What can imaging tell us about cognitive impairment and dementia?

Table 1 Causes of dementia and dementia syndromes

Types of dementia
Primary dementias
Alzheimer’s disease
Late-onset Alzheimer’s disease - most common form 60%-70% of all dementias
Early-onset Alzheimer’s disease - under 65 yr of age, chromosome 14 implicated, Down’s syndrome
Familial AD - inheritable form present in at least 2 generations within families
Dementia with Lewy bodies
Frontotemporal dementia
Mixed dementia - more than one form of pathology for, e.g., Lewy bodies with Alzheimer’s disease
Less common forms
Parkinson’s disease
Progressive supranuclear palsy
Huntington’s disease
Secondary dementias
Vascular/multi infarct dementia
Vascular with Alzheimer’s disease
Creutzfeldt-Jakob disease
Intracranial mass lesions
Normal pressure hydrocephalus
Subdural haematomas
Trauma
Infections - primarily human immunodeficiency virus
Alcohol
Other documented causes
Vitamin deficiencies - vitamins E, B and folic acid are implicated
Medications
Other causes like depression