The new science of dementia

People with dementia may struggle with many aspects of their lives that we all take for granted, such as remembering new information, holding a conversation, decision-making, reading, writing and understanding times and places.

Dementia is a disease that damages brain cells, leading to progressive deterioration in memory, thinking and communication, as well as personality changes. Nearly 50 million people worldwide are living with the condition and numbers are expected to rise as the population gets increasingly older. About two-thirds of dementia cases are Alzheimer’s disease, but there are over 200 other types of dementia. Even within these categories, patients may present in different ways.

For example, some people may not know they have dementia or that their abilities are limited by it, while others will be aware, at least some of the time. However, as the disease progresses through its early, middle and late stages, more areas of the brain are involved and the symptoms of the different types of dementia start to look more similar.

Five things about dementia everyone should know

Dementia is different from normal ageing: We may all have the odd memory lapse as we get older, such as occasionally losing our car keys, but this is not the same as dementia. Diagnoses can take a while: The time it takes to get a dementia diagnosis doubles when the patient is under 65. It’s genetic: The APOE4 gene variant carries a three-fold greater risk of Alzheimer’s disease if you have a copy from just one parent, and an eight-fold greater risk if you have copies from both. One in four of us have one copy, and one in 50 have two.

There are different types: Author Terry Pratchett had an unusual form of dementia called posterior cortical atrophy, which affects the outer parts of the back of the brain. It may be a sub-category of Alzheimer’s or a separate form altogether. It can be caused by certain medications: Occasionally, dementia can be the side effect of a drug that affects neurotransmitters in the brain – as with certain drugs used to treat insomnia and IBS. Once the medication is stopped, dementia goes away.

While MRI and CT scans are often used to confirm a diagnosis of dementia – following simpler question-and-answer tests – some of the changes to the brain that may be seen in dementia are also seen in other situations, such as menopause. So it’s difficult to be absolutely sure. In fact, many people living with dementia haven’t been formally diagnosed, and it’s thought that more than a quarter of cases could actually be misdiagnosed.

In several high-profile cases, patients have been wrongly diagnosed with, and treated for, Alzheimer’s disease. One example is Alex Preston, who was diagnosed in 2014 in Leicester, UK, and continued taking medication for seven years, until he discovered the diagnosis was wrong.

Science Daily