Do some people only perceive half of the world around them?
Imagine looking in the mirror while putting on makeup or shaving. You probably try to make sure you’ve equally groomed both sides of your face. Although it’s likely very easy for you to tell if you haven’t, people with a neurological condition called “hemispatial neglect” can actually perform poorly in this everyday task.
Hemispatial neglect is a lack of awareness for objects in one side of the visual field. However, it’s not a sensory disorder, because the visual system itself is intact. Instead, hemispatial neglect is considered an attention-based deficit. This condition most commonly happens after someone experiences damage to 1+ areas in a group of brain regions called the perisylvian network.
Hemispatial Neglect and Brain Function
Although regions in the left brain hemisphere’s perisylvian network are associated with language, regions in the right perisylvian network are more often involved in paying attention to objects in the space around us. Damage to perisylvian regions usually happens through a stroke involving blood vessels that supply these areas [i.e., middle cerebral artery (MCA)]. The exact location of the damage impacts the type of neglect a person will experience.
Hemispatial neglect is most often seen in patients who had a right MCA stroke, typically resulting in neglect of objects in the left visual field. Someone with neglect of the right visual field would likely have had left-sided brain damage.
Sometimes, people aren’t aware of whole objects in the neglected hemisphere, including people or their own body parts. A person with hemispatial neglect often doesn’t realize the attention-based deficit, which is why personal grooming might not be so easy for some of these individuals.
Unfortunately, there is no established treatment for neglect. Research is ongoing in this area using rehabilitation by learning new strategies, pharmacological management, and neurostimulation.
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