01Purpose and principlesWhat the assessment is for and the core concepts behind it.
Prepare the assessment before interpreting performance. Introduce yourself in the person's visual field, reduce background noise, ensure hearing aids and glasses are available and working, use a qualified interpreter and control pain, breathlessness, thirst and fatigue. Record language, literacy, education and motor or speech impairment. Communication barriers can falsely lower cognition and appear as withdrawal or refusal.
For any new or fluctuating change, assess delirium first. The 4AT combines alertness, orientation, attention and acute change or fluctuation and is rapid enough for acute settings. A score of four or more supports possible delirium and a score of one to three supports possible cognitive impairment, but clinical concern overrides a negative screen. Treat causes, provide multicomponent care and repeat when the course changes.
Obtain collateral chronology: onset, progression, fluctuation, memory, language, visuospatial and executive difficulty, hallucinations, sleep and functional consequences. Dementia usually produces persistent decline interfering with daily life, while delirium is acute and fluctuating. Depression, medicines, alcohol, sleep apnoea, sensory loss, thyroid disease and other neurological conditions can mimic or worsen cognition.
Select a validated cognitive instrument for the setting rather than combining fragments of several tests. GPCOG includes patient assessment and informant information and is designed for primary care. More detailed tools can characterise domains but should follow licensing and local practice. No score establishes a subtype; history, examination, functional decline, medication review, blood tests and imaging complete diagnostic assessment.
Mood review asks about enjoyment, sadness, anxiety, energy, guilt, concentration, sleep, appetite, psychomotor change and thoughts of death in the person's own words. Older adults may emphasise pain, fatigue, memory or loss of function. PHQ-9 and GDS support severity and monitoring but are affected by physical illness; assess suicide, psychosis, neglect and safeguarding directly at every concerning presentation.
Hearing loss contributes to isolation, cognitive load, falls and apparent confusion. Ask about conversation, telephone, television, tinnitus, vertigo, asymmetry, discharge and sudden onset. Examine canals and tympanic membranes; wax may coexist with sensorineural loss. Audiology provides pure-tone and functional assessment. Sudden sensorineural loss, unilateral neurological signs or persistent unilateral symptoms needs urgent specialist review.
Vision screening includes distance and near acuity using current correction, field and diplopia symptoms, eye pain and ability to manage ordinary tasks. Cataract, refractive error, glaucoma, macular disease and diabetic retinopathy are common but require different pathways. Acute loss or painful red eye is not a routine optometry problem. Ensure diabetic and glaucoma surveillance and accessible lighting and contrast.
Integrate domains rather than treating them as competing labels. Hearing loss can worsen a cognitive score; delirium can produce depressive withdrawal; dementia can impair hearing-aid use; visual loss can cause formed hallucinations. Address reversible barriers, then reassess. When capacity is questioned, assess the specific decision after support rather than equating a screen result or dementia diagnosis with incapacity.
Communicate results without premature labels. State the tool, conditions, score, limitations, collateral and next step. Arrange memory assessment for persistent cognitive decline, mental-health care for significant depression, audiology or ENT and optometry or ophthalmology. Provide safety advice for driving, medicines, finances, falls and home risk proportionate to the identified impairment.
After an abnormal cognitive screen, assess reversible contributors without promising that all impairment will reverse. Review anticholinergic and sedative medicines, sleep, alcohol, mood and vascular risk; undertake physical and neurological examination and locally recommended blood tests. Structural imaging helps exclude treatable lesions and supports subtype diagnosis when appropriate. Refer to a memory service unless the cause is already established and specialist assessment would not benefit the person.
Management starts during assessment. Provide written and spoken information in accessible form, correct sensory devices, reduce high-risk medicine complexity and address driving, cooking, finances and vulnerability without removing autonomy unnecessarily. Ask carers about change and strain. If depression and cognitive disorder coexist, treat both and monitor function and risk; improvement in mood does not retrospectively exclude neurodegeneration.
Key points
- Screening identifies who needs further assessment; it does not establish dementia, depression, incapacity or a specific sensory diagnosis by itself.
- First priority for new cognitive change is delirium assessment with 4AT and a search for underlying causes; dementia and delirium commonly coexist.
- Establish cognition and function before illness from collateral, then optimise hearing, vision, language, pain and arousal before longer-term testing.
- Use a validated cognition tool appropriate to setting, such as GPCOG in primary care, and interpret education, language, cultural and motor effects.
- Assess daily executive consequences: medicines, money, cooking, navigation, appointments and vulnerability may change before basic memory complaints become obvious.
- Screen mood with direct history plus a validated measure such as PHQ-9 or GDS; bereavement, apathy and somatic illness can alter presentation.
- Always ask directly about hopelessness, self-harm and suicide when depression is possible; a questionnaire score cannot replace risk formulation.
- Hearing assessment starts with history, otoscopy and functional communication; arrange audiology and urgent ENT when the pattern requires it.
- Check visual acuity with usual correction, near vision and field symptoms and ask whether vision limits medicines, falls, reading and faces.
- An abnormal screen leads to collateral, medication and medical review, functional assessment and the appropriate dementia, mental-health, audiology or eye pathway.
02Indications, selection and cautionsWhen it is useful, when urgency changes and important limitations.
Acute onset, fluctuation, inattention and altered arousal point to brain failure from illness or medication and require immediate cause assessment.
Months or years of decline in memory, language, visuospatial or executive ability with daily functional effect suggests a neurocognitive disorder.
Loss of interest, hopelessness, withdrawal, anxiety, sleep or appetite change and somatic preoccupation may dominate over reported sadness.
