15.5 SUMMING UP

Normal Versus Abnormal Aging and Cognitive Functioning

• Most aspects of cognitive functioning remain stable during the normal course of aging. However, fluid intelligence, processing speed, recalling verbal information on demand, maintaining attention, and multitasking decline in older adults. But these declines do not generally impair daily functioning.
• The disorders that are most common among older adults are depression and generalized anxiety disorder. These disorders can lead to impaired cognitive functioning that may superficially resemble symptoms of a neurocognitive disorder.
• Brain injury, most commonly from a stroke, can produce various cognitive deficits. Among the deficits that may follow a stroke or a head injury are aphasia, agnosia, and apraxia.
• Legally prescribed medications or illegal substances can alter awareness, emotional states, and cognitive functioning.

Delirium

• According to DSM-5, delirium is characterized as a disturbance in attention and awareness as well as changes in another aspect of cognitive functioning. These symptoms develop rapidly and fluctuate over the course of a 24-hour period.
• Delirium most commonly occurs among the elderly, the terminally ill, and patients who have just had surgery.
• Delirium can arise from substance intoxication or withdrawal; delirium can also arise from a medical condition—such as an infection or head trauma—or as a result of anesthesia.
• Treatment for delirium that targets neurological factors often addresses the underlying physical cause, typically through medication.
• Treatments that target psychological and social factors include correcting sensory impairments, helping patients increase their awareness of the here and now, and educating people who interact with the delirious patient about the symptoms of the disorder.

Dementia (and Mild Versus Major Neurocognitive Disorders)

• Dementia is the umbrella term for a set of cognitive disorders that involve deficits in memory and aphasia, apraxia, agnosia, or problems with executive functions.
• Dementia can give rise to hallucinations and delusions.
• All types of dementia are caused by neurological factors. The most common type of dementia—that due to Alzheimer’s disease—is a progressive disorder characterized by neurofibrillary tangles and amyloid plaques in the brain. Although symptoms may emerge before age 65, the late-onset form is much more common.
• Vascular dementia is caused by reduced or blocked blood flow to the brain, usually because of narrowed arteries or strokes.
• Other types of dementia are caused by medical conditions:
  
  • Parkinson’s disease is a progressive disorder that affects motor functions.
  • Lewy bodies build up inside certain types of neurons and cause the neurons to die, leading to progressive, irreversible dementia.
  • HIV disease can eventually destroy white matter and subcortical brain areas; however, in some cases this type of dementia can be arrested and even reversed with antiretroviral medication.
  • Huntington’s disease is a progressive disease that involves death of neurons in brain areas that are involved in cognition, emotion, and motor control.
  • Head trauma is caused by accidents or incurred as part of an athletic sport.
  • Substance use problems or medications can lead to temporary or persistent dementia.
• Mild neurocognitive disorder is characterized by evidence of a modest decline in cognitive function from baseline but people are able to function independently. In contrast, major neurocognitive disorder is characterized by significant cognitive decline and impaired ability to function independently.
• Treatments for dementia that target neurological factors include medications that affect the levels of acetylcholine or glutamate.
• Psychological and social interventions for people with dementia are designed to improve the patients’ quality of life. Methods include the use of memory aids, reality orientation therapy, reminiscence therapy, and restructuring of the environment.