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Dementia vs Alzheimer’s? A Dementia Overview

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The dividing line between dementia vs Alzheimer’s consists of determining the primary cause of the memory and cognition problems that affect people with either disease. Dementia and Alzheimer’s are often confused with each other because both diseases impair brain functioning and produce similar symptoms. However, the origins of most dementias are, for the most part, recognized and understood while the origin of Alzheimer’s and reasons why some people develop the disease are not yet fully comprehended.

What is Alzheimer’s Disease?

Several discernible clues that are detectable through brain imaging scans can tell doctors whether someone is suffering from AD:

  •  Noticeable shrinkage of brain tissue
  • Noticeable enlargement of ventricles (spaces filled with cerebrospinal fluid that act as a cushion for the brain)
  • Atrophy of the hippocampus, the area responsible for memory
  • Cortical atrophy, the area responsible for higher reasoning, judgment and abstract thinking
  • Evidence of abnormal electrical activity provided by EEG scans
  • Plaques and tangles

Plaques and tangles, abnormal strands and cluster of protein fragments that inhibit communications among nerve cells choke the classic Alzheimer’s brain. Specifically, plaques form when beta amyloid pieces begin clumping together because of their chemical stickiness.

When clumps grow large enough to impede cell-to-cell synaptic signaling, the individual suffering from these plaques will quickly develop a variety of cognitive deficiencies, especially concerning recognition, attention, and memory.

An electron microscope can easily detect tangles affecting neurons due to their disorganized structure. Normally, strands composed of tau protein are parallel and organized, allowing vital molecules and cell parts to be transported along these track-like strands.

When something happens to tau proteins, the brain’s ability to keep the strands organized is lost, resulting in tangles and knots that disintegrate and fail to transport essential nutrients to all parts of the brain.


When discussing dementia vs Alzheimer’s rates of progression, the main difference involves the time between someone developing Alzheimer’s symptoms and the time it takes before an accurate diagnosis is made. Signs of AD can start 20 to 25 years prior to an official diagnosis while dementia patients can receive a diagnosis within weeks of initially showing symptoms of brain impairment, especially if they have suffered a stroke or medical condition that effectively reduces blood flow to the brain.

Dementia vs Alzheimer’s–A Dementia Overview

So what is dementia when it is not caused by Alzheimer’s disease? Some of the features of dementia that are different from Alzheimer’s includes:

Dementia can be age-related–Alzheimer’s is not. As we age, the ability of our organs, tissues and vessels to operate optimally begins to deteriorate. Theories of aging attempt to explain why healthy human bodies rapidly decline in functioning after age 60 or 65 but none have been substantiated with conclusive evidence.

Dementia that is accelerated by chronic high blood pressure, Parkinson’s disease, high cholesterol, diabetes and stroke (vascular dementia) is due to blood vessels experiencing irreversible damage coupled with these vessels’ inability to provide the brain with sufficient amounts of blood-borne nutrients and oxygen.

 People diagnosed with a certain dementia type do not have the standard plaques and tangles that are always found in the brains of AD patients. According to an article published in the International Journal of Geriatric Psychiatry (2009) titled “Apathy is a prominent neuropsychiatric feature of radiological white-matter changes in patients with dementia” by M. Jonsson et al,  brain imaging scans reveal that acute changes in the white matter of the brain commonly occur in dementia and elderly patients.

White matter consists mostly of myelinated axons and glial cells that are responsible for transmitting electrical signals between lower brain areas and the cerebrum. Healthy white matter appears whitish-pink on MRI and CT scans. White matter affected by dementia is blurred and darker than it should be due to tiny vessels not supplying enough blood to keep the white matter functioning properly.

Dementia vs Alzheimer’s–Personality ChangesHuman Neurons

Because these two cognitive disorders exhibit different pathological disturbances that affect different pathways in the brain, certain cognitive and personality changes  are attributed to one disorder more than the other. For example, apathy is seen in almost half of all people suffering from non-Alzheimer’s dementia while aggression and irritability is seen in more AD patients than dementia patients. This suggests to researchers that when comparing dementia vs Alzheimer’s, patients with dementia suffer more “deep brain” or neocortical damage than AD patients.

Moreover, people with Alzheimer’s dementia also experience more mood changes, paranoia and extreme anxiety than those with non-AD dementia. In those who have damaged blood vessels due to strokes, high cholesterol and hypertension, the chance of having audio and visual hallucinations are higher than in patients with Alzheimer’s.

Dementia Caused by Brain Tumors or Head Injuries

Dementia symptoms caused by brain tumors or head injuries are temporary if the condition is not severe and can be successfully treated. Once a benign, operable brain tumor is removed and brain swelling decreases, the person suffering dementia symptoms usually recovers full use of their cognitive abilities. Subdural hematomas often cause dementia-like symptoms but these are also eliminated if surgical decompression of the area is successfully employed.

Understanding why the line between the dementia vs Alzheimer’s comparison is often blurred may help family members recognize the early signs of Alzheimer’s in parents or grandparents as well as dementia in cases of old age or stroke.