SERIES - Healthy aging: how to distinguish normal brain changes from dementia or Parkinson's disease

The brain controls numerous bodily processes. It is also the place where our consciousness arises, where our thoughts and feelings develop. Therefore, if something changes in the brain, it can have an impact on both body and mind. These changes increase with age. This is frightening. The fear of dementia is particularly great, but so is the fear of other so-called neurodegenerative diseases, in which regions of the brain are damaged.

But not every age-related deviation from normal functioning is pathological. The following explains what are truly signs of dementia and what changes occur in the brain with age. It also explains how doctors assess brain health.

The brain in old age : How symptoms manifest

Memory begins to decline as early as age thirty. However, we continue to gain experience. "My medical students can remember the names of new medications much better than I can," explains Tania Zieschang, Director of the University Clinic for Geriatrics at Oldenburg Hospital, in an interview. "But I can better assess which patients are most likely to benefit from the new drugs and what potential interactions with other medications might occur."

Older people are also less able to concentrate on one thing for as long as they used to be, or to multitask. This is annoying, but normal. It's also no cause for concern if you can't immediately recall the name of an acquaintance when you run into them while shopping.

"Such a situation is made more difficult by the fact that many older people are aware of their declining brain function when it comes to word finding," says Zieschang. "They then put themselves under pressure." This increases their stress level, and thus their brain becomes even more blocked.

Signs of dementia are present when someone can no longer immediately recall more than just a single word or detail. For example, if a person can no longer remember a phone conversation with their daughter from the previous day, meaning entire episodes are completely missing.

Another warning sign is when someone loses interest in a beloved hobby. Or when non-strenuous activities that were previously enjoyed and performed regularly are neglected, such as reading the newspaper daily. "Family members should also be concerned if interest wanes in people with whom a person has a close emotional bond," emphasizes Zieschang.

The crux of the matter with Parkinson's disease is that the first signs can easily be mistaken for purely age-related changes: sleep disturbances, neck or other muscle pain, and a diminished sense of smell. Typical symptoms of Parkinson's, however, include problems with writing, arm and leg movements, a frozen facial expression, or changes in the tone of voice.

The brain in old age: These are the changes

The normal age-related changes have the same cause as the diseases: nerve cells are irretrievably lost. The dense network in the brain thins out. As a result, for example, impressions can no longer be processed and categorized as efficiently. This is why even mild noise distracts older people more.

In dementia or Parkinson's disease, however, the death of nerve cells is far more drastic than in the normal aging process. In these neurodegenerative diseases, certain proteins clump together in the brain for reasons that are still unclear. These clumps adhere to the outside of nerve cells, disrupting their function. Eventually, they die.

In Alzheimer's disease, the most common form of dementia, further harmful processes occur. Sticky fibers form inside the nerve cells. These consist of a different protein than the outer clumps, but they have the same effect: they too are toxic. Both the clumps and the fiber bundles then trigger inflammation in the brain.

Only once this infernal trio has become established do the affected nerve cells die. A veritable mass die-off occurs. Gaps appear in the dense network.

However, not all brain regions are affected equally. Alzheimer's dementia begins in the hippocampus, the region where memory is stored. Patients become forgetful as a result. They might see a toothbrush and even pick it up, but they no longer know what it is or how to use it. As the disease progresses, areas in the cerebrum are affected, leading to word-finding difficulties, disorientation, and other cognitive impairments.

In Parkinson's disease, however, only one type of cell dies in a brain region below the cerebrum. This region is responsible for controlling the body's muscles.

However, our brain is extremely resourceful: for several years it can compensate for the damage. Therefore, patients often don't realize for a long time that thousands of nerves are missing in their brain. This is because, like on a road construction site, bypasses are built: nerves next to the damaged areas relay the signals. But eventually, these bypasses also fail.

The more neural pathways were present before the onset of dementia, the more alternative pathways existed. Therefore, a life in which someone regularly and intensively engages their brain with diverse activities acts as a bulwark against cognitive decline in dementia. Dementia doesn't develop later in these individuals, but its negative effects become apparent later.

The brain in old age: These are the testing options

If someone is experiencing forgetfulness, a simple blood test can reveal whether a vitamin deficiency is present. Deficiencies in certain B vitamins or vitamin D can cause concentration problems or mild forgetfulness. Depression can also resemble the early stages of dementia. This should be discussed with a general practitioner or a psychiatrist.

Numerous tools exist for a reliable diagnosis when the first signs of dementia appear.

To find out whether constantly misplacing a mobile phone is simply age-related absentmindedness or actually a symptom of dementia, the Mini-Mental State Examination (MMSE) can help. This test can easily be administered at home with a family member.

Here, simple questions such as those about the day and month, place of residence, or basic arithmetic must be answered. Objects in the room must be named. The test also assesses whether someone can remember five unrelated words that the examiner lists at the beginning of the test. The so-called clock-drawing test is revealing: people with dementia are often no longer able to correctly draw a clock with a given time.

If deficits are noticed during testing – or even in everyday life – neurologists or psychiatrists specializing in dementia should conduct more comprehensive analyses. These involve in-depth testing of cognitive abilities. Furthermore, simple blood tests are now available in the EU and the USA that can detect existing Alzheimer's dementia. Brain scans, taken using MRI or a special X-ray technique, reveal shrunken areas and also regions containing toxic protein clumps.

However, both blood tests and brain scans only provide a reliable diagnosis if the person is already showing initial signs of cognitive impairment. This is because all these analytical methods only indicate the presence of clumps in the brain. But not everyone with these clumps has dementia. It cannot even be said with certainty that affected individuals will develop Alzheimer's disease.

In other words, if someone already has clumps but no cognitive impairment, then the analyses indicate an increased risk of Alzheimer's dementia in that person. Currently, there are no medications that reduce this risk. This differs from other diseases that occur more frequently with age. For example, heart disease: If someone has high blood pressure or high cholesterol, they are advised to take blood pressure-lowering medication or statins to reduce their risk.

In Parkinson's disease, a doctor can detect slowed movements, muscle stiffness, tremors, and balance problems and clearly attribute them to the disease.

A diagnosis of dementia or Parkinson's disease is devastating. But certainty can also be helpful: family, friends, and neighbors understand why someone no longer recognizes them or sometimes reacts strangely. It's possible to take preventative measures in the early stages of dementia and realize long-held dreams or plans before it's too late.