Sensory Development during the Early Years

Content

The vestibular system
The Hearing Organ
Perception of smell.
Visual perception
Some Important Questions

The first sensory organs develop within the inner ear as early as four months after conception, and begin to function whilst the baby is still in the womb. Within the inner ear there are two chambers:-

The vestibular system monitors balance and physical movements and presents related information to the body and brain. (Sense of movement within space and the influence of gravity.)
The cochlea is the hearing apparatus and this organ monitors the varying frequencies of a sound coming into the ear from the environment. (Auditory senses of hearing)

The very early development and functional ability of the sensory organs of the ear can be related to the importance of movement and accompanying sounds considered to be of primary importance to the young child’s learning.

The vestibular system

All movement is sensed in the inner ear by three semi-circular canals and this is called the vestibular system.

During the baby’s early movements within the womb each of the semi-circular canals senses a particular direction of movement The small and gentle body movements within the womb give the baby its first related neurological information. After the birth the baby can gradually experience a greater and ever developing range of neurological information from the vestibular system.

The vestibular system senses the head movements by the movement of fluid within the three semi-circular canals within each respective ear. The three looped shaped canals are positioned one in each working plane and thereby register movements – forward and backward, from side to side and body rolling – vertical or horizontal rotation. The fluid inside the canals moves across a dense inner lining of small hair like nerve endings. Thus, the information on movement recorded by the nerve sensors in each of the canals can be integrated one unto the other such that the young infant becomes aware of the body’s movements under the influence of gravity.

The sensory receptors within the vestibular system send information to an area of the brain called the Cerebellum and to the eyes. The Cerebellum could be described as the gatekeeper to the brain. From the cerebellum messages are sent to the appropriate areas of left and right brain hemispheres.

The messages sent to the eyes are co-ordinated with visual information. The integration of this sensory information allows the eyes to accommodate the tilting effect on our vision. When we tilt our head we can still see the world ‘straight’. Our visual images do not rotate with our head position in the same way as they do when we use a camera.

However, if a person spins round and round and then stops s/he will get ‘dizzy’. This dizziness is caused by the central fugal force which continues to spin the fluid around inside the semi-circular canals for a short while after the body has stopped moving. The movement of the fluid is communicated to the nerve cells at the back of the eyes and this creates the false illusion that the world is spinning while the body remains still. In reality neither the body nor the world is spinning, it is only the fluid inside the semi-circular canal that is still moving in a spiralling rotation.

The vestibular system is very sensitive and can easily be disrupted by drugs and alcohol. It is not known specifically what influence drugs may have on the neurological information presented by the vestibular system to the brain. Research suggests that disruptions caused by brain damage, drugs, and/or trauma, can disrupt the vestibular information presented to the brain.

During the early years learning is strongly influenced by the organisation of neurological information from the vestibular system. When the baby learns to sit up, to crawl and finally stand, the vestibular information is integrated with other sensory information and the young child learns to discriminate proprioceptive information about the body’s movement within a given space.

The young child’s first movements are initiated by primitive reflexes (automated reflex actions). As the child develops the ability to move according to his own will the primitive reflexes are superseded by posture reflexes. The postural reflexes accommodate movement and balance related to an upright human posture. Some areas of research suggest that early disruptions in the development of the vestibular system can adversely affect the child’s later development and in particular those areas of learning that require an integration of sensory information from different modalities.

The vestibular system supports the synchronisation of learning related to movement and balance associated with both fine and grossed motor control. Remedial programmes related to the vestibular system are also considered it to be supportive to the development of postural reflexes the integration of sensory information. Research suggests that successful development of neurological function associated with the vestibular system, the suppression of primitive reflexes and the development of postural reflexes is indeed essential to normal physical and intellectual development.

