Tremors, seizures, paralysis: This brain disorder is more common than multiple sclerosis - but often goes undiagnosed

IMAGINE suddenly losing the ability to move a limb, walk or speak. You would probably recognise this as a medical emergency and get to hospital.

- BENJAMIN SCRIVENER

Now imagine the doctors at the hospital run some tests and then say, "Good news! All your tests were normal, clear scans, and nothing is wrong. You can go home!" Yet, you are still experiencing very real and disabling symptoms.

Unfortunately, this is the experience of many people with functional neurological disorder. Even worse, some are blamed and reprimanded for exaggerating or faking their symptoms.

So, what is this disorder, and why is it so challenging to recognise and treat?

What is functional neurological disorder?

Neurological disorders are conditions that affect how the nervous system works. The nervous system sends and receives messages between the brain and other parts of your body to regulate a wide range of functions, such as movement, speaking, vision, thinking and digestion.

To the untrained eye, functional neurological disorder can resemble other conditions such as stroke, multiple sclerosis or epilepsy.

But, unlike these conditions, functional neurological symptoms aren't due to damage or a disease process affecting the nervous system. This means the disorder doesn't appear on routine brain imaging and other tests.

Functional symptoms are, instead, due to dysfunction in the processing of information between several brain networks. Simply put, it's a problem of the brain's software, not the hardware.

What are the symptoms?

Functional neurological disorder can produce a kaleidoscope of diverse and changing symptoms. This often adds to confusion for patients and make diagnosis more challenging.

Symptoms may include paralysis or abnormal movements such as tremors, jerks and tics. This often leads to difficulty walking or coordinating movements.

Sensory symptoms may involve numbness, tingling or loss of vision.