BUSS Model

Babies are born entirely dependent on the care of others for their survival, both physically and emotionally, and this underpins the vulnerability of a child’s experience.  With consistent, loving care the potential of a developing child seems infinite while, conversely, the consequences of abuse and neglect can seem catastrophic.  The emphasis of a large body of work with children with developmental trauma is currently on their emotional and psychological wellbeing, focusing on harnessing relationships to lay down new experiences alongside their early ones.

Whilst Sarah Lloyd, the primogenitor of the BUSS model, was working in Fife CAMHS (Child and Adolescent Mental Health Services) (2005 – 2013) she was part of a team developing a therapeutic service for local children who were in adoptive or foster care.  The team were offering traditional psychological therapies and became aware of a significant group of children who weren’t able to make use of these. They were seemingly dysregulated on a bodily level, as well as an emotional and relational level. Wanting to understand more about how children grow into themselves on a bodily level, as well as why this process halted for children who had experienced early adversity, Sarah turned to sensory integration.  Sensory integration theory maps out how the brain and central nervous system develop in response to movement, but there was very little mention of the relationships and conditions necessary for babies to thrive. Similarly, in the attachment and trauma literature, there was a plenty of information about the process by which children grow into themselves on a bodily level. This was the foundation for the BUSS model.

A solution seemed to be to build a model that could bring together an understanding of the body and motor development with a psychological understanding of the impact of trauma on the developing child.  The result is the BUSS (Building Underdeveloped Sensorimotor Systems) model, which brings together an understanding of how a baby and young child’s sense of themselves on a bodily level develops through experiences of being touched, held and moving.   Sitting alongside a neurodevelopmental understanding of the impact of trauma on the developing brain, attachment theory, child development theory and drawing on sensory integration theory, the model focuses on the development of the vestibular, proprioceptive and tactile systems.  

The BUSS model takes as its starting point the understanding that without nurturing relationships, babies don’t progress through the stages of movement that are needed to feed the brain and central nervous system. They do not possess enough information to build an internal map of the body and lay the foundation for well coordinated movement.  Clinical experience suggests that these systems aren’t severed in the way that might be seen in children with sensory processing disorders, rather they are underdeveloped because of a lack of adequate movement experiences at critical stages of development.  The BUSS model explores the potential for rebuilding the gaps in these systems left by early adversity, using games and activities within relationships that offer a child a loving, attuned base to grow from.

Playing games and doing activities designed to fill gaps in essential patterns of movement has a significant effect on a child’s bodily regulation.  It allows children to feel confident in their movements and the messages their body gives them about their physiological state, providing a solid foundation for the development of social and emotional skills and learning.

Improved bodily regulation has a significant impact on a child’s emotional wellbeing and regulation, helping them feel more comfortable with themselves on a bodily level. This has the added effect of enhancing the relationship between parent and child. A side-effect of this therapeutic care is that children harbour less anger, a change noted by several parents that the BUSS team have worked with. Children faced with fighting against their bodies to accomplish things like moving and playing expend large amounts of energy and effort, tiring them out and making them susceptible to quick-to-rise anger. Children being treated through the BUSS model have grown in energy and capacity.  Click here to read some quotes from parents, and here for some longer testimonials.  

It is important to note that children with an underdeveloped sensory system are not the same as children who have a sensory processing disorder.  Although a child with an underdeveloped system may move in a similar way to a child with a sensory processing disorder, the methods of treatment and therapy are different. For a child who has experienced abuse and neglect, it’s usually the case that the system isn’t demolished, it just hasn’t been built yet. 

The human body is amazing, and babies are equipped with reflexes and reactions designed to move their body through integral stages of development. These range from gaining head control to moving; the crucial part involving the movement from lying down to a crawling position. Unlike other animals, the brain and central nervous system of the human baby is still at an early stage of development at birth and babies need an attuned adult, nurturing care and movement experiences to allow them to grow into their bodies on a physical and an emotional level.

