Conditions in which a decline in cognitive function is the primary clinical feature, and the deficit is acquired rather than developmental.
An acute, fluctuating disturbance in attention and awareness, developing over a short period, with an additional cognitive disturbance, that is a direct physiological consequence of an underlying medical condition, substance, or other cause.
A progressive neurocognitive disorder marked by early, prominent changes in personality, behavior, or language, with relative sparing of memory and visuospatial function in its earliest stages -- distinguishing it from the memory-first presentation typical of Alzheimer's disease.
A significant cognitive decline from a previous level of performance in one or more cognitive domains, with evidence from history, physical exam, or laboratory findings that the cognitive disturbance is the direct pathophysiological consequence of a medical condition not separately named elsewhere in this chapter (such as normal-pressure hydrocephalus, a brain tumor, or vitamin B12 deficiency).
A major or mild neurocognitive disorder whose cognitive decline is attributable to cerebrovascular disease, typically showing a stepwise course tied to vascular events or evidence of significant cerebrovascular disease on history, exam, or imaging.
A progressive decline in one or more cognitive domains (most characteristically memory and learning), caused by Alzheimer's disease pathology, at either a Major (interferes with independence) or Mild (independence preserved) level.
A neurocognitive disorder attributable to documented HIV infection, with cognitive decline not better explained by non-HIV conditions, including HIV-associated opportunistic infections or malignancies affecting the central nervous system.
A neurocognitive disorder attributable to Huntington's disease, a genetic, progressive neurodegenerative condition featuring characteristic choreiform movements alongside executive dysfunction and, often, mood and behavioral changes.
A neurocognitive disorder attributable to more than one underlying etiological process occurring together -- for example, Alzheimer's disease pathology combined with cerebrovascular disease -- rather than any single cause fully accounting for the clinical picture.
A neurocognitive disorder that develops in the context of established Parkinson's disease, with motor symptoms (tremor, rigidity, bradykinesia) typically preceding the onset of cognitive decline by a substantial period.
A rapidly progressive neurocognitive disorder attributable to a prion disease (such as Creutzfeldt-Jakob disease), typically featuring motor features including myoclonus, ataxia, or rigidity alongside cognitive decline.
A neurocognitive disorder that arises following an impact to the head or another mechanism of rapid brain movement within the skull, with cognitive symptoms presenting immediately after the injury or after recovery of consciousness and persisting past the acute post-injury period.
A neurocognitive disorder meeting full criteria for a major or mild neurocognitive disorder, for which, despite a thorough workup, no specific underlying etiology can be identified or confirmed.
A neurocognitive disorder characterized by fluctuating cognition, recurrent detailed visual hallucinations, spontaneous parkinsonism, and REM sleep behavior disorder, occurring together as a core diagnostic cluster.
Persistent neurocognitive impairment that remains after the period of acute intoxication or withdrawal has passed, attributable to the persisting effects of substance or medication use rather than to intoxication, withdrawal, or delirium alone.
A residual classification used when a presentation clearly meets criteria for a neurocognitive disorder (evidence of cognitive decline affecting independence or requiring accommodation), but there is not enough information to specify a subtype or etiology, or the clinician chooses not to specify.
Apply the evidentiary distinction between NCD Due to Unknown Etiology and NCD Due to Multiple Etiologies.
Recognize a potentially reversible medical cause of cognitive decline that is distinct from Alzheimer's disease.
Distinguish Unspecified Neurocognitive Disorder (workup not yet done) from NCD Due to Unknown Etiology (thorough workup completed, no cause found) and from delirium.
Use rate of progression to distinguish NCD Due to Prion Disease from the much slower course of NCD Due to Alzheimer's Disease.
Recognize that psychiatric symptoms often precede motor and cognitive decline in NCD Due to Huntington's Disease, distinguishing it from a primary depressive episode.
Recognize Frontotemporal Neurocognitive Disorder's behavior-first presentation, distinguished from Alzheimer's-type NCD's memory-first pattern.
Distinguish NCD Due to HIV Infection from Substance/Medication-Induced NCD when both HIV status and substance history are present.
Recognize Substance/Medication-Induced Major or Mild Neurocognitive Disorder's persistence beyond acute intoxication/withdrawal, distinguished from a co-occurring neurodegenerative cause.
Distinguish Neurocognitive Disorder Due to Traumatic Brain Injury's cognitive-decline core from PTSD's re-experiencing, avoidance, and hyperarousal symptoms following the same traumatic event.
Recognize Delirium's acute, fluctuating course and identifiable medical trigger, distinguished from Major Neurocognitive Disorder due to Alzheimer's Disease's gradual course and from a depressive presentation.
Distinguish Major Neurocognitive Disorder due to Alzheimer's Disease's gradual, progressive decline from Delirium's acute, fluctuating course and from Vascular Neurocognitive Disorder's stepwise pattern.
Recognize Vascular Neurocognitive Disorder's stepwise course tied to vascular events, distinguished from Alzheimer's-type gradual decline and from Delirium's acute fluctuating course.
Recognize Neurocognitive Disorder with Lewy Bodies' core symptom cluster, distinguished from Parkinson's disease NCD by the timing of motor versus cognitive symptom onset.
Recognize Neurocognitive Disorder Due to Multiple Etiologies when positive evidence supports more than one contributing cause, distinguished from attributing the full picture to vascular disease alone.