Depending on the exact cause of dementia, the presenting signs and symptoms may vary. Short-term memory loss is common, as evidenced by forgetting recent events. The early (mild) stages of dementia are characterized by forgetting where items were placed, asking questions repeatedly, and having difficulty learning new information.
It is at times difficult to differentiate between normal aging and dementia. Normal aging is characterized by slowness in the retrieval of information. Those with dementia have a difficult time recording new information. For example, the aged individual may have a hard time recalling the name of a friend they have not seen in a long-time. Those with dementia can be told something and not recall it. A husband may tell his wife (who has dementia) that friends are coming over for dinner, and the wife will not remember this when the friends arrive.
Misusing words, difficulty finding the right word, or general words to describe a specific item is a trait of dementia. A demented person uses the word "thing" to describe many items. Personality changes, making poor decisions, and mood swings are common symptoms of early dementia. Increased confusion at night, also known as sun-downing, is a common feature of early dementia.
Patients with early dementia can compensate well when they are in familiar environments. Problems are often first noticed when one gets out of their routine such as going on vacation or entering the hospital. Patients often become very anxious, depressed, scared, or have emotionally liable moods. These moods are often the direct results of the patient being aware of progressive dementia.
As the disease progresses, the patient has difficulty carrying out tasks of daily living such as bathing, handling finances, grooming, dressing, and preparing meals. This is when independence is significantly impaired, and patients will need to adjust to their living environment. During this middle (moderate) stage of progression, the patient may struggle with incontinence, become combative or resistant to help and physical care, and have an increased potential for wandering away from home.
Those with advanced (severe) dementia are dependent on others for care. They have very limited memory and usually are not oriented to place, time, and often name. Patients with advanced dementia may not know the name of their spouses or children.
Loss of the swallowing reflex is a common complication of advanced dementia, which leads to medical complications such as malnutrition and aspiration pneumonia. It has not been found that feeding tubes reduce the rates of aspiration pneumonia in the demented patient.
Malnutrition decreases the ability to fight off infection and increases the risk of death from infection. Loss of the swallowing reflex increases the risk of dehydration. Patients with advanced dementia have more seizures.
Behavioral changes are more common as dementia advances. With the patient going from calm and pleasant to entirely out of control within minutes, mood swings can occur. Personality changes are seen in dementia, with the demented patient showing an increased incidence of irritability, suspiciousness, and fearfulness. Hallucinations and delusions are hallmarks of advancing dementia. Hallucinations are a misinterpretation of sensory stimuli. They can include seeing things not there, such as dead relatives, or hearing voices when there are none. Delusions are fixed false beliefs. Common delusions include thinking people are out to get them, thinking that someone is trying to poison them, or believing they are God.
Clinical history and exams can help differentiate between some of the different types of dementia. Alzheimer's is the most common dementia and the most likely diagnosis when dementia presents. Some salient features of Alzheimer's include early memory loss with cognitive impairment and at least one other area deficit such as language dysfunction, agnosia, apraxia, visuospatial disorder, and executive dysfunction. It typically has an insidious onset and a progressive course. A storage deficit highlights memory impairment; patients cannot recall something with a clue. For example, when performing the mini-mental status exam (MMSE) and the patient is asked to recall three items after five minutes, the patient will not be able to recall them even after being given a clue. As the disease progresses, long-term memory becomes impaired. Later changes also include seizures, apathy, aggression, wandering, agitation, depression, and anxiety.
Vascular dementia can have either an abrupt or insidious onset, and the progression can be stepwise, fluctuating, or a continuous decline. Patients with vascular dementia typically have cardiovascular risk factors such as hypertension, hyperlipidemia, and diabetes. Focal neurological deficits (e.g., speech, hearing, or vision problems) are common in those with vascular dementia. Memory impairment is not as pronounced in the early stage, whereas executive function (concentration, decision making, and higher-order problem solving) is impaired early.
DLB accounts for 10-15% of cases (National Institute on Aging, 2022). DLB typically presents with memory loss, early impairment of executive function, more problems in attention, visuospatial function, and constructional abilities compared to AD, and more autonomic involvement. Patients typically have recurrent visual hallucinations. There are often repeated falls and occasional syncope.
The National Institute on Aging (2022) explains that frontotemporal dementia (FTD) is characterized by a shrinking of the brain's frontal and temporal anterior lobes and often presents with personality and behavioral changes over memory loss, at least early on. This disease runs in families. Symptoms of FTD fall into three clinical patterns that involve changes in behavior and problems with language and movement disorders. Patients are typically impulsive, act socially unacceptable, are disinhibited, lack insight, and are agitated or socially withdrawn. Those with language disturbance have difficulty speaking or understanding speech. Frontotemporal dementia occurs at a younger age than Alzheimer's, typically between 45 and 65.
