Memory loss is a common complaint in the primary care setting. It is particularly common among older adults but also may be reported by younger people. Sometimes family members rather than the patient report the memory loss (typically in an older adults, often one with dementia).
Clinicians and patients are often concerned that the memory loss indicates impending dementia. Such concern is based on the common knowledge that the first sign of dementia typically is memory loss. However, most memory loss does not represent the onset of dementia.
The most common and earliest complaints of memory loss usually involve
Difficulty remembering names and the location of car keys or other commonly used items
As memory loss becomes more severe, people may not remember to pay bills or keep appointments. People with severe memory loss may have dangerous lapses, such as forgetting to turn off a stove, to lock the house when leaving, or to keep track of an infant or child they are supposed to watch. Other symptoms (eg, depression, confusion, personality change, difficulty with activities of daily living) may be present depending on the cause of memory loss.
Etiology of Memory Loss
The most common causes of memory loss (see table Characteristics of Common Causes of Memory Loss) are
Age-associated memory impairment (most common)
Mild cognitive impairment
Dementia
Depression
Age-associated memory impairment refers to the worsening of memory that occurs with aging. In people with this condition, it takes longer to form new memories (eg, a new neighbor's name, a new computer password) and to learn new complex information and tasks (eg, work procedures, computer programs). Age-associated memory impairment leads to occasional forgetfulness (eg, misplacing car keys) or embarrassment. However, cognition and the ability to perform most activities of daily living are not impaired. Given sufficient time to think and answer questions, patients with this condition can usually do so, indicating intact memory and cognitive functions.
Patients with mild cognitive impairment have actual memory loss, rather than the sometimes slow memory retrieval from relatively preserved memory storage in age-matched controls. Mild cognitive impairment tends to affect short-term (also called episodic) memory first. Patients have trouble remembering recent conversations, the location of commonly used items, and appointments. However, memory for remote events is typically intact, as is attention (also called working memory—patients can repeat lists of items and do simple calculations). The definition of mild cognitive impairment is evolving; mild cognitive impairment is now sometimes defined as impairment in memory and/or other cognitive functions that is not severe enough to affect daily function. Up to 50% of patients with mild cognitive impairment develop dementia within 3 years (1).
Patients with dementia have memory loss plus evidence of cognitive and behavioral dysfunction. For example, they may have difficulty with finding words and/or naming objects (aphasia), doing previously learned motor activities (apraxia), or planning and organizing everyday tasks, such as meals, shopping, and bill paying (impaired executive function). Their personality may change; for example, they may become uncharacteristically irritable, anxious, agitated, and/or inflexible.
Depression is common among patients with dementia. However, depression itself can cause memory loss that simulates dementia (pseudodementia). Such patients usually have other features of depression.
Delirium is an acute confusional state, which may be caused by a severe infection, a medication (adverse effect) or drug, or medication or drug withdrawal. Patients with delirium have impaired memory, but the main reason they present is usually severe, fluctuating global changes in mental status (primarily in attention) and cognitive dysfunction, not memory loss.
Less common causes of memory loss that may be reversed with treatment include the following:
Depression (can cause pseudodementia)
Neurosarcoidosis
Other disorders may be remediable, depending on the extent and degree of tissue damage. They include
Unusually long seizures
Certain types of stroke
Overuse of certain medications and other substances (including alcohol)
Etiology reference
1. Roberts RO, Knopman DS, Mielke MM, et al: Higher risk of progression to dementia in mild cognitive impairment cases who revert to normal. Neurology 82 (4):317–325, 2014. doi: 10.1212/WNL.0000000000000055 Epub 2013 Dec 18.
Evaluation of Memory Loss
The highest priority when evaluating memory loss is
To identify reversible causes, including depression, anxiety, and delirium, which requires rapid treatment
The evaluation then focuses on distinguishing the few cases of mild cognitive impairment and early dementia from the greater number with age-associated memory impairment or simply normal forgetfulness.
Full evaluation for dementia usually requires more time than the 20 to 30 minutes that is commonly allotted for an office visit. Evaluation by a neuropsychologist may also be required.
History
History should, when possible, be taken from the patient and family members separately. Cognitively impaired patients may not be able to provide a detailed, accurate history, and family members may not feel free to give a candid history with the patient listening.
History of present illness should include a description of the specific types of memory loss (eg, forgetting words or names, getting lost) and their onset, severity, and progression. Clinicians should determine how much symptoms affect day-to-day function at work and at home. Important associated findings involve changes in language use, eating, sleeping, and mood. Clinicians should also evaluate the patient's capabilities for operating a motor vehicle because some jurisdictions require clinicians to report patients with impaired driving capabilities to local licensing authorities.
Review of systems should identify neurologic symptoms and other factors that may suggest a specific type of dementia, such as the following:
Parkinsonian symptoms and hallucinations in Lewy body dementia
Focal neurologic deficits in vascular dementia
Head trauma (eg, due to a recent fall) suggesting subdural hematoma
Inability to look upward or downward and falling backward in progressive supranuclear palsy
Choreiform movements in Huntington disease
Gait disturbance and urinary incontinence in normal-pressure hydrocephalus
Low energy, dry skin, and weight gain in hypothyroidism
Balance problems and difficulty with fine motor movements in vitamin B12 deficiency
Past medical history should include known disorders and complete prescription, over-the-counter, and illicit drug use history.
Family and social histories should include the patient's baseline levels of intelligence, education, employment, and social functioning. Previous and current substance abuse is noted. Family history of dementia or early mild cognitive impairment is queried. Social history should also include unusual dietary habits.
Physical examination
In addition to a general examination, a complete neurologic examination is done, with detailed mental status testing.
Mental status testing assesses the following by asking the patient to do certain tasks:
Orientation (give their name, the date, and their location)
Attention and concentration (eg, repeat a list of words, do simple calculations, spell "world" backwards)
Short-term memory (eg, repeat a list of 3 or 4 items after 5, 10, and 30 minutes)
Long-term memory (eg, answer questions about the distant past)
Language (eg, name common objects)
Praxis and executive function (eg, follow a multiple-stage command)
Constructional praxis (eg, copy a design or draw a clock face)
Reading
Calculation
Various scales can be used to screen for impairment in these components. A common way to screen is with the Montreal Cognitive Assessment (1) or the Folstein Mini-Mental Status Examination (2). These tests usually require less than 10 minutes to administer.
Red flags
In patients with memory loss, the following findings are of particular concern:
Impaired daily function
Loss of attention or altered level of consciousness
Symptoms of depression (eg, loss of appetite, psychomotor slowing, suicidal ideation)
Speed of symptom onset
Memory loss that develops rapidly may indicate a disorder such as Creutzfeldt-Jakob disease or a brain tumor
Interpretation of findings
Presence of actual memory loss and impairment of daily function and other cognitive functions help differentiate age-related memory changes, mild cognitive impairment, and dementia.
Mood disturbance is present in patients with depression but is also common in patients with dementia or mild cognitive impairment. Thus, differentiating depression from dementia can be difficult until memory loss becomes more severe or unless other neurologic deficits (eg, aphasia, agnosia, apraxia) are evident.
Inattention helps differentiate delirium from early dementia. In most patients with delirium, memory loss is not the presenting symptom. Nonetheless, delirium must be excluded before a diagnosis of dementia is made.
One particularly helpful clue is how the patient came to medical attention. If the patient initiates the medical evaluation because of worries about becoming forgetful, age-associated memory impairment is the likely cause. If a family member initiates a medical evaluation for a patient who is less worried about memory loss than the family is, dementia is much more likely than when the patient initiates the evaluation.
