Tendencies In Understanding, Prognosis And Treatment Of Dementia
Dementia is an umbrella term used for a progressive or chronic syndrome due to disease of the brain (Dementia, 2007). The prevalence of dementia increases with age becoming more common from the age of 65 (Maria and Pimentel, 2009). Dementia is prevalent amongst the younger population although it is less common. Alzheimer’s disease (AD) accounts for 60% to 80% of cases, therefore, being the most common form of dementia (Alzheimer’s Association, 2016). It is characterised by impairments regarding memory, communication, problem-solving, judgement, and behavioural changes (Alzheimer’s Association, 2018). Neuropsychological assessments provide information about which abilities are impaired and preserved (Maria and Pimentel, 2009). They are often adopted by physicians in order to diagnose and examine the cognitive impacts AD has on the patient. Advancements in scientific technology have resulted in neuroimaging methods, such as Magnetic Resonance Imagining (MRI), which provides information regarding changes the brain undergoes as a result of dementia. There is no definitive onset or cure for AD (Jack et al., 2008) however, neuropsychological assessments and neuroimaging methods have contributed towards our understanding, prognosis, and treatment of dementia.
The onset of AD occurs years before diagnosis therefore, by the time a diagnosis occurs the brain has already undergone a substantial amount of neuronal loss (Dickerson and Sperling, 2008). This is due to the accumulation of beta-amyloid plaques which causes cell death and tau tangles which prevent neurons from getting their nutrients. This neuronal damage causes difficulty in cognitive and bodily function and is ultimately fatal (Alzheimer’s Association, 2018). Thus, it is vital that physicians are able to detect AD at the earliest possible stage. Neuropsychological assessments are widely used in the detection, diagnosis, and management of AD. Some of these assessments have been proven to be highly sensitive to the identification and specificity of AD. For example, the Mini-Mental State Examination (MMSE; Folstein et al., 1975) which examines memory, language, attention, and visual-spatial ability yielded an 85% sensitivity and 90% specificity at a cut-off point of 24 out of 30 therefore,, displaying a high accuracy for identifying and discriminating between dementia patients (Creavin et al., 2016). Moreover, neuropsychological assessments have become increasingly useful in the early identification of dementia (Weintraub, Wicklund, Salmon 2012). In a study that examined subjects’ cognitive change across a 9-year period preceding a diagnosis of AD, they found that the MMSE score declined faster for AD subjects than those without AD with an acceleration 3 years before clinical diagnosis (Amieva et al., 2005). Furthermore, a meta-analysis investigating the prognosis of AD patients using the MMSE found a decline in cognitive ability over an average of a 2-year period (Han et al., 2000). This was further supported by another longitudinal study which found that over a 2-year period, the changes observed on the MMSE were statistically significant demonstrating that the AD patient’s cognitive ability progressively gets worse (Cortes et al., 2008). This suggests that it would be beneficial to use the MMSE with prodromal individuals years before the development of AD to track and attempt to delay the impairment in their cognitive ability. Therefore, this demonstrates how neuropsychological assessments, such as MMSE, improve our understanding and enables us to track the prognosis of dementia.
Moreover, there is a great need for neuroimaging methods that enable physicians to establish biomarkers and improve the understanding of the early disease. (Jack et al., 2008). MRI appears to be a useful tool in being able to identify prodromal AD (Jack et al., 1999; Killiany et al., 2001). Structural MRI (sMRI) can be used to examine patterns of structural change in individuals prior to clinical cognitive decline (Davatzikos et al., 2008). Killiany et al. (2001) conducted a 3-year longitudinal study that investigated whether sMRI could predict if those who have mild memory impairments develop onto AD. They found that sMRI readings of the entorhinal cortex, superior temporal sulcus, and anterior cingulate were of most use in distinguishing between who will develop onto AD. The sensitivity (95%) and specificity (90%) were also high for the sMRI when distinguishing those with mild memory impairments who developed AD (Killiany et al., 2001). This is further supported by Davatzikos et al.’s (2008) research which showed that sMRI yielded a 90% predictive ability and accuracy for diagnosis of mild cognitive impairment (MCI) which is considered the prodromal stage of AD. Additionally, the sMRI scans collated over the prior years displayed an increase in structural abnormality of the brain suggesting that the disease gets progressively worse. Therefore, sMRI is particularly useful in contributing towards our understanding and to aid in diagnosis and prognosis as clinicians can assess structural differences in the brain to determine whether the individual will develop AD thus, consequently put specific treatment into place which will delay the progressive memory impairment.
