Author: Ainsley Martin, MS, CCC-SLP Edited by: Heather Bolan, MA, CCC-SLP
With recent medical advances, there has been an increase in overall life expectancy and survival from what previously would have been fatal events. With this increase in longevity, there is also an increase in age-related diseases. According to Brown in 2015, "the resultant life extension without reducing aging has increased the extent of ageing and age-related disease." One such age-related condition is dementia. While dementia would not be considered a normal part of aging, one of the primary risk factors for the development of dementia is advanced age.
According to the Alzheimer's Association, in the United States 5.7 million Americans are currently living with Alzheimer's disease resulting in overall costs of $277 billion. Note, this just accounts for Alzheimer's disease and does not account for other commonly diagnosed forms of dementia. By the year 2050, this is projected to increase to 14 million Americans with costs reaching over $1.1 trillion (Alzheimer's Association, 2018). As of 2010, the World Health Organization (WHO) projected that there were 35.6 million persons living with dementia. Statistically, a person is newly diagnosed with dementia approximately every four seconds (WHO, 2012).
These statistics are without a doubt alarming. There are equally concerning statistics regarding caregivers of persons with dementia. In the United States alone, informal caregivers (people who are not paid for providing caregiving services) provide an average of 18.4 billion hours of care which has been valued at $232 billion (Alzheimer's Association, 2018).
As medical speech-language pathologists (SLPs), these statistics can affect us in many ways. With an increase in life expectancy, especially as the Baby Boomer generation ages, we can expect to see many more patients with dementia on our caseload. Medical professionals, across all medical settings (SNF, acute, IRF, HH, outpatient) need to not only be familiar with dementia, but they also must be knowledgeable of the types of dementia syndromes and etiologies, assessment and treatment indicated by disease progression, providing family member education and counseling, and best methods to support these people with dementia (PWD) in operating at their maximum level of function for as long as possible. Dementia is also likely to impact us not only on a professional level but also on a personal level.
In this article, we will review what dementia is and how it is diagnosed as well as identify the most common dementia subtypes along with their clinical and neurological presentations. The overall goal of this series is to empower medical SLPs with the foundational knowledge to provide evidence-based care for people with dementia as well as increasing their confidence in working with a challenging but rewarding patient population.
*If by chance there is a family member or informal caregiver reading this article, my hope is that you too will be empowered in knowing that with appropriate interventions and support, your loved one should have a good quality of life. There are resources available to aid you in this journey which will be detailed in the second article in this series.
What Exactly is Dementia?
Dementia is not a disease in itself but refers to a group of symptoms associated with a decline in overall cognitive function. This decline in cognitive function is significant enough to impact daily life from the completion of complex to even simple tasks as dementia progresses. Impaired memory is most often the hallmark symptom of dementia. There are also different types of dementia based on different disease processes. Dementia can also be classified as reversible or irreversible.
Reversible Dementia: A reversible dementia is a type of dementia caused by an illness or another medical condition. As implied in the name, the symptoms of dementia can be reversed with appropriate medical intervention. The brain will also not show the same neuroanatomical changes as would be expected in irreversible dementias. Once the primary illness is managed, the symptoms should disappear. However, there may be some residual impairments in cognition. Some examples of reversible dementias include; Vitamin B 12 deficiency, depression, lead poisoning, tumors, meningitis, respiratory failure, encephalopathy, and delirium (Grover & Somani, 2016).
Irreversible Dementia:
An irreversible dementia, is a type of dementia in which the symptoms cannot be reversed and are expected to worsen over time. There are changes in the overall structure of the brain- essentially the brain is atrophying or shrinking. As the brain shrinks, there are changes in thinking skills that also affect other body functions. Irreversible dementias are terminal.
The most common example of irreversible dementia is Alzheimer’s dementia.
How is Dementia Diagnosed?
For a true diagnosis of dementia, certain criteria must be met including clinical symptomology, brain degeneration observed through neuroimaging, and neuropathologic change in the brain (Bayles, McCullough, & Tomoeda, 2019; Grover & Somani, 2016; Hyman et al, 2012). Dementia is also a diagnosis of exclusion meaning that all other medical conditions or causes must be ruled out first.
Clinical symptoms: For a diagnosis of dementia, there is generally impairment and at least one other cognitive function which is significant enough to interfere with daily living. Other domains of cognition which could be affected include reasoning, language, vision, or behavior. Symptoms have a gradual onset and worsen over time.
