1 Psychology and human development1.2 Awareness, sleep and consciousness
1.2.7 Unconscious function after brain injury
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Written by Resident Doctor Committee · Published
New in the 2027 syllabus
The College added this topic for exams from January 2027.
Dissociations after injury
Phenomenon | What still works | What is lost |
|---|---|---|
Blindsight | Responses better than chance to some visual stimuli | Reported visual experience in the affected field |
Implicit learning in amnesia | Improvement in a practised skill | Recollection of having practised |
Anosognosia | Some abilities unrelated to the deficit | Awareness of their own impairment |
Blindsight follows damage to the primary visual cortex. Visual processing can still guide responses, though the person reports no normal visual awareness.
Neglect is impaired attention to part of space. It is not a primary defect of the sensory field. Stimuli the person does not report may still influence their behaviour.
Arousal and awareness need to be assessed separately. Being awake does not on its own show that the person is aware of their surroundings.
Limits of assessment
Motor or language impairment can stop someone responding even when their cognition is intact. Interpret a lack of response with care.
Delirium is an acute, fluctuating disturbance of attention and awareness. A new change should prompt a search for an underlying physical illness or drug effect.