"I was born and bred in Liverpool city centre," says Rose Griffiths, 74. "But now I sound like the Queen. All I can say in my original voice is: 'Oh ey!'" At least things have moved closer to home since Griffiths had her stroke 10 years ago. "When I first started to talk again, the consultant told me I sounded Russian, then Polish. After that, it was German. My daughters thought it was really funny."

Griffiths - who does indeed sound like a well-spoken southerner - is suffering from foreign accent syndrome, a rare and baffling complication that can follow a neurological "event" such as a stroke or brain injury. A new case came to light recently in the United Kingdom when a stroke patient woke up with an Italian accent, despite never having visited Italy. Althia Bryden, 58, had lost the power of speech for three months but after an operation to remove a blockage in the brain, she started sounding Italian, even speaking some of the language. "I wake up most mornings hoping that my old voice will be back again... I can even hear the accent in my head when I'm thinking," she said.

The condition also hit the news last year with nationwide coverage of Zoe Coles, 36, from Lincolnshire, who woke up one morning with a Welsh accent, even though she'd never actually been to Wales. Coles had not even been able to roll her R's before she suddenly acquired this trait. "I am struggling a lot. You are born with a voice, you grow up and develop a way of speaking," she said at the time. "That has been taken away from me."

According to the medical literature, foreign accent syndrome is not really related to accent at all, but caused by the patient's struggle to form words after damage to part of the brain controlling the rhythm of speech. It's also extremely rare: only about 100 people have been diagnosed with this condition since the first known case, in 1907.

Coles maintains she's had no treatment, no support and barely leaves the house. How different, then, from Griffiths, who today is among 50 local people gathering for their monthly coffee morning at the Brain Food Café in Liverpool.

Each is suffering from a different neurological condition: Parkinson's disease, multiple sclerosis, the aftermath of a stroke or a road traffic accident. What these people have in common is a love of community, and an aspiration to improve their lives.

The Brain Food Café sits within the glass-roofed, purpose-built building of the Brain Charity. The organisation was founded in 1992 after Prof Ian Williams, the medical director of the nearby Walton Centre neurological hospital, recognised that more support was needed in the community for people after discharge.

"People told us it was like falling off a cliff when you leave hospital, and we wanted to provide social support," says Pippa Sargent, the charity's CEO. "This place offers community life for people who've otherwise been excluded: advice on diagnosis, support for carers, as well as neuropsychotherapy and confidence coaching."

At today's coffee morning, an outreach team from Merseyside Police is offering tips on avoiding cybercrime. There are details of forthcoming day trips: after the successful trip to Sefton Park Palm House, a jaunt to Liverpool Cathedral is planned. Elsewhere in the bright and airy centre, people are socialising, or attending the specially modified gym in pursuit of their "personal best" on the bike or the rowing machine.

Despite her own health problems, Griffiths volunteers at the Brain Food Café three days a week, making tea and coffee. A single mother to two girls since the death of Eddie, her husband, 27 years ago, Rose was at work when she suffered a stroke in 2014. "I woke up later in hospital not able to speak or walk, paralysed down my right side. It was very frightening," she says.

The Brain Charity via YouTube

At first, Griffiths could communicate only by nodding, shaking her head and laughing. After years of speech therapy, she has learnt to talk again, but her conversation is slow and halting. She still laughs a lot. "I had to learn to laugh," she says. Physically, laughter was still something she had at her disposal, so she started using it as a mode of communication. "It is my way of coping: humour is the most important thing."

Griffiths is an endearing presence, personifying guts and determination. Her condition is also characterised by aphasia - an inability to recall the right word. She still carries around a ring binder of laminated pages with pictures of crayons, a suit, a bunch of keys, to train her brain. "Name five cheeses," says one exercise. "Name five things in a bedroom."

When asked whether she lives alone, Griffiths pauses for a moment to gather herself. "What's the word?" she asks. "Like a sister, but smaller. That's right: my daughter. I live with my daughter." When asked when she met her husband, she says, "Four and one," to mean 41 years ago. Talking to her is like solving an ingenious and delightful puzzle.

Griffiths's story would not feel out of place in The Man Who Mistook His Wife For a Hat, the 1985 smash-hit book by British neurologist Oliver Sacks. But though foreign accent syndrome itself is rare, neurological illnesses are far from uncommon. According to the campaigning group the Neurological Alliance, there are 600 different related conditions, and one in six of us will experience one of them.

They range from migraine to stroke, Parkinson's disease and dementia, and the consequence of brain injuries from trauma such as road traffic accidents. Some of the symptoms can be bizarre, such as with Capgras syndrome, where a person holds a delusion that a spouse or friend has been replaced by an identical impostor, or Cotard's delusion, where a person believes they do not exist, or are already dead.

Then there is stiff-person syndrome, a rare autoimmune condition that causes progressive muscle stiffness in the lower back, legs and torso. Only two in a million people suffer from this, including the Canadian singer Celine Dion, who was diagnosed after she noticed changes in her voice, while on tour. Perhaps more familiar is prosopagnosia, otherwise known as "face blindness". Stephen Fry and Brad Pitt are among the one in 50 who struggles to recognise the faces of acquaintances, but also sometimes partners, family members and close friends - a trait which leads the American actor to worry that others see him as "remote and aloof, inaccessible, self-absorbed". People who have prosopagnosia are mostly born with it, but it can also come on after a head injury or a stroke.

Quotidian or quirky, the symptoms of brain injuries or disease give scientists a unique opportunity to study cognitive processes: by seeing what goes wrong, they can also understand what usually goes right. Most importantly, they can work to alleviate suffering, because neurological conditions are now the leading cause of ill health worldwide, having caused 11.1 million deaths in 2021. According to a study published in The Lancet in March 2024, the number of people living with or dying from disorders of the nervous system has risen dramatically over the past three decades, affecting 43 per cent of the world's population, or 3.4 billion people.

Mark Edwards is a professor of neurology and interface disorders at the Institute of Psychiatry, Psychology and Neuroscience at King's College London, and co-founder of the Brain & Mind clinic. "There are many different routes to developing superficially similar symptoms," he says. "Problems involving the brain are often complex, resulting in physical, mental, behavioural and psychosocial fallout, coupled with a lot of stigma and misunderstanding.

"Human beings are complex," he adds. "You can't treat them like a car, and just replace a part and make people better. Making the right diagnosis and finding the right treatment takes time."

Because of this, the medical profession has historically struggled to treat people with neurological conditions, and often fallen short. According to the report It's All in Your Head from the Brain Charity, 37 per cent of people wait more than two years or more for a diagnosis of a neurological condition. Almost half leave their GP feeling uninformed about what's wrong with them, and without a clear view of "next steps". Some 49 per cent say a lack of support and information has led to high feelings of fear for the future.

Prof Edwards points out the difficulty of managing neurological difficulties in a short hospital admission. "People may seem superficially OK, for example, after a brain injury and their scans might look fairly normal," he says. "But when they get home, it becomes clear there are serious issues with cognition, behaviour and personality change. Because their symptoms aren't physical, they are seen as being a 'bad person'."

Many of the problems in traditional treatment are caused by the division between specialisms. "We talk about holistic approaches to care, but the world of health care is sorted into mind and body - what we call the Cartesian split," says Dr Michael Dilley, a consultant neuropsychiatrist at King's College Hospital with special interests in traumatic and acquired brain injury and functional neurological disorder, and also a co-founder of Brain & Mind. "Hence, we have the person with complex needs surrounded by multiple different disciplines."

Mental health conditions go hand in hand with neurological dysfunction, according to Dr Dilley. "Fifty per cent of people develop depression, a third anxiety, and 25 per cent have cognitive issues," he says. "And yet they are often not treated. What is really needed is a joined-up approach from neurology, psychiatry and psychology. Yet there are only 35 neuropsychiatrists in the UK."

As a result, Prof Edwards and Dr Dilley started Brain & Mind in 2018, an independent clinic which takes an "integrated" approach towards dealing with neurological conditions, addressing psychological and behavioural issues as well as physical ones. "We formulate an underlying idea of what is keeping a patient's symptoms going and offer a bespoke multidisciplinary approach, looking at practical, psychological and social interventions," says Dr Dilley. So a patient may have physio, speech therapy and cognitive behavioural therapy to help them marshal their thoughts.

Callum Alexander was a fit and healthy 25-year-old marketing executive when he contracted a bout of gastroenteritis on a work outing in summer 2019. "I was unwell in the night, and woke up shaking slightly," he says. "But within minutes, my body started going into spasms - as if I was being shocked with a defibrillator every second. My arms and legs were flying everywhere. It was really alarming."

The ambulance didn't come, so his family drove him to A&E. "Twenty-five medics came running out," says Alexander. "Once they had ascertained it wasn't a seizure, any panic receded. They told me, 'We don't know what this is,' and, 'It's just one of those things.'" He didn't undergo any specialist investigations. Within four days, Alexander's symptoms receded and eventually disappeared, meaning he could return to work a few weeks later.

He thought that was the end of it, but a year later, Alexander went to bed with a similar digestive complaint. "I woke up violently: with the same process, but it was accelerated," he says. "This time, the ambulance did come. I was having rhythmic, full-body convulsions, my arms and legs splayed and my head snapping back." He recalls the process being exhausting, rather than painful.

Alexander was given muscle relaxants, which knocked him out for four days. "Apparently, the crash team was called at one point," he says. This time, he was given the full range of MRI scans, blood tests and scans - all of which came back normal. "The consultants stopped coming on their ward rounds, and I wasn't offered any treatment," says Alexander. "I didn't despair, because I tend to be calm in a crisis, and I knew I'd recovered from this before."

