• Strokes and transient ischaemic attacks (TIAs) are acute neurological events, presumed to be vascular in origin, that are caused by cerebral ischaemia, cerebral infarction, or cerebral haemorrhage.
• Symptoms and signs develop rapidly, are usually focal (although they can be global), and include numbness, weakness or paralysis, slurred speech, and visual disturbances (characteristically a sudden visual loss in one half of the visual field, or visual loss in one quarter of the visual field, or visual loss in one eye). Headache is not a typical feature of ischaemic stroke or TIA.
• Stroke:
• With stroke, the symptoms and signs persist beyond 24 hours or cause death within 24 hours.
• Non-disabling stroke is a stroke with symptoms or signs that last for more than 24 hours but resolve later, leaving no permanent disability.
• Disabling stroke is a stroke which leaves the person unable to carry out all their usual activities:
• The severity of disability is operationally defined with reference to a disability scale.
• For example, disabling stroke is often defined as a score of 2 or more on the Modified Rankin Scale of Disability [van Swieten et al, 1988].
• People with a score of 2 have slight disability. They cannot carry out all previous activities but can look after their own affairs without assistance.
• Minor stroke is stroke with few mild symptoms on initial assessment:
• In research, 'minor stroke' is often defined as a score less than 4 on the National Institutes of Health Stroke Scale (NIHSS) [National Institutes of Health, 2003].
• The NIHSS has a theoretical maximum score of 42. In practice, however, the maximum score is 31, which would be obtained for someone with complete hemiparesis, hemianopia, hemi-neglect, and aphasia.
• TIA:
• With TIA, the symptoms and signs resolve within 24 hours.
• The symptoms and signs of a TIA usually resolve within minutes, or may last a few hours. Therefore, people who have continuing neurological signs when first assessed should be assumed to have had a stroke.
• Stroke with rapid recovery:
• In practice, the distinction between TIA and stroke with rapid recovery can only be made retrospectively and, apart from guiding investigation to exclude other conditions, is of little clinical importance.
• Subarachnoid haemorrhage:
• Although it is classified as a type of stroke, subarachnoid haemorrhage is not usually included in guidelines on stroke diagnosis and management.
• Sudden and violent headache is characteristic of subarachnoid haemorrhage.

[Intercollegiate Stroke Working Party, 2008; National Collaborating Centre for Chronic Conditions, 2008]