Brain imaging: This can include computerized tomography (CT scans), magnetic resonance imaging (MRI), or positron emission tomography (PET scans). With dementia, brain imaging would be expected to show atrophy and degeneration in the brain beyond what would be expected with normal aging. Degeneration will also likely be most apparent in the white matter (the substance that allows different portions of the brain to communicate). As mentioned, dementia is a diagnosis of exclusion. Brain imaging is also helpful in ruling out other causes such as brain tumors or other cerebrovascular diseases.
Neuropathologic change: There are changes in the structure of the brain which are associated with certain irreversible dementias. For example, neurofibrillary plaques and tangles are associated with Alzheimer's disease while deposits of the alpha-synuclein protein are seen in Lewy Body Dementia. Additional neuropathic changes include the loss of synapses and neurons. Neuropathologic changes are currently confirmed only an autopsy.
Additional testing: With advances in medical technology, genetic testing to identify the presence of genes most commonly associated with the development of dementia and identification of biomarkers from cerebrospinal fluid (obtained through lumbar puncture) to determine the presence of certain proteins associated with dementia causing disease processes are becoming increasingly available. Blood tests are also frequently used to rule out other medical conditions or disease processes.
Although this testing is available, many of our patients and family members may ask themselves if going through all the testing is really worth it. The advantages of going through such extensive testing include; identification of the disease process and the type of dementia, a greater knowledge of the disease progression, medications can be more tailored to the specific disease and dementia type, and patients can be matched to clinical trials. However, testing can be time-consuming, expensive, and uncomfortable. It is up to the person and their family members to determine the best course of action in accordance with their goals of care.
The 4 Most Common Irreversible Dementias
There are many different dementia diagnoses differentially diagnosed through imaging, clinical symptoms, and neuropathologic changes. The most commonly diagnosed irreversible dementias include Alzheimer's dementia, vascular dementia, dementia with lewy bodies, and frontotemporal dementia. Additional dementia diagnoses include mixed dementia (often a combination of Alzheimer's and vascular dementia), dementia with Down Syndrome, dementia associated with Huntington's disease, and dementia secondary to Creutzfeldt-Jakob disease (Bayles, McCullough, & Tomoeda, 2019). As this article is meant to be a general overview, only the most commonly diagnosed types of dementia will be reviewed here.
Mild Cognitive Impairment (MCI)
While MCI is not considered a type of dementia, it is mentioned here because MCI often precedes dementia and is often referred to as the pre-dementia stage. Similar to a diagnosis of dementia, there must be impairment in at least one cognitive domain which cannot be explained by other causes such as aging, educational status, or other disease processes. However, different from a diagnosis of dementia, the ability to complete activities of daily living (ADLS) is spared. Most often caused by Alzheimer's disease, MCI is considered a stage of Alzheimer's disease, However, MCI does not always indicate dementia will develop.
Alzheimer's Dementia (AD)
As mentioned previously, Alzheimer's dementia, resulting from Alzheimer's disease, is the most commonly diagnosed type of irreversible dementia. AD is broken into three phases; the preclinical phase in which neurologic changes develop in the brain prior to the emergence of any clinical symptomology, mild cognitive impairment, and full dementia. Changes in cognitive function are gradual and progressive secondary to brain atrophy. AD is also characterized by the neurofibrillary plaques and tangles (currently only seen on autopsy) and is associated with the APOE4 gene. While each person with dementia will present differently, there is a predictable decline in function. However, in patients even with advanced AD, procedural memory (memory of completing certain procedures or routines), rhythm, and automatic tasks are often spared. As SLPs, the focus of our treatment often includes procedural memory.
Vascular Dementia (VaD)
Vascular dementia is the second most commonly diagnosed dementia. VaD refers to cognitive decline consistent with a vascular pathology (involving blood flow to the brain). This was previously referred to as multi-infarct dementia as VaD was previously suspected to be the result of repeated cerebrovascular accidents (CVAs) or strokes; however, recent research has indicated VaD can result from other vascular pathologies. Neurologically, VaD is associated with lacunar infarcts and degeneration of white matter in the brain. The decline in cognitive function with VaD as not as predictable as the decline with AD. As opposed to a steady decline, persons with VaD present with a stepwise decline in function. A person with VaD may operate at their baseline level consistently until there is a new vascular event resulting in a drop in cognitive function. Following this, a new baseline is established until the next vascular event. While a decline in memory is to be expected with most dementias, clinically, patients with VaD will also present with primary deficits in attention and executive function.
