Cognitive functioning can have a significant impact on an older person's health and wellbeing. Cognitive impairment can result from a number of conditions, including delirium, dementia and depression:

A range of symptoms and behaviours are associated with different types of cognitive impairment. Some symptoms are similar across delirium, dementia and depression, and an accurate diagnosis is important.

Refer to Differentiating the 3D's - Dementia, Delirium, and Depression (on next page) for a comparison of characteristic features.

How can I recognise and prevent cognitive decline?

The following actions are recommended to prevent cognitive decline and maintain cognition and emotional health:

An accurate diagnosis is important. Assess cognitive status and consider the need for specialist geriatric or psychiatric assessment.

Provide optimal pain management.

Implement measures to prevent cognitive functional decline:

Differentiating the 3D's - Dementia, Delirium and Depression

Feature	Dementia	Delirium	Depression
Onset	Slow and insidious - deterioration over months or years	Sudden - over hours or days	Often abrupt - may coincide with life changes
Course	Symptoms are progressive over a long period of time; not reversible	Short and fluctuating - often worse at night and on waking Usually reversible with treatment of the underlying condition	Typically worse in the morning. Usually reversible with treatment
Duration	Months to years	Hours to less than one month - not often longer	At least two weeks - can last for months or years
Psychomotor activity	Wandering/exit seeking or Agitated or Withdrawn (may be related to coexisting depression)	Hyperactive delirium: agitation, restlessness, hallucinations Hypoactive delirium: sleepy, slow-moving	Usually withdrawn, apathy
Alertness	Generally normal	Fluctuates - may be hypervigilant through to very lethargic	Normal
Attention	Generally normal	Impaired - difficulty following conversation, fluctuates	Normal
Mood	Depression may be present in early dementia	Fluctuating emotions - e.g. anger, tearful outbursts, fear	Depressed mood Lack of interest or pleasure in usual activities Change in appetite (increase or decrease)
Thinking	Difficulty with word-finding and abstraction	Disorganised, distorted, fragmented	Intact - themes of helplessness and hopelessness present
Perception	Misperceptions usually absent (can be present in Lewy body dementia)	Distorted - illusions, hallucinations, delusions; difficulty distinguishing between reality and misperceptions	Usually intact (hallucinations and delusions only present in severe cases)

References:

Clinical Epidemiology and Health Service Evaluation Unit and Delirium Clinical Guidelines Expert Working Group. 2006, Clinical practice guidelines for the management of delirium in older people. Victorian Government Department of Human Services, on behalf of the Australian Health Ministers' Advisory Council (AHMAC), Melbourne.

Registered Nurses Association of Ontario, 2003, Screening for delirium, dementia and depression in older adults. RNAO, Toronto, Canada.

Toronto Best Practice Implementation Steering Committee, 2007, Recognizing Delirium, Depression and Dementia (3 D's): Comparison Chart. Ontario Ministry of Health and Long-Term Care

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