Neurocognitive Disorders PDF

AS2402 NEUROCOGNITIVE DISORDERS Perspectives on Neurocognitive Disorders Most neurocognitive disorders develop much later in life, whereas intellectual disability and specific learning disorders are believed to be present from birth. There are two main categories...

AS2402 NEUROCOGNITIVE DISORDERS Perspectives on Neurocognitive Disorders Most neurocognitive disorders develop much later in life, whereas intellectual disability and specific learning disorders are believed to be present from birth. There are two main categories of cognitive disorders: delirium, which is typically a temporary state characterized by confusion and disorientation, and mild or major neurocognitive disorder, which is a progressive condition involving the gradual decline of various cognitive functions. In DSM-5, the term neurocognitive disorders replaced the previous label of organic mental disorders. Initially, these disorders were grouped under organic mental disorders along with mood, anxiety, personality, hallucinosis, and delusional disorders. The word organic indicated that brain injury or dysfunction was believed to be involved. However, the term "organic" became meaningless due to the broad range of disorders it encompassed. As a result, traditional organic disorders like delirium, dementia, and amnestic disorders were kept together, while others were categorized with disorders sharing similar symptoms, such as anxiety and mood disorders. After dropping the term "organic," DSM-IV used "cognitive disorders" to describe conditions like delirium, dementia, and amnestic disorders, emphasizing impairment in cognitive abilities. However, this term also included conditions like schizophrenia and depression, where cognitive issues are not primary. In DSM-5, "neurocognitive disorders" became the category name for dementia and amnestic disorders, while delirium retained its label. This change aimed to address the overlap between different types of neurocognitive impairments and disorders. Delirium The disorder known as delirium is characterized by impaired consciousness and cognition for several hours or days. Delirium is one of the earliest recognized mental disorders. Descriptions of people with these symptoms were written more than 2,400 years ago. Individuals with delirium seem confused, disoriented, and disconnected from their environment. They struggle to concentrate on even basic tasks. Their memory and language abilities are significantly impaired. Delirium disorder, which affects 10% to 15% of patients in acute care settings like emergency rooms, is most common among older adults, those undergoing medical procedures, cancer patients, and people with AIDS. While previously thought to be temporary, delirium can have lasting effects, with approximately 40% to 50% of individuals dying within a year. Medical professionals are increasingly concerned about delirium, advocating for its inclusion as a vital sign for older adults. Various medical conditions, including drug intoxication, withdrawal, infections, head injuries, and brain trauma, can cause delirium. Older adults are particularly vulnerable due to their higher medication use and reduced drug elimination efficiency. Delirium can lead to serious consequences such as falls and hip fractures, often exacerbated by improper medication use. Delirium is not exclusive to older adults, children with high fevers or taking certain medications can also experience it. It frequently occurs in individuals with dementia and can increase the risk of mortality, especially in critical care settings. Other factors, such as sleep deprivation, immobility, and stress, can trigger delirium. 13 Handout 1 *Property of STI Page 1 of 5  AS2402 Research into delirium's underlying mechanisms suggests lasting disruptions in brain connectivity. While such research may aid prevention and treatment, ethical concerns arise regarding informed consent, especially since those experiencing delirium cannot provide it. Additionally, the anxiety-provoking nature of fMRI testing can exacerbate the disorientation experienced by those with delirium. Prevention Preventive efforts for delirium are most effective when targeting susceptible individuals. Proper medical care for illnesses and therapeutic drug monitoring can significantly reduce the risk of delirium. Managed care and patient counseling on drug use have led to more appropriate prescription drug use among older adults. Structured multidisciplinary interventions during hospital stays, such as the Hospital Elder Life Program, are highly effective in preventing delirium. These programs involve reorienting the patient, providing aids for vision and hearing, ensuring adequate sleep and physical activity, maintaining hydration and nutrition, involving the patient in therapeutic activities, and reducing psychoactive drug dosages. However, implementing these programs requires significant hospital resources to target those at risk for delirium consistently. Major and Mild Neurocognitive Disorders Major neurocognitive disorder (previously labeled dementia) is a gradual deterioration of brain functioning that affects memory, judgment, language, and other advanced cognitive processes. Mild neurocognitive disorder is a new DSM-5 disorder that was created to focus attention on the early stages of cognitive decline. The individual experiences modest cognitive impairments but can still function independently with some accommodations, such as making extensive to-do lists or creating detailed schedules. Neurocognitive disorders can result from various medical conditions and drug or alcohol misuse, leading to negative changes in cognitive function. Conditions such as infection or depression can cause reversible neurocognitive impairment, while disorders like Alzheimer's disease are irreversible. Although delirium and neurocognitive disorder can coexist, neurocognitive disorder typically progresses gradually, affecting all aspects of cognitive functioning. In the early stages, memory impairment is