Most therapeutic and curative programmes for brain damage and or neurological dysfunction appear to be based on slow rocking movements experienced within the womb and during early infancy, when the baby’s movements embrace the body as a whole and involve the infants’ ability to extend and contract. (Goddard-Blythe, S. 2004; Doman, G. 1974; The Institute for the Achievement of Human Potential; Handle; The sun rise programme at the Option Institute MA, USA. )

‘…..the vestibular system may be the expert in movement but it receives its training through movement……. practice is therefore an essential ingredient of every child’s play, a baby’s first playground is the floor.’ (Goddard, 2004:16)

The movement development of the human infant is slow and complex compared to that of the fawn or the foal. Freedom to play provides vital training during the early years. ‘training of these systems is a gradual process during which maturation of the vestibular pathways involved will take until at least 7 years of age, and continue through puberty and beyond……. Knowledge of one’s own position in space is essential for orientation, directional awareness, and effective operations in space. Immature vestibular functioning is frequently found amongst children who have specific learning difficulties’ (Goddard, 2004:17) and/or brain damage. (Doman, G. 1974)

This suggests that the child’s release from primitive reflexes is related to the development of consciously organised movement through interactive play. Is it that learning is initially dependent upon the neurological information presented to the brain by the vestibular system?

It appears to be generally recognized by those involved with the education of children with profound physical disabilities that vestibular stimulation is particularly important for their wellbeing and future development. The Rompa educational catalogue presents an extensive range of equipment that can give gentle vestibular stimulation to those children who have very limited mobility and in particular those who have not gained an independent upright posture.

The author has organized her own series of remedial exercises designed to promote optimum vestibular stimulation, and associated neurological integration, similar to vestibular information experienced while in the mother’s womb. Using simple equipment that assimilates womb conditions these exercises are presented with minimal external stimulus, combined with facilitated very slow, smooth and gentle rocking movements. The foetal like rocking movements were presented on an air bed or in a basket supported by the floor and the earth’s gravitational force. The three planes of rotation: side to side, forward and back, and horizontal rolling on the floor involved a single smooth movement of up between 90to-360 degrees.

The author’s hypothesis being that by reinstating the very earliest vestibular experiences the brain can identify and correct any neurological faults or areas of weakness established as foundations to subsequent learning experiences. However, the notable success of this work to date has been founded on merely circumstantial evidence, unsupported by any scientific research outside of that presented within other established remedial programmes that have included one or more exercises similar to the vestibular programme used by the author.

The Hearing Organ

‘Both rhythm and sound are created as a result of movement – rhythm is a sequence of movements in time, and sound is made up of vibrations.’ (Goddard, 2004:68)

The ear is the first sensory organ to develop and actively function whilst the baby is in the womb. The reception of vibrations related to sound develops within the inner ear during the first four months development in the womb. Hearing the sounds produced by the mothers bodily functions is combined with later perceptions of sounds related to the mother’s speech and then external sounds from the environment; all be it somewhat muffled and a little distorted by the physical structure and body of fluid around the foetus within the womb.

This very early development and functional ability can be related to the importance of movement and accompanying sounds considered to be of primary importance to the young child’s learning. Within the inner ear there are two chambers:-

The vestibular system monitors balance and physical movements and presents related information to the body and brain.

The cochlea is the hearing apparatus and this organ monitors the varying frequencies of a sound coming into the ear from the environment.

‘both chambers within the inner ear need to work together to produce the dual elements of music – rhythm and sound’. The human ear can detect vibrations that travel in the form of sound waves, covering varying frequencies from 16hz (low)to 25000hz(high)…………………..Modern music has a comparatively limited range of low frequencies. Classical music contains a wide spectrum of frequencies and is far richer in the high frequencies.’ (Goddard, 2004:69)

Our capacity to hear the potential range of sounds detected by the human ear diminishes notably throughout our life time. Between childhood and adolescence the average person’s range of hearing decreases down to the frequency range required for accurate reception and production of the persons first language. .Research also suggests that children who have high levels of musical experience and musical skills acquire and retain greater auditory perceptual skills. (Goddard, 2004:chapters 5-6)

Our capacity to hear the potential range of sounds detected by the human ear diminishes notably throughout our life time. Between childhood and adolescence the average persons range of hearing decreases down to the frequency range required for accurate reception and production of the persons first language. .Research also suggests that children who have high levels of musical experience and musical skills retain and acquire greater auditory perceptual skills. (Goddard, 2004:chapters 5-6)

‘Both rhythm and sound are created as a result of movement – rhythm is a sequence of movements in time, and sound is made up of vibrations.’ (Goddard, 2004:68)

The reception of vibrations related to sound normally develops whilst the baby is in the womb. Initially the unborn baby hears the sounds produced by the mother’s bodily functions and later sounds related to the mother’s speech. Before the birth the baby can hear external sounds from the environment, however, they will be somewhat muffled and a little distorted by the mother’s physical structure and the body of fluid within the womb.

