Although the terms dementia and Alzheimer’s disease are sometimes used interchangeably, there is a difference between Alzheimer’s disease and dementia. Dementia is a general term that describes a group of symptoms involving intellectual impairment that is caused by neuron damage.
Alzheimer’s disease is one factor that can cause a very specific form of dementia. Dementia, on the other hand, can be caused by a variety of underlying factors, such as diseases, stroke, infection, traumatic injury, substance abuse, etc. The main difference is that dementia is a clinical syndrome that can be caused by many factors, and Alzheimer’s disease is simply one of these factors.
What Is Dementia?
The most common definition of dementia describes it as a cognitive impairment involving memory, reasoning and orientation. This impairment significantly affects social and occupational functioning. Dementia symptoms include:
- Memory loss
- Impairment of executive functions, such as planning, decision-making and following complex instructions
- Difficulties with speech
- Loss of orientation
- Neuropsychiatric symptoms, such as hallucinations, delusions, apathy, agitation and aggression
- Motor deficits
The symptoms of dementia may depend on the underlying cause of dementia and the brain regions affected. For example, frontotemporal dementia involves damage to areas involved in the control of impulsive behavior. This type of dementia can result in inappropriate social and sexual behaviors. On the other hand, Lewy body dementia is characterized by decreased motor function, including tremors, stiffness of limbs, slowness of movement and loss of reflexes.
Despite these differences, all types of dementia involve cognitive deficits that are severe enough to impair function in everyday life.
Types of Dementia
Dementia is caused by a variety of factors and is classified based on which brain regions are affected, the primary cause of dementia and the permanence of symptoms. The different types of dementia include:
- Primary dementia: In this type of dementia, the symptoms are the primary manifestation of the disease and not a secondary consequence of a different disease like HIV. This includes Alzheimer’s disease, frontotemporal dementia, Lewy body dementia and Parkinson’s disease dementia. Dementia caused by these diseases is irreversible and progressive — symptoms worsen over time.
- Secondary dementia: This includes conditions where the symptoms of dementia develop as secondary symptoms to a pre-existing disease or physical condition. This includes vascular dementia caused by pathologies of blood vessels in the brain. Vascular dementia is often observed after a stroke and is irreversible. Other examples of secondary dementia include dementia caused by trauma, tumors and accumulation of spinal fluid. Dementias caused by tumors and accumulation of spinal fluid are considered to be reversible.
- Reversible dementia: These dementias can be cured, and they are caused by metabolic conditions, infections, mood disorders and substance misuse.
A few of the causal factors involved in reversible dementia include:
- Thiamine or vitamin B1 deficiency
- Metabolic disorders, such as kidney or liver dysfunction
- Thyroid conditions
- Alcohol misuse
- Drug misuse including prescription drugs
- Inflammation, such as meningitis and encephalitis
Alzheimer’s disease is the most prevalent form of dementia, and the disease accounts for almost two-thirds of all progressive dementia cases. The Alzheimer’s disease definition states it is a neurodegenerative disorder that impairs cognitive functions like memory, decision-making, thinking, language and visuospatial abilities.
Alzheimer’s disease causes the formation of β-amyloid plaques between neurons and neurofibrillary tangles composed of tau protein inside neurons. Essentially, these plaque clumps can disrupt communication between brain neurons. In addition, the plaques and neurofibrillary tangles have neurotoxic effects in areas of the brain cortex, causing Alzheimer’s disease symptoms.
Characteristics of Alzheimer’s disease
The symptoms of Alzheimer’s disease are similar to those of dementia and include:
- Progressive memory loss
- Difficulties in complex tasks involving planning and following instructions
- Difficulty in executing motor functions
- Impairments in problem-solving and reasoning
- Disorientation and confusion
- Hallucinations and delusions
- Changes in mood and personality
In most cases, Alzheimer’s disease is not caused by a single factor but by a combination of factors involving genetics, environmental factors, lifestyle choices and habits. Age also increases the risk of Alzheimer’s disease. Effects of Alzheimer’s disease include a progressive worsening of cognitive deficits and functional abilities over time. The cognitive decline at the onset involves general forgetfulness, an inability to follow complex instructions and difficulty learning new information.
