Alzheimer's Dementia

Memory is the process of storage of data in the cerebral cortex area of the brain, and retrieval of the data through the reticular formation part of the brain (Baddely, 1992). Storage and retrieval of memory happen mainly by usage of the five senses which are; sight, hearing, smell, touch and taste. The retrieval of data using the memory happens after it is triggered by a stimulus through one or more of the five senses. There are different types of memory, including; short term, long term and sensory memory. The three types of memory work in relation to each other. First, the stimulus triggers one or more of the five senses stimulating the cerebral cortex which on its role obtain or reject this data, starting with the sensory then the short

term than long term memory.
Sensory memory is the shortest memory; where the individual’s brain sorts through the stimuli that were received through their senses. Sensory memory will often hold the fusillade of sensations just long enough for the individual’s brain to look at it and it decides which information will need attention. According to Baddeley’s model of working memory, short term memory is of the essential ways humans are able and encode memories into long-term memory. Likewise, it is where the humans combine the recent information with the old information. Short-term memory stores just small amounts of information for a short amount of time. The information that is stored in humans long term memory is the most important and will be more permanent (Baddeley & Hitch, 1974).
There are several prototypes of instant memory that are recognized the capacity properties of short-term memory (STM) and the processing functions of working memory (WM) (Anderson, 1983). STM has limited numbers of an item that can be sustained using some simple stratagems as preparation or chunking. Working memory is frequently thought to be malleable with a limited amount of attentional assets that are used for handling and influencing of information. The capability of Working Memory has been associated with solving problems, reasoning, reading ability, and intelligence.
The first experimental data that was tested to see whether there is unitary memory system or a distinct subsystem of memory was done by Baddeley and Hitch (1974). Baddeley and Hitch (1974) indicated that if there was a single capacity memory for any cognitive action, then, by loading information into the short term memory, participants would have experience issues finishing any kind of difficult assignment in the meantime. Also, they found that loading memory with three or four digits did not affect secondary task performance, but rather keeping up to six digits did cause impairment. They discussed that short-term memory can only hold up to three or four items; their findings indicated that recalling a small number of digits and executing more difficult oral tasks do not rely on the same type cognitive properties.

There are different diseases and syndromes that could also affect the memory.

Some syndromes may be acute or chronic and may be reversible or irreversible. The most common group of syndromes affecting the memory is called dementias. Alzheimer’s Dementia, it is the most common type of dementias, and it has two types; the first type is early onset dementia happens before the age of 65 years and it has a hereditary correlation mainly with chromosome 21. Type 1 Alzheimer’s disease usually happens with Down syndrome (trisomy 21). The second type is late onset dementia happening after the age of 65 and is not associated with any hereditary factors. Another type of dementia is age related, which usually affects the individual that are 60 and above. Also, age-related dementia mainly affects recent memories but mostly the old memories are unaffected. According to (Roman, 2002) the second most common type of dementia is Vascular Dementia it occurs to the individuals that are suffering from diabetes mellitus and hypertension. Vascular Dementia is unique in that it is usually associated with focal neurological signs. Cerebro-vascular is another dementia where usually happens during accidents to those older than 60 and in those having Diabetes Mellitus and hypertension conditions. Global Dementia affects all types of memory, including sensory, short-term and long-term memory. The global type of dementia happens mostly after trauma affecting the tissue of the brain. Fronto-temporal Dementia (Pick’s disease) affects the frontal and temporal lobes of the brain, causing memory loss for short and long term memory and primarily changes the personality and behavior of the person. Korsakoff-confabulation Disease often happens after drinking a large amount of alcohol and causes loss of memory and confabulation (filling the blank areas of a story with fake details). Korsakoff dementia may end in a coma due to hypoglycemia and Thiamine deficiency, but it is reversible if treated early

with Thiamine then glucose with careful monitoring of the blood glucose level. Huntington’s disease it is an autosomal-dominant disease on chromosome 4, it is an association between Chorea (involuntary movements and memory loss) usually has a tragic ending in committing suicide. Pseudo Dementia (Depression) is one of the main types of dementias that usually happens in association with major depressive episodes (MDE). Major depressive episodes happen due to lack of desire to remember, and is usually reversible with treatment of the MDE by pharmacotherapy and psychotherapy.