14.2 Dementia, Delirium & Depression in Older Adults
Key Takeaways
- Differentiating the '3 Ds'—Dementia (chronic, progressive), Delirium (acute, fluctuating, reversible), and Depression (subacute, affective)—is a critical competency for Singapore registered nurses.
- Delirium screening using the 4AT or Confusion Assessment Method (CAM) requires immediate identification of underlying medical triggers (hypoxia, infection/UTI, electrolyte imbalance, constipation, urinary retention, anticholinergic drugs).
- Dementia care in Singapore follows MOH Clinical Practice Guidelines, prioritizing person-centered care, non-pharmacological behavioral management, environmental adaptations, and caregiver stress reduction.
- Under the Mental Capacity Act (MCA Cap. 177A), nurses assess decision-specific mental capacity, support Lasting Power of Attorney (LPA) execution, and adhere to best-interest decision-making protocols.
- Major depressive disorder in older adults often manifests as pseudodementia or somatic complaints; evaluation via the Geriatric Depression Scale (GDS-15) guides pharmacological and psychosocial referrals.
Dementia, Delirium & Depression in Older Adults
Cognitive and affective disorders represent a major challenge in gerontological nursing across Singapore's healthcare spectrum. The "3 Ds"—Dementia, Delirium, and Depression—frequently present with overlapping behavioral symptoms in hospitalized and community-dwelling older adults. Differentiating these conditions is essential for timely, life-saving clinical interventions and proper care planning under Singapore's legal and professional frameworks.
Differential Diagnosis of the "3 Ds"
Accurate clinical differentiation relies on analyzing onset, clinical course, level of consciousness, attention, and physiological reversibility.
| Feature | Delirium | Dementia | Depression |
|---|---|---|---|
| Onset | Acute (hours to days) | Insidious / Chronic (months to years) | Subacute (weeks to months) |
| 24-Hour Course | Fluctuating, nocturnal worsening (sundowning) | Stable progressive decline | Diurnal variation (worse in morning) |
| Consciousness | Impaired, altered, or clouded | Intact until end-stage disease | Unimpaired |
| Attention | Severely inattentive, unable to focus | Unimpaired in early/moderate stages | Reduced focus due to psychomotor slowing |
| Memory | Immediate & recent recall impaired | Short-term memory lost early; long-term lost late | Selective memory impairment; "I don't know" responses |
| Reversibility | Highly Reversible upon addressing underlying cause | Irreversible (progressive degeneration) | Reversible with treatment |
| Primary Triggers | Physical illness, infection, drugs, metabolic derangement | Neurodegenerative pathology (Alzheimer's, Vascular) | Psychosocial distress, bereavement, neurotransmitter imbalance |
Delirium: Assessment & Urgent Nursing Interventions
Delirium is a medical emergency characterized by acute brain dysfunction. In Singapore acute hospitals, delirium occurs in up to 30% of elderly medical inpatients and up to 50% of surgical/orthopedic patients.
Subtypes of Delirium
- Hyperactive Delirium: Restlessness, agitation, hallucinations, hypervigilance, and climbing out of bed.
- Hypoactive Delirium: Lethargy, somnolence, reduced motor activity, withdrawal, and delayed responsiveness. Frequently unrecognized or misdiagnosed as depression or fatigue.
- Mixed Delirium: Fluctuates unpredictably between hyperactive and hypoactive states.
Rapid Screening Tools: 4AT and CAM
Nurses perform immediate screening using the 4AT (Rapid Clinical Instrument for Delirium and Cognitive Impairment):
- 1. Alertness: Normal (0), Mild sleepiness (0), Clearly abnormal (4).
- 2. AMT4 (Age, Date of Birth, Place, Current Year): 4 correct (0), 1 error (1), 2+ errors/untestable (2).
- 3. Attention (Months backwards): Achieves 7+ months (0), Starts but achieves <7 (1), Untested/cannot start (2).
- 4. Acute Change or Fluctuating Course: Evidence of change in mental status within 24 hours: No (0), Yes (4). A total 4AT score ≥4 strongly indicates delirium.
Alternatively, the Confusion Assessment Method (CAM) requires:
- Feature 1: Acute Onset and Fluctuating Course AND
- Feature 2: Inattention AND
- EITHER Feature 3: Disorganized Thinking OR Feature 4: Altered Level of Consciousness.
Emergency Management: The PINCH ME Protocol
Nurses systematically investigate underlying physiological triggers using the PINCH ME mnemonic:
- Pain: Unmanaged acute or chronic pain (evaluate using Abbey Pain Scale for non-verbal patients).
