PSY 363

Chapter 13: Neurocognitive Disorders

Overview of Neurocognitive Disorders (NCDs)

  • NCDs involve cognitive decline that is acquired in life affecting one or more cognitive domains.
  • Assessment methods for diagnosis include:
    • Neuropsychological testing
    • Neuroimaging
    • Individual’s medical history
  • The DSM-5 provides diagnostic descriptions to aid clinicians in identifying NCDs and their possible causes.
  • The term NCD serves as a replacement for 'dementia'.

Characteristics of Neurocognitive Disorders

  • Major Neurocognitive Disorder:
    • Involves significant cognitive decline from a previous level of performance.
  • Mild Neurocognitive Disorder:
    • Involves modest cognitive decline from a previous level of performance.

Cognitive Domains and Assessment

  • Neurocognitive domains are classified in the DSM-5 with various abilities and assessment tasks:
    • Complex Attention:
    • Abilities: Sustained, selective, and divided attention.
    • Assessment tasks: Maintaining attention over time, separating signals from distractors, attending to multiple tasks.
    • Executive Function:
    • Abilities: Planning, decision making, working memory, and cognitive flexibility.
    • Assessment tasks: Performing tasks requiring choice between alternatives, holding information in memory while manipulating stimuli.
    • Learning and Memory:
    • Abilities: Immediate memory span, recent memory.
    • Assessment tasks: Remembering a series of digits or words, encoding new information.
    • Language:
    • Abilities: Expressive and receptive language skills.
    • Assessment tasks: Naming objects, understanding word definitions.
    • Perceptual-Motor Skills:
    • Abilities: Visual perception, visuoconstructional skills, praxis.
    • Assessment tasks: Assembling items, recognizing faces.
    • Social Cognition:
    • Abilities: Recognition of emotions and theory of mind.
    • Assessment tasks: Identifying emotions in faces and understanding others' mental states.

Delirium

  • Delirium is characterized by:
    • Disturbances in attention or awareness, often with a clouding of consciousness.
    • Symptoms may appear abruptly and fluctuate over time.
    • Causes may include:
    • Substance intoxication/withdrawal
    • Head injury
    • High fever
    • Vitamin deficiency
    • Infection
    • More common in older adult patients in medical or psychiatric care.

Causes and Treatment of Delirium

  • Causes:
    • Infection
    • Central nervous system disorders
    • Metabolic disorders
  • Tests:
    • Delirium Rating Scale–Revised-98 (DRS-R-98)
    • Pharmacological treatments: Haloperidol, Risperidone.

Dementias Classifications in the DSM-5

  • Major Neurocognitive Disorder (NCD):
    • Significant cognitive decline that interferes with independent functioning.
    • Must not be attributed to another disorder.
  • Mild Neurocognitive Disorder (Mild NCD):
    • Modest cognitive decline that does not interfere with independent functioning.

Types of Dementias (Table 27.2)

  • Tauopathies:
    • Disorders involving accumulation of tau proteins, such as Alzheimer’s disease (tau forms amyloid and tangles).
    • Corticobasal Degeneration: Neuron loss in the cortex and basal ganglia.
    • Frontotemporal Disorders (FTD): Neuron loss in frontal and temporal lobes.
    • Progressive Supranuclear Palsy (PSP): Neuron loss in upper brainstem.
  • Synucleinopathies:
    • Accumulation of alpha-synuclein proteins in neurons, e.g., Lewy body dementia, Parkinson’s disease dementia.
  • Vascular Dementias:
    • Result from injuries to the cerebral blood vessels, including Multi-infarct dementia and subcortical vascular dementia (Binswanger's disease).
  • Mixed Dementias:
    • Combination of disorders, such as Alzheimer's with vascular symptoms.
  • Other Dementias:
    • Prion-related dementias (e.g., Creutzfeldt-Jakob disease).
    • Huntington’s disease and secondary dementias (e.g., Wilson’s disease, multiple sclerosis).
    • Infectious dementias (e.g., AIDS dementia).
    • Drug-related dementias from chronic use of substances like alcohol or ecstasy.

Alzheimer’s Disease

  • A major neurocognitive disorder characterized by progressive declines in memory and cognitive function.
  • Diagnostic criteria include showing evidence of cognitive decline and the possible presence of genetic mutations associated with Alzheimer’s disease.
  • Stages of Alzheimer’s Disease:
    • Symptoms worsen progressively through early, middle, and late stages.
    • Factors contributing to rapid decline in early stages:
    • Younger age of onset
    • Higher education levels
    • Poor cognitive status upon diagnosis.

