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Tau Brain Scans

The deadly disease Alzheimer's takes a terrible toll on not just memories but also lives of millions year on year. Although doctors use checklists of symptoms and signs to detect Alzheimer's, these methods are open to major variations in medical opinion about a single patient. There is a danger of Alzheimer's disease - AD - being confused with any other dementia or common declining intellectual disabilities.


Sometimes, memory loss need not be the first symptom of Alzheimer's and it could be behavioral or language changes or difficulty in everyday activities. Hence, doctors treating Alzheimer are always left to face uncertainty in trying to diagnose the disease in the living, and only an autopsy can confirm the disease for certain.

A pioneering brain image - Tau brain imaging - can detect the build-up of destructive proteins linked to Alzheimer's. This is the beginning of diagnosing the condition and testing of new drugs. Reported in the journal Neuron, tau brain scan can identify living clumps of a protein called tau that is closely linked to the disease. With this new diagnosis, patients can be helped early to make the most of their remaining life span. This definitive diagnosis can tell Alzheimer's disease apart from other disorders.


To understand this, it is relevant to know that Alzheimer's patients lose their brain's nerve fibers and there is an abnormal buildup of protein that damages nerve cells. Patients who begin with mild memory loss soon worsen to become restless, anxious, confused and moody. Patients lose their ability to talk or care for themselves in the final stages.


Tauopathies are a set of neuro-degenerative diseases associated with phosphorylated tau protein aggregation in the human brain. In Alzheimer's, tau protein is deposited within the neurons as neurofibrillary tangles. The German psychiatrist and later Neuro pathologist Dr. Alois Alzheimer was the first to describe this disease as pre senile dementia.

It is the associated protein tau that causes the tangles to aggregate in an insoluble form. The tau protein is referred to as 'PHF' or paired helical filaments. There are other conditions as well in which such neurofibrillary tangles are observed and these include progressive supranuclear palsy, chronic traumatic encephalopathy, Parkinson-dementia complex, ganglioglioma, meningioangiomatosis and tuberus sclerosis among others. These non-Alzheimer's tauopathies are grouped as Pick's complex.


A protein called tau (τ) is very closely linked to Alzheimer's and tangles of tau are thought to be one way in which the brain cells are killed. Researchers have developed a chemical that could bind to tau and then be detected during a brain scan. This was tested on mice and people and it showed that suspected Alzheimer's could be revealed by this technology that could detect tau.

Dr Makato Higuchi, National Institute of Radiological Sciences, Japan says that this emission tomography image of tau accumulation provides robust information on brain regions and also risk for tau-induced neuronal death. Although this research is at an early stage, it could eventually lead to identifying Alzheimer's.

As another Alzheimer's expert says "Tau can be compared to railroad ties that stabilize a train truck that brain cells use to transport food, messages and other vital cargo throughout neurons. In Alzheimer's, changes in tau protein causes the tracks to become unstable in neurons of the hippocampus, the center of memory. Abnormal tau spreads from cell to cell, disseminating pathological tau in the brain cortex".


While researchers have already tried time-tested medical imaging techniques to detect this disease, and while magnetic resonance imaging and computed tomography scan only rule out other disorders, there is no positive detection tool for Alzheimer's. Tau imaging highlights a new method for detecting tau, which would be a key player in both Alzheimer's and frontotemperal dementia in the living brain. The tau scan is capable of visualizing the protein inside the brain and is important for assessing whether treatments in clinical trials are hitting the target.

If the tau scan is shown to be effective, then it could become a potential aid for providing people with accurate diagnosis for monitoring the disease progression. The new focus for Alzheimer's treatment is halting the toxic tau.


A set of researchers at the Mayo Clinic in the US were able to look at the evolution of tau using neuro pathologic measures. Just like one could identify the changing seasons by looking at the rings of a tree, and the aging of the tree by viewing the cross section, studying the different stages of Alzheimer's gives a perspective of the cognitive impact of a wide range of amyloids and tau severity. At the Mayo brain bank, a collection of thousands of post mortem brains have allowed to understand changes in tau and amyloid that occur over a period of time.