Difficulty following groups, telephone or television, repeated requests and apparent inattention improve when communication is adapted.
Falls, reading difficulty, missed medicines, trouble recognising faces or navigating dim spaces can precede a direct visual complaint.
Intent, plan, means, psychosis, severe agitation or inability to sustain basic needs requires urgent protection and specialist assessment.
03Method and interpretationA systematic approach to the test and its findings.
Read from the initial assessment onwards. Tests may run in parallel in urgent care; first-line, preferred, confirmatory, definitive and gold-standard labels appear only when the chapter explicitly states them.
- 01
4AT delirium screenFirst step - Why
- Identify possible delirium rapidly in acute care.
- Interpretation and limitations
- Interpret alertness, AMT4, attention and acute change together; repeat with fluctuation and investigate causes even when the score is low but concern persists.
- 02
Collateral cognitive history - Why
- Establish onset, baseline and functional consequence.
- Interpretation and limitations
- Ask a reliable informant about memory, executive, language, visuospatial, behaviour and IADL change, with the person's consent where possible.
- 03
Validated cognitive assessment - Why
- Quantify persistent impairment after communication is optimised.
- Interpretation and limitations
- Use a complete locally approved tool such as GPCOG and interpret language, education, hearing, vision, motor ability and mood.
- 04
Mood and suicide assessment - Why
- Detect depression and immediate psychological risk.
- Interpretation and limitations
- Combine direct clinical interview with PHQ-9 or GDS; separately formulate intent, plan, means, protective factors, psychosis, neglect and safeguarding.
- 05
Hearing assessment - Why
- Separate conductive, sensorineural and urgent patterns.
- Interpretation and limitations
- Take onset and functional history, perform otoscopy and arrange audiology; sudden, asymmetric or neurological loss changes referral urgency.
- 06
Visual assessment - Why
- Measure acuity and identify urgent eye disease.
- Interpretation and limitations
- Test distance and near vision with correction, ask fields, diplopia, pain and flashes or floaters and refer according to acuity, onset and examination.
- 07
Targeted medical work-up - Why
- Find reversible contributors and diagnostic mimics.
- Interpretation and limitations
- Review medicines and alcohol and select FBC, renal, liver, calcium, glucose, thyroid, B12 or folate, infection tests and neuroimaging from history and examination.
04Clinical next stepsHow the result changes management or prompts escalation.
01First cognitive sequenceDelirium first, then persistent cognitionFirst stepA cognitive concern is new or its chronology is uncertain.+
- 1Optimise communication, obtain baseline collateral and use 4AT while assessing acute physiology and medicines.
- 2Treat underlying causes and repeat cognition after fluctuation, arousal, pain and sensory barriers improve.
- 3If decline persists, complete validated cognitive, functional, medical and imaging assessment through the dementia pathway.
02Mood sequenceScreen, assess risk and diagnose in contextWithdrawal, low mood, anxiety, somatic change or cognitive complaint raises depression concern.+
- 1Explore symptoms, losses, function, alcohol and medicines and use PHQ-9 or GDS to support—not replace—the interview.
- 2Ask directly about self-harm, suicide, psychosis and neglect and arrange same-day safety care when risk is acute.
- 3Offer severity-appropriate psychological, social and medicine treatment and monitor symptoms, function and adverse effects.
03Sensory sequenceCorrect communication before judging cognitionHearing or visual loss affects safety, participation or test validity.+
- 1Restore glasses, aids, batteries, lighting and quiet communication and check for wax, pain or sudden onset.
- 2Measure functional hearing or acuity and arrange audiology, optometry, ENT or ophthalmology at the urgency indicated.
- 3Adapt medicines, falls prevention, written information and home support and repeat cognitive or mood screening under fair conditions.
05Risks, monitoring and follow-upComplications, safety checks and further assessment.
- Repeat 4AT and clinical assessment when arousal or behaviour changes and track the underlying cause rather than following score alone.
- For persistent cognitive concern, monitor IADLs, medicines, driving, finances, nutrition, wandering and carer strain as well as test scores.
- Follow mood symptoms, suicide risk, sleep, appetite, social participation and function after psychological, social or medicine intervention.
- Confirm hearing aids, wax treatment, glasses and eye referrals were completed and assess whether communication and falls improved.
- Reassess decision-specific capacity whenever the decision or cognition changes; a diagnosis or screening result never determines capacity globally.
06Special situationsVariants, exceptions and circumstances that change the usual approach.
Delirium can be hypoactive
Quiet withdrawal and sleepiness are often missed but carry the same need for urgent cause assessment.
A screen is not capacity
Capacity concerns one decision and requires supported understanding and weighing, not a cognitive cut-off.
Senses alter cognition
Poor hearing increases cognitive load and can lower scores without representing new neurodegeneration.
Depression can look cognitive
Low motivation and slowed processing may mimic dementia, but both conditions may also coexist.
Function supplies meaning
Errors in medicines, money and navigation often matter more diagnostically than a small score change.
07Common pitfallsFrequent interpretation and management errors.
- 01
Diagnosing dementia during untreated delirium from one low bedside score.
- 02
Testing without hearing aids, glasses, interpreter or adjustment for literacy and motor impairment.
- 03
Assuming dementia means incapacity for every decision.
- 04
Using a depression score without asking directly about suicide and psychosis.
- 05
Treating sudden hearing or visual loss as routine ageing.
- 06
Calling withdrawal depression without checking pain, delirium, medicines, bereavement and sensory loss.