Dementia
Dementia is a syndrome, often associated with neurodegenerative diseases such as Alzheimer's, and characterized by a general decline in cognitive abilities that affects a person's ability to perform everyday activities. This typically involves problems with memory, thinking, behavior, and motor control. Aside from memory impairment and a disruption in thought patterns, the most common symptoms of dementia include emotional problems, difficulties with language, and decreased motivation. The symptoms may be described as occurring in a continuum over several stages. Dementia is an incurable, progressive neurocognitive disorder, with varying degrees of severity and many forms or subtypes. The condition has a significant effect on the individual, their caregivers, and their social relationships in general. Dementia is not the same as age-related decline in cognition and memory, with no change in intelligence.
The most common form of dementia is Alzheimer's. Dementia can be caused by brain injuries and stroke. It has also been described as a spectrum of disorders with subtypes of dementia based on which known disorder caused its development, such as Parkinson's disease for Parkinson's disease dementia, Huntington's disease for Huntington's disease dementia, vascular disease for vascular dementia, HIV infection causing HIV dementia, frontotemporal lobar degeneration for frontotemporal dementia, Lewy body disease for dementia with Lewy bodies, and prion diseases. Subtypes of neurodegenerative dementias may also be based on the underlying pathology of misfolded proteins, such as synucleinopathies and tauopathies. The coexistence of more than one type of dementia is known as mixed dementia.
Diagnosis is usually based on history of the illness and cognitive testing with imaging. Imaging can help to determine the dementia subtype, and to exclude other causes. Blood tests are usually taken to rule out other possible reversible causes such as hypothyroidism.
Although the greatest risk factor for developing dementia is aging, dementia is not a normal part of the aging process; many people aged 90 and above show no signs of dementia. Risk factors, diagnosis and caregiving practices are influenced by cultural and socio-environmental factors. Several risk factors for dementia, such as smoking and obesity, are modifiable by lifestyle changes. Screening the general older population for the disorder is not seen to affect the outcome.
Dementia is currently the seventh leading cause of death worldwide and has 10 million new cases reported every year. In the UK it is the leading cause of death. It is one of the main causes of disabilities in those aged over 65. There is no known cure for dementia. Acetylcholinesterase inhibitors such as donepezil are often used in some dementia subtypes and may be beneficial in mild to moderate stages, but the overall benefit may be minor. There are many measures that can improve the quality of life of a person with dementia and their caregivers. Cognitive behavioral therapy may give some benefit for treating the associated symptoms of depression.
Signs and symptoms
The signs and symptoms of dementia may vary depending on the underlying subtype, but may be grouped into three areas: cognitive, neuropsychiatric, and physical.The cognitive symptoms of dementia relate to the area of the brain affected. Typically this includes memory plus one other cognitive region. The most commonly affected areas of brain function include memory, language, attention, problem solving, and visuospatial function affecting perception and orientation. Signs of dementia include wandering, and getting lost in a familiar neighborhood, using unusual words to refer to familiar objects, forgetting the name of a close family member or friend, forgetting old memories, and being unable to complete tasks independently. People developing dementia can often fall behind on bill payments; specifically mortgage and credit cards, and a crashing credit score can be an early indicator of the disease. The symptoms progress at a continuous rate over several stages, and they vary across the dementia subtypes. Most types of dementia are slowly progressive with some deterioration of the brain well established before signs of the disorder become apparent.
The behavioral symptoms can include agitation, restlessness, inappropriate behavior, sexual disinhibition, and verbal or physical aggression. Behavioral symptoms in dementia are thought to be often due to unmet needs or untreated physical symptoms. Many of these symptoms may be improved by non-pharmacological measures such as appropriate exercise and empowering carers.
Psychological symptoms can include depression, hallucinations, delusions, apathy, and anxiety. Also common are personality changes with the progression of dementia, such as increases in neuroticism, and a decline in conscientiousness.
