Cognitive impairment is an inclusive term to describe any characteristic that acts as a barrier to the cognition process or different areas of cognition. Cognition, also known as cognitive function, refers to the mental processes of how a person gains knowledge, uses existing knowledge, and understands things that are happening around them using their thoughts and senses. Cognitive impairment can be in different domains or aspects of a person's cognitive function including memory, attention span, planning, reasoning,

decision-making In psychology, decision-making (also spelled decision making and decisionmaking) is regarded as the Cognition, cognitive process resulting in the selection of a belief or a course of action among several possible alternative options. It could be ...

, language (comprehension, writing, speech), executive functioning, and visuospatial functioning. The term cognitive impairment covers many different diseases and conditions and may also be symptom or manifestation of a different underlying condition. Examples include impairments in overall

intelligence Intelligence has been defined in many ways: the capacity for abstraction, logic, understanding, self-awareness, learning, emotional knowledge, reasoning, planning, creativity, critical thinking, and problem-solving. It can be described as t ...

(as with

intellectual disabilities Intellectual disability (ID), also known as general learning disability (in the United Kingdom), and formerly mental retardation (in the United States), Rosa's Law, Pub. L. 111-256124 Stat. 2643(2010).Archive is a generalized neurodevelopmental ...

), specific and restricted impairments in cognitive abilities (such as in

learning disorders Learning disability, learning disorder, or learning difficulty (British English) is a condition in the brain that causes difficulties comprehending or processing information and can be caused by several different factors. Given the "difficulty ...

dyslexia Dyslexia (), previously known as word blindness, is a learning disability that affects either reading or writing. Different people are affected to different degrees. Problems may include difficulties in spelling words, reading quickly, wri ...

), neuropsychological impairments (such as in

attention Attention or focus, is the concentration of awareness on some phenomenon to the exclusion of other stimuli. It is the selective concentration on discrete information, either subjectively or objectively. William James (1890) wrote that "Atte ...

working memory Working memory is a cognitive system with a limited capacity that can Memory, hold information temporarily. It is important for reasoning and the guidance of decision-making and behavior. Working memory is often used synonymously with short-term m ...

executive function In cognitive science and neuropsychology, executive functions (collectively referred to as executive function and cognitive control) are a set of cognitive processes that support goal-directed behavior, by regulating thoughts and actions thro ...

), or it may describe drug-induced impairment in cognition and memory (such as that seen with

alcohol Alcohol may refer to: Common uses * Alcohol (chemistry), a class of compounds * Ethanol, one of several alcohols, commonly known as alcohol in everyday life ** Alcohol (drug), intoxicant found in alcoholic beverages ** Alcoholic beverage, an alco ...

glucocorticoids Glucocorticoids (or, less commonly, glucocorticosteroids) are a class of corticosteroids, which are a class of steroid hormones. Glucocorticoids are corticosteroids that bind to the glucocorticoid receptor that is present in almost every vertebra ...

, and the

benzodiazepine Benzodiazepines (BZD, BDZ, BZs), colloquially known as "benzos", are a class of central nervous system (CNS) depressant, depressant drugs whose core chemical structure is the fusion of a benzene ring and a diazepine ring. They are prescribed t ...

s.). Cognitive impairments may be short-term, progressive (gets worse over time), or permanent. There are different approaches to assessing or diagnosing a cognitive impairment including neuropsychological testing using various different tests that consider the different domains of cognition. Examples of shorter assessment clinical tools include the Mini Mental State Examination (MMSE) and the

Montreal Cognitive Assessment The Montreal Cognitive Assessment (MoCA) is a widely used screening assessment for detecting cognitive impairment. It was created in 1996 by Ziad Nasreddine in Montreal, Quebec. It was validated in the setting of mild cognitive impairment (MC ...

(MoCA). There are many different syndromes and pathologies that cause cognitive impairment including

dementia Dementia is a syndrome associated with many neurodegenerative diseases, characterized by a general decline in cognitive abilities that affects a person's ability to perform activities of daily living, everyday activities. This typically invo ...

, mild neurocognitive disorder, and

Alzheimer's disease Alzheimer's disease (AD) is a neurodegenerative disease and the cause of 60–70% of cases of dementia. The most common early symptom is difficulty in remembering recent events. As the disease advances, symptoms can include problems wit ...

Cause

Cognitive impairments may be caused by many different factors including

environmental factors An environmental factor, ecological factor or eco factor is any factor, abiotic or biotic, that influences living organisms. Abiotic factors include ambient temperature, amount of sunlight, air, soil, water and pH of the water soil in which an ...

or injuries to the brain (e.g.,

traumatic brain injury A traumatic brain injury (TBI), also known as an intracranial injury, is an injury to the brain caused by an external force. TBI can be classified based on severity ranging from mild traumatic brain injury (mTBI/concussion) to severe traumati ...

), neurological illnesses, or

mental disorder A mental disorder, also referred to as a mental illness, a mental health condition, or a psychiatric disability, is a behavioral or mental pattern that causes significant distress or impairment of personal functioning. A mental disorder is ...

s. While more common in elderly people, not all people who are elderly have cognitive impairments. Some known causes of cognitive impairments that are more common in younger people are: chromosomal abnormalities or genetic syndromes, exposure to

teratogens Teratology is the study of abnormalities of physiological development in organisms during their life span. It is a sub-discipline in medical genetics which focuses on the classification of congenital abnormalities in Dysmorphic feature, dysmor ...

while '' in utero'' (e.g., prenatal exposure to drugs),

undernourishment Malnutrition occurs when an organism gets too few or too many nutrients, resulting in health problems. Specifically, it is a deficiency, excess, or imbalance of energy, protein and other nutrients which adversely affects the body's tissues a ...

poisoning Poisoning is the harmful effect which occurs when Toxicity, toxic substances are introduced into the body. The term "poisoning" is a derivative of poison, a term describing any chemical substance that may harm or kill a living organism upon ...

autism Autism, also known as autism spectrum disorder (ASD), is a neurodevelopmental disorder characterized by differences or difficulties in social communication and interaction, a preference for predictability and routine, sensory processing d ...