When abuse or neglect mean that children have missed out on the early stages of development, it can  be helpful to take them back through those patterns of movements so that their brain and central nervous system have enough information to allow their bodies to work in a smooth, well-coordinated way. This can be challenging for children and young people who have missed these developmental stages, as the natural drive to meet these stages found in new-born children is gone. The BUSS model was founded to help build these developmental bridges, no matter the cause. Movement is key in rediscovering these developmental shortcomings.

The first stage of utilising movement in the BUSS model is to create games centred on crawling and spending time on the stomach. The details of why these activities are integral to a child’s development are listed below. The activities are catered, with the assistance and knowledge of parents, to each child; the objective is to make these games fun in order to facilitate developmental change in a relaxed environment.

Why is ‘Tummy Time’ important?

Spending time on the stomach gives an advantage to movement support when a baby reaches their developmental stages. 1.

When a child is born, the spine is formed into the shape of a C, resulting in a ‘curled’ appearance within the first few months.   It is this flexed  position that is most efficient , as a new-born, for utilising oxygen, feeding and digestion (Kranswoitz, C., Lopiccol, A., 2017).

Healthy spinal support is crucial to not only a child’s development but to an adult’s health too. 2.

However, this C-shape is made redundant once a baby starts to move. The inverted S-shape, the shape our spines naturally form, has to take precedence, as this is the most efficient form to distribute weight during movement and to balance mechanical stress at rest. This typically occurs within the first year of a baby’s life. Once babies are able to walk and accomplish movement unaided, this inverted S-shape becomes the norm.

The process of restructuring begins in the first days and weeks of a baby’s life. As a baby spends time on their stomach and back the neck muscles develop so that the spine can begin to form the first part of the inverted S-shape: the cervical curve at the top of our spine. The skeletal and muscular changes are crucial for the development of core strength, which begin with the head. Visualising a baby on their stomach, their head is usually set to an angle of 90 degrees perpendicular to their body. This position gives them the best view of the world around them, and allows for enhanced comprehension of new experiences and sensations. The process and action of crawling, or ‘commando crawling’, both allows a baby to explore new sensations and engages their entire body in movement and action: building synaptic connections. From this bedrock, developmental milestones can be attained.

If babies have missed movement experiences in their early days, weeks and months, the structuring of the spine and muscle is not developed to move forward into childhood and adolescence. Movement becomes strenuous, painful and incensing. While it may seem simple, creating activities that focus on spending time on the stomach, colloquially referred to as ‘tummy time’, is one of the most important methods the BUSS model uses to repair developmental breaches.

I always find it helpful to have a picture in my head of what the stages of development look like, and if we think again about typical development, baby’s follow a fairly well established sequence of events here – they move from lying on their tummies to beginning to get themselves into a better position for moving.

Utilising the above diagram, we can chart the movement of a child through their movement-based developmental milestones. A baby starts by crawling on their stomach, with their head positioned perpendicular to their body. From this point, the baby has built enough support to use their forearm to lift their upper body. After approximately seven months the baby has achieved the skeletal and muscular conditioning to be able to use a single arm to support themselves while they use their other hand for other activities. As the baby learns to sit, crawl and then walk , their lumbar spine develops. Muscle and spinal toning continues, until a baby begins walking independently, the culmination of these early developmental stages. It is clear that missing any of these can lead to detrimental growth in later life, and this is what the BUSS model focuses on restoring.

Books written by Sarah Lloyd are available on Amazon, and there is more information about them in the resources section too, which you can find here.

Pictorial references:

  1. Unknown author, licensed under CC BY-SA
  2. Unknown author, licensed under CC BY-SA

As stated in the section above, crawling is an integral part to a baby’s first stages towards future development. It increases spinal and muscular strength and control, as well as helping to refine motor skills and appendage dexterity. The BUSS model places high emphasis on this developmental stage to diagnose and treat areas of a child’s development that could be missing.

Crawling independently typically occurs when a baby is between eight to nine months old. They are capable of rocking backwards, forwards, to each side and in diagonal directions. The wrists and fingers benefit from this adverse movement, preparing finger extensions and the wrist to move in these directions in the future. Crawling here involves rapid, clumsy movements that propel the baby forwards a few feet.

