At times it may be necessary to carry out some reflex tests during a review, if I suspect that a child has retained one or more primitive reflexes connected to their hands and mouth. Normally these reflexes will have inhibited during baby’s first year, but occasionally they are retained and can impact speech and language. It may be possible to help the child integrate the reflexes with some exercises to minimise any difficulties.
Rooting and Sucking
Both these reflexes influence the movement of the tongue and lips. The Rooting reflex emerges at birth as the lips purse in search of food and, once in contact, draw the object into the mouth. If the object is a nipple or teat of a bottle, the reflex has served its purpose and the baby satisfies their hunger by feeding, thus activating the Sucking reflex. The tongue muscles push the nipple or teat to the roof of the mouth and rhythmic sucking releases the milk.
If rooting does not result in the discovery of food because the baby has been separated from the mother or they are being fed by intravenous drip, after a couple of days the Rooting reflex will wane. This means that the sensitive muscles around the mouth used in the pursing movement will not be exercised fully and this may impact the future control of these muscles when the child starts to experiment with speech.
Other difficulties may occur if the Sucking reflex does not inhibit within its rightful period of 3-4 months postnatal. Its continued presence can affect the development of a more mature swallow pattern as the tongue is positioned further forward in the mouth and the ability to chew is hampered. An immature swallow pattern can result in the formation of an arched palate. Also, the retention of this reflex may affect full closure of the mouth, breathing patterns and in turn influence the way that words come to be articulated.
The Babkin response is present from birth for approximately four months, with a palmar-mandibular link of pressure on the palm eliciting a rotation of the head to the midline, flexion of the head and the mouth opening in anticipation of feeding. If this response continues, the child may find that any task using the hands provokes mouth movements and vice versa, creating the possibility of tension in facial muscle usage and it would be an indicator that the motor development aspect of speech and language has not progressed correctly.
A baby’s hand movements develop from a kneading action to a whole hand grasp as objects are interrogated by placing in the mouth and the sensory world around the baby is interpreted through hand and mouth investigation and thence onto a pincer grip of thumb and forefinger. If the Palmar reflex is retained, the thumb and four fingers move as one, with difficulty shown in pincer grip holds and independent movement of fingers for fine motor skills. In the babbling phase during the second half of the first year, the baby’s toes can be seen extending and flexing prior to vocalisation.
Refinement of both hand and feet movements require the function of the cerebral cortex and corticospinal tract and a major phase in the myelination of the corticospinal tract and the part of the cerebellum responsible for both articulation of the hands, feet and mouth around this time will facilitate this. Sensitive responses to palmar and/or plantar reflex tests and speech difficulties in the older child may point to neurological development delays relating to this myelination stage.
A study in 1925 found that children with speech and language difficulties were more likely than their peers to have cross-laterality or ambiguous laterality issues. Further research done in subsequent years supported this finding. When we refer to speech and language, we include the ability to listen and decode language for writing and comprehension too. We learn to read and write through using most of our senses; through listening, looking, speaking and holding a pencil, relying on good proprioceptive feedback and balance as our vestibular system interacts with the visual system.
The impact of cross or ambiguous laterality issues
Cross laterality means that when we test the hands, feet, eyes and ears for dominance there will be a mix of left and right answers. In some cases, a person will be able to perform equally well with either hand or foot and they would be classified as having ambiguous laterality. Either situation can mean that the brain has to work harder to handle incoming signals. Children with learning difficulties often complain of extreme tiredness. Processing sensory information is simply not happening in the most efficient manner.
We expect a certain amount of ambiguity in a child up to the age of 7-8 years, but after demyelination around this age, when the brain prunes away those neural connections that are no longer useful, we should see the same choice of side for each action.
The brain is very adaptable, it functions with neural plasticity and although there are locations in the brain with defined sensory processing centres, for instance the left hemisphere is home to the major speech and language processing areas, there are other parts of the brain which can also process speech and language.
The role of the leading ear
If your right ear is the leading ear, or dominant ear, it prefers to pick up the auditory signals and sends the information across the corpus callosum to be interpreted in the left hemisphere. If your left ear is dominant, the signals received will be processed in the right hemisphere first, where interpretation is adequate but once the input is more complex, the information will need to be referred to the left hemisphere afterwards for full understanding. In fact, signals will be dancing across the hemispheres all the time, as you will have input from the eyes and the proprioceptive feedback from your body placement as well.
There are many aspects to the jigsaw of learning or comprehension dysfunction and cross-laterality indications are just some of the pieces we look for, to try and understand what is going on for that person. Some children (and adults) experience confusion when they feel that their comprehension levels are poor. They can hear well, but they can neither retain details well, nor cope when a lot of information is fired at them.
How do we find out which is the leading ear?
During an assessment for the Johansen programme there are monaural and dichotic audiometric tests to perform which help determine which is the leading ear. On the audiogram for the threshold hearing test, you can often see the plot lines for the readings cross over each other on the trajectory from 250-8000 Hz. This is another indicator that the auditory processing is not operating smoothly.
All the results are input into the specialist music software so that individualised compositions can be made, facilitating new neural pathways to grow for a better processing of sound for the client.
Orton, S. T. (1925), ‘“Word-blindness” in school children’. Arch. Neur. Psychiat, 14, 5, 581–615.