Many people believe that parkinsonism only affects movement, but those with Parkinson’s dementia experience slow thoughts, memory loss and a lower attention span.

According to Parkinson’s UK, a diagnosis of Parkinson’s dementia occurs if symptoms appear a year or more after the onset of movement problems. However, when dementia symptoms appear before, or at the same time as, symptoms of Parkinson’s, this is called dementia with Lewy bodies.

What causes Parkinson’s dementia?

Cognitive decline among Parkinson’s disease sufferers is caused by changes in the structure of the brain. Research is currently under way to help determine how the brain becomes damaged, leading to dementia.

Parkinson’s dementia does not affect everyone who suffers with Parkinson’s, but the consequences of dementia can be greater due to the combination of motor and cognitive impairments.

While Alzheimer’s disease mainly affects language and memory, Parkinson’s dementia reduces problem solving, speed of thought, memory and mood.

In most cases, dementia is a sign of the progression of Parkinson’s disease, rather than the sufferer having both Parkinson’s and Alzheimer’s.

What is dementia with Lewy bodies?

People experiencing dementia with Lewy bodies might display the following symptoms:

  • Fluctuating levels of attention and confusion
  • Sleeping problems
  • Mood and motivation swings
  • Hallucinations and delusions
  • Issues with visual perception
  • Memory loss
  • Decision-making and planning problems
  • Parkinson’s-like slow movement, stiffness and tremors
  • Dizzy spells and fainting
  • Other signs include problems with blood pressure, constipation, incontinence and swallowing.

Types of Parkinson’s disease

According to Parkinson’s UK, the term parkinsonism covers a range of illnesses, including Parkinson’s and other conditions with similar symptoms.

As a neurodegenerative condition, Parkinson’s disease affects the nerve cells in the substantia nigra part of the brain. This lowers the level of a chemical called dopamine, which helps to control body movement.

While the precise cause of Parkinson’s is still a mystery, common symptoms include:

  • Tremors, usually affecting the hands
  • Slow movement (known as bradykinesia)
  • Stiff limbs and muscles
  • Balance problems.

These symptoms typically take several years to develop, with the progression of the disease differing from person to person. Parkinson’s disease is not fatal, but the complications can be serious.

Here is an overview of Parkinson’s disease and the types of conditions that may present with similar symptoms:

Idiopathic Parkinson’s disease

Most sufferers have idiopathic Parkinson’s disease. The word idiopathic simply means the cause is unknown. Progressive degeneration of the brain cells responsible for co-ordinating movement occurs, resulting in common symptoms such as tremors, rigidity and slow movement.

Vascular parkinsonism

Also known as arteriosclerotic parkinsonism, this affects those with restricted blood supply to similar regions of the brain that are implicated in idiopathic Parkinson’s disease. People who have suffered a mild stroke can sometimes develop this form. Typical symptoms include trouble with memory, sleep, mood and movement.

Drug-induced parkinsonism

Some drugs can cause parkinsonism, such as neuroleptic drugs which treat schizophrenia and other psychotic disorders. These are designed to block the action of the chemical dopamine in the brain.

Drug-induced parkinsonism only affects a small number of people, and most recover within months, often within days or weeks when they stop taking the drug responsible.

Multiple system atrophy (MSA)

Like Parkinson’s, MSA can cause stiffness and slow movement in the early stages. However, people with MSA can also develop symptoms that are not associated with early Parkinson’s, such as unsteadiness (leading to falls), bladder problems and dizzy spells.

Progressive supranuclear palsy (PSP)

PSP affects a person’s eye movement, balance, mobility, speech and swallowing. It’s also known as Steele-Richardson-Olszewski syndrome.

Other tremors

If a tremor is your only symptom, you might be suffering from another condition which is not a parkinsonian disorder.

Rarer causes of parkinsonism

There are a number of much rarer, potential causes of parkinsonism, such as Wilson’s disease, which is an inherited disorder where the body retains too much copper.

Is Parkinson’s disease hereditary?

According to Parkinson’s UK, while Parkinson’s can be hereditary, this is very rare, with only a tiny number of cases being reported where people have passed it down to their children via their genes.

Currently, there are no blood or laboratory tests available to diagnose Parkinson’s disease. Diagnosis is based on a person’s medical history and a neurological examination. Improvement after initiating medication is another sign of Parkinson’s disease.

Need support?

If you are worried about Parkinson’s dementia affecting yourself or a family member, a dementia assessment can provide comfort and peace of mind. Call us on 0330 124 1970 to arrange a free, no-obligation, Mini-ACE cognitive test (worth £100).

Approved by Dr Darren Cotterrel MBBCh, MRCPsych, MSc, FRCPS