Mild neurocognitive disorder is characterized by moderate cognitive decline from a prior level of performance in one or more cognitive domains:
- Complex Attention: tasks take longer to complete than previously, work needs to be double-checked for errors, difficulty thinking and processing information when multi-tasking (i.e., talking on a cell phone and driving)
- Executive Functions: requires more effort to finish multistep projects, trouble resuming a task that was interrupted, has difficulty organizing, planning or making decisions, trouble following shifting conversations
- Learning and Memory: difficulty recalling recent events, relies on reminders and list-making
- Language: word-finding difficulty, grammatical errors in expressive language
- Perceptual-Motor: may rely more heavily on maps or notes for directions, may expend more effort on motor tasks such as typing, knitting, or assembly
- Social Cognition: minor changes in behavior or personality, less ability to read social cues such as facial expressions, decreased empathy, or decreased inhibition
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).