Signs of dementia may include changes in gait, falls, repetitive movements, parkinsonism, or seizures. In later stages, incontinence both urinary and fecal may be prominent features that can prove challenging for both the person affected and the caregiver. Dementia can also affect the person's eating and drinking, often causing swallowing issues and weight loss that worsen as the illness progresses to later stages. Pain can also affect people with dementia, potentially as many as 79.6% of people with dementia in nursing homes may experience pain. However pain can be difficult to assess as people with dementia may be unable to communicate this verbally and instead it may manifest as behavioral symptoms.
People with dementia often have one or more other health conditions as comorbidities; some such as high blood pressure or diabetes, are associated with a risk for dementia, and others such as depression, and anxiety are associated with dementia itself. There is also an increased prevalence of sarcopenia and frailty.
Stages
The course of dementia is often described in three major stages that show a pattern of progressive cognitive and functional impairment. The Global Deterioration Scale uses seven stages in the development of dementia, with mild dementia only appearing as stage 4.Other scales used are the Brief Cognitive Rating Scale, Clinical Dementia Rating, and the Functional Assessment Staging Tool. The BCRS is a quick assessment that coincides with the GDS. It uses five axes in assessment – concentration, memory, orientation, functioning and self-care. FAST places more emphasis on functioning in daily living. CDR evaluates six main areas including memory, judgement, problem-solving, and personal care. The mini–mental state examination is an often used test to screen cognitive ability. RUDAS, the Rowland Universal Dementia Assessment Scale, is a short dementia screening test for use in diverse multi-ethnic communities designed to overcome language and cultural differences.
Pre-dementia
Pre-dementia includes a pre-clinical stage, before the onset of symptoms, and prodromal the early clinical symptoms.Pre-clinical
Sensory dysfunction, most notably the loss of the sense of smell is claimed for the pre-clinical stage, which may precede the first clinical signs of dementia by up to ten years. Anosmia is associated with depression and a loss of appetite leading to poor nutrition. It is suggested that anosmia may come about because the olfactory epithelium is exposed to the environment, and the lack of blood–brain barrier protection allows toxic elements to enter and cause damage to the chemosensory networks.Prodromal
Pre-dementia states considered as prodromal are mild cognitive impairment and mild behavioral impairment. Signs and symptoms at the prodromal stage may be subtle, and the early signs often become apparent only in hindsight. In mild cognitive impairment, that progresses to a dementia subtype, changes in the person's brain have been happening for a long time, but the symptoms are just beginning to appear. These problems, however, are not severe enough to affect daily function. If and when they do, the diagnosis becomes one of a dementia subtype, such as minor neurocognitve disorder of Lewy body disease, for example. The person may have some memory problems and trouble finding words, but they can solve everyday problems and competently handle their life affairs. During this stage, it is ideal to ensure that advance care planning has occurred to protect the person's wishes. Advance directives exist that are specific to people living with dementia. These can be particularly helpful in addressing the decisions related to feeding which come with the progression of the illness. Mild cognitive impairment has been relisted in both DSM-5 and ICD-11 as "mild neurocognitive disorders", i.e. milder forms of the major neurocognitive disorder subtypes. But MCI does not always progress to dementia, and sometimes symptoms resolve.Kynurenine is a metabolite of tryptophan that regulates microbiome signaling, immune cell response, and neuronal excitation. A disruption in the kynurenine pathway may be associated with the neuropsychiatric symptoms and cognitive prognosis in mild dementia.
Early
In the early stage of dementia, symptoms become noticeable to other people. In addition, the symptoms begin to interfere with daily activities, and will register a score on a mini–mental state examination. MMSE scores are set at 24 to 30 for a normal cognitive rating and lower scores reflect severity of symptoms. The symptoms are dependent on the type of dementia. More complicated chores and tasks around the house or at work become more difficult. The person can usually still take care of themselves but may forget things like taking pills or doing laundry and may need prompting or reminders.The symptoms of early dementia usually include memory difficulty, but can also include some word-finding problems, and problems with executive functions of planning and organization. Managing finances may prove difficult. Other signs might be getting lost in new places, repeating things, and personality changes.
In some types of dementia, such as dementia with Lewy bodies and frontotemporal dementia, personality changes and difficulty with organization and planning may be the first signs.