Major neurocognitive disorder

Major neurocognitive disorder (previously called dementia) is an acquired disorder of cognitive function that is commonly characterized by impairments in memory, speech, reasoning, intellectual function, and/or spatial-temporal awareness. The potential causes of dementia are diverse, but the disorder is mainly due to neurodegenerative and/or vascular disease and as such, most forms are associated with increased age. Initial diagnosis should focus on the patient history, followed by cognitive assessments (e.g., the mini‑mental state exam) and physical examination. To confirm or rule out specific etiologies, additional laboratory tests or imaging studies are often necessary. Pharmacotherapy is available but is often met with little success because of the chronic and progressive nature of dementia.

An important differential diagnosis is pseudodementia, which is primarily associated with cognitive deficits in older patients with depression. In contrast to patients with dementia, individuals with pseudodementia can often recall the onset of their cognitive impairments, overestimate their symptoms, and are remarkably responsive to treatment with antidepressants.

Neurodegenerative brain diseases

• Alzheimer disease (> 50% of dementia cases)
• Parkinson disease
• Frontotemporal dementia
• Dementia with Lewy bodies
• Progressive supranuclear palsy
• Huntington disease

Additional causes

• Cerebrovascular disease (20% of dementia cases)
  • Multi-infarct dementia
  • Diffuse white matter disease (subcortical arteriosclerotic encephalopathy)
• Hypoxic brain damage
• Normal pressure hydrocephalus
• After head trauma, intracranial bleeding or brain tumors
• Drug/alcohol‑related (e.g., Wernicke‑Korsakoff syndrome)
• Wilson disease
• Vitamin deficiencies (thiamine, B6, B12, folate)
• Metabolic: exsiccosis, uremia, electrolyte imbalances, hypothyroidism and hyperthyroidism, hypoparathyroidism, and hyperparathyroidism
• Environmental toxins
• Inflammatory/infectious
  • Syphilis
  • Progressive multifocal leukoencephalopathy
  • HIV
  • Creutzfeldt-Jakob disease

References:^[1]

• General: memory impairment
• Additional cognitive impairment
  • Speech: aphasia, word-finding difficulties, semantic paraphasia
  • Intellectual capacities, reasoning, planning capabilities, and self-control
  • Spatial-temporal awareness (however, the awareness of oneself remains stable for a long time)
  • Apathy
• Changes in personality, mood, and behavior
  • Early stages: depression
  • Later stages: seemingly unconcerned mood and cognitive impairment is downplayed
• Dementia associated with CNS infections
  • Most types of CNS infections cause acute neurological or psychiatric symptoms rather than dementia.
  • Infections that may cause symptoms of dementia include:
    • Chronic meningitis
    • HIV and HIV-related opportunistic infections
    • Neurosyphilis

References:^[1]

General

• Personal and collateral history of cognitive and behavioral changes
• Drug history
• Screening for depression
• Physical and neurological examination

Diagnostic criteria for major neurocognitive disorder (previously dementia) in accordance with DSM-5

• Significant cognitive decline in at least one of the following domains
  • Learning and memory
  • Language
  • Executive function
  • Complex attention
  • Perceptual-motor
  • Social cognition
• Cognitive deficits interfere with everyday life, patient becomes dependent on help with complex activities (e.g., paying bills)
• Cognitive deficits do not occur exclusively in the context of a delirium
• Cognitive deficits are not better explained by another mental disorder (e.g., major depression)

Unlike major cognitive impairment, in mild cognitive impairment the ability to function in daily life is preserved.