Diagnostic Criteria for Alzheimer's Disease (Table 3)

  • For major NCD due to Alzheimer's disease, diagnosis is classified as:
    • Probable: Evidence of a genetic mutation, decline in memory and cognitive function, progressive cognitive decline, no evidence of another condition contributing to decline.
    • Possible: Genetic indication lacking, but showing all symptoms.

Pseudodementia

  • Symptoms caused by severe depression that mimic early-stage Alzheimer’s disease.
  • Individuals often have a prior undiagnosed history of depression.

Biological Theories of Alzheimer’s Disease

  • Neurofibrillary tangles:
    • Composed of tau protein affecting microtubule stability.
  • Amyloid plaques:
    • Develops years before symptoms are evident and is one of the first pathologies in Alzheimer's.
  • Secretases:
    • Proteins that trim parts of amyloid precursor protein (APP), contributing to plaque formation.

Risk Factors for Alzheimer's Disease

  • Genetic predisposition
  • Cigarette smoking
  • Obesity
  • Lack of physical exercise

Medications for Alzheimer's Disease (Table 6)

  • Namenda® (memantine):
    • Type: N-methyl D-aspartate (NMDA) antagonist.
    • Mechanism: Blocks toxic effects of excess glutamate.
    • Side Effects: Dizziness, headache, constipation, confusion.
  • Razadyne® (galantamine):
    • Type: Cholinesterase inhibitor.
    • Mechanism: Prevents breakdown of acetylcholine.
    • Side Effects: Nausea, vomiting, diarrhea, weight loss.
  • Exelon® (rivastigmine):
    • Type: Cholinesterase inhibitor.
    • Mechanism: Prevents breakdown of acetylcholine and butyrylcholine.
    • Side Effects: Same as Razadyne.
  • Aricept® (donepezil):
    • Type: Cholinesterase inhibitor for all stages of AD.
  • Side Effects: Similar gastrointestinal reactions as above.

Behavioral Strategies for Alzheimer's Disease

  • Strategies focus on maximizing patients’ daily functioning and offering support to caregivers.
  • Goals include:
    • Increasing patient independence.
    • Reducing wandering and aggression.
    • Providing social support for caregivers.

Frontotemporal Neurocognitive Disorder

  • Affects the frontotemporal area, showing symptoms such as:
    • Personality changes: apathy, loss of inhibition, obsessiveness, and poor judgment.
    • Gradual neglect of personal habits and communication abilities.

Neurocognitive Disorder with Lewy Bodies

  • Characterized by the accumulation of Lewy bodies affecting cognitive and motor functions.
  • Symptoms include progressive memory loss and changes in mood and movement.

Vascular Neurocognitive Disorder

  • Results from blood supply deprivation in the brain, presenting as multi-infarct dementia (MID).

Pick’s Disease

  • Rare, progressive degenerative disease affecting frontal and temporal lobes.
  • Symptoms include social disinhibition and personality changes before cognitive decline.

Neurocognitive Disorder Due to Parkinson's Disease

  • Caused by significant dopamine loss, affecting movement and cognition.
  • Symptoms include:
    • Akinesia: difficulty initiating movement.
    • Bradykinesia: general slowing of motor activity and cognitive functions remaining mostly intact.

Neurocognitive Disorder Due to Huntington’s Disease

  • A hereditary condition leading to widespread brain deterioration and cognitive decline.

Neurocognitive Disorder Due to Prion Disease (Creutzfeldt-Jakob Disease)

  • Neurological disease from abnormal protein accumulations transmitted from animals.

Neurocognitive Disorder Due to Traumatic Brain Injury (TBI)

  • Caused by trauma, with an estimated 2.8 million incidents in the U.S. annually.
  • Symptoms persist beyond the acute injury period.

Postconcussion Syndrome (PCS)

  • A constellation of physical, emotional, and cognitive symptoms lasting weeks to years post-TBI.
  • Symptoms include fatigue and headaches.

Neurocognitive Disorders from Infectious Diseases and Substances

  • Various infectious diseases, medications, and environmental toxins can lead to neurocognitive disorders.
  • Notable examples:
    • Neurosyphilis, HIV, drugs leading to cognitive decline.

Substance/Medication-Induced Neurocognitive Disorders

  • Including those caused by alcohol (e.g., Korsakoff’s Syndrome).
  • Symptoms: memory issues, confabulation, lack of insight, apathy.

Conclusion on Treatment Options

  • No viable treatment for Alzheimer’s disease; however, innovative methods and traditional emotional support strategies are in development.
  • Biopsychosocial perspectives open a path for understanding and addressing cognitive disorders effectively.

Note: This study guide captures detailed aspects of neurocognitive disorders, providing a comprehensive overview for academic reference.