To be able to fully answer this question in a way that is understandable, we first need to clarify one basic mix-up. In practice, I see that the term spasticity is widely used and often in the wrong context. Whenever parents notice an increase in tightness in the body of their child, they usually assume that spasticity increased. We explain the relationship between sepsis and extracellular matrix (ECM).
It is right to say that spasticity represents one type of hypertonia (heightened muscle tone) but it is wrong to say that every increase in the muscle tone or tightness is a consequence of increased spasticity. Very often this is not the case. Firstly, because other types of heightened muscle tone or muscle tone disorders can be present in the clinical features of the child’s condition: rigidity, dystonia, choreoathetosis. I will discuss about rigidity, dystonia, and choreoathetosis in a separate article. Here, I will concentrate on the relation between spasticity and the extracellular matrix (ECM).
Extracellular Matrix (ECM)
ECM is the fluid part of the connective tissue made by its main cell – fibroblast. It is the physical microenvironment in which cells operate. The space around and between cells comprises an intricately organized elastic mesh of locally secreted protein, collagen fibres, and polysaccharide molecules, as well as ion-rich water and glycosaminoglycans (GAGs) – such as hyaluronic acid – that make up ECM.
It fills out all our bodily tissues. It gives volume and contributes to the shape of the body. For simple understanding: it is the gelatine that comes out of the bones when you cook them. In ECM, the exchange of nutrients and waste products and transport of signalling proteins take place on the cellular level. In simple words, cells get the nutrients and get rid of the waste products through ECM. In its structure, ECM is colloid and it can change viscosity in regard to the circumstances and internal and external influences. In other words, its consistency can vary from very soft to very hard.
Of course, when it comes to the living organism, the viscosity of ECM is constantly fluctuating and adapting to different influences. But in the essence – if an organism is healthy, ECM is fluid enough allowing normal circulation and metabolic exchange on the cellular level.
On the other hand, if ECM is exposed to massive inflammation, its viscosity increases. It becomes less fluid and stiffer. The same happens if it is exposed to the coupled high velocity – high intensity mechanical stress. Children and adults with different neurological diagnoses are experiencing exactly these phenomena.
Why is the stiffness of ECM an important element in answering the question?
Because ECM stiffness largely contributes to the increase of the general tension of a child’s body. While the neurological components of the tension in the child’s body (spasticity) are closely monitored and checked by physicians and rehabilitation therapists, the stiffness of ECM is widely overlooked.
I will give a simple example: you all know the situation when we wake up in the morning how our back can feel stiff. We feel tension, sometimes even pain. The range of movement in the joints is reduced. It is only when we get up and start to move around, after a few minutes, that we feel that the tension reduces, and joints become more mobile.
During the night as we sleep, ECM gets stiffer because we do not move much. In the morning, when we start moving again, extracellular matrix gets to be more fluid.
This example shows how ECM stiffness increases tension even in the body of a healthy individual and reduces mobility in the joints and generally influences our movements. But that does not mean that a healthy person has spasticity (heightened muscle tone). It is important to understand that difference. Children with spasticity experience the influence of both elements: spasticity and ECM stiffness and they experience the combined effect.
An increase in ECM viscosity fuels spasticity and vice versa.
Those are separate processes but they influence each other. Basically, when we talk about children with cerebral palsy or other neurological diagnoses (Rett syndrome etc.), the stiffness of extracellular matrix reaches another level which we can’t observe in healthy individuals who sporadically feel discomfort because of back stiffness.
During BDA assessments we regularly observe children with the stiff and immobile spine. The chest is as hard as a wooden box and does not move or moves superficially during the breathing. Stiff and dry bones of the cranium etc.
Why does ECM get stiffer anyway?
Super-stiffness develops as a result of a few combined factors:
- Chronic underlying inflammation which exists in a higher or lower degree in all children with cerebral palsy, Rett syndrome and other neurological conditions.
Inflammation makes ECM lose some portion of water content and makes it hard. That process can further progress towards fibrosis, which makes body segments even stiffer. In the process of fibrosis development, additional collagen is being accumulated and in the same time the body segment loses its elasticity.
- The immobility of the child, where the level of the severity plays a huge role. If the child is not able to produce enough of their own movements, there will be no mobility which would reduce the viscosity of extracellular matrix and make it more fluid.
- The bad quality of movements. It is shown that the lack of normal control and coordination of the movement, i.e. misuse of it, contributes to micro-tearing and micro-injuries of the muscles and connective tissues which results in added inflammation.