As the disease progresses, deficits in memory loss, orientation, decision-making and communication become worse. Similarly, there is a progressive loss in the ability to conduct daily activities like managing finances and cooking. Over time, there is a complete loss of functional autonomy.
These changes are evaluated and categorized using assessment scales by clinicians for the diagnosis and treatment of Alzheimer’s disease. According to the commonly used Global Deterioration Scale (GDS), there are seven stages of Alzheimer’s disease. Each stage marks a further decline in cognitive abilities and the ability to perform daily functions.
Differentiating Between Dementia and Alzheimer’s Symptoms
When it comes to signs of dementia vs. Alzheimer’s disease, the two are similar. Since Alzheimer’s disease is a specific type of dementia, it shares core dementia symptoms. These include cognitive impairment involving memory, executive function (reasoning, thinking, decision-making) and speech. Besides these core symptoms, Alzheimer’s disease also involves behavioral changes and psychological symptoms such as depression, anxiety, apathy, hallucinations and delusions.
Many types of dementia share those symptoms, but most do not generally share all the symptoms observed in Alzheimer’s disease. For example, Lewy body dementia involves motor deficits that are absent in Alzheimer’s disease. These individuals also experience hallucinations much earlier than those with Alzheimer’s disease and are more likely to have sleep disturbances.
Vascular dementia shares many of the symptoms of Alzheimer’s disease, but the symptoms appear and progress differently. For example, cognition declines immediately after a stroke in vascular dementia patients, but the decline is gradual in Alzheimer’s disease patients. Because of reasons like these, the magnitude and the sequence of symptoms is critical in diagnosing different dementias.
Dementia and Alzheimer’s Treatment
Dementia may be categorized as either reversible or irreversible, with reversible dementia being able to be treated and potentially cured. There are no cures for progressive dementias, but the symptoms can be managed with therapy. Alzheimer’s disease is irreversible and has no cure. Since progressive dementias like Alzheimer’s disease share common symptoms, many of the treatments for Alzheimer’s disease and other dementias are similar.
Treatment for Alzheimer’s disease generally involves medications to delay the rate of cognitive decline. Treatment also includes pharmacological and non-pharmacological options for psychological and behavioral symptoms. Alzheimer’s treatment guidelines help with the appropriate care and treatment of patients. Some of the available treatment options include:
- Medications for cognitive deficits: Dementia involves a decline in cognitive function, usually caused by deficits of acetylcholine, a neurotransmitter. Cholinesterase inhibitors are a class of drugs that prevent the degradation of acetylcholine and help slow the rate of cognitive decline.
- Antipsychotics for the treatment of paranoia and agitation
- Antidepressants like citalopram for the treatment of anxiety and depression
- Non-pharmacological treatments like cognitive training, music therapy and physical therapy
- Sedatives or hypnotics for disruption of sleep patterns
- Novel therapeutics: Currently, research on new Alzheimer’s disease therapies is underway involving anti-inflammatory drugs, stem cells and insulin
Dementia may be either irreversible or reversible, and reversible dementias are usually a secondary manifestation of other illnesses or physical conditions. In these cases, dementia can be treated by treating the primary cause of the illness or condition, such as nutritional deficiency, infection, hypoglycemia or substance use. However, many types of progressive dementia are irreversible and have no cure in most cases. Early diagnosis and treatment of dementia can delay the decline in cognitive function and help manage the neuropsychiatric symptoms.
Options for the treatment of dementia symptoms like cognitive deficits involve cholinesterase inhibitors. Neuropsychiatric symptoms like agitation, depression and hallucinations may be treated with medications like antipsychotics and antidepressants. Dementia treatment guidelines are necessary since many of those drugs may have adverse side effects, depending on the type of dementia.
Specific treatments are used to manage individual symptoms found in certain types of dementia. In the case of Lewy body dementia, medications such as levodopa may be used to manage motor deficits, but these drugs can worsen the symptoms of hallucinations. In cases like vascular dementia, treatment may focus on reducing the risk of further damage to blood vessels in the brain.
