Somatosensory cortex damage after TBI can cause problems with sensation. It can also make balance and movement more challenging.
In this article, you will learn more about somatosensory cortex damage and how to treat it.
What is the Somatosensory Cortex?
The somatosensory cortex lies on a ridge of the cerebral cortex called the postcentral gyrus. It is found in the parietal lobe.
This cortex is in charge of processing all bodily sensations. These come from receptors found throughout the body that detect:
- Proprioception (position of the body in space)
When nerves detect one of these sensations, they send that information to the brain’s thalamus. The thalamus then passes that on to the somatosensory cortex.
There are four areas of the sensory cortex. Each is arranged so that a particular area receives information from a certain part of the body.
Areas of the body that are more sensitive, such as the hands and lips, take up more space in the cortex than others.
This also means that those areas are more vulnerable to damage.
Symptoms of Somatosensory Damage
Damage to the sensory cortex can cause a variety of disorders, depending on where the damage occurred.
The following are some common symptoms of somatosensory cortex damage after brain injury.
Lesions on the sensory cortex can cause problems with identifying where on the body a sensation occurs.
The person might be able to recognize that a feeling is coming from their hand or arm. But they would not be able to point to a specific place on their hand.
In severe cases, the patient will not even be able to locate where the sensation is coming from at all.
Loss of Proprioception
Proprioception refers to the ability to recognize where the body is in space. It’s what allows people to walk without constantly watching their feet, for example. It’s also how you can tell your arms are moving.
This sense is controlled by receptors located in the muscles, joints, and tendons. These receptors detect things like movement speed and stretched muscles and send this information to the brain.
After damage to the somatosensory cortex, however, this skill can become lost. As a result, actions such as balancing, walking, and even reaching can be more difficult.
People with proprioceptive problems are also more vulnerable to muscle sprains or tears because they cannot sense when their muscles are being over-stretched.
Agraphesthesia and Tactile Agnosia
Similarly, somatosensory cortex damage can cause difficulties with recognizing things traced on the skin.
For example, a person with this problem would not be able to tell whether an X or an O was written on the palm of their hand.
People with this disorder often also have trouble identifying an object by touch alone. If their eyes are closed, they cannot tell if they are holding a fork, a pen, or a book. It all feels the same.
This is known as tactile agnosia.
Finally, somatosensory cortex damage can produce numbness or tingling/prickling sensations in certain parts of the body (i.e. paresthesia).
Since the face and hands have the most receptors and take up the largest area of the cortex, they are vulnerable to numbness and/or tingling. This usually occurs on the opposite side of the body that the damage is located.
Injury to the sensory cortex can also cause problems with the ability to detect heat or cold.
Treating Somatosensory Cortex Damage
Many of the effects of somatosensory cortex damage are serious. However, there is hope for recovery.
Like all other types of brain injuries, sensory issues can be treated by rewiring the brain through neuroplasticity. This can allow other areas of the brain to take over that skill.
The best type of therapy to help accomplish this is sensory reeducation exercises. Sensory reeducation, also known as sensory retraining, is a form of therapy that helps the brain relearn how to process sensation again.
It’s proven effective at activating neuroplasticity and helping people regain feeling.
Sensory Reeducation Exercises
The following are some exercises that can help restore your brain’s ability to interpret your senses. Most of the exercises involve the sense of touch.
Every time you touch something, you stimulate your brain and encourage it to rewire itself.
Repeat each exercise at least 10 times and try to practice for about 15 minutes a day. The more consistently you practice the faster you can make progress:
- Tabletop touch therapy. Place objects with different textures such as Velcro and silverware on a table in front of you. Without looking at them, pick them up and feel them. Try to distinguish the different textures.
- Sensory locating. Close your eyes and have someone else place their hand on your arm. Next, point to the place where you think they touched you. If you get it wrong, have them move your hand to the correct spot. This helps retrain your brain to recognize where they touched you.
- Temperature differentiation. Soak one cloth in cold water and another one in hot water. Have someone place the cold cloth on your arm while you close your eyes. Then, have them switch to the warm cloth. See if you can feel a difference. Alternate back and forth between hot and cold 10 times.
- Texture handling. Have someone place different objects in your hand with your eyes open. See how they feel. Once you have gone through all the objects, repeat the exercise again with your eyes closed.
To regain proprioception, different treatments can be used. Some examples include:
- Balance exercises
- Weight-bearing exercises
- Passive movement training
- Electrical stimulation
Using a combination of these techniques appears to be most effective. Talk to an occupational therapist for more info on these exercises.
Overcoming Somatosensory Cortex Damage
Damage to the somatosensory cortex can cause problems with balance, movement, and processing sensory information.
Fortunately, through sensory training, it is possible to recover most of your senses and balance after brain injury.
This demonstrates an important fact of TBI recovery: the brain is a remarkably adaptable organ, and with enough repetition, you can recover almost any skill. Including sensation.