The physical aspects of movement create vibration and vibration creates sound; all vibration emanates sound and thereby gives a deeper meaning to the different perceptions of our worldly domain. Early development and functional ability can be related to the importance of movement and accompanying sounds which are considered to be of primary importance to the young child’s learning.

Audible sounds and visual stimulus give reflective feedback to movement. For example a baby’s rattle in the reflex grasp of the very young baby continually and accurately describes every aspect of the baby’s random movements in terms of associated visual and auditory stimulus.

‘Natural soundscapes illustrate movement through melodic and rhythmic sounds that differ according to time and place and illustrate intervals and timbre.’(Ceppi&zini, 1998: 90).

Music is processed in many different areas in the brain, and perceived in both the right and left hemisphere. In the young child the right hemisphere is thought to be more developed and is considered ‘responsible for melody recognition, language comprehension, rhythm, spatial orientation, and picture recognition.’ (Goddard, 2004:77-78)

Musical instruments give accurate ‘sound’ reflections:-

The kinaesthetic information related to physical movement (as in cause and effect or action and reaction)
Audible sound vibrations related to movement
Observed visual information (as in cause and effect or action and reaction)

‘Singing and instrumental training develop fine motor coordination, but they also train the matching of motor output to visual input…….Musical training also helps to develop left-hemisphere abilities such as sound discrimination, timing, numerical skills, and expressive language….’ (Goddard, 2004:77-78)

Perception of smell.

At birth the young infant immediately engages in an awareness of smell which helps the baby find the milk in the mother’s breast and also initiates the babies bond with the natural mother through the sense of smell. The mother-baby bond is also supported by the specific identification of vocal sounds. The reciprocal ability of both baby and mother to accurately identify each other can be present from birth and retain perfect accuracy even in the presence of other new mothers and their new born babies. This may be due to survival instincts but still it is dependent upon sensory perception and neurological recognition.

Visual perception

Visual perception can only start to develop once the baby’s eyes are open after the birth. Then visual skills are initially dependent upon the babies developing ability to control the eye muscles in order to gain focussing skills. Visual focussing skills and corresponding neurological perceptual skills develop throughout the early years. The work of Glen Doman and Delecato illustrated that babies can learn to read if the printed words are presented in a large enough size and at the right distance, so as to meet their limited visual focusing skillls. This work brought into question the belief that reading ability was age related. The work successfully illustrated the primary importance of visual focussing skills rather than intellectual maturity. This work presented that very young children have the mental capacity to meet written language in the same way that they develop comprehension of verbal language.

Visual skills and corresponding neurological perceptual skills develop throughout the early years.

Some Important Questions

Does the order of sensory development in the normal baby, in itself, have an influence upon related issues of sensory priority and integration during early learning of basic skills.

The chart below illustrates a simple division between those sensory senses that are initiated and develop before birth and those that develop after birth.

Organ	Time of development	Sensory reception
Semi-circular canals within the ear	From app. four months in the womb	Body orientation in space and related influence of gravity
Inner ear- the structures for the reception of sound vibrations –	From app. four months in the womb	Hearing-reception of sounds from 100 htz to
Smell receptors within the nose and taste buds in the mouth.	Birth onwards	Taste of mother’s milk and smell of mother’s body and additional perfumes.
Visual perception through the eyes	Birth onwards	Perception of light followed by a perception of movement which encourages the development of visual focusing skills.

Some important questions to consider in relation sensory development, sensory integration and learning are as follows:-

Is there a special link between those sensory perceptions developed at the same time i.e. the sense of proprioceptive awareness and hearing developed before birth and visual perception and the sense of taste and smell developed after birth.
Do the senses that develop before birth gain a neurological priority over those developed after birth.
Does a disability in the senses developed before birth have a greater or lesser effect on learning than a sensory disability such as blindness that can only limit sensory development after birth.
Are we born with an order of sensory dominance and/or preference or does this develop as a result of worldly sensory experiences gained after we are born.

It is easy to appreciate that the young pre-talking child can indeed comprehend complex language long before they would be capable of using that level of language themselves. Thus, when considering the young child’s relationship to sensory information and perceptual skills related to learning we need to consider complex variables and complex neurological issues beyond the simplicity of sensory perception. However, the order and of sensory development in the normal baby may in itself have an influence upon related issues of sensory priority and integration during early learning of basic skills.