By nine months old, the typically-developing baby is  able to stand on their hands and knees and shift their weight from one hand to the other while reaching out, without dropping their stomach to the floor.  These are the first stages of coordinated crawling. A  baby in this stage possesses strong spinal and muscular toning in the head and shoulders, prepared for crawling unimpeded.  

Crawling, here, becomes the prelude to a baby making another key developmental stage: walking. These advances are linked like a chain, as without a single link the entire chain can be disassembled. To better illustrate the nuances of this key stage in  a baby’s development, it is imperative to break apart the individual pieces and examine them as part of the whole; split into Gross Motor Skills, Fine Motor Skills and Sensory Advances. This, along with other methods, is how the BUSS model works with children to determine what developmental stages may have been missed.

Gross Motor Skills

Crawling  is demanding for a baby; it uses both sides of their body together (bilateral integration and sequencing) in movement. The right hand and left leg must move together, and vice-versa. Synaptic connections strengthen, developing brain activity. The outcome is that the body adapts to work as a single unit; movement and perception working simultaneously to propel the baby forwards.

Crawling helps strengthen the joints close to the core, centred on the shoulders and hips. Proximal joint stability, as it is called, creates a benchmark for refining motor skills in the joints that are furthest away from the body. As the baby crawls, they gradually strengthen their entire palette of motor control, starting with the joints responsible for keeping them mobile.  Fine motor skills can then be pioneered, and their strengthened core can support them to when they start trying to walk independently.

Crawling also helps the baby to develop what is called postural control. A baby needs to be able to hold their body in an upright and stable position, to be able to sit, stand and walk. An important step towards postural control is what is called co-contraction, where different parts of the body work together so that the body can do increasingly-complex tasks. To be able to crawl, the baby needs to contract all the muscles around their stomach so that is stationary while their arms and legs are moving their body forward. Crawling cements this process, articulating postural control to be able to efficiently move and control bodily functions.

Fine Motor Skills

One of the first instances of a baby being able to hold their body away from the floor is crawling. In this practise, and over the course of a typical development, a baby’s hands are placed flat, with fingers positioned forwards. Crawling with hands in this position develops the arches of the hand. The arches in the hand help to mould around objects when grasping objects. Using the example of catching a ball, the hand moulds itself around the ball as it is caught, allowing for the highest degree of grip. Strengthening the hand arches also allows dexterity control, dictating the degree to which the hand exerts grip on an object. Handwriting can be effected here. Crawling with the hands flat elongates and strengthens the muscles in the fingers and increases the potency of the hand arches.

Specialisation, a topic with broad-ranging meanings for child development (Ayres has covered this extensively in her book, Sensory Integration and the Child (A. Jean Ayres, Los Angeles: 2005)), in this context means the specialisation of the hand to fulfil fine tasks. The baby’s brain and central nervous system repeatedly refines the functions of the extremities, focusing connections to individual fingers to accomplish specialised tasks. For the developing child, the fingers near their little finger, the ulnar side of the hand, become the stabilising part of the hand and the thumb and index finger, the radial side, the working and practical side. This is most commonly seen in writing: the ulnar side provides a support, while the radial side manipulates a pen to write. Crawling strengthens the synaptic connections between the hand and the brain, allowing fine motor skills to be polished.

Sensory Advances

Although the focus of  motor development and crawling is on the physical and synaptic connections there are changes in the brain and the visual system. When the baby is crawling, eye movement is active – looking from hand to hand as they move forward and tracking where they are going. This ability to visually track from left to right and right to left is important not only at the crawling stage, but all through the lives of humans. Without this developed visual processing, children can only read one half of a page of text.

As well as tracking their movement from side to side, a baby is also negotiating their environment. They are looking at where they are and where they  want to go. The process of crawling helps to develop  binocular vision, as well as depth and space perception. Children and adults benefit from honed visual perception, from being able to absorb information from a page of notes to driving down a road sheathed in ice.

Click here to read experiences of the BUSS Model in our ‘What People Say’ section, where there is the opportunity to have a look at profiles of early, middle aged, and adolescent interventions, using the BUSS model.

Click here to read about experiences of training based around the BUSS model.



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