NEUROPSYCHOLOGY L9

Blindsight: patient is convinced that he/she is blind but is still able to process visuospatial information.  Lesion concerns the geniculostriate system with an intact tectopulvinar system. 

Blindsight: patient is convinced that he/she is blind but is still able to process visuospatial information. 

-  geniculostriate system (intact/ lesion)

- tectopulvinar system (intact/ lesion)

Agnosia: not being able to recognize an object, whereas the visual system is completely intact.

So the disturbance should be in the cooperation between the occipital and the temporal lobe, the occipito-temporal connection.

To recognize an object, you also have to remember how the object looks like from various different angles. In other words, you have to see it and remember it. 

2 types of agnosias?

Apperceptive agnosia and Associative agnosia

In Apperceptive agnosia you are not able to make a 'percept' of the object.

Failure to make a percept can also occur when one is unable to process the various ingredients of an object at the same time, i.e. simultaneously. In other words, simultaneous agnosia is often part of the disorder.

Associative agnosia implies that one is unable to recognize an object

- not because of a perceptual failure

- but because one has forgotten the meaning of the object (meaningful associations with the object are missing)

In case of an Associative agnosia one is able to copy;

In case of an Apperceptive Agnosia one is not able to copy

Associative agnosia or Apperceptive Agnosia ?