Cognitive assessment

Mini-Mental State Examination (MMSE)

• Definition: a screening tool that assesses the degree of cognitive impairment in individuals with suspected dementia ^[2]
  • Orientation capabilities: questions regarding year, season, date, day, month, country, state, city, address, and floor level
  • Registration (immediate memory): Three words are mentioned that must be repeated immediately.
  • Attention and calculation: Beginning with 100, the patient counts backwards every 7 numbers (100, 93, 86, 79, etc.). The patient is asked to spell a word backwards, e.g., “price”.
  • Recall (short-term memory): The patient is asked to repeat the 3 previously given words after some time.
  • Speaking capabilities and understanding: ability to rename objects shown, repeat a sentence, accomplish a 3-part order, read and follow a written request, write a complete sentence, and trace a geometric figure
• Diagnostic criteria
  • A maximum of 30 points is possible
  • A patient who scores 24 points or less is generally considered to have dementia.
    • 20–24 points: mild dementia
    • 13–20 points: moderate dementia
    • < 13 points: advanced dementia

Montreal Cognitive Assessment (MoCA)

• Definition
  • A screening tool that assesses cognitive impairment
  • Includes testing of memory, visuospatial ability (e.g., by drawing a clock and copying a drawing of a cube), executive function, attention, language, abstraction (e.g., identifying similarity between a train and a bicycle), recall, and orientation to time and place.
• Diagnostic criteria
  • A maximum of 30 points is possible
    • 18–25 points: mild cognitive impairment
    • 10–17 points: moderate cognitive impairment
    • < 10 points: severe cognitive impairment

Saint Louis University Mental Status Examination (SLUMS) ^[3]

• Definition: a screening tool to assess the degree of cognitive impairment in individuals with suspected dementia
  • Orientation: questions regarding time (i.e., day of the week, year) and place (i.e., state)
  • Memory
    • Five objects are named and the patient is asked to recall them after later
    • A series of numbers are provided which the patient needs to recall backwards (e.g., if you say 42, they should say 24)
    • You tell the patient a short story and inform them to pay careful attention because you'll ask a few questions about it immediately afterwards (e.g., what is the main character's name and job)
  • Attention and calcuation
    • The patient is theoretically provided with a $100 budget and are told that they buy a dozen apples for $3 and a tricycle for $20
    • Ask how much money they have spent and how much they have left
  • Executive function
    • The patient is asked to draw the hour markers and a specific time within an empty clock face (i.e., circle)
    • Provide the patient with a drawing of a triangle, square (draw it larger than the other shapes), and rectangle, then ask them to place an X in the triangle and determine which figure is the largest in size
• Diagnostic criteria
  • A maximum of 30 points is possible
  • A patient who scores 19 points or less suffers from neurocognitive impairment

Clock-drawing test

• Procedure: The patient is given a sheet of paper with an empty circle on which they are asked to draw a clock indicating the current time (including numbers and hands).
• Purpose: If an individual is unable to correctly draw the numbers and hands on the clock, a deficit in spatial or abstract thinking may be present. These deficits are commonly already present during the early stages of dementia.

Lab tests

• In all patients: screening for vitamin B12 deficiency (cobalamin) and hypothyroidism
• More specialized tests should be ordered in patients with a rapid progressive course of dementia, young patients (< 60 years), or patients with symptoms giving reason to suspect the presence of a certain disease
  • Serum electrolytes, renal and liver function tests, folate, homocysteine
  • Ceruloplasmin: decreased in Wilson disease (may be associated with symptoms of dementia)
  • Syphilis serology when there is a high clinical suspicion for neurosyphilis.
  • HIV
  • Lyme disease
  • Rheumatological screen (ESR, ANA, CRP)
  • ApoE genotyping
• Lumbar puncture and CSF analysis (only in selected patients with suggestive clinical features or other abnormal tests)
  • To reveal CNS infection/inflammation (e.g., in meningitis or encephalitis)
  • To detect specific biomarkers (e.g., in Alzheimer disease)

Imaging

• In all patients: noncontrast head CT or MRI
  • To detect reversible causes of dementia (e.g., brain tumor, subdural hematoma, NPH, past cerebral ischemia)
  • Multiple lacunar infarcts in vascular dementia
  • Reduced hippocampal volume in Alzheimer disease
• PET, SPECT: in selected patients with suggestive clinical features/abnormal other tests to distinguish between different neurodegenerative disorders (e.g., Alzheimer disease, atypical parkinsonian disorders, and frontotemporal dementia)
• EEG: when structural abnormality is suspected

The differential diagnoses listed here are not exhaustive.

