Dementia is caused by changes occurring within the brain that cause a decline in abilities. Symptoms of dementia can be caused by a number of conditions with those over the age of 65 most at risk of developing the condition.
The most common types of dementia include:
Alzheimer’s is most common form of dementia. It’s estimated that Alzheimers accounts for around 60 to 80 percent of cases of dementia.
Symptoms of Alzheimers: Early symptoms can include apathy, depression and a difficulty in remembering recent events or people’s names.
More advanced symptoms that are commonly seen include confusion, disorientation, reduced cognitive functionality and behavioral changes. Physical impairments may include trouble speaking, swallowing and reduced mobility.
Brain changes: The onset of Alheimers can be triggered by changes in the brain.Deposits of the protein fragment beta-amyloid (plaques) and twisted strands of the protein tau (tangles) and characteristic commonly associated with Alheimers. In addition it is commonplace to see evidence of nerve cell damage and death within the brain.
Vascular dementia is the second most prevalent root cause of dementia. This form of dementia has traditionally been known as multi-infarct or post-stroke dementia.
Symptoms: The initial symptoms displayed tend to relate to an inability to comprehend the steps required to complete a task or impaired judgment. This differs from Alzheimer’s where memory loss is regarded as the prominent early symptom. As the name suggests this form of dementia is brought about due to vascular issues within the brain, primarily microscopic bleeding or blockages in the blood vessels. An individual’s physical and mental functioning is impacted differently based on the location of their brain injury.
Brain changes: vascular problems within the brain can be detected through brain imaging. However evidence of vascular damage does not rule out a diagnosis of Alzheimer’s as it is possible for an individual to be affected by several types of dementia simultaneously. If it an individual is affected by two or more types of dementia at any one time they are considered to have what is called ‘Mixed Dementia’.
Dementia with Lewy Bodies (DLB)
Symptoms: Suffers of dementia with Lewy Bodies display similar symptoms to those associated with Alheimer’s. However early distinguishing syptoms can include sleep disturbances, hallucinatins, muscle rigidity or other issues relating to movement that are commonly seen individuals coping with Parkinson disease.
Brain changes: Lewy bodies are abnormal accumulations of the protein alpha-synuclein. Where these accumulations occur in the cortex of the brain dementia can result. People with Pakinson’s disease also see these Alpha-synuclein occurring in their brain. However the pattern of these aggregates may appear different from those with dementia with Lewy bodies.
Dementia can be caused just due to the presence of the Lewy Bodies. However they can also be present within the brain at the same time as the brain changes due to Vascualr Dementia or the onset of Alheimer’s disease. Again when this occurs the individual is said to have “Mixed Dementia” with each abnormality potentially contributing to different dementia symptoms displayed.
An individual is said to have Mixed Dementia when abnormalities associated with more than one type of dementia occur simultaneously. This form of dementia is increasingly common and more prevalent than previously believed.
In mixed dementia abnormalities linked to more than one type of dementia occur simultaneously in the brain. Recent studies suggest that mixed dementia is more common than previously thought.
Brain changes: Most commonly associated with changes that occur in the brain due to more than one type of dementia, primarily Alzheimer’s and Vascular dementia. However abnormalities caused due to other forms of dementia may also occur.
As Parkinson’s disease advances , it often results in a progressive dementia with symptoms not unlike dementia with Lewy bodies or Alzheimer’s.
Symptoms: A common early syptom of the disease is difficulty with movement. If dementia develops, symptoms are often much like the syptoms associated with dementia with Lewy bodies.
Brain changes: Alpha-synuclein clumps are likely to begin in an area deep in the brain called the substantia nigra. It is believes that the degeneration of dopamine producing nerve cells is caused by the development of these clumps.
Frontotemperal dementia includes dementias such as behavioral variant FTD (bvFTD), primary progressive aphasia, Pick’s disease and progressive supranuclear palsy.
Symptoms: Changes in behavior and personality are common syptoms and can be accompanied by a difficulty with language. Nerve cells in the side and front regions of the brain are particularly affected.
Brain changes: Unusually there are no distinguishing microscopic abnormalities that are linked to all cases. Generally symptoms of FTD develop at a younger age (around age 60) and individuals survive for fewer years than those with other dementia conditions such as Alzheimer’s.
CJD is the most common human form of a group of rare, fatal brain disorders. It can affect both people and certain other mammals. Variant CJD occurs in cattle and is more commonly referred to as ‘Mad Cow Disease’. It is possible for Variant CJD to be transmitted to people under certain circumstances.
Symptoms: CJD impairs memory, coordination and causes significant changes in behavior. It is a rapidly fatal disorder.
Brain changes: CJD occurs due to misfolded prion protein that causes a “domino effect” in which prion protein throughout the brain misfolds and thus malfunctions.
Normal pressure hydrocephalus
Symptoms: Individuals affected by Normal Pressure Hydrocephalus can have difficulty walking, memory loss and a loss of control of their bladder.
Brain changes: It is caused by fluid buildup within the brain. The surgical installation of a shunt in the brain can sometimes allow this excess fluid to be drained.
Huntington’s disease occurs due a defective gene on chromosome 4. It is a progressive disorder so symptoms with typically worsen over time.
Symptoms: Mental symptoms typically take the form of changes in mood. This can include irritability and depression alongside a severe decline reasoning skills Physical symptoms are characterised by irregular involuntary movements.
Brain changes: Huntington’s disease is casued by a gene defect which results in abnormalities in a brain protein. Over time this leads to worsening symptoms.
Korsakoff syndrome is a chronic memory disorder caused by severe deficiency of thiamine (vitamin B-1). Alcohol missues is the common common cause of a lack of thiamin.
Symptoms: Unlike most other forms of dementia thinking and social skills can seem relatively unaffected but individuals may have severe issues with their memory.
Brain changes: Thiamine helps brain cells produce energy from sugar. When thiamine levels fall too low, brain cells cannot generate enough energy to function properly.