often noticeable as difficulty registering ongoing events. For instance, individuals may recall past events but struggle to remember recent occurrences. Agnosia, the inability to recognize and name objects, is one of the most familiar symptoms. Facial agnosia, the inability to recognize even familiar faces, can be extremely distressing to family members. A general decline in intellectual function stems from impairments in memory, planning, and abstract reasoning. Perhaps partly because people with neurocognitive disorder are aware that they are deteriorating mentally, emotional changes often occur as well. Common side effects are delusions (irrational beliefs), depression, agitation, aggression, and apathy. Neurocognitive disorders, including major and mild forms, affect a significant number of individuals globally. While major neurocognitive disorder can develop at any age, it's more common among older adults. Alzheimer's disease, a common cause of the neurocognitive disorder, is predicted to increase dramatically, particularly among the elderly. Research indicates that neurocognitive disorders are relatively common among older adults, with the chances of developing them increasing rapidly after the age of 75. DSM-5 identifies various classes of neurocognitive disorders based on etiology: (1) Alzheimer’s disease, (2) vascular injury, (3) frontotemporal degeneration, (4) traumatic brain injury, (5) Lewy body disease, (6) Parkinson’s 13 Handout 1 *Property of STI Page 2 of 5  AS2402 disease, (7) HIV infection, (8) substance use, (9) Huntington’s disease, (10) prion disease, and (11) another medical condition. Neurocognitive Disorder due to Alzheimer’s Disease In 1907, the German psychiatrist Alois Alzheimer first described the disorder that bears his name. He wrote of a 51-year-old woman who had a “strange disease of the cerebral cortex” that manifested as progressive memory impairment and other behavioral and cognitive impairments, including suspiciousness. He called the disorder an “atypical form of senile dementia”; after that, it was referred to as Alzheimer’s disease. The DSM-5 diagnostic criteria for neurocognitive disorder due to Alzheimer’s disease include multiple cognitive deficits that develop gradually and steadily. Predominant are impairment of memory, orientation, judgment, and reasoning. The inability to integrate new information leads to a failure to learn new associations. Individuals with Alzheimer’s disease forget important events and misplace objects. Their interest in nonroutine activities narrows. They tend to lose interest in others and, as a result, become more socially isolated. As the disorder progresses, they can become agitated, confused, depressed, anxious, or even combative. Many of these difficulties become more pronounced later in the day, known as "sundowner syndrome," possibly due to fatigue or a disruption in the brain's biological clock. People with neurocognitive disorder due to Alzheimer’s disease also display one or more other cognitive disturbances, including aphasia (difficulty with language), apraxia (impaired motor functioning), agnosia (failure to recognize objects), or difficulty with activities such as planning, organizing, sequencing, or abstracting information. These cognitive impairments have a serious negative impact on social and occupational functioning, and they represent a significant decline from previous abilities. Alzheimer's disease is a leading cause of neurocognitive disorder, affecting approximately 60% to 70% of individuals with the condition globally, which amounts to over 50 million people worldwide and 5.5 million in the United States. Research suggests that the disease progresses slowly during the early and later stages but more rapidly during the middle stages, with an average survival time of about 4 to 8 years. However, many individuals may live dependently for more than 20 years. Early detection is crucial as it allows for early intervention, which has been shown to have the greatest impact. Studies have shown that cognitive deterioration in Alzheimer's disease is slower during the early and later stages but more rapid during the middle stages. The disease typically appears during the 60s or 70s, although it can occur earlier, sometimes referred to as early onset, during the 40s or 50s. Approximately 60% to 70% of neurocognitive disorder cases are attributed to Alzheimer's disease. Research has also indicated a potential link between education level and the onset and progression of Alzheimer's disease. While some early research suggested that the disease might occur more often in individuals with limited education, later studies indicate that higher education levels may predict a delay in the onset of symptoms. However, individuals with higher education levels may experience a more rapid decline once symptoms become more severe, suggesting that education provides a buffer period of better functioning rather than preventing the disease. It may be due to the development of a mental "reserve" through education, which helps individuals cope with cognitive deterioration for a longer period. A biological version of this theory, known as the cognitive reserve hypothesis, suggests that mental activity associated with education builds up a reserve of synapses, serving as an initial protective factor against the development of Alzheimer's disease. Additionally, research indicates that Alzheimer's disease may be more prevalent among women, with estrogen potentially playing a protective role against the disease. However, studies on hormone use among women and its effect on Alzheimer's disease have yielded mixed results, 13 Handout 1 *Property of STI Page 3 of 5  AS2402 with some suggesting an increased risk associated with estrogen use. Further research is ongoing to determine the individual effects of estrogen and progestin on dementia. Vascular Neurocognitive Disorder Vascular neurocognitive disorder is a progressive brain disorder that is a common cause of neurocognitive deficits. It is one of