Visuospatial disorders Flashcards
What is agnosia? (3)
Inability to recognise previously familiar objects that you could before injury
Can be in a specific modality: Visual, Auditory (inability to recognise sounds, can hear sound but don’t know what it represents ) or Tactile
Usually modality specific but if injury is big, might have several agnosias
What is visual object agnosia and the lesion associated? (5)
Relatively rare condition
Definition: Failure of recognition that can not be attributed to elementary sensory deficit (eyesight is still intact), mental deterioration (not confused and mentally impaired), attentional disturbance, aphasic misnaming (not language deficit, not inability to name what you see) or unfamiliarity
Usually modality specific (with instant recognition if information can be presented via another modality)
Lesion: Occipital lobe and its temporal projections
Impairment in the higher visual processes necessary for recognition with relative preservation of elementary vision
Patient unable to identify familiar objects when presented visually. Can ‘see’ the object and may be able to describe its parts or copy a picture of it. Have no idea what it is or how it may be used (i.e., cannot interpret sensation).
Patient will reach for presented objects to get info through tactile modality, they can see it bc they can reach for it but cant recognise it
Immediate recognition when presented via another sense modality
What is the difference between agnosia and anomia?
Distinguish from anomia
Anomic can demonstrate its use, can recognise the object but cant think of the word
Will not improve when information presented via another modality.
Breakdown of the language neural syst
Patient unable to identify the object or the general semantic class to which it belongs.
Patient with language prob can show you how its used but cant name it, agnosic cant show you how its used bc cant recognise it
What is prosopagnosia and the lesion associated?
Inability to recognise familiar faces.
Recognise a face as a face but can not determine who it belongs to
Patients learn to identify people by using extrafacial cues eg scent, clothing, height, voice, gait
Deficit of the ability to identify visually similar members of the one class (bird watcher, farmer)
Lesion: bilateral occipital
What is unilateral neglect? (7)
Characterised by a failure to attend, respond or orient to a stimulus or side opposite the lesion which is not referrable to a sensory or motor deficit
The vis field isnt affected, its a cog deficit, dont put attention across all the vis field
May extend to all sensory modalities i.e. neglect of visual, auditory and somatosensory stimuli on the side of the body and/or space opposite the lesion
Often modality specific
When asked to draw a picture, bisect a line or read they perform as if one half of the object, line or word does not exist
Common deficit, esp after stroke
Patient is often unaware of the deficit so dont make effort to compensate for the deficit
Most commonly reported following a posterior parietal lesion of the right hemisphere
May also be seen following right frontal lesions and lesions of the cingulate gyrus or of the thalamus and basal ganglia
What is the clinical presentation of unilateral neglect? (4)
Commonly seen after stroke or in association with a tumour
If the tumor is impacting any of the areas that could give rise to this disorder
Often transient with the most conspicuous features in many cases lasting no more than a few weeks
Often seen in association with sensori-motor deficits including VFD’s and hemiparesis
Most cases of severe and persisting neglect involve RH lesions
Studies of unselected cases (ie including those with aphasia) consistently demonstrate that left visual neglect is more frequent and severe (RH damage) than right visual neglect (LH damage)
Most often see patients that neglect the left hand side of space
What is the incidence of unilateral neglect?
Figures vary:
40-45% following RH CVA
15% following LH CVA stroke
NB. May be task specific eg., evident in reading but not drawing
What are some severe forms of unilateral neglect?
Asked to lift arms: will lift only one
Asked to draw a clock face: reproduce only half or crowd all numbers into one side
Asked to read a compound word such as ice-cream or football: read cream and ball
Dressing: May fail to put on left side of clothes
Grooming: Shave or apply makeup to only one side of the face
Unaware that anything is wrong (anosognosia)
Wont try and compensate for their deficit
What happens in the acute stages of unilateral neglect? (8)
Most severe signs seen in the acute stages of CVA neglect of the half of space contralateral to the lesion
Patients attention systematically orients towards stimuli lying on the extreme part of the non-neglected side: May eat from only one side of the plate, neglect to lock the wheelchair on the left, may hit walls and door frames on the neglected side bc aren’t attending to the neglected side
May be characterised by marked deviation of head, eyes and trunk away from the contralesional field.
Test visual fields: The very placement of one’s hand to the patient’s right renders him unable to maintain central fixation.
Test vis field in the 4 quadrants, patients will be compelled to loook into the non neglected side of place = compulsive orientation
Scanning saccades restricted to the ipsilesional side although patient may have full ocular movement to command
Saccades will be confined to one side of space
Have to drag their attention to one side of space
In severe cases patients may fail to recognise contralateral extremities as their own n
May experience difficulty in remembering left sided details of internally represented familiar scenes
Affects mental representations (describe only non neglected side of remembered places)
Thus, impaired perception, action and mental representation of the contralesional half of space
Most striking signs resolve quite rapidly
With appropriate testing may see residual signs
What happens in the later stages of unilateral spatial neglect?
Extinction to Double Simultaneous Stimulation
Patient asked to fix gaze.
Test visual fields by presentation of a single stimulus on one side. Do the same on the other. Patients fields will be ‘Full to Confrontation’ i.e., detection appears normal in both the left and the right visual fields (cf with hemianopic pt)
If test 2 quadrants at same time, will only see one pt (the one in the non neglected side)
When two objects are presented at the same time, one in each field, only one of the stimuli is reported ‘Extinction to Double Simultaneous Stimulation’.
When there’s competition for attention, the non neglected side will always win
Preferentially respond to things in the non neglected part of space
How can we test for unilateral spatial neglect? (6)
Spatial and exploratory tasks (eg. pattern crossing, line bisection)
Copying tasks (Normal ppl start from left to right, if start on right could be a sign of neglect)
Drawing from memory even of objects with well known symmetrical configuration
Reading
Multiple-choice tasks
Description of a scene
What is object centered neglect?
Neglect left side of the figure although then reproduce the right side of a figure that is further to the left
Dont neglect left side of space but the left side of every object they see
What happens when people with left brain damage read?
Have a list of words, will make mistakes on the right hand side of the words
What happens when people with right brain damage read?
Neglect left hand side of word so make mistakes there
Patient wont be able to obtain meaning from the info they read
What is constructional apraxia?
An impairment in combinatory or organising activity so that desired synthesis can not be achieved
Seen on tests where individual elements must be arranged in a given spatial relationship to form a unitary structure
Inability to perceive how two or more parts form a whole
See it on: Paper and pencil tests, 2-D constructional eg., Block Design, Rey Fig., 3-D constructional tasks