Testing
Diagnosis of memory loss is primarily clinical. However, any brief mental status examination is affected by the patient's intelligence and educational level and has limited accuracy. For example, patients with high educational levels can score falsely high, and those with low levels can score falsely low.
If the diagnosis is unclear, more accurate, formal neuropsychologic testing can be done; results have higher diagnostic accuracy.
If a medication or substance is the suspected cause, it can be stopped or another medication substituted as a diagnostic trial.
Treating apparently depressed patients may facilitate differentiation between depression and mild cognitive impairment.
If patients have neurologic abnormalities (eg, weakness, altered gait, involuntary movements), MRI or, if MRI is unavailable, CT is required.
For most patients, serum vitamin B12 measurement, a complete metabolic panel (including serum creatinine, liver function tests, calcium, magnesium, and glucose) and thyroid function tests are needed to exclude potentially readily reversible causes of memory impairment.
Evaluation references
1. Nasreddine ZS, Phillips NA, Bédirian V, et al: The Montreal Cognitive Assessment, MoCA: A brief screening tool for mild cognitive impairment. J Am Geriatr Soc 53 (4):695–699, 2005. doi: 10.1111/j.1532-5415.2005.53221.x
2. Folstein MF, Folstein, McHugh PR: "Mini-mental state". A practical method for grading the cognitive state of patients for the clinician. J Psychiatr Res 12 (3):189–198, 1975. doi: 10.1016/0022-3956(75)90026-6
Treatment of Memory Loss
Patients with age-associated memory impairment should be reassured. Some generally healthful measures are often recommended to help maintain function and possibly decrease the risk of dementia.
Patients with depression are treated with medications and/or psychotherapy.
Patients with memory loss and signs of depression should be treated with nonanticholinergic antidepressants, preferably selective serotonin reuptake inhibitors (SSRIs). Memory loss tends to resolve as depression does.
Delirium is treated by correcting the underlying condition.
Rarely, dementia is reversible with a specific treatment (eg, supplementary vitamin B12, thyroid hormone replacement, shunting for normal-pressure hydrocephalus).
Other patients with memory loss are treated supportively.
General measures
The following can be recommended for patients who are worried about memory loss:
Regular exercise
Consumption of a healthy diet with lots of fruits and vegetables
Sufficient sleep
Not smoking
Minimized use of alcohol or other substances (eg, marijuana)
Participation in social and intellectually stimulating activities
Regular physical examinations
Stress management
Prevention of head injury
These measures, with control of blood pressure, cholesterol levels, and plasma glucose levels, also tend to reduce risk of cardiovascular disorders. Some evidence suggests that these measures may reduce risk of dementia, but this effect has not been proved.
Some experts recommend
Learning new things (eg, a new language, a new musical instrument)
Doing mental exercises (eg, memorizing lists; doing word puzzles; playing chess, bridge, or other games that use strategy)
Reading
Working on the computer
Doing crafts (eg, knitting, quilting)
These activities may help maintain or improve cognitive function, possibly because they strengthen neuronal connections and promote new connections.
Patient safety
Occupational and physical therapists can evaluate the home of impaired patients for safety with the goal of preventing falls and other accidents. Protective measures (eg, hiding knives, unplugging the stove, removing the car, confiscating car keys) may be required. If patients wander, signal monitoring systems can be installed, or patients can be registered in the Safe Return program. Information is available from the Alzheimer's Association (Safe Return program).
Clinicians should know their role in notifying local licensing authorities about patients with dementia; requirements for reporting vary by state (in the United States) and by country.
Ultimately, assistance (eg, housekeepers, home health aides) or a change of environment (eg, living facility without stairs, assisted-living facility, skilled nursing facility) may be indicated.
Environmental measures
Environmental measures can help patients with dementia.
Patients with dementia usually function best in familiar surroundings, with frequent reinforcement of orientation (including large calendars and clocks), a bright, cheerful environment, and a regular routine. The room should contain sensory stimuli (eg, radio, television, night-light).
