Vascular dementia Vascular dementia, in the form of multi-infarct or post-stroke dementia, is considered the second most common type of dementia, and it can be seen in combination with AD or other dementias. Vascular dementia develops when blood flow is impaired, depriving areas within the brain of necessary oxygen and nutrients. The damage can result from widespread small vessel disease (multi-infarct) or from blockage of a major artery (cerebrovascular accident or stroke). A hallmark of vascular dementia is the sudden onset of symptoms (e.g., after a single major infarct blocks the blood supply to a significant portion of the brain) and/or a stepwise progression of symptoms over time (e.g., following a series of mini-strokes or infarcts in small vessels). This feature differentiates vascular dementia from AD, in which the progression of symptoms is subtle and gradual. Because the pathology underlying this type of dementia is not unique to the vessels of the brain, but is systemic, individuals with vascular dementia also have a high risk of cardiovascular conditions (e.g., coronary artery disease, myocardial infarction, high blood pressure, high cholesterol) and peripheral vascular disease, a relevant fact to keep in mind when working with this population. Symptoms of vascular dementia vary depending on the specific area or areas of brain involvement. Whereas the first noticeable symptom in AD is almost always memory loss,
individuals with vascular dementia may not present with early memory loss, but instead with impaired executive functions (e.g., poor judgment, inability to make plans), depending on the location of vascular lesions. Individuals who experience major vessel stroke and resulting vascular dementia may also present with typical physical impairment (i.e., hemiparesis or hemiplegia) and/or language deficits (i.e., expressive, receptive, or global aphasia). A diagnosis of vascular dementia is made based on clinical presentation, neurocognitive testing, and brain imaging studies. Magnetic resonance imaging (MRI) of the brain may show characteristic abnormalities associated with vascular damage, but it may not be conclusive. Some changes in the brain that are consistent with vascular dementia can coexist with the distinct brain changes seen in AD, leading to a diagnosis of mixed dementia (i.e., evidence of any two or more dementias are present). Because vascular dementia is closely tied to other cardiovascular conditions, managing risk factors associated with heart disease can play a role in preventing later cognitive decline. Preventive treatment may include monitoring blood pressure, weight, blood sugar, and cholesterol and maintaining a high level of physical activity. Active management of risk factors, even after diagnosis, is essential to comprehensive care. Alzheimer’s dementia shows a slow, somewhat steady progression, vascular dementia progresses in a stepwise fashion, and LBD often shows significant fluctuations over time. Figure 1: Progressive Course of the Most Common Dementias
Dementia with Lewy bodies and Parkinson’s disease dementia Dementia with Lewy bodies is the third most common cause of dementia and is often considered to include two types of presentations: Lewy body dementia (LBD) and Parkinson’s disease dementia (PDD). The pathology and clinical picture of these two dementias are similar, and their diagnoses are generally related to the timing of the onset of symptoms. If parkinsonian motor symptoms precede cognitive symptoms by 1 year or more, the dementia is classified as PDD, but if cognitive symptoms precede or are concurrent with Parkinson’s motor symptoms, LBD is diagnosed. Lewy bodies are abnormal deposits of the protein alpha- synuclein that form inside nerve cells within the brain. Alpha- synuclein is normally present in a healthy brain, but abnormal clumps of this protein in central nervous system neurons are a hallmark of LBD and PDD. A definitive differentiation among AD, LBD, and PDD can be difficult because the neuropathology of AD can coexist with Lewy bodies. Lewy body pathology leads to patterns of decline similar to those seen in AD, including problems with memory, judgment, and behavior changes; although memory impairment is the hallmark symptom of AD, it may not be the first symptom to appear in LBD. Daily fluctuations in cognitive symptoms (e.g., level of arousal, attention, facility of speech) may be apparent in LBD, but they are not as common in AD. People with LBD may also experience visual hallucinations, sleep disorders, and autonomic dysregulation. Finally, parkinsonian motor symptoms of tremor, bradykinesia, rigidity, and postural instability are seen with PDD and can develop with LBD.
Note. From Western Schools, 2020.
The progressive courses of the three most common types of dementia are distinctly different and are depicted in Figure 1. Mixed dementias More common than previously thought, mixed dementias present with pathology and symptoms of two or more types of dementia – most commonly Alzheimer’s and vascular dementia, but sometimes LBD or other dementias. Patients with mixed dementias often present with the classic memory Frontotemporal dementia Frontotemporal dementias (FTDs) are a group of conditions affecting the nerve cells in the frontal and temporal lobes of the brain with hallmark symptoms related to personality, behavior, and emotional and language disorders. FTD is the most common type of dementia in individuals younger than age 60. The early onset and the usual relative sparing of memory until late in the
and cognitive impairment seen with AD, but they may have a stepwise progression of clinical deterioration (as seen in vascular dementia) or more fluctuation of cognitive impairment (as seen in LBD).
disease can result in a misdiagnosis of a psychiatric disorder prior to an accurate diagnosis of FTD. FTD is characterized by the early and rapid onset of severe personality and behavior disturbances, including impairments in personal interactions, judgment, planning, and social functioning. Inappropriate comments to others and irrational decision making regarding
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