The word agnosia derives from Greek and means ‘without knowledge’. Agnosia refers to impairment of the ability to process and interpret sensory information. This may affect the person’s ability to recognise/identify their immediate environment and things/people within it. There are many different types of agnosias, some of which are common following brain injury and others which are rarely seen.
Examples of more frequently seen agnosias include:
- Visuo-Spatial Agnosia: impairment of visual and spatial perception which results in difficulties with:
- Visual recognition of objects and environmental landmarks.
- Perception of the spatial relationships between different objects and/or landmarks.
- Achromatopsia: the loss of colour vision.
- Prosopagnosia: impairment of the ability to recognise familiar faces. The person may however retain the ability to recognise other people by their voice.
- Astereognosis (tactile agnosia): impairment of the ability to recognise objects by touch. The person may still be able to recognise the objects by sight.
- Topographical Agnosia: difficulty in navigation of the environment and inability to recall the spatial arrangement of familiar surroundings.
- Anosognosia: impairment of awareness/insight. The person may deny that they have difficulties even when there is clear evidence to the contrary e.g. deny having mobility problems even when requiring a wheelchair.
- Body Scheme Disorders: inability to recognise right from left or an inability to identify parts of the body e.g. asomatognosia is the inability to recognise parts of the body and to perceive their relative position in space. This may affect balance and coordination.
Agnosia may have an impact on the person’s ability to carry out everyday activities. Examples of difficulties the person may experience include (this is not an exclusive list):
- Difficulty carrying out activities of daily living such as shaving, brushing teeth, washing and dressing, eating and drinking and leisure activities e.g. reading, writing, using the phone, watching TV etc.
- Difficulty managing work/education, child care, housework, gardening etc.
- Difficulty locating items in drawers, cupboards, wardrobes or bags e.g. finding cutlery in a drawer, coffee on a shelf.
- Difficulty finding the way to work, shops, social events, appointments and return home etc.
- Difficulty managing family/social events. This may lead to them avoiding previously enjoyed activities with subsequent risk of increasing social isolation.
Agnosia may result in distress and anxiety for the person. Awareness of these difficulties may result in the person feeling confused and frustrated as they may be unable to carry out a range of simple everyday tasks.
The person with significant executive functioning impairment may have limited insight into the cause of their difficulty which may result in anxiety and distress. In this context, the person may experience feelings of frustration and anger etc, which may contribute to agitation and potentially aggression. These difficulties may impact on the person’s ability to cooperate fully with care and treatment.
Cognitive and communicative impairments may affect the person’s ability to understand these difficulties and the implications for their everyday life. Difficulties with cognition and communication may affect the person’s ability to recognise the problem and to communicate their difficulties to others.
Following brain injury, the person may experience one or more of the above difficulties which impacts on their ability to participate safely and effectively in a wide range of activities, whether these are personal and domestic, leisure or work related activities of daily living.
How to Help the Person with Agnosia