Dementia is the general name for a decline in cognitive abilities that impacts a person's ability to perform everyday activities. This typically involves problems with memory, thinking, and behavior. Aside from memory impairment and a disruption in thought patterns, the most common symptoms include emotional problems, difficulties with language, and decreased motivation. The symptoms may be described as occurring in a continuum over several stages. Dementia ultimately has a significant effect on the individual, caregivers, and on social relationships in general. A diagnosis of dementia requires the observation of a change from a person's usual mental functioning and a greater cognitive decline than what is caused by normal aging.
Delirium is a specific state of acute confusion attributable to the direct physiological consequence of a medical condition, effects of a psychoactive substance, or multiple causes, which usually develops over the course of hours to days. As a syndrome, delirium presents with disturbances in attention, awareness, and higher-order cognition. People with delirium may experience other neuropsychiatric disturbances, including changes in psychomotor activity, disrupted sleep-wake cycle, emotional disturbances, disturbances of consciousness, or, altered state of consciousness, as well as perceptual disturbances, although these features are not required for diagnosis.
Vascular dementia (VaD) is dementia caused by problems in the blood supply to the brain, resulting from a cerebrovascular disease. Restricted blood supply (ischemia) leads to cell and tissue death in the affected region, known as an infarct. The three types of vascular dementia are subcortical vascular dementia, multi-infarct dementia, and stroke related dementia. Subcortical vascular dementia is brought about by damage to the small blood vessels in the brain. Multi-infarct dementia is brought about by a series of mini-strokes where many regions have been affected. The third type is stroke related where more serious damage may result. Such damage leads to varying levels of cognitive decline. When caused by mini-strokes, the decline in cognition is gradual. When due to a stroke, the cognitive decline can be traced back to the event.
Wernicke-Korsakoff syndrome (WKS) is the combined presence of Wernicke encephalopathy (WE) and Korsakoff syndrome. Due to the close relationship between these two disorders, people with either are usually diagnosed with WKS as a single syndrome. It mainly causes vision changes, ataxia and impaired memory.
Encephalopathy means any disorder or disease of the brain, especially chronic degenerative conditions. In modern usage, encephalopathy does not refer to a single disease, but rather to a syndrome of overall brain dysfunction; this syndrome has many possible organic and inorganic causes.
Cognitive disorders (CDs), also known as neurocognitive disorders (NCDs), are a category of mental health disorders that primarily affect cognitive abilities including learning, memory, perception, and problem-solving. Neurocognitive disorders include delirium, mild neurocognitive disorders, and major neurocognitive disorder. They are defined by deficits in cognitive ability that are acquired, typically represent decline, and may have an underlying brain pathology. The DSM-5 defines six key domains of cognitive function: executive function, learning and memory, perceptual-motor function, language, complex attention, and social cognition.
Toxic encephalopathy is a neurologic disorder caused by exposure to neurotoxic organic solvents such as toluene, following exposure to heavy metals such as manganese, as a side effect of melarsoprol treatment for African trypanosomiasis, adverse effects to prescription drugs, or exposure to extreme concentrations of any natural toxin such as cyanotoxins found in shellfish or freshwater cyanobacteria crusts. Toxic encephalopathy can occur following acute or chronic exposure to neurotoxicants, which includes all natural toxins. Exposure to toxic substances can lead to a variety of symptoms, characterized by an altered mental status, memory loss, and visual problems. Toxic encephalopathy can be caused by various chemicals, some of which are commonly used in everyday life, or cyanotoxins which are bio-accumulated from harmful algal blooms (HABs) which have settled on the benthic layer of a waterbody. Toxic encephalopathy can permanently damage the brain and currently treatment is mainly just for the symptoms.
Memory disorders are the result of damage to neuroanatomical structures that hinders the storage, retention and recollection of memories. Memory disorders can be progressive, including Alzheimer's disease, or they can be immediate including disorders resulting from head injury.
Organic brain syndrome, also known as organic brain disease, organic brain damage, organic brain disorder, organic mental syndrome, or organic mental disorder, refers to any syndrome or disorder of mental function whose cause is alleged to be known as organic (physiologic) rather than purely of the mind. These names are older and nearly obsolete general terms from psychiatry, referring to many physical disorders that cause impaired mental function. They are meant to exclude psychiatric disorders. Originally, the term was created to distinguish physical causes of mental impairment from psychiatric disorders, but during the era when this distinction was drawn, not enough was known about brain science for this cause-based classification to be more than educated guesswork labeled with misplaced certainty, which is why it has been deemphasized in current medicine. While mental or behavioural abnormalities related to the dysfunction can be permanent, treating the disease early may prevent permanent damage in addition to fully restoring mental functions. An organic cause to brain dysfunction is suspected when there is no indication of a clearly defined psychiatric or "inorganic" cause, such as a mood disorder.
