It has been reported that Robin Williams may have been affected by Parkinsonian

They are two of the most devastating conditions — but the cruel double whammy of both Parkinson’s and dementia affects around 100,000 Britons.

These people have Parkinsonian symptoms — slow movement and problems with gait — as well as confusion, memory loss, hallucinations and delusions associated with dementia.

They may get Parkinson’s first, then develop dementia a year or more later — known as Parkinson’s dementia.

Or, if dementia is diagnosed before or at the same time as Parkinson’s symptoms develop, they are said to have ‘dementia with Lewy bodies’ — a type of dementia that shares symptoms with Alzheimer’s disease and Parkinson’s.

Parkinson’s dementia and dementia with Lewy bodies are the same problem — the difference is the order of the symptoms.

It’s been reported that the actor Robin Williams might have been affected by this ghastly disorder when he took his life this summer.

He’d suffered from Parkinson’s for three years — then last week a leaked pathologist’s report revealed there was ‘diffuse Lewy body dementia’ in his brain.

Lewy bodies are tiny clumps of abnormal proteins produced by the brain when its cells are not working properly.

They cause memory problems, although these don’t tend to be as severe as with Alzheimer’s — which is linked to a build-up of the protein beta-amyloid.

Another key difference is that Lewy body dementia affects regions of the brain responsible for vision, causing powerful hallucinations, nightmares and spatial-awareness problems.

Studies suggest that up to 80 per cent of people with Parkinson’s will develop Parkinson’s dementia.

Professor David Burn, clinical director of the charity Parkinson’s UK, says: ‘People with Parkinson’s will already have Lewy bodies in the bottom of the brain, which controls movement.

'In Parkinson’s dementia, the Lewy bodies spread up to areas involved in memory, cognition and vision.

‘For the patient with dementia with Lewy bodies, the problem starts at the top of the brain and spreads down — they tend to go to their doctor with cognitive problems, then develop Parkinson’s or get both simultaneously.’

In your 50s, the illness is more likely to start as Parkinson’s. Dementia with Lewy bodies usually affects people in their 70s, says Ian McKeith, professor of old-age psychiatry at Newcastle University and chairman of the Lewy Body Society.

Diagnosis is usually via a brain scan that tests for dopamine, a chemical that is lower in people with Parkinson’s and Lewy body dementia.

Symptoms vary — but it’s a harsh blow for patients, says Professor Burn.

Margaret Kelly would agree. Her husband Reggie, 76, a father-of-three and former supermarket manager, was diagnosed with Lewy body dementia in 2009, when he was 71.

Up to 80 per cent of people with Parkinson’s will develop Parkinson’s dementia

‘Every form of Alzheimer’s is cruel, but I do think this is the cruellest,’ says Margaret, 75, from North-East London.

‘Reggie was such a fit man. Now he’s like a baby. He can’t speak and he’s so confused he doesn’t know me any more.’

Four years before his diagnosis, Reggie couldn’t move his legs away from the sink while washing up.

Margaret then started noticing changes in his behaviour — he would become quiet and expressionless at times.

A GP diagnosed depression, but antidepressants didn’t help.

Reggie went on to develop a shuffling gait, and in 2006 a neurologist diagnosed Parkinson’s.

Medication helped control those symptoms but in 2009 Reggie’s behaviour changed dramatically.

‘He became terribly aggressive,’ says Margaret.

‘He’d wreck the shed looking for a screwdriver. He’d never admit he couldn’t remember where it was.’

Memory tests showed signs of Lewy body dementia. Around this time, Reggie started having hallucinations, some of which were horrific.

Since his 40s, he’d suffered with nightmares and restless leg syndrome — the urge to move your legs at night.

It is thought there may be a link between sleep disturbances and Parkinson’s and Lewy bodies.

The cause of Lewy body dementia is largely unknown but the risk increases with age. Both Lewy body dementia and Parkinson’s are slightly more common in men.

Patients may be prescribed Parkinson’s medication and cholinesterase inhibitors, such as Aricept and Exelon.

These particularly help with hallucinations, says Professor McKeith. Correct diagnosis is vital, as some Parkinson’s drugs can worsen hallucinations.

15% The proportion of all dementia cases diagnosed as Lewy body dementia Advertisement

Although dementia and Parkinson’s specialists are well aware of Lewy bodies dementia, GPs and the public are less so.

A U.S. study found half of patients with Lewy body dementia saw the doctor more than ten times before diagnosis.

Motor symptoms of Parkinson’s can mask cognitive issues.

And hallucinations, delusions and movement problems aren’t usually associated with dementia, as Bridget Hunt discovered after her mother Rose developed Lewy body dementia.

‘We never thought it could be dementia because of the hallucinations,’ says Bridget, 60, of York. Rose started seeing things in her early 70s.

Other symptoms included struggling to add up, shuffling, a tremor in her arm and spatial-awareness problems.

At 80, she was finally diagnosed with Lewy body dementia. Aricept slowed the disease down, but her increasing disorientation is difficult to witness, says Bridget.

While Rose still lives at home, Reggie moved to a care home in 2011 after a serious fall. Margaret, who is disabled, visits him every week.

‘I desperately want to take him home,’ she says. ‘He’s not the same man I knew but we’ve still got him.’