"To believe in the things you can see and touch is no belief at all. But to believe in the unseen is both a triumph and a blessing."
— Bob Proctor
Hemispatial inattention is an attention disorder that prevents the patient from attending to stimuli on one side. While it can happen to either the right or the left side, it usually only becomes a clinical problem when the right hemisphere of the brain is damaged and the patient is unable to attend to the left side of the world. It is quite variable in presentation and is more likely a set of problems rather than one specific condition.
It is a problem that is often confused with homonymous hemianopsia. Hemispatial inattention may occur with or without a homonymous hemianopsia. While homonymous hemianopsia is a physical loss of visual field to the same side in both eyes, visual neglect is an attention problem to one side of their body. We can divide patients into three groups; those with a homonymous hemianopsia and no hemispatial inattention; those with hemispatial inattention only (no hemianopsia) and, those with both homonymous hemianopsia and hemispatial inattention. It is important to determine the status of the neglect versus field loss so that proper treatments can be initiated.
Hemispatial inattention is more than a visual condition, a patient with hemispatial inattention may not respond to a voice when the person is on the left side and may not be able to recall memories of objects or places that would normally be to his left in a specific situation. A man with hemispatial inattention may only shave one side of his face while a patient with only a hemianopsia would compensate by turning his head and eyes to shave both sides of his face. These problems can relate to brain injury in different areas, but are often associated with damage in the right parietal lobe of the brain. The patient may or may not have a loss of visual field, but due to the left hemispatial in-attention cannot learn to compensate because they cannot mentally attend to left side.
Visual neglect usually indicates a worse outcome. Over time the natural course for visual neglect is to slowly improve, but outcomes are quite variable. An 18 month period has been suggested, but results are variable. Occupational therapy may improve outcomes in many patients and visual field expanders may have potential to help in some cases.
Severe hemispatial inattention can be suspected by gross observation alone. The subtle forms can be less obvious, but more crucial for patients with mild neglect who may be attempting to fully reintegrate into the world again including desires to drive or return to work which are situations where even mild hemi-spatial in-attention could be dangerous.
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