Neglect syndrome is a serious neurological condition that profoundly alters a person’s perception of the world. It is a failure of the brain’s attentional system to process space and stimuli on one side, not an impairment of the senses. The person acts as if one half of their reality does not exist, despite having functional eyes and ears. This cognitive failure affects awareness of objects, people, and their own body within their environment.
Understanding the Core Concept of Neglect
The condition is formally known as Unilateral Spatial Neglect or Hemispatial Neglect, reflecting the single side of space that is ignored. This is distinct from sensory loss, such as a visual field cut (hemianopsia). A person with neglect can physically see or hear stimuli on the affected side, but their brain does not register or attend to that information.
The fundamental issue is a profound attention disorder, where the brain develops a bias directing all attention toward the side of the brain injury. The individual fails to report, respond to, or orient toward stimuli located on the side opposite the brain damage. This lack of awareness can extend to their own body, the space immediately surrounding them, and the environment.
What Causes Neglect Syndrome
Neglect syndrome is caused by acute damage to one hemisphere of the brain, most commonly following a stroke. Ischemic strokes (blood clot blockage) or hemorrhagic strokes (bleeding in the brain) are the primary cause. The resulting lack of attention is directed at the side of space opposite the injury.
The majority of cases involve damage to the right cerebral hemisphere, resulting in the neglect of the left side of space. This occurs because the right hemisphere plays a dominant role in attending to both sides of the world. When the right hemisphere is damaged, the left hemisphere’s attention to the right side is unopposed, creating a strong attentional bias. The specific brain regions implicated are the temporo-parietal junction and the inferior parietal lobe.
While stroke is the most frequent cause, other types of brain injury can also lead to the syndrome. These include traumatic brain injury, a brain tumor, or inflammatory infections affecting the relevant cortical areas.
How Neglect Affects Daily Life
The manifestations of neglect syndrome interfere with a person’s ability to complete basic daily tasks. Visual and sensory neglect is the most recognizable form. A person might only eat food from the right half of their plate, or only shave or apply makeup to the right side of their face, leaving the left side unattended.
In reading, a person may only read the right half of words or sentences (neglect dyslexia), causing text to make no sense. When navigating, they frequently bump into objects or people on the neglected side because they do not register their presence. This inattention can include auditory or tactile stimuli, where the person does not respond to sounds or touch on the affected side.
Motor intentional aiming deficits, or motor neglect, represent another facet of the syndrome. Even if muscles on the affected side are not paralyzed, the person may have difficulty initiating movement with the neglected limb. They may also exhibit anosognosia, an unawareness of their own deficit, often leading them to deny that anything is wrong.
The condition can also affect internal mental representations (representational neglect). When asked to mentally picture a familiar location and describe it, a patient will only describe the details on the right side of their mental image. This demonstrates that neglect is an impairment in how the brain constructs and attends to space, both real and imagined.
Assessing and Diagnosing Neglect
The diagnosis of neglect syndrome relies on standardized, paper-and-pencil tests designed to quantify the attention deficit. These assessments are administered by neurologists and occupational therapists to differentiate true neglect from simple sensory or motor impairments.
A common method is the Line Bisection Test, where the patient marks the center of several horizontal lines. A person with neglect consistently marks the subjective center far to the right of the actual midpoint, ignoring the left portion. Cancellation Tasks, such as the Star Cancellation Test, require the patient to cross out a specific target symbol scattered among distractors. Patients with neglect systematically miss all targets located on the left side of the page.
Copying and drawing tasks are also informative. When asked to draw a complex object, the patient frequently omits or crowds all details onto the right side of the drawing. These simple, observable tasks provide objective evidence of the brain’s failure to attend to contralesional space.
Treatment and Recovery Approaches
The goal of treatment for neglect syndrome is to reorient the patient’s attention toward the neglected side of space and integrate that side back into awareness.
Behavioral Interventions
One widespread intervention is visual scanning training, which teaches the patient to actively turn their head and eyes to the neglected side. This strategy involves structured exercises that encourage a systematic exploration of the entire environment.
Limb activation therapy (LAT) focuses on encouraging the patient to actively move the affected limb, even minimally. Movement of the limb on the neglected side provides a strong sensory signal that helps draw attention to that side of space.
Specialized Techniques
Specialized techniques include prism adaptation, where the patient wears glasses that shift their visual field to the right, forcing them to look left to locate targets. The prism glasses create a mismatch between what the eyes see and what the brain expects, which can temporarily recalibrate spatial attention when corrected.
While many patients show spontaneous recovery in the initial weeks following a stroke, early and consistent intervention is associated with better long-term functional outcomes. Recovery involves a combination of these strategies, along with occupational and physical therapy, to maximize the patient’s ability to function independently.