Figure 2: Frontotemporal Disorders
The need to evaluate dementia can be picked up during a routine examination, patient or family concern, or routine screening. The workup includes performing a mental status examination. Standardized tests can be used to document mental decline, monitor decline, and help make the diagnosis. Mental status examinations test the patient's memory and intellectual function. These tests look for memory impairment, language disturbance, ability to carry out purposeful movements, and ability to recognize objects. Mental status exams ask the patient to report the date and location, recall lists of items, write sentences, follow written commands, name objects, and copy diagrams. According to A. Rosenzweig (2020), The American Academy of Neurology recommends using the mini-mental state exam (MMSE) or the memory impairment screen as tools to screen for dementia. However, the MMSE offers no suggestions as to how much assistance the person might need in daily life, nor does it try to apply the deficit in a cognitive area to practical living.
Scores on the MMSE range from 0 to 30, with scores of 25 or higher being traditionally considered normal. Scores less than ten generally indicate severe impairment, while scores between 11 and 20 indicate moderate dementia. Those with Alzheimer's have, on average, a decline in the MMSE score. The MMSE of 3-4 points per year occurs if they go untreated. It is important to note that one needs an IQ of about 90 to get a normal score on the MMSE (Rosenzweig, 2020).
The MMSE takes about 10 minutes to complete. It measures aspects of cognition that include orientation, word recall, attention and calculation, language abilities, and visual construction. Scores may need to be adjusted or interpreted differently to account for a person's age, educational level, and ethnicity/race.
Other testing is often employed. Early changes in mental decline are often not picked up on the MMSE. If the spouse or caregiver notices changes and the MMSE is normal, more sensitive testing may need to be utilized. If the diagnosis is in doubt, more extensive testing, known as neuropsychological testing, typically done by a specialist, is performed.
Neuropsychological testing is a more comprehensive method for the evaluation of mental status. Testing is done by a neurologist, psychiatrist, or psychologist. It looks at higher cognitive functions, including but not limited to abstract, logical, and conceptual reasoning, visuospatial orientation, memory, verbal fluency, and reasoning. The test identifies cognitive impairment in patients with higher baseline cognitive abilities and determines if dementia is present in its milder stages. It is more sensitive than other types of testing and can differentiate between mild cognitive impairment and dementia. The test is helpful for those who do not speak English as their native language and those with limited education. It also can help pick up anxiety and depression.
The workup of dementia rules out other causes of mental decline and consists of imaging and laboratory evaluation. Recommended tests include a vitamin B12 level and thyroid test and a complete blood count, glucose, kidney function test, electrolyte tests, and liver function tests. Other tests can be performed if the patient is deemed at high risk and the clinician has reason to suspect a rarer cause of dementia, including serology for syphilis, HIV testing, genetic testing, Lyme disease titers, testing for heavy metals, urinalysis, erythrocyte sedimentation rate, and serum folic acid. A lumbar puncture is sometimes performed if cerebral Lyme disease, cerebral vasculitis, neurosyphilis, or HIV is suspected as a cause of dementia.
Testing for depression is critical as memory loss can be one of the manifestations of depression. Depression can present with memory loss, and memory loss can reverse with the treatment of depression. In addition, depression complicates the course of dementia if they both exist.
Many patients with dementia undergo an imaging examination to rule out other disease causes. Its ability to identify a reversible cause of dementia is low. Still, non-contrast computed tomography or magnetic resonance imaging is recommended for the initial evaluation of a patient with dementia. Neuroimaging in dementia is most likely helpful in a 61-year-old woman with an MMSE score of 20 and a history of breast cancer. Imaging can rule out brain tumors, subdural hematomas, stroke, or normal-pressure hydrocephalus. Those who are younger than 60, had recent head trauma, a history of cancer, gait disturbance, urinary incontinence, localized neurologic signs or symptoms, or those with a rapid or atypical course of dementia have the greatest chance of having a diagnostic yield from imaging studies. The only way to confirm the diagnosis is to perform a brain biopsy, which is rarely done or necessary.
More advanced testing includes photon emission tomography (PET) scans or single-photon emission computed tomography (SPECT) scans. These tests are not routinely done but are often done in research settings to help distinguish between different types of dementia. Current guidelines do not recommend their routine use.