There is an estimated 3 to 4 million people in the US with some form of Alzheimer's and there is a tendency for the number to increase over the years. Therefore, a good diagnostic tool is a must. Tau imaging represents significant advancement in the field and it is hoped that combined tau and amyloid positive PET scans may in the future help researchers get closer to an affirmative diagnosis of Alzheimer's disease.


Alzheimer's disease

Alzheimer's disease is a progressive mental disorder that brings about changes in the brain slowly leading to dementia. Named after the German physician Alois Alzheimer, Alzheimer's disease has 2 characteristic neuronal changes : Loss of cholinergic cells in the basal forebrain and the development of neuritic plaques in the cerebral cortex. Neurofibrillary tangles can also occur due to Neuritic plaques.

Here the brain cells degenerate and die thus causing a decline in the mental functioning and memory of a person. Alzheimer's disease (AD) or Presenile dementia as it was earlier known as, is one of the primary causes of dementia. The levels of the brain neurotransmitters serotonin, norepinephrine and acetylcholine are found to be low in AD. This kind of brain disorder causes loss of social and intellectual skills of a person. In severe cases it interferes with the day-to-day activities of a person.


Alzheimer's disease causes

  • Most scientists believe that Alzheimer's disease is caused due to increase in production and accumulation of a protein called beta-amyloid protein. The accumulation of this protein leads to nerve cell death.
  • Environment factors that causes a change in the brain's functioning can also lead to Alzheimer's disease
  • Genetic causes
  • Abnormal levels of elements like aluminum and lead
  • Chronic cerebrovascular condition resulting from high blood pressure can lead to cerebral microbleeds. These microbleeds over a long period can result in mild cognitive impairment.
  • Head injury
  • Some viruses
  • Lifestyle changes that causes change in the brain's functioning can also lead to Alzheimer's disease


There are 4 major cognitive deficits arising out of AD :

1. Amnesia : Memory loss is probably the most common symptoms of Alzheimer' disease.
2. Aphasia : Loss of Language - Failure to recollect names of objects
3. Apraxia : Inability to perform voluntary movements
4. Agnosia : Inability to recognize people and places


Alzheimer's disease symptoms
  • Forgetfulness, unusual difficulty in remembering things
  • Mild confusion
  • Occasional memory lapse
  • Disorientation day, date, etc.
  • Problem with speaking and writing
  • Problem in thinking and reasoning
  • Decision making problems
  • Depression, anxiety, mood swing and many such behavioral problems
  • Problems with cognitive skills like calculating, judgment, etc


Alzheimer's disease diagnosis

1. A physical examination and a neurological examination to check:


  • Muscle tone and strength
  • Sense of touch and sight
  • Reflexes
  • Balance
  • Coordination, etc.

2. Brain imaging (CT scans, MRI) to check for tumors, etc.
3. Lab tests for thyroid etc so as to rule out other possibilities for memory loss


Treating Alzheimer's disease

As this disease is of degenerative nature, there is no permanent cure. Early diagnosis and changes in lifestyle can slow down its progression or improve the quality of life for the afflicted.


  • Drugs to deal with cognitive changes and memory symptoms
  • Drugs to increase acetylcholine or butylcholine levels. eg; Donepezil hydrochloride or rivastigmine, a cholinergic agonist or Cholinesterase inhibitor.
  • Vitamin E combined with Cholinesterase inhibitors
  • Alternate medicines like Ginkgo Biloba, Brahmi, Gotu kola, Ginseng and St. John's Wort
  • Exercise
  • Well balanced and nutritious food
  • Lifestyle changes that help deal with and improve the current condition

Pick's Complex

This is a less common form of dementia, more prominent in those under the age 65. Frequently misdiagnosed as Alzheimer's disease, Pick's patients initially exhibit marked personality and behavioral changes. And gradually the ability to speak coherently declines.


Although there is no cure for Pick's complex presently, it can however be managed well and the quality of life improved. According to Arnold Pick, who first described the disease in 1892, Pick's disease causes an irreversible decline in a person's functioning for several years. Pick's affects adults between the ages of 40 and 60 and is more common in women than men.


