The health of iconic singer Celine Dion continues to deteriorate due to her struggle with an untreatable neurological disorder, making her future return to the performance arena highly uncertain, according to inside sources speaking to Radar Online.

Reliable sources have shared that the 55-year-old diva's condition is significantly more severe than publicized, as she confronts stiff-person syndrome, a rare disease that progressively restricts mobility.

"Celine's movement capacity is seriously hampered, to be frank," one insider confessed.

Despite the fact that Dion publicly acknowledged her diagnosis and has expressed her commitment to regaining her strength, insiders are doubtful about her ability to resume touring. "Celine is experiencing tremendous pain," stated one source. "Despite having the finest healthcare team that money can afford, the prognosis isn't encouraging. Her ailment is not curable, and despite her diligent work with medical professionals and therapists, her condition isn't improving."

In related news previously reported by RadarOnline.com, Dion is purportedly relocating to her native Canada after divesting herself of her $30 million Las Vegas property.

Dion, who performed for fans in over 1,100 shows near Caesars Palace over the last two decades, recently parted with her Las Vegas residence. The diva has also recently cancelled a scheduled international concert.

"Celine has the support of her 11 siblings in Canada," revealed an insider. "This close-knit and loving network is a valuable source of support for her in these challenging times."

In December, Dion disclosed her stiff-person syndrome diagnosis. This condition results in involuntary muscle spasms that can lead to further health complications and, in some cases, can be fatal within six years of being diagnosed.

In these trying times, sources suggest that Dion has found a stalwart supporter in fellow artist Shania Twain.

"Celine and Shania share a strong bond that has lasted for years. They have provided each other with quiet, unwavering support and served as confidantes for decades," disclosed a source.

One insider shared, "Shania wants to assure Celine that she's not alone in this battle. It can be an isolating experience, especially when attempting to keep the struggle out of the public eye."