Learning Objectives
- Describe how delirium presents.
- Describe how major neurocognitive disorder presents.
- Describe how mild neurocognitive disorder presents.
Unlike many of the disorders we have discussed thus far, neurocognitive disorders often result from disease processes or medical conditions. Therefore, it is important that individuals presenting with these symptoms complete a medical assessment to better determine the etiology behind the disorder.
There are three main categories of neurocognitive disorders—delirium, major neurocognitive disorder, and mild neurocognitive disorder. Within major and minor neurocognitive disorders are several subtypes due to the etiology of the disorder. For this book, we will review diagnostic criteria for both major and minor neurocognitive disorders, followed by a brief description of the various disease subtypes in the etiology section.
It is important to note as well that the criteria for the various NCDs are based on defined cognitive domains. These include the following, with a brief explanation of what it is:
- Complex attention – Sustained, divided, or selective attention and processing speed
- Executive function – planning, decision-making, overriding habits, mental flexibility, and responding to feedback/error correction
- Learning and memory – includes cued recall, immediate or long-term memory, and implicit learning
- Language – Includes expressive language and receptive language
- Perceptual-motor – Includes any abilities related to visual perception, gnosis, perceptual-motor praxis, or visuo-constructional
- Social cognition – Includes recognition of emotions and theory of mind
Delirium
Delirium is characterized by a notable disturbance in attention along with reduced awareness of the environment. The disturbance develops over a short period of time, representing a change from baseline attention and awareness, and fluctuates in severity during the day. There is also a disturbance in cognitive performance that is significantly altered from one’s usual behavior. Disturbances in attention are often manifested as difficulty sustaining, shifting, or focusing attention. Additionally, an individual experiencing an episode of delirium will have a disruption in cognition, including confusion of where they are. Disorganized thinking, incoherent speech, and hallucinations and delusions may also be observed during periods of delirium.
Delirium is associated with increased functional decline and risk of being placed in an institution. That said, most people with delirium recover fully with or without treatment, especially if not elderly, but if undetected or the underlying cause is untreated, it may progress to stupor, coma, seizures, or death (APA, 2022).
Major Neurocognitive Disorder
Individuals with major neurocognitive disorder show a significant decline in both overall cognitive functioning (see the previously listed six domains) as well as the ability to independently meet the demands of daily living such as paying bills, taking medications, or caring for oneself (APA, 2022). While it is not necessary, it is helpful to have documentation of the cognitive decline via neuropsychological testing within a controlled, standardized testing environment. Information from close family members or caregivers is also important in documenting the decline and impairment in areas of functioning.
Within the umbrella of major neurocognitive disorder is dementia, a striking decline in cognition and self-help skills due to a neurocognitive disorder. The DSM-5-TR (APA, 2022) refrained from using this term in diagnostic categories as it is often used to describe the natural decline in degenerative dementias that affect older adults; whereas neurocognitive disorder is the preferred term used to describe conditions affecting younger individuals such as impairment due to traumatic brain injuries or other medical conditions. Therefore, while dementia is accurate in describing those experiencing major neurocognitive disorder due to age, it is not reflective of those experiencing neurocognitive issues secondary to an injury or illness.
Mild Neurocognitive Disorder
Individuals with mild neurocognitive disorder demonstrate a modest decline in one of the listed cognitive domains. The decline in functioning is not as extensive as that seen in major neurocognitive disorder, and the individual does not experience difficulty independently engaging in daily activities. However, they may require assistance or extra time to complete these tasks, particularly if the cognitive decline continues to progress.
It should be noted that the primary difference between major and mild neurocognitive disorder is the severity of the decline and independent functioning. Some argue that the two are earlier and later stages of the same disease process (Blaze, 2013). Conversely, individuals can go from major to mild neurocognitive disorder following recovery from a stroke or traumatic brain injury (Petersen, 2011). The DSM-5-TR describes major and mild NCD as existing on a spectrum of cognitive and functional impairment (APA, 2022, pg. 685).
Key Takeaways
You should have learned the following in this section:
- The criteria for the various NCDs are based on the cognitive domains of complex attention, executive function, learning and memory, language, perceptual-motor, and social cognition.
- Delirium is characterized by a notable disturbance in attention or awareness and cognitive performance that is significantly altered from one’s usual behavior.
- Major neurocognitive disorder is characterized by a significant decline in both overall cognitive functioning as well as the ability to independently meet the demands of daily living.
- Mild neurocognitive disorder is characterized by a modest decline in one of the listed cognitive areas with no interference in one’s ability to complete daily activities.
Review Questions
- What are the six cognitive domains the diagnostic criteria for NCDs are based on?
- Define delirium. How does this differ from mild and major neurocognitive disorders?
- What are the main differences between mild and major neurocognitive disorders?
