Question

Can you discuss three neurocognitive disorders?

Answer 1

Major and mild NCDs are better described as existing on a spectrum of cognitive and functional impairment. The core feature of NCDs is acquired cognitive decline in one or more cognitive domains. Diagnostic criteria include a concern about cognition on the part of the individual, and performance on an objective assessment that falls below the expected level or that has been observed to decline over time. Both a concern and objective evidence are required for diagnosic because they are complementary.Major and mild neurocognitive disorders (NCDs) are subtyped according to the known causative factor underlying the cognitive decline. The classification is made on the basis of a combination of time course, characteristic domains affected, and associated symptoms. For certain etiological subtypes, the diagnosis depends substantially on the presence of a potentially causative entity, such as Parkinson’s or Huntington’s disease, or a traumatic brain injury or stroke in the appropriate time period. For other etiological subtypes the diagnosis is based primarily on the cognitive, behavioral, and functional symptoms.

1. Frontotemporal Neurocognitive Disorder

Frontotemporal neurocognitive disorder (NCD) comprises a number of syndromic variants characterized by the progressive development of behavioral and personality change and/or language impairment. The behavioral variant and three language variants (semantic, agrammatic/nonfluent, and logopenic) are characterized by distinct patterns of brain atrophy and distinctive neuropathology. Those affected may lose interest in socialization, self- care, and personal responsibilities, or display socially inappropriate behaviors. Insight is usually impaired. Affected individuals may develop changes in social style, and in religious and political beliefs, with repetitive movements, hoarding, changes in eating behavior, and hyperorality. In later stages, loss of sphincter control may occur. Cognitive decline is less prominent in this type, and formal testing may show relatively few deficits in the early stages. Common neuro- cognitive symptoms are lack of planning and organization, distractibility, and poor judgment. Deficits in executive function in this type include poor performance on tests of mentalflexibility, abstract reasoning, and response inhibition. But learning and memory are found to be rarely affected in most cases, and perceptual-motor abilities are almost always preserved in the early stages. Individuals with language-variant major or mild frontotemporal NCD are found to have primary progressive aphasia with gradual onset. There are three subtypes : semantic variant, agrammatic/nonfluent variant, and logopenic variant. Each variant has distinctive features and corresponding neuropathology.

2.Neurocognitive Disorder Due to Traumatic Brain Injury

NCD due to traumatic brain injury (TBI) is resulted as an effect due to impact to the head, or due to mechanisms of rapid movement or displacement of the brain within the skull, like those happened during blast injuries. Traumatic brain injury is defined as brain trauma with specific characteristics that include at least one of the following: loss of consciousness, post- traumatic amnesia, disorientation and confusion, or, in more severe cases, neurological signs. Neurological signs include a positive neuro imaging obtained, a new onset of seizures or a marked worsening of a pre- existing seizure disorder, visual field cuts, anosmia, hemiparesis. In this type of NCD the symptoms are developed immediately after the brain injury occurred or after the individual recovers consciousness after the injury but when the symptoms persist past the acute post-injury period. The cognitive presentation is reported to be variable. Difficulties in the domains of complex attention, executive ability, learning, and memory are found to be common. Also slowing in speed of information processing and disturbances in social cognition are reported . In more severe TBI in which there is brain contusion, intracranial hemorrhage, or penetrating injury, there may be additional nurocognitive deficits, such as aphasia, neglect, and constructional dyspraxia.

3. Neurocognitive Disorder Due to Prion Disease

Neurocognitive disorder (NCD) due to prion disease includes NCDs due to a group of subacute spongiform encephalopathies caused by transmisible agents known as prions. Examples of such diseases include Creutzfeldt-Jakob disease, variant Creutzfeldt-Jakob disease, kuru, Gerstmann-Sträussler- Scheinker syndrome, and fatal insomnia. The most common type is sporadic Creutzfeldt-Jakob disease. Variant CJD is mostly rarer and is associated with transmission of bovine spongiform encephalopathy called “mad cow disease.” Individuals with CJD present with neurocognitive deficits has ataxia, and abnormal movements such as myoclonus, chorea, or dystonia. Sometimes a startle reflex is also reported. This type of NCD progress usually with in 6 months. Many individuals with this disorder can have atypical presentations. Sometimes the disease is confirmed only by biopsy or at autopsy. Individuals with variant CJD can have psychiatric symptoms. These include low mood, withdrawal, and anxiety. Prion disease is usually diagnosed with oat least one of the characteristic biomarker features: recognized lesions on magnetic resonance imaging with DWI (diffusion-weighted imaging) or FLAIR (fluid-attenuated inversion recovery), tau or 14-3-3 protein in cerebro- spinal fluid, characteristic triphasic waves on electroencephalogram, or, for rare familial forms, family history or genetic testing.