Dementia

Hello! I promised you to write about dementia, didn't I?
Here it is... :)
Dementia actually means a syndrome of acquired cognitive impairment due to brain dysfunction that is of sufficient severity to interfere with usual social or occupational functioning. In the lecture yesterday, the group mentioned that there are two types of dementia: cortical or subcortical. Alzheimer's Disease (AD) is associated with cortical dementia, while Parkinson's Disease (PD) is associated with subcortical dementia. 
Maybe you are wondering, what are the differences between dementia and normal aging? How about the difference between dementia in AD and PD?

In normal older adults, their ability to do tasks that involve immediate recall of a large number of items (eg 7 or more words or digits) is lower than younger adult. However, when the older adults were asked to learn a list of 15 words over five trials and then recall them 30 minutes later, their result is comparable with younger adults, while patients with dementia cannot do delayed recall task. 
In normal older adults, vocabulary levels remain stable, while it is impaired in patients with dementia. Abstract reasoning also declines in normal older adults, but it is not obvious in daily life because they can compensate by experience and acumen over a lifetime, while in patients with dementia, you can see the abstract reasoning skill is impaired even in daily life.

Next, how about the difference between AD and PD? First of all, let's study the definition of these two disorders. AD is a progressive degenerative brain disorder characterized by neuronal atrophy, synapse loss, and the abnormal accumulation of diffuse and neuritic plaqes and neurofibrillary tangles. PD is a neurodegenerative disorder consisting of symptoms of parkinsonism ( a cluster of motor symptoms consisting of slowness of movement, difficulty initiating movement, hypokinetic speech, masked facies, muscular rigidity, a shuffling or unsteady gait, abnormal posture, and disturbances in equilibrium) PLUS a pill-rolling type of resting tremor. Second, if you remember, I mentioned that AD and PD were associated with dementia, BUT... dementia is a condition that is much wider than AD and PD. AD and PD are causes of dementia, but there are other kinds of dementia and not all PD patient has dementia. As I said, AD is correlated with cortical dementia, while PD is correlated with subcortical dementia. This correlation can be seen from the different features of both disorders.

First, in general, memory disorder is more prominent in AD rather than in PD, while frontal lobe related-tasks (planning, sequencing multiple steps, set-shifting) is more prominent in PD than in AD. Why?? pls remember this : cortical dementia --> AD --> changes in medial lemboral limbic structures (entorhinal cortex, hipocampus) then the association cortices of the frontal, temporal, and parietal lobes. MOST SUBCORTICAL STRUCTURES and primary motor and sensory cortices are intact. 

Second, in terms of language ability, during the early onset of AD, phonemic fluency is intact in AD. AD patients are severely impaired in word finding ability, language comprehension, and naming, while PD patients have dysarthic speech and their semantic and phonemic fluency are impaired. Dysarthic speech is characterized by poor articulation (this is not the case in AD perhaps because primary motor and sensory cortices are not affected).

Third, attention is not affected in AD, while in PD there is a fluctuation of alertness. Fourth, even though memory disorder is more prominent in AD, in both AD and PD, memory is affected. However, AD patient is still poorer on delayed recall and recognition or retrieval test. Last but not least, the visuospatial ability is intact in both disorder, but in PD, it's more affected earlier compared with AD.

fiuhh... Hope you are not confused by this post. Just as an extra, there are other types of dementia..(let me know if you want to know about this too..hehehe)

:):) HAPPY SUNDAY!!
recommended book: The Notebook. Allison, the main female character, has Alzheimer's Disease. It can reach a point when someone cannot remember the family. The book describes the disease better than the movie (coz when I watched the movie, I didn't realize that Alison had hallucination, it is part of the symptom of AD)
to know more about parkinsonism, u can watch the movie: Awakenings.
http://www.youtube.com/watch?v=FURflBxeTyI
The Notebook and AWakenings movies are very inspiring and touching. At the end of the day, it's all about human dignity. That's why we learn psychology. We might not be able to cure the patient (just like what Oliver Sacks experienced in Awakenings) *oops sorry spoiler*, but at the end of the day, how do we treat other people as fully human with heart and soul? :):)