Neurocognitive disorders (NCDs) represent a decline from a previous level of cognitive functioning. This article covers evaluation and management of major NCDs.
CLASSIFICATION (DSM5)
Mild Neurocognitive Disorder
- Modest cognitive decline from previous level
- Does not interfere with independence in everyday activities
Major Neurocognitive Disorder
- Significant cognitive decline
- Interferes with independence in everyday activities
COGNITIVE DOMAINS
1. Complex attention
2. Executive function
3. Learning and memory
4. Language
5. Perceptual-motor function
6. Social cognition
ALZHEIMER DISEASE
- Most common cause (60-80% of dementia cases)
- Insidious onset, gradual progression
- Early: Memory impairment (especially recent memory)
- Later: Language, visuospatial, executive dysfunction
Pathology
- Amyloid plaques (extracellular)
- Neurofibrillary tangles (intracellular tau)
- Hippocampal atrophy
Biomarkers
- CSF: Low Aβ42, elevated tau/phospho-tau
- Amyloid PET imaging
- FDG-PET: Temporoparietal hypometabolism
Treatment
- Cholinesterase inhibitors (donepezil, rivastigmine, galantamine)
- Memantine (moderate-severe)
- Disease-modifying therapies emerging
VASCULAR DEMENTIA
- Second most common cause
- Stepwise decline often with focal neurological signs
- History of stroke or vascular risk factors
- MRI: White matter hyperintensities, lacunar infarcts
Treatment
- Vascular risk factor modification
- Cholinesterase inhibitors may help
FRONTOTEMPORAL DEMENTIA
- Younger onset (typically 45-65)
- Behavioral variant: Personality changes, disinhibition, apathy
- Language variants: Progressive aphasia
MRI: Frontal and temporal atrophy
Treatment
- Symptomatic (SSRIs for behavioral symptoms)
- No disease-modifying treatments
LEWY BODY DEMENTIA
- Visual hallucinations (early and prominent)
- Fluctuating cognition
- Parkinsonism
- REM sleep behavior disorder
Treatment
- Cholinesterase inhibitors (rivastigmine preferred)
- AVOID antipsychotics (severe sensitivity)
EVALUATION
History
- Timeline of symptoms
- Functional impairment
- Collateral information essential
Cognitive testing
- MMSE, MoCA
- Neuropsychological testing
Laboratory
- CBC, CMP, TSH, B12, folate
- Consider: HIV, syphilis, heavy metals
Imaging
- MRI brain (structural)
- Consider PET if diagnosis unclear
MANAGEMENT PRINCIPLES
Nonpharmacological
- Structured routine
- Caregiver education and support
- Safety measures (driving, wandering)
- Advance care planning
Behavioral symptoms
- First: Address medical causes, environmental factors
- SSRIs for depression/anxiety
- Antipsychotics only if severe (black box warning)
Caregiver support
- Respite care
- Support groups
- Anticipatory guidance