How Do We Control Balance?

The problem of balance had never crossed my mind until I had an attack of vertigo a few years ago. It was weird. It felt like being carried by the waves in a chopping sea. I had to hold on to the bed to avoid being thrown off. But I knew I was lying on a stationary bed.

What is ‘postural balance’? What keeps us upright and steady?

The nervous system controls balance. When we move, stand, walk, jump, turn, etc., a very complex mechanism is in operation that we are unaware of. To keep us in balance while continuing these activities, the body must coordinate multiple sensory inputs and motor responses in precision.

Three sensory systems take part in collecting information relating to balance:

Vision – The eyes see the surrounding objects and detect space changes. They sense whether you or your environment is moving.

Imagine watching buildings, trees, cars and people passing by from inside a parked car; then compare this perception with what you see when driving.

Vestibular system – These sense organs are located in the inner ear. They detect equilibrium, motion and spatial orientation. It helps determine if your body is stationary, moving, turning or rotating.

A problem with the vestibular organs can cause vertigo—the spinning sensation even when you are perfectly still.

Have you had experience on a swing ride at the funfair or on a ferry crossing the chopping sea? You get the picture if you have.

Somatosensory system – Sensory receptors (proprioceptors) in the skin, muscles and joints detect the spatial position and movement of the body. The sensory input from the neck and ankles is especially important. They determine the direction of the head, the body movement relative to the supporting surface, and the positions of different body parts relative to each other.

Without looking, we can tell whether the surface we are standing on is hard, soft, stationary, or moving. By the way, do you have to look at your feet when climbing stairs?

Three parts of the brain are involved in processing these sensory impulses and maintaining balance:

Anatomy of the brain
The precise coordination of nerve impulses in the brain is crucial for postural balance.

The brain stem is the posterior part of the brain that joins the spinal cord. All nerve connections between the brain and the rest of the body pass through here.

The brain stem receives sensory impulses and passes them to the cerebellum and cortex for further processing. It transmits motor impulses which control movements of the eyes, head, limbs and the rest of the body.

The cerebellum is the coordination centre. It integrates sensory impulses, controls motor activities, and enables us to perform voluntary tasks such as dancing and writing. The cerebellum regulates posture, movement and balance.

Patients with damaged cerebellum have difficulty maintaining balance and maintaining proper muscle coordination.

The cerebral cortex plays a key role in memory, attention, perception, cognition, awareness, thought, language, and consciousness. We are aware of ourselves and our surroundings through the cortex. The information and experience stored in the cortex help the body make voluntary or involuntary actions. That’s why we can maintain balance and have clear vision while moving.

Ageing problems, health conditions, and some medicines compromise balance. And poor balance is one of the main causes of falls.

Do you have any issues with your balance?

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