Cognitive Development – Attention Disorders
Neglect
Lesions to the ‘what path’ will typically lead to a specific impairments in object
recognition, including impaired recognition of certain classes of objects like faces.
Lesions to ‘where path’ will typically lead to deficits in spatial attention.
Another group of syndromes classified as spatial attention deficits following brain
damage to the ‘where stream’ is neglect/extinction.
o Neglect is characterised by a very substantial failure to pay attention to half
of the world (lesion is typically on the right side).
o Other than Balint’s syndrome, neglect typically occurs after unilateral brain
damage, in far the most cases lesions to the right side.
o The failure to attend and respond occurs for stimuli presented to the
contralesional side of space. Performance with stimuli presented to the
ipsilesional side is relatively intact.
Contralesional: the visual field that projects onto the lesioned
hemisphere. For instance, the left visual field will be contralesional
side of a right hemisphere lesion.
Ipsilesional: the visual field that projects on the intact hemisphere.
The right visual field projects onto the left hemisphere. Therefore, the
right visual field will be the ipsilesional side of the right hemisphere
lesion.
o Spatial neglect can be demonstrated using a variety of simple visual tests:
Cancellation task: patients are presented with an array of small line
segments and are asked to manually cancel out all the line segments
they can find. Neglect patients tend to perform accurately with lines
appearing within the ipsilesional side of space but to miss out many of
the contralesional side of space.
Line bisection task: patients are presented with a series of horizontal
lines and are asked to mark the middle of the line. Neglect patients
tend to underestimate the contralesional side of the line and
therefore misjudge the middle point towards the ipsilesional side of
the line.
Copying: patients tend to copy only half of an image.
o Neglect deficits can be evident in a variety of reference frames. For instance,
patients may show neglect in representational space, personal space or near
space. In addition to space-based neglect, the symptom can also occur in an
object-based manner.
o Neglect seems more prevalent following unilateral right hemispheric lesions
that damage the inferior parietal lobe. This evidence has been supported by a
review study conducted by Mort and colleagues (2003).
o Another related pattern to neglect is extinction:
Neglect
Lesions to the ‘what path’ will typically lead to a specific impairments in object
recognition, including impaired recognition of certain classes of objects like faces.
Lesions to ‘where path’ will typically lead to deficits in spatial attention.
Another group of syndromes classified as spatial attention deficits following brain
damage to the ‘where stream’ is neglect/extinction.
o Neglect is characterised by a very substantial failure to pay attention to half
of the world (lesion is typically on the right side).
o Other than Balint’s syndrome, neglect typically occurs after unilateral brain
damage, in far the most cases lesions to the right side.
o The failure to attend and respond occurs for stimuli presented to the
contralesional side of space. Performance with stimuli presented to the
ipsilesional side is relatively intact.
Contralesional: the visual field that projects onto the lesioned
hemisphere. For instance, the left visual field will be contralesional
side of a right hemisphere lesion.
Ipsilesional: the visual field that projects on the intact hemisphere.
The right visual field projects onto the left hemisphere. Therefore, the
right visual field will be the ipsilesional side of the right hemisphere
lesion.
o Spatial neglect can be demonstrated using a variety of simple visual tests:
Cancellation task: patients are presented with an array of small line
segments and are asked to manually cancel out all the line segments
they can find. Neglect patients tend to perform accurately with lines
appearing within the ipsilesional side of space but to miss out many of
the contralesional side of space.
Line bisection task: patients are presented with a series of horizontal
lines and are asked to mark the middle of the line. Neglect patients
tend to underestimate the contralesional side of the line and
therefore misjudge the middle point towards the ipsilesional side of
the line.
Copying: patients tend to copy only half of an image.
o Neglect deficits can be evident in a variety of reference frames. For instance,
patients may show neglect in representational space, personal space or near
space. In addition to space-based neglect, the symptom can also occur in an
object-based manner.
o Neglect seems more prevalent following unilateral right hemispheric lesions
that damage the inferior parietal lobe. This evidence has been supported by a
review study conducted by Mort and colleagues (2003).
o Another related pattern to neglect is extinction:
