Dementia and chronic cognitive impairment



Dementia is a progressive and irreversible condition causing decline and impairment of cognitive function to a degree that impacts on a person’s daily functioning.

Mild cognitive impairment (MCI) is a less severe chronic memory impairment that does not affect day to day functioning. 10-15% of people with MCI will go on to develop dementia.

The most common types of dementia are:

  • Alzheimer’s disease (50-75%), can co-exist with other types of dementia as a ‘mixed dementia’
  • Vascular dementia (up to 20%)
  • Lewy body dementia (10-15%)
  • Frontotemporal dementia (2%)

Signs and symptoms

  • Deterioration in cognitive function, memory loss, language problems, disorientation
  • Behavioural & psychological symptoms of dementia – psychosis (delusions and/or hallucinations), agitation, disinhibition, poor sleep cycle, anxiety, wandering, restlessness
  • May show progressive decline (e.g. Alzheimer’s) or stepwise progression (Vascular)
  • Visual hallucinations, fluctuating cognition, Parkinsonism (Lewy body)
  • Personality change, disinhibition, behavioural disturbance (Frontotemporal)


  • Physical examination, bloods (FBC, U&Es, LFTs, CRP, B12, folate, TFTs, random glucose, calcium/albumin), other investigations to exclude reversible causes and rule out delirium
  • MoCA / ACE III / 4AT (exclude delirium)
  • Collateral history from next of kin (crucial!), consider IQCODE
  • CT head to look for small vessel disease/areas of atrophy/exclude bleed or lesion
  • Capacity assessment if required (consider AWI

Differential diagnosis

  • Depression
  • Delirium
  • Hypothyroidism
  • Normal pressure hydrocephalus
  • Vitamin deficiency (thiamine/B12)
  • Adverse drug effects (polypharmacy, opioids, benzodiazepines, anticholinergics)
  • Sensory impairment (sight or hearing loss)


If you suspect a patient has chronic cognitive impairment and have excluded acute causes refer the patient to the appropriate team (usually an outpatient memory clinic) for further specialist assessment.

Medications may be started by a specialist:

  • Cognitive enhancers (donepezil, memantine, rivastigmine)
  • For agitation (e.g lorazepam), antipsychotics (e.g risperidone), antidepressants

It’s also important to consider optimising the inpatient environment – e.g. side rooms, flexible visiting, familiar staff, ensure orientated to time and place (clock, calendar in room), clear signage for toilets etc.

Last reviewed: 21/02/2024

Next review date: 21/08/2024

Author(s): Core Trainee in Psychiatry, NHS Borders & Medical Education Fellow, NHS Lothian.

Author email(s):

Reviewer name(s): Medical Education Fellow, NHS Lothian.