Visuospatial dysgnosia is a loss of the sense of "whereness" in the relation of oneself to one's environment and in the relation of objects to each other.
Visuospatial dysgnosia is often linked with
topographical disorientation
Topographical disorientation is the inability to orient oneself in one's surroundings, sometimes as a result of focal brain damage. This disability may result from the inability to make use of selective spatial information (e.g., environmental l ...
.
Symptoms
The syndrome rarely presents itself the same way in every patient. Some symptoms that occur may be:
*
Constructional apraxia
Constructional apraxia is a neurological disorder in which people are unable to perform tasks or movements even though they understand the task, are willing to complete it, and have the physical ability to perform the movements. It is characterized ...
: difficulty in constructing: drawing, copying, designs, copying 3D models
*
Topographical disorientation
Topographical disorientation is the inability to orient oneself in one's surroundings, sometimes as a result of focal brain damage. This disability may result from the inability to make use of selective spatial information (e.g., environmental l ...
: difficulty finding one's way in the environment
*
Optic ataxia: deficit in visually-guided reaching
*
Ocular motor apraxia: inability to direct gaze, a breakdown (failure) in starting (initiating) fast eye movements
*
Dressing apraxia
Apraxia is a motor disorder caused by damage to the brain (specifically the posterior parietal cortex or corpus callosum), which causes difficulty with motor planning to perform tasks or movements. The nature of the damage determines the disorde ...
: difficulty in dressing usually related to inability to orient clothing spatially, and to a disrupted awareness of body parts and the position of the body and its parts in relation to themselves and objects in the environment
*
Right-left confusion: difficulty in distinguishing the difference between the directions left and right
Lesion areas
Studies have narrowed the area of the brain that, when damaged, causes visuospatial dysgnosia to the border of the occipito-temporoparietal region.
Predominantly,
lesions
A lesion is any damage or abnormal change in the tissue of an organism, usually caused by injury or diseases. The term ''Lesion'' is derived from the Latin meaning "injury". Lesions may occur in both plants and animals.
Types
There is no de ...
(damage, often from stroke) are found in the angular gyrus of the right hemisphere (in people with left-hemisphere language), and are usually unilateral, meaning in one hemisphere of the brain.
Bilateral lesions produce more complex dysgnosic signs such as object anomia (inability to name an object),
prosopagnosia
Prosopagnosia, also known as face blindness, (" illChoisser had even begun tpopularizea name for the condition: face blindness.") is a cognitive disorder of face perception in which the ability to recognize familiar faces, including one's own f ...
(inability to recognize faces),
alexia (inability to read), dressing apraxia, and memory impairment in conjunction with visuospatial dysgnosia symptoms.
Visuospatial dysgnosia has many symptoms in common with
Bálint's syndrome
Bálint's syndrome is an uncommon and incompletely understood triad of severe neuropsychological impairments: inability to perceive the visual field as a whole ( simultanagnosia), difficulty in fixating the eyes ( oculomotor apraxia), and inabili ...
and can present simultaneously. Visuospatial dysgnosia, along with Balint's syndrome, has been connected with
Alzheimer's disease
Alzheimer's disease (AD) is a neurodegenerative disease and the cause of 60–70% of cases of dementia. The most common early symptom is difficulty in remembering recent events. As the disease advances, symptoms can include problems wit ...
as a possible early sign of the disease.
Generally, the first symptom of Alzheimer's onset is loss of memory, but visual or visuospatial dysfunction is the presenting symptom in some cases and is common later in the disease course.
Therapies
For patients with visuospatial dysgnosia, the information input may be strengthened by adding tactile, motor, and verbal perceptual inputs. This comes from the general occupational therapy practice of teaching clients with intellectual dysfunctions to use the most effective combinations of perceptual input modalities, which may enable them to complete a task.
References
{{Reflist, 2
Dementia
Agnosia