Dementia with Lewy bodies can only be definitively diagnosed after death with an autopsy of the brain (or in rare familial<unk> s, via a genetic test), so diagnosis of the living is referred to as probable or possible. Diagnosing DLB can be challenging because of the wide range of symptoms with differing levels of severity in each individual. DLB is often misdiagnosed or, in its early stages, confused with Alzheimer's disease. The majority of individuals with Lewy body dementias receive an inaccurate initial diagnosis—such as Alzheimer's,<unk> , other dementias or a psychiatric diagnosis—resulting in reduced support and increased fear and uncertainty, sometimes for many years. Comparing the rates of detection of DLB in autopsy studies to those diagnosed while in clinical care indicates that as many as one in three diagnoses of DLB may be missed. Another complicating factor is that DLB commonly occurs along with Alzheimer's; autopsy reveals that half of people with DLB have some level of changes attributed to AD in their brains, which contributes to the wide-ranging variety of symptoms and diagnostic difficulty. Living with an uncertain diagnosis and prognosis is a concern expressed by both individuals with DLB and their caregivers and difficulty gaining a diagnosis and differing interactions with healthcare professionals are common experiences; once diagnosed, there are still difficulties finding a doctor knowledgeable in treating DLB. Despite the difficulty in diagnosis, a prompt diagnosis is important because of the serious risks of sensitivity to antipsychotics and the need to inform both the person with DLB and the person's caregivers about those medications' side effects. The management of DLB is difficult in comparison to many other neurodegenerative diseases, so an accurate diagnosis is important. Criteria The 2017 Fourth Consensus Report established diagnostic criteria for probable and possible DLB, recognizing advances in detection since the earlier Third Consensus (2005) version. The 2017 criteria are based on essential, core, and supportive clinical features, and diagnostic biomarkers. The essential feature is dementia; for a DLB diagnosis, it must be significant enough to interfere with social or occupational functioning. Positron emission tomography, for example, using PiB is helpful in the diagnosis of DLB. The four core clinical features (described in the Signs and symptoms section) are fluctuating cognition, visual hallucinations, REM sleep behavior disorder, and signs of<unk> . Supportive clinical features are marked sensitivity to antipsychotics; marked autonomic dysfunction; nonvisual hallucinations; hypersomnia (excessive sleepiness); hyposmia (reduced ability to smell); false beliefs and delusions organized around a common theme; postural instability, loss of consciousness and frequent falls; and apathy, anxiety, or depression. Direct laboratory-measurable biomarkers for DLB diagnosis are not known, but several indirect methods can lend further evidence for diagnosis. The indicative diagnostic biomarkers are: reduced dopamine transporter uptake in the basal ganglia shown on PET or SPECT imaging; low uptake of 123iodine-metaiodobenzylguanidine shown on myocardial scintigraphy; and loss of atonia during REM sleep evidenced on polysomnography. Supportive diagnostic biomarkers (from PET, SPECT, CT, or MRI brain imaging studies or EEG monitoring) are: lack of damage to medial temporal lobe (damage is more likely in AD); reduced occipital activity; and prominent slow-wave activity on EEG. Probable DLB can be diagnosed when dementia and at least two core features are present, or when one core feature and at least one indicative biomarker are present. Possible DLB can be diagnosed when dementia and only one core feature are present or, if no core features are present, then at least one indicative biomarker is present. DLB is distinguished from Parkinson's disease dementia by the time frame in which dementia symptoms appear relative to parkinsonian symptoms. DLB is diagnosed when cognitive symptoms begin before or at the same time as parkinsonian motor signs. Parkinson's disease dementia would be the diagnosis when Parkinson's disease is well established before the dementia occurs (the onset of dementia is more than a year after the onset of parkinsonian symptoms). Known as the one-year rule, the distinction is acknowledged to be arbitrary; it recognizes overlap between the conditions along with key differences, while allowing for variations in treatment and prognosis and providing a framework for research. DLB is listed in the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) as major or mild neurocognitive disorder with Lewy bodies. The differences between the DSM and DLB Consortium diagnostic criteria are: 1) the DSM does not include low dopamine transporter uptake as a supportive feature, and 2) unclear diagnostic weight is assigned to biomarkers in the DSM. Lewy body dementias are classified by the World Health Organization in its ICD-10, the International Statistical Classification of Diseases and Related Health Problems, in chapter VI, as diseases of the nervous system, code 