the more common causes of neurocognitive disorder, second only to Alzheimer’s disease. The word vascular refers to blood vessels. When the blood vessels in the brain are blocked or damaged and no longer carry oxygen and other nutrients to certain areas of brain tissue, damage results. Because multiple sites in the brain can be damaged, the profile of degeneration—the particular skills that are impaired— differs from person to person. DSM-5 lists as criteria for vascular neurocognitive disorder cognitive disturbances such as declines in speed of information processing and executive functioning (such as complex decision making). In contrast, those with Alzheimer’s disease have memory problems as their initial cognitive disturbance. The prevalence of vascular neurocognitive disorder is approximately 1.5% in people 70 to 75 years of age and increases to 15% for those over the age of 80. The risk for men is slightly higher than among women, in contrast with the higher risk among women for Alzheimer’s type dementia, and this has been reported in many developed and developing countries. Other Medical Conditions that cause Neurocognitive Disorder Frontotemporal neurocognitive disorder is a broad term for various brain disorders that damage the frontal or temporal regions of the brain, affecting personality, language, and behavior. Pick’s disease is a rare neurological condition—occurring in about 5% of those people with neurocognitive impairment—that produces symptoms similar to that of Alzheimer’s disease. Neurocognitive disorder due to traumatic brain injury includes symptoms that persist for at least a week following the trauma, including executive dysfunction (such as difficulty planning complex activities) and impairments in learning and memory. Those who are at greatest risk for TBI are teens and young adults, especially those accompanied by excessive alcohol use or lower socio-economic class. Neurocognitive disorder due to Lewy body disease. Lewy bodies are tiny protein deposits that gradually damage brain cells. The symptoms of this disorder develop slowly and include reduced alertness and attention, vivid visual hallucinations, and motor impairments similar to those in Parkinson's disease. Neurocognitive disorder due to Parkinson’s disease. Parkinson's disease is characterized by motor problems such as stooped posture, slow body movements (bradykinesia), tremors, and jerky walking. Affected individuals also experience changes in their voice, speaking in a soft monotone. These motor changes result from damage to dopamine pathways, leading to tremors and muscle weakness. Lewy bodies are also present in the brains of affected individuals. While the course of the disease varies widely, about 75% of those who survive more than ten years with Parkinson's disease develop neurocognitive disorder, with rates estimated to be 4 to 6 times higher than in the general population. Neurocognitive disorder due to HIV infection. This impairment seems to be independent of the other infections that accompany HIV; in other words, the HIV infection itself appears to be responsible for the neurological impairment. The early symptoms of neurocognitive disorder resulting from HIV are cognitive slowness, impaired attention, and forgetfulness. Affected individuals also tend to be clumsy, to show repetitive movements such as tremors and leg weakness, and to become apathetic and socially withdrawn. 13 Handout 1 *Property of STI Page 4 of 5  AS2402 Like neurocognitive disorder from Parkinson’s disease and several other causes, neurocognitive disorder resulting from HIV is sometimes referred to as subcortical dementia because it primarily affects the inner areas of the brain, below the outer layer called the cortex. Neurocognitive disorder due to Huntington’s disease also follows the subcortical pattern. The search for the gene responsible for Huntington’s disease reads like a detective story. For some time, researchers have known that the disease is inherited as an autosomal dominant disorder, meaning that approximately 50% of the offspring of an adult with Huntington’s disease will develop the disease. Neurocognitive disorder due to prion disease is a rare progressive neurodegenerative disorder caused by prions—proteins that can reproduce themselves and cause damage to brain cells, leading to neurocognitive decline. One type of prion disease, Creutzfeldt-Jakob disease, is believed to affect only one in every million individuals. A concerning development in the study of Creutzfeldt-Jakob disease is the discovery of 10 cases of a new variant possibly linked to bovine spongiform encephalopathy, commonly known as "mad cow disease." This finding prompted a ban on beef exports from the United Kingdom for several years due to concerns that the disease could be transmitted from infected cattle to humans. However, definitive information regarding the link between mad cow disease and the new form of Creutzfeldt-Jakob disease is still lacking. Substance/Medication-Induced Neurocognitive Disorder Prolonged drug use, especially combined with poor diet, can damage the brain and, in some circumstances, can lead to neurocognitive disorder. This impairment, unfortunately, lasts beyond the period involved in intoxication or withdrawal from these substances. The DSM-5 criteria for substance/ medication-induced neurocognitive disorder include memory impairment and at least one of the following cognitive disturbances: aphasia (language disturbance), apraxia (inability to carry out motor activities despite intact motor function), agnosia (failure to recognize or identify objects despite intact sensory function), or a disturbance in executive functioning (such as planning, organizing, sequencing, and abstracting). References American Psychiatric Association. (2022). Diagnostic and Statistical Manual of Mental Disorders (5th Ed., text rev.) Barlow, D., Durand, V., Hofmann, S. (2023). Psychopathology: An Integrative Approach to Mental Disorders (9th Ed). Cengage. 13 Handout 1 *Property of STI Page 5 of 5