As previously mentioned, in the vast majority of cases, dementia is not a normal part of ageing, and you can actively minimise your risk of developing Alzheimer’s and other dementias. Many active lifestyle changes can reduce your risk. These include:

• Reducing your risk of getting cardiovascular disease – stopping smoking, having an active non-sedentary lifestyle, losing weight if you are overweight, eating a healthy balanced diet with fresh fruit and vegetables as well as drinking less alcohol.
• If you have diabetes, keep on top of your medication and make active lifestyle changes such as managing you blood pressure and blood sugar levels.
• Keeping yourself mentally active – even something as simple as reading, doing crosswords or playing Sudoku.
• Brain training games have a beneficial short-term effect in improving cognition
• Loneliness and social isolation can also increase your risk of dementia, therefore volunteering in local communities or doing group sports is beneficial.

Brain Changes in Alzheimer’s Disease

There are two key pathological hallmarks of Alzheimer’s: beta-amyloid plaques, which form within brain tissue and around vessels (cerebral amyloid angiopathy) and tangles within neurons of a protein called tau. Together, these contribute to the neurodegeneration (death of neurons and synaptic connections) which leads to the overall shrinkage (atrophy) of brain matter within the cortex and hippocampus. The death of neurons and atrophy of key brain regions correlates with disease progression and symptom severity.

There are many symptomatic and pathological overlaps among the types of dementias. Lewy bodies of alpha-synuclein (the key protein involved in Parkinson’s disease and dementia with Lewy Bodies) can also sometimes be found in the brains of Alzheimer’s patients. There may also be the build-up of fatty plaques (atherosclerosis) within the vessels of the brain which cause vascular dementia and stroke. There may also be the presence of TDP-43 (key motor-neuron disease protein) in the brain of Alzheimer’s patients. The combination of two or more dementias together is called mixed dementia, and the most common mixed dementia is Alzheimer’s disease and vascular dementia.

It is now known that up to one-third of all supposed Alzheimer’s cases over the age of 85 might actually not be Alzheimer’s at all. A newly identified form of dementia, called limbic-predominant age-related TDP-43 encephalopathy or LATE, produces symptoms that are nearly identical to those of AD in older persons, but are caused by the TDP-43 protein rather than amyloid. This discovery has major implications for correct diagnosis, treatment strategies, prognosis, and for scientists researching mechanisms and treatments for Alzheimer’s.

Alzheimer’s Disease Diagnosis

Short-term memory loss or subtle, early symptoms of dementia may be overlooked or attributed to medications, stress, depression and anxiety, which can mimic AD. However, if these symptoms gradually worsen and persist, then that may be a sign of dementia.

Unfortunately, there is no single test for diagnosing Alzheimer’s or any other dementia. If your GP is concerned that the symptoms may be due to dementia, they may refer you to a specialist – usually a neurologist and/or psychiatrist at a dedicated memory clinic. A neurologist will assess for physical signs of dementia, whereas a psychiatrist will evaluate the cognitive symptoms. A neurologist may also recommend a CT or MRI scan of the brain to assess any brain pathology to rule-out or confirm diagnosis.

At the memory clinic, a standardised questionnaire called the mini mental state examination (MMSE) is used to assess cognitive ability. This is a set of 30 questions, in which a score greater than 24 indicates normal cognitive abilities. Mild cognitive impairment is usually considered between 19-23 points, moderate cognitive impairment between 10-18 points, and severe cognitive impairment at 9 points or lower. However, these scores need to be adjusted for educational attainment and age.

In combination with the MMSE, brain scans, and exclusion of other causes (e.g. by blood tests for medication interactions), a positive diagnosis can eventually be made. This can take some time due to the subtlety of early symptoms. However, as the disease progresses, diagnosis may become easier.