Mild Cognitive Impairment (MCI)

This review of literature will examine the previous research which relates to this topic, giving an evaluation and summary of each piece.
As previously mentioned, for many years, researchers have been studying the “gap” between the normal ageing process and the onset/early onset of Alzheimer’s Disease (AD). This “gap” has since become known as the intermediate stage, Mild Cognitive Impairment (MCI). The discovery of this intermediate stage is a relatively new topic which requires further research into certain areas. Some of these areas include: an agreed upon diagnostic criteria, the causes and the treatments. Without an agreed upon diagnostic criteria, it is difficult for researchers and rating scales to clarify what is categorised as Mild
In 1986, The National Institute of Mental Health (NIMH) categorised deficits in memory as Age-Associated Memory Impairment (AAMI). This term was used to describe memory changes during the ageing process which were thought to be a part of normal cognition. This proved to be difficult with widespread application as the term was associated with older adult’s performance rather than the performance of younger people. This led to the re-categorisation of the term, naming it Age Associated Cognitive Decline (AACD). This time the term recognised that other cognitive domains besides memory could be affected during the normal ageing process. In more recent years, The Canadian Study of Health and Ageing defined the term as “Cognitive Decline, No Dementia” (CIND) which refers to an intermediate stage which is not severe enough to be classed as a form of Dementia. The term itself is diverse in nature in regards to cognitive dysfunction and is therefore the closest term associated with Mild Cognitive Impairment (MCI). After gaining more knowledge about the disease, Mild Cognitive Impairment (MCI) is now recognised as a brain disease which is not associated with the normal ageing process (Petersen,
Both subtypes differ symptoms-wise but are both said to have an impact on the progression to Alzheimer’s Disease (AD). The aMCI subtype affects a single cognitive domain such as memory whereas the naMCI subtype affects one or more cognitive domains such as language, attention and visual spatial skills (Roberts & Knopman, 2013). The number of cognitive domains affected is also said to have an impact on the underlying brain disease, the severity of the disease and the progression of MCI to Alzheimer’s Disease (AD). The multi-cognitive domain subtype (naMCI) is thought to be more severe than the single cognitive domain subtype (aMCI) as the progression rate from MCI to Alzheimer’s Disease (AD) is higher (Roberts & Knopman, 2013). This was shown in a Cardiovascular Health Study which found individuals with the aMCI subtype progressed to Alzheimer’s Disease (AD) at 6 % per year while those with the naMCI subtype progressed at 16% per year (Petersen, 2004). However, when the aMCI subtype was compared against healthy individuals, those with the aMCI subtype progressed to Alzheimer’s Disease (AD) at 10-15% per year whereas the healthy individuals progressed at 1-2% per year (Petersen et al, 2001). These findings suggest that although one subtype is more likely to progress onto Alzheimer’s Disease (AD), both subtypes can lead onto