Clouding of consciousness, also called brain fog or mental fog, occurs when a person is slightly less wakeful or aware than normal. They are less aware of time and their surroundings, and find it difficult to pay attention. People describe this subjective sensation as their mind being "foggy".
Toxic leukoencephalopathy is a rare condition that is characterized by progressive damage (-pathy) to white matter (-leuko-) in the brain (-encephalo-), particularly myelin, due to causes such as exposure to substance use, environmental toxins, or chemotherapeutic drugs. The prevalence of this disease is infrequent and often goes unreported, especially in cases resulting from substance use. Magnetic resonance imaging (MRI) is a popular method to study and diagnose the disease. However, even with technological advances, the exact mechanism and underlying pathophysiology of toxic leukoencephalopathy remains unknown and is thought to vary between sources of toxicity. The clinical severity of toxic leukoencephalopathy also varies among patients, exposure time, concentration, and purity of the toxic agent. Some reversibility of the condition has been seen in many cases when the toxic agent is removed.
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. A cognitive impairment can be in different domains or aspects of a person's cognitive function including memory, attention span, planning, reasoning, decision-making, language, 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 ,specific and restricted impairments in cognitive abilities, neuropsychological impairments, or it may describe drug-induced impairment in cognition and memory. Cognitive impairments may be short-term, progressive or permanent.
Alcohol-related dementia (ARD) is a form of dementia caused by long-term, excessive consumption of alcohol, resulting in neurological damage and impaired cognitive function.
Alcohol withdrawal syndrome (AWS) is a set of symptoms that can occur following a reduction in alcohol use after a period of excessive use. Symptoms typically include anxiety, shakiness, sweating, vomiting, fast heart rate, and a mild fever. More severe symptoms may include seizures, and delirium tremens (DTs); which can be fatal in untreated patients. Symptoms start at around 6 hours after last drink. Peak incidence of seizures occurs at 24-36 hours and peak incidence of delirium tremens is at 48-72 hours.
Sundowning, or sundown syndrome, is a neurological phenomenon associated with increased confusion and restlessness in people with delirium or some form of dementia. It is most commonly associated with Alzheimer's disease but also found in those with other forms of dementia. The term "sundowning" was coined by nurse Lois K. Evans in 1987 due to the timing of the person's increased confusion beginning in the late afternoon and early evening. For people with sundown syndrome, a multitude of behavioral problems begin to occur and are associated with long term adverse outcomes. Sundowning seems to occur more frequently during the middle stages of Alzheimer's disease and mixed dementia and seems to subside with the progression of the person's dementia. People are generally able to understand that this behavioral pattern is abnormal. Research shows that 20–45% of people with Alzheimer's will experience some variation of sundowning confusion. However, despite lack of an official diagnosis of sundown syndrome in the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5), there is currently a wide range of reported prevalence.
A neurological disorder is any disorder of the nervous system. Structural, biochemical or electrical abnormalities in the brain, spinal cord or other nerves can result in a range of symptoms. Examples of symptoms include paralysis, muscle weakness, poor coordination, loss of sensation, seizures, confusion, pain, tauopathies, and altered levels of consciousness. There are many recognized neurological disorders, some relatively common, but many rare. They may be assessed by neurological examination, and studied and treated within the specialties of neurology and clinical neuropsychology.
Nutritional neuroscience is the scientific discipline that studies the effects various components of the diet such as minerals, vitamins, protein, carbohydrates, fats, dietary supplements, synthetic hormones, and food additives have on neurochemistry, neurobiology, behavior, and cognition.
Post-intensive care syndrome (PICS) describes a collection of health disorders that are common among patients who survive critical illness and intensive care. Generally, PICS is considered distinct from the impairments experienced by those who survive critical illness and intensive care following traumatic brain injury and stroke. The range of symptoms that PICS describes falls under three broad categories: physical impairment, cognitive impairment, and psychiatric impairment. A person with PICS may have symptoms from one or multiple of these categories.
