What is Stiff Person Syndrome? The 'human statue' condition afflicting Celine Dion

Stiff person syndrome is a rare neurological condition that can take years to diagnose and requires tailored treatment.

Singer Celine Dion revealed she would be cancelling the remainder of her Courage World Tour after experiencing difficulties living with the condition.

The star initially announced that she had been diagnosed with Stiff Person Syndrome (SPS) in an Instagram video in December.

Upon cancelling her world tour, she said: I'm so sorry to disappoint all of you once again... and even though it breaks my heart, it's best that we cancel everything until I'm really ready to be back on stage... I'm not giving up… and I can't wait to see you again!"

What is Stiff Person Syndrome?

SPS is a rare, progressive neurological disorder of the central nervous system and affects around one in a million people, according to the National Organization for Rare Disorders (NORD).

If left untreated it can lead to permanent disability or death.

The symptoms usually develop slowly over several months or years, often beginning with muscle stiffness and discomfort which can come and go - but the stiffness gradually becomes fixed.

Some develop a "statue-like" appearance due to the rigidity.

Many also experience painful muscle spasms that can last a few minutes to several hours and may affect the whole body or certain muscles. The spasms can be triggered by unexpected loud noises, minor physical contact, cold environments, stress, or situations that cause heightened emotions, says the NORD.

Spasms in the chest and respiratory muscles can be serious and require ventilation or emergency treatment, while spasms in the legs often lead to falls.

Experts still do not know the exact cause of SPS and it is often underdiagnosed.

Who is affected by Stiff Person Syndrome?

The condition is twice as likely to affect females than males, according to the National Institute of Neurological Disorders and Stroke.

It is frequently associated with other autoimmune diseases such as type-I diabetes, thyroiditis, vitiligo, and pernicious anemia.

The condition only occurs in about one in every million people.How is Stiff Person Syndrome treated?

There is no cure for SPS but treatment, such as anti-seizure drugs, painkillers and anti-anxiety medication, can help lessen symptoms.

The condition is thought to have features of an autoimmune disease, according to the National Institute of Neurological Disorders and Stroke.

Several symptoms improve with anti-anxiety and muscle relaxant drugs, or with drugs that alleviate muscle spasms, such as baclofen or gabapentin.

For a singer like Dion, bright lights and loud noises that could occur while performing could trigger muscle spasms.

Want a quick and expert briefing on the biggest news stories? Listen to our latest podcasts to find out What You Need To Know.