In institutions, staff members can wear large name tags and repeatedly introduce themselves. Changes in surroundings, routines, or people should be explained to patients precisely and simply, omitting nonessential procedures.
Frequent visits by staff members and familiar people encourage patients to remain social. Activities can help; they should be enjoyable and provide some stimulation but not involve too many choices or challenges. Exercises to improve balance and maintain cardiovascular tone can also help reduce restlessness, improve sleep, and manage behavior. Occupational therapy and music therapy help maintain fine motor control and provide nonverbal stimulation. Group therapy (eg, reminiscence therapy, socialization activities) may help maintain conversational and interpersonal skills.
Medications
Eliminating or limiting medications with central nervous system (CNS) activity often improves function. Sedating and anticholinergic drugs, which tend to worsen dementia, should be avoided.
Alzheimer disease or dementia with Lewy bodies and may be useful in other forms of dementia. Efficacy wanes over time.
N-methyl-d-aspartate) antagonist, can be used in moderate to severe dementia.
1). However, cholinesterase inhibitors are not usually recommended to enhance cognition or memory in patients with mild cognitive impairment because evidence of efficacy is insufficient and risk of adverse events (particularly gastrointestinal [2]) is increased.
Treatment references
1. Petersen RC, Thomas RG, Grundman M, et alN Engl J Med. 352 (23):2379–2388, 2005. doi: 10.1056/NEJMoa050151 Epub 2005 Apr 13.
2. Russ TC, Morling JR: Cholinesterase inhibitors for mild cognitive impairment. Cochrane Database Syst Rev 2012 (9): CD009132, 2012. Published online 2012 Sep 12. https://doi.org/10.1002/14651858 CD009132.pub2
Geriatric Essentials: Memory Loss
Mild cognitive impairment is common with aging. Prevalence estimates vary by study but generally increase with age; some studies report approximately 7% at age 60 and as high as 25% after age 80 (1).
Dementia is one of the most common causes of institutionalization, morbidity, and mortality among older adults. Aging itself accounts for most of the risk of dementia. Prevalence of dementia is
About 1% at age 60 to 64
3% at age 65 to 74
Almost 15% of people aged 75 to 79
About 25% of people aged 80 to 84
30 to 50% at age > 85
60 to 80% among older nursing home residents
Geriatric essentials reference
1. Petersen RC, Lopez O, Armstrong MJ, et al: Practice guideline update summary: Mild cognitive impairment. Report of the Guideline Development, Dissemination, and Implementation Subcommittee of the American Academy of Neurology. Practice Guideline. Neurology 16;90 (3):126–135, 2018. doi: 10.1212/WNL.0000000000004826 Epub 2017 Dec 27.
Key Points
Memory loss and dementia are common in older adults and are common sources of worry for them.
Age-associated memory impairment is common, causing slowing, but not deterioration, of memory and cognition.
Diagnose primarily based on clinical criteria, particularly mood, attention, presence of true memory loss, and effect on daily function.
Promptly exclude possible reversible and treatable causes of dementia (certain types of stroke, depression, seizures, head trauma, brain infections, hypothyroidism, HIV infection, normal-pressure hydrocephalus, brain tumors, vitamin B12 deficiency, overuse of certain medications and substances including alcohol).
A complete medication and substance use history is critical because sedating and anticholinergic drugs can cause memory loss that can be reversed by stopping the drug.
If patients have neurologic abnormalities (eg, weakness, altered gait, involuntary movements), do MRI or CT.
Self-reported memory loss is usually not due to dementia.
Delirium and depression must be ruled out before diagnosing dementia.
More Information
The following English-language resource may be useful. Please note that THE MANUAL is not responsible for the content of this resource.
Alzheimer's Association: This web site has information about dementia in general and Alzheimer disease (such as statistics, causes, risk factors, early symptoms and signs, options for care, and daily care of someone with Alzheimer disease). It also includes tips to improve brain health and links to support groups and local resources.