Two weeks after his admission, he was discharged with a diagnosis of functional neurological disorder, or FND.

According to the National Organisation for Rare Disorders, FND is a medical condition characterised by dysfunction in how the brain and body sends and/or receives signals, rather than a structural disease process such as multiple sclerosis or stroke. Although nothing shows up in scans or tests, FND can encompass a wide variety of symptoms, such as limb weakness or seizures.

Prof Edwards is one of the country's top experts in FND. "Put simply, there is a problem with the system in the brain that connects our conscious self with the automatic machinery of the body," he says. "The view used to be that these symptoms were related to a past trauma but it is clearly more complex and more individual than that, with many routes to developing the problem." The ideal treatment is based on "expert rehabilitation", involving neurological and psychological therapies.

In past incarnations, FND was known as "hysteria" and conversion disorder; then - after the First World War - "shell shock".

"Unlike many people in my situation, I was lucky to get any diagnosis at all," says Alexander. "But the consultant wasn't really able to give me a full picture of what FND meant. She made some vague analogies comparing my brain to a computer with dysfunctions in the software rather than the hardware, and told me to go away and meditate."

Over the next few days, Alexander's condition changed, from jerky epileptic-style seizures to less vigorous, but continual, convulsions. "A medical friend came to see me, and she was so shocked, she said I looked like someone with cerebral palsy," he says. "If I was sitting down, I rocked, quite aggressively. I could not stand without a stick, or my legs gave way. My body didn't keep still, even at night - though somehow I managed to sleep."

Despite this, he says that the incredible fatigue was the worst thing, a whole day's effort expended on making his bed and going downstairs.

Fortunately, Alexander was still able to use his arms, so he could eat and drink, and even work from home: "The people on the end of a work Zoom call didn't quite know what to say when they saw me rocking away. It helped that all this happened during the Covid period as I didn't really want to go out; there was a stigma around it." Alexander discovered the peer-support FND Hope online and engaged with its support network; he is now a trustee and co-deputy chair of the charity.

"FND can be difficult to understand for the person with the disorder, their family and friends, and their healthcare team," says the National Institute of Neurological Disorders and Stroke website. "Physicians may wrongly consider symptoms as feigning or faking, which can leave patients feeling stigmatised."

Alexander says: "I guess I was lucky that no one ever accused me of faking. There was simply no way that I could consciously keep those spasms up for that amount of time."

He was lucky to receive physiotherapy on the NHS, but did not improve. Finally, Alexander was referred to the Brain & Mind clinic, where he saw Prof Edwards and finally received an explanation for his FND. "Prof Edwards explained how it was related to my initial infection and that it probably wouldn't recur. Finally, I was given proper physiotherapy. I spent the first day literally sitting up and standing down again."

The physio taught Alexander how to walk again "like a toddler. I'd become so fatigued from questioning my movement that I had to learn to stop making it such a conscious effort, and for my walking to become instinctive again." He says this realisation was like "flicking a switch".

Over a period of several months, Alexander's convulsions abated, and he learnt to walk, run and drive again. "In November 2023, I was at a friend's wedding, and I suddenly realised: I feel fine again." He's now looking ahead: "But if the FND does come back, I'll know that I've lived through it twice and recovered."

The treatment at Brain & Mind may be bespoke and cutting edge, but at £500-£800 for an initial assessment, it is sadly beyond the budget of most patients. Hence, the rest of the neurology population relies on organisations such as the Brain Charity and its on-site café.

Back in Liverpool, there is a constant worry over how the charity will afford to carry on. "We have holes in the roof and the lottery funding for the gym runs out in three years," says CEO Pippa Sargent. "Funding is a challenge and reliability is difficult. We'd love to be able to plan and have stability."

It's heartbreaking to think of this community without the Brain Food Café. Back at the Liverpool coffee morning, Edna, 66, is explaining how the organisation "simply gives her the motivation to carry on" after a stroke that left her with impaired balance and subject to regular falls. "I have the courage to leave my house and not be treated any differently compared with outside," she says. "I have made friends here." She attends the gym for chair yoga three times a week.

Then there is 37-year-old Kimberly Woodward, who has never seen a neurologist nor had a diagnosis but struggled with delayed development as a child. "I love meeting people and everyone is nice here - they understand," she says. She is writing a play with new-found friend Peter. Upstairs in the gym is Ian Lucas, bent double with Parkinson's disease, but who has raised £1,100 for Parkinson's charities by cycling on the specially modified exercise bike.

And finally, we return to Rose Griffiths, whose foreign accent syndrome has not stopped her joining the Brain Charity choir. "After my stroke, I couldn't speak but I could sing!" she beams, launching into entirely fluent versions of Big Spender and This Is Me. "Coming to the centre, singing my heart out - it's like a weight off. It helps me to fight."