The prevalence of Alzheimer’s disease among older adults is on the rise. Alzheimer’s disease (AD) is a slowly progressive neurological disorder that impacts the memory and other cognitive functions, including thinking and reasoning skills. It is the most common form of neurodegenerative dementia, and it starts slowly and progressively worsens and eventually severely impairs an individual’s memory, thinking, the pattern and social behavior. Dementia is characterized by some symptoms, which include loss of memory, difficulties in speech and problem-solving abilities, and cognitive deficits. Symptoms of dementia are exhibited when the brain is impaired by certain diseases, such as Alzheimer’s disease. Medical experts are yet to come up with a cure for Alzheimer’s disease (AD). According to Korolev, approved medications for the treatment of AD control the symptoms of the disorder but do not slow down the progression or reverse the course of the disease (2014). Distinguishing between Alzheimer’s disease and other dementia-causing neuropathologies is difficult. This paper discusses the research being conducted to characterize, diagnose, and treat Alzheimer’s disease.
The earliest AD-associated neuropsychiatric symptoms are apathy, anxiety, and irritability with the latter two symptoms often being provoked in situations that the patient finds challenging (Apostolova, 2016). Even though age is the greatest risk factor for the development of AD, old age is not sufficient to cause AD on its own (Apostolova, 2016). According to Apostolova, other major risk factors include the presence of one or more apolipoprotein gene E4 alleles (APOE4), low educational and occupational attainment, family history of AD, moderate or severe traumatic brain injuries, and cardiovascular risk factors (2016). Alzheimer’s disease eventually progresses into severe disability and the inability to function effectively in daily life. Essentially, the disease gradually damages perceptional processes such as memory, orientation, and speech making it hard for patients to function once the condition progresses. People with Alzheimer’s disease usually have trouble communicating, learning, thinking, and reasoning – problems severe enough to have an impact on an individual’s work, social activities and family life. Language disturbance, especially word-finding difficulties, is a common early symptom in AD but is generally mild (Apostolova, 2016). A subtle decline in visuospatial skills likewise occurs in the mild dementia stages and progresses throughout the disease (Apostolova, 2016). Executive dysfunction, on the other hand, begins even earlier in the predementia stages and, similar to all other cognitive domains, worsens over the disease course (Apostolova, 2016). Persons who have Alzheimer’s disease exhibit mild to moderate depressive symptoms during the early stages of the disease. Furthermore, not only may they have disturbances of appetite and sleep but also alterations in perception (hallucinations) or thought (delusions). In addition to the classic neuropsychiatric behaviors, anosognosia (that is the lack of insight) often manifests early on and poses another difficult management problem (Apostolova, 2016).
The gold standard for the diagnosis of Alzheimer’s disease is based on the pathological evaluation (Korolev, 2014). The medical onset of Alzheimer’s disease can be grouped into three periods namely preclinical, mild cognitive impairment (MCI), and AD dementia. The onset of preclinical stage starts with asymptomatic cerebral amyloidosis. In this phase, the monomeric amyloid beta (Aβ) begins to aggregate, leaving its reservoir in the cerebrospinal fluid (CSF) and begins to accumulate on the neuronal surface and synapses (Hane, 2017). Additionally, future efforts are exploring whether more complex activities of daily living (that is, financial competency, navigating complex telephone trees) and other subjective and informant questionnaires related to engagement (that is, physical activities, cognitive stimulation) or emotional states (that is, social isolation, apathy, withdrawal) may be associated with biomarker evidence of preclinical AD (Rentz, 2013). At this phase, Alzheimer’s disease is not yet detectable using current medical techniques. Moreover, no cognitive deficits of note are evident at this phase. A person in the preclinical stage is more likely to develop Alzheimer’s disease over time.
The second stage of Alzheimer’s disease is mild cognitive impairment (MCI). In this phase, persons suffering from the condition experience a reduction in cognitive functions, though at a level in which the person is still able to remain an independent and functional member of society. Even though there have been advances made in Alzheimer’s disease imaging modalities and biomarkers, neuropathologies, which cause mild cognitive impairment, still requires a subjective look at by a clinician through cognitive and functional tests. These laboratory tests though cannot diagnose mild cognitive impairment. Mild cognitive impairment (MCI) can be distinguished from dementia by determining whether the sufferer is experiencing significant interference in the ability to perform normal routine tasks. Positron emission tomography (PET) imaging and cerebrospinal fluid (CSF) analysis are still viable methods of differentiating dementia symptoms (Hane, 2017). What is more, at this phase, neuroimaging and laboratory studies can only be used for investigational purposes to aid in the clinical procedures for Alzheimer’s disease, not for detecting the disease. The third stage, AD dementia, can be confirmed with postmortem neuropathological study. At this point, Alzheimer’s disease can be differentiated from other dementia-causing diseases. According to Apostolova, the American Academy of Neurology (AAN) guidelines for the diagnostic evaluation of dementia requires physicians to obtain a structural imaging scan in every patient with objective cognitive decline (2016).
Big strides have been made in the advancement of Alzheimer’s disease research, for instance, the advances in fluid and imaging biomarkers. What is more, the recent discovery and validation of amyloid PET imaging have the potential to change the approach to the clinical diagnosis of Alzheimer’s disease since it facilitates the detection of moderate to severe amyloid deposition in the brain (Apostolava, 2016). Medical researchers have had to consider other means through which they can detect an impending Alzheimer’s disease due to the invasiveness of cerebrospinal fluid (CSF) collection. Their research has led them to explore more accessible regions in the body e.g. fluid biomarkers. Moreover, one challenging executive task that does show promise for detecting subtle changes related to preclinical AD is a dual task paradigm (Rentz, 2013). Dual tasking requires an individual to perform two tasks simultaneously (for example, a visuospatial task and a verbal task together) on the premise that cognitive resources are limited and that the interference between the two tasks will cause dual task coordination deficits (Rentz, 2013).
Moreover, researchers have recently discovered means through which they can non-invasively probe the brain due to the breakthrough in the advancement of brain imaging technology. Ultimately, these newly developed measures will need to be simple, cost-effective, and capable of capturing the subtle changes that can differentiate healthy aging from preclinical AD (Rentz, 2013).
The prevalence of Alzheimer’s disease among older adults is on the rise. Big strides have been made in the research to characterize and diagnose the condition. Approved medications, which help control the symptoms of Alzheimer’s disease are used to treat symptoms. However, they do not cure the condition, and neither do they derail the progression of the disorder. Additional research is imperative for understanding the condition better and possibly find a cure.
Hane, F. T., Robinson, M., Lee, B. Y., Bai, O., Leonenko, Z., & Albert, M. S. (2017). Recent progress in Alzheimer’s disease research, part 3: diagnosis and treatment. Journal of Alzheimer’s Disease, 57(3), 645-665.
Apostolova, L. G. (2016). Alzheimer disease. Continuum: Lifelong Learning in Neurology, 22(2 Dementia), 419.
Korolev, I. O. (2014). Alzheimer’s disease: a clinical and basic science review. Medical Student Research Journal, 4, 24-33.
Rentz, D. M., Rodriguez, M. A. P., Amariglio, R., Stern, Y., Sperling, R., & Ferris, S. (2013). Promising developments in neuropsychological approaches for the detection of preclinical Alzheimer’s disease: a selective review. Alzheimer’s research & therapy, 5(6), 58.