ICD-10 Code: G31.84
Mild neurocognitive disorder is part of a cluster of diagnoses called the neurocognitive disorders. Neurocognitive disorders are a group of psychiatric conditions that include:
The key distinction between major and mild neurocognitive disorder is that individuals with major neurocognitive disorder experience a substantial decline in function that includes a loss of independence as a result of profound cognitive impairment, whereas individuals with mild neurocognitive disorder experience only a modest cognitive decline and, as a result, function relatively independently.
Neurocognitive disorders involve impairments in cognitive abilities such as memory, problem solving and perception. Cognitive deficits are acquired rather than developmental. Although cognitive impairments are present in many mental disorders (e.g., schizophrenia, bipolar disorders), only disorders whose core features are cognitive are included in neurocognitive disorders. Neurocognitive disorders represent impairment in cognition that has not been present since birth or the early developmental period. Thus, individuals with this disorder experience a decline from a previously attained level of functioning.
Neurocognitive disorders most commonly occur in older adults, but they can affect younger people as well. Reduced cognitive capacity may include problems with complex attention, executive functioning, learning and memory, expressive and receptive language, perceptual-motor abilities, changes in behavior, and trouble performing everyday tasks. These symptoms may be caused by a neurodegenerative condition, such as Alzheimer's disease, dementia, frontotemporal lobar degeneration, or Lewy body disease. They can also be caused by illnesses such as Parkinson's or Huntington's disease, or traumatic brain injury or stroke. Neurocognitive disorders can also develop as a result of substance abuse or HIV infection.
Mild neurocognitive disorder is an acquired disorder that affects 2-10% of adults by age 65 and 5-25% of adults by age 85.
Mild neurocognitive disorder is characterized by moderate cognitive decline from a prior level of performance in one or more cognitive domains:
The acquired cognitive decline is noted by concern on part of the individual, a knowledgeable informant, or the clinician. The cognitive performance is also evaluated through an objective neuropsychological assessment, with performance compared with norms appropriate to the patient's age, educational attainment, and cultural background, to determine if the performance within the cognitive domains falls below the expected level. Mild neurocognitive performance deficits are typically defined as 1-2 standard deviations below average (between the 3rd and 16th percentiles).
The development and course of mild neurocognitive disorder varies greatly due to the number of causal subtypes. The symptoms associated with traumatic brain injury or stroke subtypes will improve after initial inflammation or swelling reduce.
Neurodegenerative diseases such as Alzheimer's disease or frontotemporal lobar degeneration are associated with a slow onset and steady progression of symptoms. Environmental and genetic factors also vary by subtype and age of onset within the subtypes. Overall, the strongest risk factor for major and mild neurocognitive disorders is age due to the increased risk of neurodegenerative and cerebrovascular disease.
Individuals with neurocognitive disorders can present with a wide variety of mood disturbances including depression, apathy, anxiety, and elation. Sleep disturbance is also common and may include symptoms of insomnia, hypersomnia, or circadian rhythm disorder. Delirium commonly co-occurs with neurocognitive disorders in the older population. For younger individuals, neurodevelopmental disorders such as attention-deficit/hyperactivity disorder are a frequent comorbidity.
Mild neurocognitive disorder is individualized based on the etiological or pathological entity underlying the cognitive decline.
The following are links to treatment recommendations based on the causal diagnosis: