grasp reflex
The plantar reflex, like the palmar grasp reflex, emerges at 11 weeks in utero but it is inhibited a little later, usually by the time the infant learns to stand. The reflex is tested by gently stroking the sole of the foot behind the toes. The toes will curl/flex downwards towards the stimulation and the foot will plantar flex/moves away from the shin.
The plantar reflex is a grasp reflex but in the human infant only weakly so. Its purpose is to complement the palmar reflex and assist the neonate in grasping onto his mother. Its presence allows for movements of the toes and foot and helps stimulate movement of the whole leg.
One of its most important roles is to inhibit the Babinski reflex within the first year of life.
What happens if the plantar reflex is retained?
Gravitational insecurity in standing is a major casualty of a retained plantar reflex. If foot placement when walking or foot position in standing is incorrect, the child will feel unstable and will not like being upright.
A child may suffer from hypersensitivity to touch on the soles of the feet and find uneven surfaces impossible to negotiate.
If balance is shifted away from the soles of the feet to the balls of the feet, the child may be a toe-walker.
The Spinal Galant Reflex
The Spinal Galant reflex emerges at 20 weeks in utero and should be inhibited by about six months of age. It may also be classified as a spinal reflex and is tested with the child either prone/on his tummy or held in ventral suspension/face down. Stimulation of the skin on one side of the spine will cause flexion/bending towards the side of the stimulus. (Stimulation to both sides of the spine from the pelvis to the neck simultaneously will cause the child to flex/bend both arms and legs, extend his head, cry out and probably empty his bladder. This is the Perez del Pulgar Marx reflex.)
The purpose and value of the Spinal Galant reflex is not fully understood but it is believed to assist with the birth process. It can also help with priming trunk movement and the initiation of the amphibian reflex, both necessary for commando crawling, crawling on hands and knees and hip rotation in walking.
What happens if the Spinal Galant reflex is retained?
A child with a Spinal Galant reflex beyond the age of one will be unable to sit still and may appear to have ‘ants in his pants’. He will fidget, squirm and not remain quietly in one position. He may dislike labels in his clothes, belts, anything round his waist and be hypersensitive to all clothing round his middle.
Distractibility, as a result of the unwanted sensations above, means that this child may have a poor attention and concentration span. As he dislikes sitting, he may prefer to work on the floor on his tummy.
Nocturnal enuresis or bed-wetting may be associated with a school aged child with a retained Spinal Galant reflex. Poor bladder control might be as a result of motor developmental delay and may also be triggered by the Spinal Galant reflex or the Perez reflex, which can be triggered when the child lies on his back or rolls over in bed.
The rooting reflex
The rooting (searching) reflex is one of many oral reflexes, which gradually appear from about twelve weeks in utero and should be present at birth. The rooting reflex emerges at about 24 weeks post-conception and is seen in utero when stimulation of the side of the mouth or cheek results in turning of the head towards the stimulus.
The rooting reflex is strongest immediately after birth and it is important that the neonate’s earliest attempts are gratified. The newborn will root or search and the reflex is triggered on contact or touch at the side of the mouth, cheek or nose. The baby turns his head towards the stimulus, opens his mouth and extends his tongue. The nipple or teat in his mouth makes contact with the roof of the mouth and this contact sets off rhythmic suckling movements – thus the ‘feeding reflex’ is put into action. If, for medical reasons, the baby is not able to feed orally immediately after birth, he may go on to have difficulties feeding at a later stage.
The rooting reflex is best tested when the baby is hungry – after a feed it may be harder to demonstrate.
The purpose of the rooting reflex is obvious. There is a need for an innate pattern to search for food before vision is developed. As the baby grows, his responses become conditioned and the sight of the breast or bottle will have him turn his head to the necessary position and he will open his mouth with no physical contact.
What happens if the rooting reflex is retained?
Hypersensitivity round the mouth area may be an issue with a retained rooting reflex.
Poor fine muscle control of the internal and external mouth area may lead to problems with correct and full articulation needed for speech.
The tongue position may be too far forward making, swallowing and chewing difficult resulting in poor control of food in the mouth and dribbling.
The suck and swallow reflexes
These reflexes gradually appear from about twelve weeks in utero and should be present at birth. The first to be seen in utero is the swallow, followed by sucking and complementary tongue movements. Ultrasound observation of foetuses has shown that suck and swallow together appears from about 23 weeks but may not be effective until at least 34 weeks – premature babies born before 34 weeks often have difficulties with efficient oral feeding.
The mechanics of sucking and suckling are different, although the terms are often used indiscriminately. Suckling describes a combination of jaw movements (up and down) and tongue movements (forwards and backwards). Sucking is a more mature movement with less jaw action and a marked improvement in lip seal, allowing for negative pressure to be built up within the mouth.
Suckling has an inhibitory effect on the ATNR, regardless of the baby’s head position. It is thought that suckling may help train monocular/one eye vision. This may only be seen in breast-fed babies – one eye will be obscured during feeding on one side and vice versa. In bottle-fed babies, the baby is usually held to the same side – a right-handed person will usually hold a baby in their left arm to feed.
The action of feeding is not only nutritional. The combination of suckling, swallowing and breathing and the coordination of these is a complex sensori-motor skill essential for the development of speech.
What happens if the suck and swallow reflexes are retained?
The sucking of fingers, thumb and clothes may continue if these reflexes are retained because there is a need for oral stimulation.
An immature swallow pattern may lead to problems will the correct development of the palate.
Poor control of muscles around the mouth may result in speech and articulation issues.
There may be a retained links with hand and mouth movement, especially if the palmar or Babkin response is also present.
The Babinski reflex
The Babinski reflex is also known as the extensor plantar response and is not to be confused with the plantar grasp reflex, which is a reflex of flexion/bending. It is present at birth and is demonstrated by stroking the outer border of the sole of the foot (on the side of the little toe). The foot will dorsiflex/the ankle will bend upwards and the toes straighten and fan out, especially the big toe.
It is normal to see this reflex in an infant of a year or perhaps two years of age and it is seen in this group only because a certain part of the nervous system, which connects the spinal cord and the brain, is poorly wired up – this is specifically described as poor myelination of the corticospinal tract.
The Babinski can be seen working with the plantar grasp reflex in babies who have yet to stand. Reflex feet and toe movements can be seen in an excited child or just before the child makes a sound, babbles or talks. A crawling baby may illicit the Babinski response and dig his big toe into the floor to help with pushing through with his foot and leg. The Babinski reflex is thought to be inhibited by the plantar grasp reflex and the presence of the adult plantar reflex.
What happens if the Babinski reflex is retained?
A retained Babinski in older children and adults is considered pathological and is a sign of neurological abnormality, which merits immediate investigation.
It is possible to see a temporary Babinski in sever hypoglycaemia/low blood sugar. This will be reversible on administration of intravenous glucose.