Dealing with overstimulation

Before you continue reading, we would like to draw your attention to the fact that Team Hersenletsel-uitleg of Braininjury Explanation has been the first to identify the problem of overstimulation (sensory overload, flooding) caused by brain injury, worldwide. They were also the first to describe this problem (in 2013). Now we would like to conclude scientific research on this. Could you please  consider to make a donation for this research?

What is a stimulus?

A stimulus is a piece of information that enters through our senses; seeing, hearing, smelling, tasting, feeling (external stimuli) or through our thoughts or our bodies (internal stimuli).


Filtering mechanism broken

The filter mechanism that normally filters stimuli in a healthy person is 'broken' in people with brain injuries. After brain injury, the brain can often only process one stimulus at a time. For example, background noise is disastrous for people with overstimulation*. The sound or voice that someone wants to hear is one stimulus, and background noise is too much*.

[* source: our questionnaires consider this as copyright]


Too many stimuli

When you, as a person with brain damage, receive more stimuli than your brain can handle, there are also unprocessed stimuli in the traffic jam. Your nervous system makes overtime to give all sound, image, smell, movement, thoughts a place. The chaos that causes this can be compared to the crowds and sounds during the morning rush hour on a motorway which suddenly became a narrow country road. Then when your passenger starts talking to you, the chaos is complete.


Offering even more stimuli (for example, talking to someone who is overstimulated and asking questions) makes things worse. If you are overstimulated, you cannot respond to new stimuli so well, you do not have the space to think and act well and you are often often overwhelmed with emotions.


Three categories of overstimulation

As our survey showed:

  • The form in which the limit is immediately exceeded. For example caused by background noise. Result: immediate overstimulation*.
  • The form in which stimuli accumulate (like a traffic jam) and at a certain instant they can no longer be processed*. Then there is overstimulation*.
    For example: someone perseveres for ten minutes in a company but then it becomes too much. This person should prevent this from happening by leaving the company within those ten minutes.
  • Delayed overstimulation by hyperfocus*. When people train themselves knowingly and willingly 'to be able to do something', the overstimulation can strike mercilessly. In this case, training has adverse effects*.

[* source: our questionnaires consider this as copyright]

More brain activity in people with brain injury

Scientists discovered that in a brain injury victim more brain cells work.
There are more brain parts involved in activities than was the case before the brain injury. That difference can be seen with PET scans. Brain parts that normally show little activity when performing an activity are actively involved in the thinking process after a brain injury.

This requires many diversions and energy. As a result, the reaction in a brain injury victim is often a bit slower and requires more energy. For every brain signal between brain cells, electricity is needed, which has to be generated and it take energy, which can make the person very tired.


Stack effect

Regardless of which form of overstimulation; cognitive, emotional or sensory, there is a stacking effect*. If a person has had to process too many cognitive stimuli due to a busy weekly schedule, then the person will become emotionally or sensibly overstimulated*.

The reverse is also true. If a person is overstimulated, cognitive performance will be negatively influenced or the person will be more emotional*.

Did you know that neurofatigue (fatigue after brain injury) almost always goes hand in hand with overstimulation*?There is also a stacking effect between different overstimulation forms*.

[* source: our questionnaires consider this as copyright]



If you are a parent and you have a child who suffers from overstimulation you can try to invent a system together with your child to indicate in which phase he or she is. For instance:

Green, everything OK

Orange, it is too much

Red, overload, I have to leave immediately


Catalog your own overstimulation form

First you have to learn to recognize your own overstimulation.

Is it mainly in the area of:

  • Hearing*,
  • Seeing*,
  • Feeling*,
  • Smelling*,
  • Touch and feel touches, feel movements, be moved,
  • See movements*, balance*, proprioception*,
  • Multitude of talking*, or you are being asked*,
  • Have to remember a lot*, multitask*

[* source: our questionnaires consider this as copyright]