Furthermore, functional MRI (fMRI) is also useful in the early diagnosis of AD (Fleisher et al., 2005). fMRI yielded an 84% sensitivity and 92.3% specificity for distinguishing between healthy individuals and those with dementia (Tripoliti, Fotiadis, and Argyropoulou, 2011). Dickerson and Sperling (2008) reviewed a number of studies involving fMRI to investigate abnormalities in-memory systems of those who have MCI and AD. The findings indicate that during prodromal AD, the medial temporal lobe (MTL) including the hippocampus shows functional abnormalities with respect to memory. When memory impairments and hippocampal atrophy are not as prominent during early MCI, hyperactivation in MTL circuits during tasks were observed. In later MCI and AD, fMRI’s demonstrate that MTL regions are no longer active whilst the patient is attempting to learn. It is suggested that regional brain hyperactivation may indicate the pathophysiologic process of AD (Dickerson and Sperling, 2008). This is further supported by Prvulovic et al. (2011) as they also suggest hyperactivation displayed in fMRI readings could be representative of risk factors which could in turn have negative effects on the brain if the individual was to develop MCI or AD. However, they suggest that although using fMRI as a tool for diagnosis seems promising, further rigorous longitudinal validation is needed which could potentially incorporate analysis of genetics and cerebrospinal fluid for more concrete findings. Nevertheless, using fMRI at the prodromal stage of MCI could be especially useful as if MTL hyperactivation is shown, clinicians would be able to use this in aid of the patient’s prognosis by putting treatment into place which could delay damage to the MTL regions.
Although there is no cure for AD, there are various treatments available which the patient can undergo which could delay or aid symptoms. As mentioned throughout this essay, the MMSE, sMRI and fMRI scans have shown that memory impairments progressively get worse for AD patients. Therefore, clinicians could suggest and help implement interventions aimed at improving their quality of life and aiding memory impairments. For example, cognitive rehabilitation is an intervention devised by clinicians together with the patient and their family to create an individualised strategy to help cognitive impairment (Wilson, 2002 as cited in Clare and Woods, 2004). This method of treatment is particularly useful with early AD with regards to memory difficulties as it enables the AD patient to make the most of the memory ability they still have and find ways of compensating for difficulties. There are several techniques which could be implemented to help the patient’s memory difficulties however, the intervention used takes into consideration the patients’ goals and what impairments are most relevant to the patient and their family (Clare and Woods, 2004). For example, to aid retrieval of memories, the patient could incorporate the expanding rehearsal technique which involves them recalling informational at gradual increasing intervals (De Vreese et al., 2001). In order for the treatment to be effective, the intervention should consist of regular sessions over a prolonged period of weeks to months (Backman, 1996 as cited in De Vreese et al., 2001). De Vreese et al. (2001) and Clare and Woods (2004) both reviewed studies using cognitive rehabilitation as a method of treatment and concluded that this treat is beneficial for AD patients with regards to their memory. Therefore, this displays how once diagnosis has occurred through measures of neuropsychological assessments and neuroimaging, treatment can be implemented in order to aid the patient with AD’s symptoms in the hope of improving their quality of life.
To conclude, both neuropsychological assessments and neuroimaging have improved our understanding, prognosis and treatment of dementia. Neuropsychological assessments could be useful in early AD and enable clinicians to assess cognitive impairments throughout the course of the disease. Neuroimaging is particularly useful in establishing biomarkers and provides an insight into changes the brain undergoes through the progressive disease. Although both neuropsychological assessments and neuroimaging methods discussed have relatively high sensitivity and specificity, if used in conjunction with one another, it would be more beneficial for diagnosis and prognosis. Furthermore, if both neuropsychological assessments and neuroimaging are used in prodromal AD, this could enable clinicians to effectively implement treatment which could aid the impairments AD patients undergo thus improving their quality of life.