- Spasticity itself through constant pull on the muscles and connective tissue increases ECM stiffness and then ECM stiffness increases hypersensitivity of the muscle stretch reflex which in return heightens spasticity. It is a closed loop. When ECM gets stiffer, it tightens tissues, makes them more rigid and sometimes even a small mechanical impact such as a light touch can trigger muscle stretch reflex. It means that an organ called muscle spindle which is situated in the muscle will react more excessively then it would be normally expected.
Logical questions to ask would be:
– How much does the stiffening of ECM contribute to the increase of the spasticity?
or
– How much does spasticity contribute to further stiffening of ECM?
The answer would be that it is impossible to say. The contribution of both elements is indistinguishable from each other.
Why is that?
When muscles are tested for spasticity and body segment is pulled or pushed to provoke spastic reaction, muscle stretch reflex is provoked and it makes muscles shorten, as a defensive mechanism.
Usually, the spastic reaction of the muscles and the reaction of muscle stretch reflex is then observed strictly as a consequence of the brain injury.
But at the moment of the test being done, the fact is that a certain level of stiffness of extracellular matrix of the tissues already exists. The stiffness of ECM makes muscle stretch reflex hypersensitive, so it triggers a spastic reaction of the muscles.
If ECM would be more fluid, muscle stretch reflex would be less sensitive. Then we would need more force and velocity to provoke that reflex and to get a spastic reaction. In reality, the test on spasticity shows us the combined effect of ECM stiffness and hyperexcitation which comes from the injured brain.
This is usually overlooked and the whole intensity of spasticity is credited only to the excitation which comes from the signalling from the brain. Finally, after explaining these pieces of the puzzle, it is possible to answer the question in a more direct way.
Why does the regular application of the BDA program reduce extracellular matrix stiffness and consequentially spasticity?
When the BDA program is done regularly, it:
– Reduces the general level of inflammation in the body (it is shown that soft tissue stimulation does that).
Inflammation reduction makes ECM less stiff and less viscous.
– Through BDA exercises you are “melting” ECM and rehydrating it (thixotropy) on a daily level.
It lowers its viscosity and makes it softer because you are applying the low velocity – steady pace mechanical stimulation. Automatically, as ECM is not as stiff any more, the muscle spindle will not react on the light mechanical stimulation and will not trigger muscle stretch reflex so easily. Further, that will reduce the frequency and intensity of the spastic reactions.
– In the long run, you are remodelling connective tissues which make positive changes in ECM viscosity long-lasting.
– With the long-term application of the BDA program, the remodelling of connective tissues improves the quality of child’s movements and increases the freedom of spontaneous mobility. In return, that allows a child to move more in general manner.
The disuse and misuse of a child’s bodily structures in that way become reduced. That reduces the level of added inflammation and its negative impact. With the improved quality of ECM, its stiffness reduces and as a bonus, spasticity reduces. Also, in many cases the dystonic type of movements reduces.
When the BDA program is stopped for a long time all of the above-mentioned benefits decrease and the raise of inflammation kicks in; the lack of soft tissue stimulation allows ECM stiffness to increase, which in return gives rise in spasticity or rigidity and dystonic movements.
I find it important to place my explanations in the right context. It does not mean that a decrease in the positive effects will happen always and in all cases if you reduce or stop doing your BDA program for a longer period of time.
We need to be aware that the scenario will depend mostly on the severity/level of the child’s condition.
The more severe the child’s condition is, the more BDA work and time will be needed to remodel their connective tissues to the level which will make positive changes stable and long-lasting.
A great number of parents can notice that the positive structural and functional progress achieved in their children does not disappear with time even if they make a pause with the BDA program.
Others who have children with severe conditions and exercise for 6 months and make a long pause can see that some of the benefits are decreasing.
Why?
Because there is simply not enough of the accumulated impact to make the achieved results stable. Don’t forget that many kids that we work with are level 5 according to the GMFCS. This classification system observes and evaluates only gross motor functions.
My experience is that inside of the 5th level alone there are so many levels of severity which GMFCS is not even designed to register. There are 5th level cases that look mild in comparison to other 5th level cases which are severe in the breathing, digestion, or metabolic exchange department.
GMFCS does not tell us anything about the severity of those other areas of functioning. Naturally, in those cases more continuous BDA work and more time is needed to make an impact which will become stable and permanent. But in some cases, that happens after 6 months, while in others, it takes 1 or 2 years of the accumulated impact.