Lewy Body Dementia (LBD)
Lewy Body Dementia (LBD) is an umbrella term for two separate types of dementia; Dementia with Lewy Bodies (DLB) and dementia associated with Parkinson's disease. The primary difference between DLB and dementia associated with Parkinson's disease is when the cognitive symptoms occur. In Parkinson's disease dementia, changes in motor function precede the changes in cognitive impairment. However, in DLB, motor and cognitive changes occur simultaneously. Both diagnoses are associated with lewy bodies or an aggregation of the alpha-synuclein protein. In LBD, there will be not only the cognitive changes, but there will also be noted changes in motor function (e.g., slow movement, tremor, rigidity), and affect (mask-like face with minimal expression). Clinically, patients with LBD will present with impaired memory, executive function, attention, and visuospatial skills. Visual hallucinations, fluctuations in awareness/concentration, and disorders in REM sleep are hallmarks of LBD. Behavioral changes such as increased agitation, shadowing, anger, apathy, and other personality changes can often occur.
Frontotemporal Dementia (FTD)
FTD is a type of dementia resulting from the degeneration of the frontotemporal lobe in the brain. The frontal lobe is responsible for a variety of cognitive functions including executive function, judgment, problem-solving, and inhibition just to name a few. The temporal lobe is primarily responsible for receptive and expressive language, memory, and sensory input. With these areas of the brain affected, persons with frontotemporal dementia can be expected to present with significant cognitive, behavioral, and communication changes depending on the extent of the degeneration and the primary areas affected. There are three categories of FTD dependent on the primary area of degeneration and the clinical symptoms.
Behavioral variant: The primary area of degeneration is in the frontal lobe. Patients with behavioral variant FTD frequently present with behavioral, social, and personality changes. This was previously known as Pick's disease.
Primary Progressive Aphasia (PPA): Degeneration is primarily in the temporal lobe and communication is primarily affected, though social and personality changes may occur as well. There are three classifications of PPA; semantic (relating to word-meaning), non-fluent (difficulty with production of speech with retention of word meanings), and logopenic (difficulty with word-finding).
Motor variant: As implied in the name, movement disorders are the primary presentation of this type of FTD. Motor variant FTD is often associated with disease processes such as motor neuron disease, ALS, and progressive supranuclear palsy.
I'm going to be honest with you all. This article is a lot to digest and frankly, it was not easy to write. As I wrote this article, I pictured in my mind patients I have treated over the years with these various types of dementia and it made me sad. Did I help enough? Could I have done more? What, if anything, could I have done differently? But this is precisely why this type of article is so important. Dementia is not going away any time soon. In order for medical SLPs to treat patients with these diagnoses, it is first important to have an underlying understanding of the different disease processes and their resulting clinical presentation. This can help in providing a framework from which we develop our assessment and treatment plans. In the next article in this series, assessment and evidence-based treatment methods will be detailed and the role of the medical SLP in caregiver support and education will also be addressed.
For more information regarding the unique presentation of different dementia types, the Alzheimer's Association has a clear and concise chart that summarizes much of the information discussed in this article.
References
(n.d.). What Is Dementia? Retrieved from https://www.alz.org/alzheimers-dementia/what-is-dementia
Alzheimer’s Association (2018) (1). “Alzheimer’s disease facts and figures”. Accessed August 18, 2019, from https://www.alz.org/media/Documents/alzheimers-facts-and-figures-infographic.pdf
World Health Organization (2012). Dementia A Public Health Priority. Albany: World Health Organization.
Bayles, K. A., McCullough, K., & Tomoeda, C. K. (2020). Cognitive-communication disorders of Mci and dementia: definition, assessment, and clinical management. San Diego, CA: Plural Publishing.
Brown G. C. (2015). Living too long: the current focus of medical research on increasing the quantity, rather than the quality, of life is damaging our health and harming the economy. EMBO reports, 16(2), 137–141. doi:10.15252/embr.201439518
Grover, S., & Somani, A. (2016). Etiologies and risk factors for dementia. Journal of Geriatric Mental Health, 3(2), 100. doi: 10.4103/2348-9995.195601
Hyman, Bradley T. et al.National Institute on Aging–Alzheimer's Association guidelines for the neuropathologic assessment of Alzheimer's disease. Alzheimer's & Dementia: The Journal of the Alzheimer's Association, Volume 8, Issue 1, 1 - 13