Which cognitive domain is MOST severely and EARLIEST affected in delirium but relatively preserved in early dementia?

Explanation

## Cognitive Profile: Delirium vs Dementia **Key Point:** Attention and concentration are the HALLMARK cognitive deficits in delirium and are impaired from onset. In contrast, early dementia often preserves attention while memory fails first. ### Cognitive Domain Comparison | Cognitive Domain | Delirium | Early Dementia | |------------------|----------|----------------| | **Attention** | ⚠️ SEVERELY impaired (earliest) | Preserved | | **Memory** | Impaired (secondary) | ⚠️ PRIMARY deficit | | **Orientation** | Fluctuates | Gradually lost | | **Language** | Incoherent, disorganized | Relatively preserved | | **Visuospatial** | Impaired | Variable (depends on type) | | **Executive function** | Severely impaired | Impaired | **High-Yield:** A patient who cannot maintain attention, cannot follow commands, and is easily distractible = DELIRIUM until proven otherwise. A patient who is alert and attentive but cannot remember recent events = DEMENTIA. **Clinical Pearl:** The **Confusion Assessment Method (CAM)** uses inattention as one of its core diagnostic criteria for delirium. If attention is preserved, delirium is unlikely. **Mnemonic:** **DELIRIUM = Attention FIRST** | **DEMENTIA = Memory FIRST** ### Bedside Testing - **Delirium:** Patient cannot perform digit span, cannot do serial 7s, cannot maintain conversation thread - **Dementia:** Patient can focus on task but cannot recall it 5 minutes later **Warning:** Do not confuse inattention (delirium) with apathy (dementia). A delirious patient is distractible; a demented patient may be apathetic but can still focus when prompted. [cite:DSM-5 Neurocognitive Disorders Section]