31.8. Clinical history and testing Diagnostic tests can be used to establish some features of the condition and distinguish them from symptoms of other conditions. Diagnosis may include taking the person's medical history, a physical exam, assessment of neurological function, testing to rule out conditions that may<unk>  similar symptoms, brain imaging, neuropsychological testing to assess cognitive function, sleep studies, or myocardial scintigraphy. Laboratory testing can rule out other conditions that can<unk>  similar symptoms, such as abnormal thyroid function, syphilis, HIV, or vitamin deficiencies that may<unk>  symptoms similar to dementia. Typical dementia screening tests used are the Mini-Mental State Examination (MMSE) and the Montreal Cognitive Assessment (MoCA). The pattern of cognitive impairment in DLB is distinct from other dementias, such as AD; the MMSE mainly tests for the memory and language impairments more commonly seen in those other dementias and may be less suited for assessing cognition in the Lewy body dementias, where testing of visuospatial and executive function is indicated. The MoCA may be better suited to assessing cognitive function in DLB, and the Clinician Assessment of Fluctuation scale and the Mayo Fluctuation Composite Score may help understand cognitive decline relative to fluctuations in DLB. For tests of attention, digit span, serial sevens, and spatial span can be used for simple screening, and the Revised Digit Symbol Subtest of the Wechsler Adult Intelligence Scale may show defects in attention that are characteristic of DLB. The Frontal Assessment Battery, Stroop test and Wisconsin Card Sorting Test are used for evaluation of executive function, and there are many other screening instruments available. Adult connected to wires from sensors for polysomnography If DLB is suspected when<unk>  and dementia are the only presenting features, PET or SPECT imaging may show reduced dopamine transporter activity. A DLB diagnosis may be warranted if other conditions with reduced dopamine transporter uptake can be ruled out. RBD is diagnosed either by sleep study recording or, when sleep studies cannot be performed, by medical history and validated questionnaires. In individuals with dementia and a history of RBD, a probable DLB diagnosis can be justified (even with no other core feature or biomarker) based on a sleep study showing REM sleep without atonia because it is so highly predictive. Conditions similar to RBD, like severe sleep apnea and periodic limb movement disorder, must be ruled out. Prompt evaluation and treatment of RBD is indicated when a prior history of violence or injury is present as it may increase the likelihood of future violent dream enactment behaviors. Individuals with RBD may not be able to provide a history of dream enactment behavior, so bed partners are also consulted. The REM Sleep Behavior Disorder Single-Question Screen offers diagnostic sensitivity and specificity in the absence of polysomnography with one question: "Have you ever been told, or suspected yourself, that you seem to 'act out your dreams' while asleep (for example, punching, flailing your arms in the air, making running movements, etc.)?" Because some individuals with DLB do not have RBD, normal findings from a sleep study cannot rule out DLB. Since 2001, 123iodine-metaiodobenzylguanidine myocardial scintigraphy has been used diagnostically in East Asia (principally Japan), but not in the US. MIBG is taken up by sympathetic nerve endings, such as those that innervate the heart, and is labeled for scintigraphy with radioactive 123iodine. Autonomic dysfunction resulting from damage to nerves in the heart in patients with DLB is associated with lower cardiac uptake of There is no genetic test to determine if an individual will develop DLB and, according to the Lewy Body Dementia Association, genetic testing is not routinely recommended because there are only rare instances of hereditary DLB. Differential Many neurodegenerative conditions share cognitive and motor symptoms with dementia with Lewy bodies. The differential diagnosis includes Alzheimer's disease; such synucleinopathies as Parkinson's disease dementia, Parkinson's disease, and multiple system atrophy; vascular dementia; and progressive supranuclear palsy, corticobasal degeneration, and corticobasal syndrome. The symptoms of DLB are easily confused with delirium, or more rarely as psychosis; prodromal subtypes of delirium-onset DLB and psychiatric-onset DLB have been proposed. Mismanagement of delirium is a particular concern because of the risks to people with DLB associated with antipsychotics. A careful examination for features of DLB is warranted in individuals with unexplained delirium. PET or SPECT imaging showing reduced dopamine transporter uptake can help distinguish DLB from delirium. Lewy pathology
medical cause of Parkinsonism
medical cause of Dementia
symptom of Pantothenate kinase-associated neurodegeneration
complications of Myotonic dystrophy
symptom of Amyotrophic lateral sclerosis
symptom of Spinocerebellar ataxia type 1
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medical cause of Dystonia