Rarer types of dementia only account for about 5% of all dementia cases. They tend to be more common among younger people with dementia (under the age of 65).
Corticobasal Syndrome (CBS)
CBS is a rare condition in which parts of the brain become damaged and begin to shrink. Sometimes referred to as ‘corticobasal degeneration’ or CBD, the terms describe the same condition. Symptoms can include problems with movement, language, memory, and visual perception. CBS usually affects people aged between 60 and 80 and is often diagnosed by a neurologist who specialises in movement disorders.
Common Symptoms
- Being stiff or slow
- Jerky movements
- Problems with balance
- Coordination issues (usually on one side of the body)
- Memory issues
- Difficulty maintaining concentration
- Issues making decisions
Progressive Supranuclear Palsy (PSP)
PSP is a condition causing problems with movement and dementia, mainly affecting people over 60. The name refers to brain areas above the nerve cells controlling eye movement. Damage here can make it hard to move the eyes properly, coordinate them, or keep eyelids open normally.
It can also cause double or blurred vision and other difficulties linked to movement and cognition.
Common Symptoms
- Issues concentrating
- Difficulty making decisions
- Difficulty problem-solving
- Problems organising tasks
- Struggling with planning
- Difficulty with visuospatial skills
- Difficulty reading
- Stuttering or difficulty speaking fluently
- Using incorrect words in sentences
- Becoming apathetic, stubborn, or impulsive
HIV-Associated Neurocognitive Disorder (HAND)
With effective antiretroviral therapy, dementia from HIV is now uncommon, but some people still experience milder cognitive impairment known as HAND. This may involve problems with memory, thinking, and mood. Symptoms usually remain stable over time rather than progressing to dementia.
Following a diagnosis of HIV, cognitive and emotional wellbeing assessments are recommended within three months, with re-assessments at least once a year.
Common Symptoms
- Issues concentrating
- Difficulty making decisions
- Memory problems
- Problems organising
- Struggling with planning
Niemann-Pick Disease Type C
A rare inherited disorder affecting cholesterol and fat processing in the body, leading to accumulation in cells, including the brain. It can occur from infancy to adulthood and may cause progressive loss of movement, walking, and swallowing abilities. If symptoms appear in late adolescence or adulthood, dementia may develop as part of the disease.
Common Symptoms
- Confusion
- Memory problems
- Difficulties with concentration and learning
Creutzfeldt-Jakob Disease (CJD)
CJD is caused by abnormal prion proteins damaging the brain. Most cases are sporadic and not inherited or transmitted. Symptoms progress rapidly, often within weeks or months. There is no cure, though some symptoms can be managed with medication. New variant CJD, linked to BSE (‘mad cow disease’), is now extremely rare.
Common Symptoms
- Memory loss
- Mood changes
- Apathy
- Clumsiness and confusion
- Unsteady walking
- Slow or slurred speech
- Jerky movements
- Shakiness
- Stiff limbs
- Incontinence
- Loss of ability to move or speak
Mild Cognitive Impairment (MCI)
MCI involves minor memory or thinking problems that are greater than expected for age but not severe enough to interfere significantly with daily life. People with MCI may need occasional help with demanding tasks, but it does not cause major daily difficulties. However, MCI increases the likelihood of developing dementia.
Between 5% and 20% of over-65s have MCI. It can be a chance to make positive lifestyle changes to reduce the risk of progression.
Common Symptoms
- Forgetting recent events or repeating questions
- Struggling with reasoning, planning, or problem-solving
- Being easily distracted
- Taking longer to find the right word
- Difficulty judging distances or navigating
Potential Impact of Other Diseases
Some people with Parkinson’s disease or Huntington’s disease may develop dementia as these illnesses progress. People with Down’s syndrome are also at higher risk of developing Alzheimer’s disease as they age.
These conditions may share symptoms with other forms of dementia depending on the underlying cause and progression.