Causes

The frontal and temporal lobes of the brain control a person's speech and personality. Excess protein build-up in these parts causes slow atrophy in these regions. The cause for this build-up of protein is unknown. Other than causing speech and behavioral changes, Pick's disease can also cause memory loss quite like those with Alzheimer's as well as socially inappropriate behavior, poor decision making, progressing to severe impairment in intellect, speech and memory. Some opine that Pick's disease may have a genetic or heredity component although not all family members are affected.


Symptoms of Pick's disease

The first sign of Pick's complex is personality changes and decline of basic functioning. Pick's can occur in an age earlier than Alzheimer's and memory loss need not be a predominant early sign of Pick's disease. Although there could be reports of Pick's occurring as young as 20 years of age, the progression is slower in Pick's disease. However, there are cases where symptoms could worsen over time and brain cells degenerate. More severe symptoms appear at later stages of Pick's. Some noticeable behavioral symptoms of Pick's disease are poor judgment, extreme restlessness especially in the early stages, overeating or drinking, lack of personal hygiene, sexual exhibitionism, decreased interest in daily activities and obsessive behavior.

Mood swings, lack of empathy, apathy, rudeness, impatience and aggression, easy distraction and being unaware of strange behavior and memory loss are some of the prominent emotional symptoms of Pick's disease. Loss of vocabulary, difficulty in speaking and understanding, uncoordinated speech and decrease in the ability to speak and write are some serious signs of Pick's.


Diagnosis of Pick's Complex

Other than careful symptomatic evaluation, brain scans and EEG, three of the following five characteristics are found to be present in the early stages. They include:


    Onset before age 65
    Personality changes
    Lack of normal behavior / Loss of control
    Lack of inhibition
    Roaming behavior
    When compared to Alzheimer's, memory loss and mental impairment occur later in Pick's.

Diet and activity

There should be a restriction on foods with high sugar content. There could be carbohydrate cravings in some. While in Alzheimer's and Parkinsons, a diet relatively high in fat and protein and low in carbohydrates is necessary, it is unclear if the same is recommended for Pick's complex. It is better to get a doctor's opinion on an appropriate heart-healthy diet. A regimen of therapeutic exercises such as brisk walking can help to regulate the patient's mood and benefit on cognitive function.


Treatment

Pick's disease, like any other dementia progresses rapidly and life gets shortened about six to eight years, although some do live for as long as twenty years. As currently there is no cure for Pick's like Alzheimer's, the aim is to maximize quality of life by way of medications to manage particular symptoms, regular supervision, and assistance.

Emotional and substantive support is an important aspect of the treatment. The family of the affected may help with the following control symptoms:


  • Eyeglasses and hearing aids to bolster the failing senses.
  • Positive behavior when symptoms set in by creating a calm and soothing atmosphere so that the patient feels safe and less anxious.
  • Speech therapy or any other physical therapy that can improve communication and movement.
  • Selective antidepressants that can provide some relief from apathy and depression and help reduce food cravings, impulse control and compulsive activity.
  • Treatment for other disorders such as anemia, thyroid disorders and kidney or liver diseases.
  • Stopping medications like paracetamol, NSAIDS, anti-cholergenics or changing them under medical guidance.

Tips for coping with Pick's complex

Being diagnosed with Pick's complex can be overwhelming especially when it involves any form of dementia. It is good to learn more about Pick's disease and frontotemporal dementia. In this way, more control can be exhibited and they will be better prepared to manage symptoms.


  • Music therapy, meditation, deep breathing exercises can help control stress and anxiety.
  • Pet therapy and visits from specially trained animals can help relieve stress and improve mood.
  • Treating depression can make it easier to handle other challenges of the disease.
  • Reaching out to family and friends for emotional support can help avoid isolation. A support group of similar patients can help overcome feelings of depression and isolation and provide a wealth of coping tips. Staying socially active will lighten the load and increase patient comfort.
  • Playing cards and word games such as scrabble, crossword and Sudoku puzzles can exercise the brain and help slow cognitive decline.
  • It would be wise for a Pick's patient to avoid medical, financial and legal confusion and instead create a design plan and discuss and document end-of-life preferences with doctors and family members.

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Bibliography / Reference

Collection of Pages - Last revised Date: September 23, 2019