"GO on, join in," urges a care worker, grabbing my hand and pulling me towards a small circle of nurses and pensioners, arms locked, dancing a gentle jig to what appears to be the Hokey Cokey.

Around us 20 or so residents of Fitzwarren House care home wield tambourines. Many clap to the strum of music therapist Laura Bolton's guitar, nodding in unison.

Behind our sprightly group, a particularly keen singer belts out each word with vim, drumming on percussions in rhythm. While he struggles to recall his own name and swathes of the life he once led evade him daily, his encyclopaedic knowledge of the popular repertoire remains untouched - and unparalleled. He never once falters on a lyric.

After one last soothing carol the sing-along comes to an end. Almost as soon as the melody stops, many of animated faces of a few seconds ago deaden; the impromptu choristers' gazes distant and unseeing again. The brief inroad into a part of their minds unscathed by the relentless sprawl of dementia halted, until the next music therapy session. The transformation during and regression post therapy is mystifying.

"As dementia progresses and the ability to comprehend and use language often declines, sometimes music is one of the only things left that people can respond to and understand," explains Laura.

Fitzwarren House chaplain Mike Dilly, who eagerly joins each weekly group session, nods: "The most wonderful thing was when we had a lady who had not spoken for about a year. We were singing this hymn and suddenly she looked up and sang the first verse, then every single verse. And then lapsed into silence again. It touched that part of her memory that could connect to her vocal skills. We also had one person who had not seriously interacted with other people but when we gave him a cymbal he tapped it in time and suddenly his world and our world meshed. Dementia is a multi-headed beast, everybody is different and at different stages but music seems to speak to everyone. We're causing people to remember ordinary songs or Sunday school songs they sang as children."

Dementia is an umbrella term for a set of symptoms including memory loss, difficulties with thinking, problem-solving or language and impaired judgement. It occurs when the brain is damaged by diseases, such as Alzheimer’s or a series of strokes.

Most people think of the condition as affecting memory only, but it also impacts the way people perceive the world around them, including their sense of orientation, sight or spatial awareness.

With an estimated 2,280 people living with dementia in Swindon and nearly 7,000 in Wiltshire, exploring new avenues to support and treat patients has never been more vital.

The power of music, especially singing, to unlock memories is well documented and increasingly being harnessed in dementia care. Music reaches parts of the damaged brain in ways other forms of communication cannot, even in the most advanced cases. The auditory system of the brain is the first to fully function at 16 weeks, which means that babies are musically receptive long before anything else - and it endures long after any other cognitive ability disappears.

But it is not merely about retrieving memories. Music has been found to have a calming effect on sufferers, ease some of the most debilitating emotional symptoms of dementia, modify behaviour by alleviating agitation and even reduce some patients' reliance on drugs.

Laura and the team at Fitzwarren House, off Kingsdown Lane, have experienced first-hand the benefits of music to patients. But with growing demand for the service they are spread thinner each year. In a bid to offer the pioneering therapy to every one of its 32 residents, including one-to-one sessions, the care home, which is run by national charity MHA recently launched an appeal to raise £26,000.

This is an ambitious target and the sum will only take the service so far. But in the short-term it could significantly improve elderly residents' quality of life and in countless cases alleviate their distress.

"Individual sessions can be particularly helpful when people are limited in their interactions with others, possibly due to mobility issues, impaired communication skills or have other unwanted symptoms of dementia such as anxiety and depression," adds Laura.

One such patient is 87-year-old Julia Harvey.

Her mind wanders and she grows flustered as I strike up a conversation. Quick on her feet, Laura intones the first words to The White Cliffs of Dover - a favourite of Julia’s, Laura later explains, and a song she performed on stage to evacuees during World War Two. Julia's face lights up instantly and the lyrics come flooding back as she and Laura launch into an spontaneous duet.

"She can become agitated," volunteers Laura softy. "She wants to leave the building, but all the agitation and anxiety go away when she starts singing. Music can really uplift her. It's immediate with her. She responds so positively.

“With music therapy you can make the music happy, fast or slow to stimulate responses and promote wellbeing.”

Not all her 'students' are in quite such an advanced stage of dementia. Sheila Johnson is still very much self-aware and, in fact, music therapy has allowed her not only to keep her mind active and the march of the condition at bay, but to fulfil her life-long dream of learning the piano, thanks to her private sessions with Laura.

"I get a lot of pleasure from music," beams the 80-year-old, nestled in an armchair in her pristine bedroom; which she takes great pains to keep immaculate, she points out.

As if to demonstrate, she croons the chorus to Moonlight Bay. She stumbles over a verse. “I always get muddled,” she mutters with a chuckle before starting over.

Her bonhomie and elegant laugh are infectious. Unfortunately she is a rare gem of optimism. Many dementia sufferers grow despondent as the condition gains ground. Some are so closed off, reaching them, even through music, is a daunting challenge for Laura.

“If you can find that extremely familiar song and make eye contact with them, they will be automatically prompted to sing it. You have to be a detective, you’re trying to find a way to make a connection all the time. It’s finding that first way in they will respond to. It’s a process of trial and error. That’s why we need these sessions, to take the time to develop that connection and relationship. With increased funding we would be able to reach more people living with dementia, for longer periods.”

Finding that one song which will unlock for a few fleeting moments someone’s mind and bring them back to the here and now can seem hopeless at times, she concedes.

“You’re always learning songs, thinking, ‘What can I try next to reach them?’ When you have a breakthrough, it’s fantastic. You want to make sure they’re still active and present in their lives. Whatever happens you can’t give up on people with dementia.”

Fitzwarren House is urging people in Swindon to support the Music Therapy Appeal by making direct donations or organising their own fundraisers.

To find out how you can fundraise go to www.bestforages.com/swmusictherapy.