The following document was written by Dr Alok Kumar Rana, MBBS; PG Diploma in Hospital Management, MRCPsych (UK) Specialty Registrar – Old Age Psychiatry, Herefordshire PCT NHS Trust, UK - Jan 2009.
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Dementia is a progressive and largely irreversible clinical syndrome that is characterised by a widespread impairment of mental function and can express as some or all of the following: memory loss, language impairment, disorientation, changes in personality, difficulties with activities of daily living, self-neglect, psychiatric symptoms (for example, apathy, depression or psychosis) and out-of-character behaviour (for example, aggression, sleep disturbance or disinhibited sexual behaviour).


(i) Cortical and Subcortical dementia

A) Cortical: Alzeimer’s Disease (AD), Frontotemporal Dementia and Creutzfeldt-Jacob disease.

B) Subcortical: Parkinson’s disease, Huntington’s disease, Normal Pressure Hydrocephalus, Multiple sclerosis.

C) Mixed: Vascular dementia, Dementia with Lewy bodies (DLB), Corticobasal degeneration and Neyrosyphilis.

  Memory Impairment Language Mathematical Skills Personality Mood Co-ordination Cognitive & Motor Speed Abnormal movements
Cortical Dementia Severe, early Dysphasia, early Impaired early Indifferent Normal Normal Normal Rare
Subcortical Dementia Moderate Normal Preserved Apathetic, inert Flat, depressed Impaired Slowed Common: choreiform or tremor

(ii) Presenile and Senile dementia

A) Presenile Dementia or early-onset dementia: dementia occurring in those under 65

B) Senile Dementia or Late-onset dementia: dementia occurring in those above 65.

Alzeimer’s Disease (AD)

AD is one cause of dementia and the core clinical symptom of AD is cognitive impairment. However, as noted above, AD is clinically heterogeneous and includes diverse non-cognitive symptoms and inevitable functional impairment. Cognitive decline is manifested as amnesia, aphasia, agnosia, and apraxia (the 4As).

Vascular Dementia:

Frontotemporal Dementia:

Lewy body dementia:

Dr Alok Kumar Rana, MBBS;
PG Diploma in Hospital Management,
MRCPsych (UK)
Specialty Registrar – Old Age Psychiatry,
Herefordshire PCT NHS Trust,


  1. Oxford Textbook of Psychiatry, Publisher: Oxford University Press, Michael Gelder et al
  2. Shorter Oxford Textbook of Psychiatry, Fifth Edition, Michael Gelder et al.
  3. Concise Textbook of Psychiatry, Second Edition, Kaplan and Sadock
  4. The ICD-10 Classification of Mental and Behavioural Disorders- WHO


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