Memory training

• Cognitive capabilities can be improved through targeted stimulation (e.g., practicing image recognition, completing arithmetic or combinatorial problems).
• Recalling past memories

Antidementia drugs ^[6]

Cholinesterase inhibitors

• Recommendation
  • First-line treatment for Alzheimer dementia (particularly mild to moderate stages) and vascular dementia
  • May be beneficial in cases of dementia with Lewy bodies, frontotemporal dementia, and Parkinson disease
• Drugs: donepezil, rivastigmine, galantamine
• Effect: Reversible cholinesterase inhibition leads to increased acetylcholine (ACh) concentration and can thus improve symptoms of some types of dementia.
• Adverse side effects
  • Nausea
  • Dizziness
  • Insomnia
  • See also symptoms of cholinergic crisis.
• Contraindications: cardiac conditions (e.g., conduction abnormalities)

“Dona Riva dances at the nursing home gala:” Donepezil, rivastigmine, and galantamine.

Memantine

• Recommendation
  • Particularly used in moderate to advanced cases of Alzheimer disease or vascular dementia
  • Memantine may be used in combination with cholinesterase inhibitors.
• Effect: NMDA-receptor antagonism, resulting in decreased glutamate-induced calcium-mediated excitotoxicity
• Adverse side effects: mostly affect the central nervous system
  • Headaches and dizziness
  • Confusion, hallucinations
  • Seizures

Adjuvant treatment

This section provides an overview of pharmacological and nonpharmacological strategies of treating associated disorders in patients suffering from dementia. The given measures do not necessarily apply to all types of dementia and individual indications and contraindications must always be considered.

• Psychomotor agitation: SSRIs, particularly citalopram
• Feeding difficulties: may require placement of a gastrointestinal tube
• Sleep disorders
  • In general, nonpharmacological treatment is preferred
    • Environmental restructuring (e.g., moving the patient to a single bedroom, if possible)
    • General sleep hygiene (sufficient exercise, limited alcohol intake in the evening, stimulus control, consistent sleep-wake cycles, etc.)
    • Evaluation of drug effects or interactions that may disturb sleep; possible adjustment of medication
  • Pharmacotherapy: not generally recommended; in some cases, melatonin or trazodone may be beneficial.
  • If specific conditions (e.g., restless legs syndrome or insomnia due to depression) are identified, these conditions should receive specific treatment.
• Pain: step-wise approach, starting with a low-dose trial in combination with systematic monitoring and reevaluation
• Anxiety: Benzodiazepines should be used carefully and only for brief periods (e.g., during stressful changes in environment that cannot be avoided); drugs with shorter half-lives (e.g., oxazepam) are generally preferable.
• Agitation/psychosis:
  • Atypical antipsychotics (e.g., risperidone) should, as a rule, be avoided; they might be considered in individual cases (especially in cases of severe psychosis and/or danger to the patient or others).
  • Conventional antipsychotics (e.g., haloperidol) provide modest benefits for some patients; haloperidol, specifically, may be helpful in controlling aggression.
• General nonpharmacologic measures
  • Avoid sudden changes in patient routine or environment; provide reassuring psychosocial interaction (e.g., speak softly and slowly; in general, avoid disagreeing with the patient).
  • Physical exercise (with specially trained personnel) may improve symptoms (especially in the case of Alzheimer disease).
  • Music therapy and animal‑assisted therapy may also be beneficial for some patients.

In general, anticholinergic substances (e.g., tricyclic antidepressants) should be avoided, as they may lead to further deterioration in cognitive functioning!