The clinical symptoms

The term SI disorder refers to a cerebro-physiological dysfunction, i.e. a condition in which the networks connecting nerve cells and brain structures are not insufficiently well developed. Generally, children are affected most: Adults are only very rarely afflicted unless the condition was already present during their childhood. The clinical conditions which can arise include the following:

• Problems with maintaining balance (vestibular perception) and insufficient basic muscle tension (hypotonicity). Affected children have to devote their entire attention to maintaining control over their body’s position and movements. If their attention is distracted by something, this control breaks down – they seem to go limp. Some children then resign themselves to this state, whilst others struggle against it. This, in turn, leads to agitation which can easily be mistaken for an attention deficit disorder (ADD/ADHD). However, in cases of sensory integration disorders it is the behavioural restlessness which causes the attention deficiency, whereas with ADS/ADHS it is the other way round.
• Oversensitivity towards tactile stimuli and (a lack of) proprioceptive awareness (i.e. awareness of relationships within one’s own body). Those affected cannot plan their movements properly and so appear to be permanently awkward and clumsy.
• Sometimes tactile and vestibular disorders occur at the same time. This condition is known as a sensory modulation disorder. The stimuli which are received by the organism are not filtered by the nervous system. This can lead to hefty defensive reactions.
 

Children suffering from a tactile defensiveness syndrome take care to avoid contact - in particular unexpected contact - with other people or with things, and when this happens they react with either aggression or anxiety, or a combination of the two. Adult sufferers tend to avoid contact of all kind, which often leads to social anxiety and behavioural abnormalities.

Vestibular defensiveness is a dramatic form of vertigo, and indeed it is sometimes called gravitational insecurity. It can be triggered by apparently trivial activities such as cycling or going up stairs. Thus SI disorders always have a psychosocial dimension to a greater or lesser extent.