Welcome back to Lesson 8. Well done on getting this far, you’ve learned so much over the past few days, and we’re nearing the end of the course. In today’s lesson, we’ll learn about dementias.
Definition of Dementia
Dementia describes a syndrome that is characterized by:
• poor memory
• the presence of other neuropsychological symptoms/conditions
• progressive overall cognitive decline
Dementia is progressive, which means that dementia continues to worsen with time and affects multiple cognitive processes (e.g., patients must have aphasia and amnesia).
The greatest risk for dementia is age: dementia is most prevalent among older adults, although there are rare instances where it develops in young adults.
It’s very different to diagnose the type of dementia when it is very advanced because all dementias lead to a general picture of impaired cognitive processing; however, in the beginning, different dementias have different symptoms and present unique clinical pictures.
When assessing dementias, pay attention to:
• onset (how did it start)
• progression (how does it progress; at what does it progress)
• how does dementia evolve
For some dementias (e.g., Alzheimer’s disease), the diagnosis can only be made definitively with an autopsy, after the patient has died.
Since dementia is progressive, it is important to see the patient for follow-up assessments so that the patients’ neuropsychological performance can be monitored. Using this information, the clinician can predict the types of difficulties that patients will experience in the future, and give feedback to the patients’ family and caregivers.
Types of Dementia
There are a number of dementias, which present with a different cluster of symptoms. Some dementias are classified as cortical, and others classified as subcortical (there is some controversy about this distinction, but it is a useful guideline).
• Cortical dementias affect the grey matter, and often present with grey matter conditions (aphasia, amnesia, agnosia, apraxia).
• Subcortical conditions affect the white matter and do not present as frequently with grey matter conditions.
Alzheimer’s disease. Alzheimer’s disease is the most common type of dementia. Its defining characteristic is that patients present with anterograde amnesia. The start of Alzheimer’s disease is gradual and difficult to narrow down. As the disease progresses, other cognitive impairments develop (e.g., aphasia).
Not all patients with memory problems have Alzheimer’s disease; what distinguishes a solely amnesic syndrome from Alzheimer’s disease is that Alzheimer’s disease will progress, and it appears alongside other cognitive difficulties. A solely amnesic syndrome is marked by only memory problems.
Dementia with Lewy bodies (DLB). Patients with DLB present with:
• walking difficulties (i.e., gait difficulties)
• very unusual and dramatic visual hallucinations
• fluctuations in their cognitive arousal (on some days they may seem more lucid, “awake” and “aware” than on other days)
These patients might report that fall a lot, but this is a result of their walking difficulties.
As DLB progresses, it resembles Alzheimer’s disease and it becomes more difficult to distinguish between these two dementias. DLB also resembles Parkinson’s disease and has some of the same movement difficulties.
Frontotemporal dementia. This type of dementia was known as Pick’s disease and is the most common type of dementia for people younger than 60 years. This dementia has an insidious onset (difficult to pinpoint the start), and is characterized by the following:
1. There are personality changes, changes in emotion regulation, less interest in hobbies/interests, loss of self-care, and flattened affect.
2. Lots of executive functioning problems, which result from damage to the frontal lobes. Patients are socially inappropriate, disinhibited, have a lack of insight into their illness, and reduced spontaneity. They can be very difficult patients.
3. Stereotypical behavior, and may develop an increased appetite.
4. Aphasic difficulties—they have anomia (struggle to name items), and reduced speech.
5. Frontal type of amnesia problems. They may fail memory tests, but they’re not true amnesics—their amnesia is of a frontal type because they benefit from cues.
Vascular dementia. Unlike the insidious onset of Alzheimer’s disease, vascular dementia is characterized by stepwise progress: The deterioration in cognitive ability is marked and noticeable. Vascular dementia might be preceded by a stroke and is the result of illnesses of the cardiovascular system. Because vascular dementia is associated with vascular disease and events such as strokes, these patients present with other symptoms that are also a result of the stroke. For example, these patients might present with hemiparesis (i.e., being paralyzed on one side of the body) or left hemineglect (as a result of a stroke in the right hemisphere).
Today we looked at dementias. In this lesson, you learned about four types of dementias. The key characteristic of dementia is that they progress and that they tend to include more than one symptom. There are other types of dementia that you can read about, including Parkinson’s disease, progressive supranuclear palsy, dementia from substance abuse (including Wernicke-Korsakoff syndrome), dementia associated with HIV-AIDs, and multiple system atrophy. I’ve included some interesting videos for you to watch if you’re interested.
Tomorrow, we will learn about epilepsy.
The author, Iris Murdoch, was diagnosed with Alzheimer’s disease and she displayed word-finding difficulties. You can read more about the symptoms that she was displaying here.
You can buy her last novel here.
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