Outlook and Prognosis
The outlook for individuals suffering from dementia depends on the type of dementia, the stage of the underlying disease and the course of treatment. Except for the case of reversible dementias, there is no cure for Alzheimer’s disease or other types of progressive dementia.
With such an outlook for Alzheimer’s disease and other progressive dementias, the aim of treatment is to help slow down the rate of decline of cognitive function and manage the symptoms. The prognosis for Alzheimer’s disease, in terms of the average life expectancy after the initial diagnosis, ranges between eight to 10 years. However, there are cases of individuals living up to 20 years after diagnosis of the disease.
The prognosis for other dementias depends on the particular type of the dementia. The life expectancy for vascular dementia is much more variable, depending on the extent of the damage caused by cerebrovascular disease. In the case of other primary dementias, individuals with frontotemporal dementia may have a life expectancy ranging from less than two years to 10 years. Life expectancy for individuals with Lewy body dementia is about eight years.
Key Points: Dementia vs. Alzheimer’s
Dementia is a clinical syndrome characterized by cognitive impairment, whereas Alzheimer’s disease is one of the many factors that may result in dementia. Other key differences between Alzheimer’s disease and dementia include:
- Alzheimer’s disease is a progressive disorder that cannot be treated
- Many types of dementia are irreversible and terminal, but reversible dementias can be potentially treated
- All dementias show core symptoms of cognitive impairment and some neuropsychiatric symptoms like agitation, anxiety, etc.
- Alzheimer’s disease can be distinguished from other dementias according to qualitative differences in symptoms as well as the progression of the condition
- Alzheimer’s disease is characterized by the presence of amyloid plaques and neurofibrillary tangles.
Understanding the differences in Alzheimer’s disease vs. dementia is vital for the early diagnosis and optimal treatment of any particular type of dementia.
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Korolev, I.O. “Alzheimer’s disease: a clinical and basic science review.” Medical Student Research Journal, September 2014. Accessed June 12, 2019. Tripathi, M., Vibha, D. “Reversible dementias.” Indian Journal of Psychiatry, January 2009. Accessed June 12, 2019. Bi, X. “Alzheimer disease: update on basic mechanisms.” Journal of the American Osteopathic Association, September 2010. Accessed June 12, 2019. Reisberg, B., Franssen, E.H. “Clinical stages of Alzheimer’s disease.” An Atlas of Alzheimer’s Disease, October 1999. Accessed June 12, 2019. Sadowsky, C.H., Galvin, J.E. “Guidelines for the management of cognitive and behavioral problems in dementia.” Journal of the American Board of Family Medicine, May 2012. Accessed June 12, 2019. Sink, K.M., Holden, K.F., Yaffe, K. “Pharmacological treatment of neuropsychiatric symptoms of dementia: a review of the evidence.” JAMA, February 2005. Accessed June 12, 2019. Douglas, S., James, I., Ballard, C. “Non-pharmacological interventions in dementia.” Advances in Psychiatric Treatment, May 2004. Accessed June 12, 2019.
Korolev, I.O. “Alzheimer’s disease: a clinical and basic science review.” Medical Student Research Journal, September 2014. Accessed June 12, 2019.
Tripathi, M., Vibha, D. “Reversible dementias.” Indian Journal of Psychiatry, January 2009. Accessed June 12, 2019.
Bi, X. “Alzheimer disease: update on basic mechanisms.” Journal of the American Osteopathic Association, September 2010. Accessed June 12, 2019.
Reisberg, B., Franssen, E.H. “Clinical stages of Alzheimer’s disease.” An Atlas of Alzheimer’s Disease, October 1999. Accessed June 12, 2019.
Sadowsky, C.H., Galvin, J.E. “Guidelines for the management of cognitive and behavioral problems in dementia.” Journal of the American Board of Family Medicine, May 2012. Accessed June 12, 2019.
Sink, K.M., Holden, K.F., Yaffe, K. “Pharmacological treatment of neuropsychiatric symptoms of dementia: a review of the evidence.” JAMA, February 2005. Accessed June 12, 2019.
Douglas, S., James, I., Ballard, C. “Non-pharmacological interventions in dementia.” Advances in Psychiatric Treatment, May 2004. Accessed June 12, 2019.