- Infection / Incontinence: Urinary tract infection (UTI), pneumonia, sepsis (check NCID infection control markers, urine dipstick, lung sounds).
- Nutrition / Hydration: Dehydration, electrolyte imbalance (hyponatremia, hypercalcemia), hypoglycemia.
- Constipation: Fecal impaction causing severe distress and delirium.
- Hypoxia: Respiratory compromise, heart failure, anemia (SpO₂ < 92%).
- Medication / Metabolic: Anticholinergics, sedatives, opioids, withdrawal, acute kidney injury.
- Environmental: Sensory overload, sleep deprivation, room changes, restraint use.
In alignment with SNB practice standards, physical restraints must be avoided; non-pharmacological reorientation, constant nursing care, and family engagement are prioritized.
Dementia & BPSD Management
Dementia encompasses major neurocognitive disorders causing irreversible cognitive and functional decline. Common types in Singapore include Alzheimer's Disease (60–70%), Vascular Dementia (second most common due to high stroke/hypertension prevalence), Lewy Body Dementia, and Frontotemporal Dementia.
Cognitive Screening
- Abbreviated Mental Test (AMT): 10-point scale. A score <7 indicates cognitive impairment requiring further diagnostic workup.
- Montreal Cognitive Assessment (MoCA): Highly sensitive 30-point tool for detecting mild cognitive impairment (MCI); cutoff <26.
Behavioral and Psychological Symptoms of Dementia (BPSD)
BPSD affects over 80% of dementia patients over the disease course, including agitation, pacing, sundowning (increased confusion in late afternoon/evening), anxiety, and delusions.
Nurse-Led Non-Pharmacological Interventions:
- Validation Therapy: Acknowledging feelings and emotional truth rather than confronting false realities.
- Reminiscence Therapy: Utilizing familiar Singaporean cultural stimuli (historical photos, dialects, traditional music).
- Environmental Adaptation: Dementia-friendly ward design featuring colored bathroom doors, clear signage, low-glare flooring, and daylight stimulation.
Pharmacological options—such as acetylcholinesterase inhibitors (Donepezil, Rivastigmine) and Memantine—are augmented by cautious short-term use of atypical antipsychotics only when severe agitation poses immediate harm, adhering to MOH black box safety guidelines.
Depression and Pseudodementia
Depression in older adults often presents atypical features, including somatic complaints (vague pain, fatigue, GI distress) and cognitive slowing known as pseudodementia.
Screening is conducted via the Geriatric Depression Scale (GDS-15), where a score ≥5 suggests depression.
Key contrasts between true dementia and pseudodementia:
- Patients with pseudodementia frequently highlight their memory flaws, express intense distress, and make minimal effort during testing ("I don't know").
- Patients with true dementia attempt to conceal deficits, minimize memory loss, and give near-miss or incorrect answers.
Singapore Legal Frameworks: Mental Capacity Act & VAA
Nurses must navigate legal requirements governing decision-making capacity for vulnerable elderly patients.
Mental Capacity Act (MCA Cap. 177A)
The MCA outlines key statutory principles:
- Presumption of Capacity: Every adult must be assumed to have capacity unless established otherwise.
- Decision-Specific Assessment: Capacity is evaluated for a specific decision at a specific time (e.g., consenting to surgery vs. choosing daily meals).
- Best Interests Principle: If a patient lacks capacity, decisions made on their behalf must be in their overall best interests, considering their prior expressed wishes and values.
Lasting Power of Attorney (LPA)
An LPA is a legal instrument enabling an individual (Donor) to appoint one or more donees to make decisions regarding Personal Welfare (medical care, living arrangements) and/or Property & Affairs should capacity be lost. Nurses verify LPA documentation before accepting medical decisions from family members.
Vulnerable Adults Act (VAA)
Under the VAA, registered nurses have a statutory responsibility to identify and report suspected abuse, neglect, or self-neglect of vulnerable elders (aged 18+ with physical/mental disabilities) to the Ministry of Social and Family Development (MSF) or hospital medical social work departments.
A nurse assesses an 85-year-old postoperative patient who suddenly becomes disoriented, visualizes insects on the bedsheets, and fluctuates between extreme restlessness and somnolence. The patient's vital signs show low-grade fever (37.9°C) and SpO₂ of 91%. Which diagnostic feature and tool best guide the nurse's immediate action?
Under Singapore's Mental Capacity Act (MCA Cap. 177A), which principle must guide a registered nurse when providing care to an older adult whose decision-making capacity is temporarily impaired?
How does cognitive impairment secondary to geriatric depression ('pseudodementia') differ clinically from primary neurodegenerative dementia during nursing assessment?