, and

child abuse Child abuse (also called child endangerment or child maltreatment) is physical abuse, physical, child sexual abuse, sexual, emotional and/or psychological abuse, psychological maltreatment or Child neglect, neglect of a child, especially by a p ...

Stroke Stroke is a medical condition in which poor cerebral circulation, blood flow to a part of the brain causes cell death. There are two main types of stroke: brain ischemia, ischemic, due to lack of blood flow, and intracranial hemorrhage, hemor ...

, dementia, depression,

schizophrenia Schizophrenia () is a mental disorder characterized variously by hallucinations (typically, Auditory hallucination#Schizophrenia, hearing voices), delusions, thought disorder, disorganized thinking and behavior, and Reduced affect display, f ...

substance abuse Substance misuse, also known as drug misuse or, in older vernacular, substance abuse, is the use of a drug in amounts or by methods that are harmful to the individual or others. It is a form of substance-related disorder, differing definition ...

, brain tumours,

malnutrition Malnutrition occurs when an organism gets too few or too many nutrients, resulting in health problems. Specifically, it is a deficiency, excess, or imbalance of energy, protein and other nutrients which adversely affects the body's tissues a ...

, brain injuries, hormonal disorders, and other chronic disorders may result in cognitive impairment with

aging Ageing (or aging in American English) is the process of becoming Old age, older until death. The term refers mainly to humans, many other animals, and fungi; whereas for example, bacteria, perennial plants and some simple animals are potentiall ...

. Cognitive impairment may also be caused by a pathology in the brain. Examples include Alzheimer's disease, Parkinson's disease,

HIV/AIDS The HIV, human immunodeficiency virus (HIV) is a retrovirus that attacks the immune system. Without treatment, it can lead to a spectrum of conditions including acquired immunodeficiency syndrome (AIDS). It is a Preventive healthcare, pr ...

-induced dementia,

dementia with Lewy bodies Dementia with Lewy bodies (DLB) is a type of dementia characterized by changes in sleep, behavior change (individual), behavior, cognition, movement, and dysautonomia, regulation of automatic bodily functions. Unlike some other dementias, mem ...

, and Huntington’s disease. Short-term cognitive impairment can be caused by pharmaceutical

drugs A drug is any chemical substance other than a nutrient or an essential dietary ingredient, which, when administered to a living organism, produces a biological effect. Consumption of drugs can be via inhalation, injection, smoking, ingestio ...

such as

sedatives A sedative or tranquilliser is a substance that induces sedation by reducing irritability or excitement. They are central nervous system (CNS) depressants and interact with brain activity, causing its deceleration. Various kinds of sedatives ...

Screening

Screening for cognitive impairment in those over the age of 65 without symptoms is of unclear benefit versus harm as of 2020. In a large population-based cohort study included 579,710 66-year-old adults who were followed for a total of 3,870,293 person-years (average 6.68 ± 1.33 years per person), subjective cognitive decline was significantly associated with an increased risk of subsequent

. In addition to a series of cognitive tests, general practitioner physicians often also rely on clinical judgement for diagnosing cognitive impairment. Clinical judgement is ideal when paired with additional tests that permit the medical professional to confirm the diagnosis or confirm the absence of a diagnosis. Clinical judgement in these cases may also help inform the choice in additional tests.

Treatment

Deciding on an appropriate treatment for people with cognitive decline takes clinical judgement based on the diagnosis (the specific cognitive problem), the person's symptoms, other patient factors including expectations and the person's own ideas, and previous approaches to helping the person.

Prognosis

When a person's level of cognition declines, it is often harder to live in an independent setting. Some people may have trouble taking care of themselves and the burden on the people caring for them can increase. Some people require supportive healthcare and, in some cases, institutionalization.

Research

The role of

light therapy Light therapy, also called phototherapy or bright light therapy is the exposure to direct sunlight or artificial light at controlled wavelengths in order to treat a variety of medical disorders, including seasonal affective disorder (SAD), circ ...

for treating people with cognitive impairment or dementia is not fully understood. Although one would expect cognitive decline to have major effects on

job performance Job performance assesses whether a person performs a job well. Job performance, studied academically as part of industrial and organizational psychology, also forms a part of human resources management. Performance is an important criterion for o ...

, it seems that there is little to no correlation of health with job performance. With the exception of cognitive-dependent jobs such as air-traffic controller, professional athlete, or other elite jobs, age does not seem to impact one's job performance. This obviously conflicts with cognitive tests given, so the matter has been researched further. One possible reason for this conclusion is the rare need for a person to perform at their maximum. There is a difference between typical functioning, that is – the normal level of functioning for daily life, and maximal functioning, that is – what cognitive tests observe as our maximum level of functioning. As the maximum cognitive ability that we are able to achieve decreases, it may not actually affect our daily lives, which only require the normal level. Some studies have indicated that childhood hunger might have a protective effect on cognitive decline. One possible explanation is that the onset of age-related changes in the body can be delayed by

calorie restriction Calorie restriction (CR, also known as caloric restriction or energy restriction) is a dietary regimen that reduces the energy intake from foods and beverages without incurring malnutrition. The possible effect of calorie restriction on body w ...

. Another possible explanation is the selective survival effect, as the study participants who had a childhood with hunger tend to be the healthiest of their era.

References

External links

{{Authority control Cognition Cognitive disorders Developmental disabilities Pediatrics