Neglect Syndrome is a neurological condition that affects a person's ability to perceive and respond to stimuli from one side of their body or environment. This syndrome is most commonly observed in patients who have experienced a stroke, particularly those with lesions in the right hemisphere of the brain. The condition is characterized by an inability to process information coming from one side of the body or the environment (often the left), and it can also impact the ability to control one's own limbs or recognize parts of the body. Neglect Syndrome is not just a sensory issue but a complex disorder that influences various aspects of cognition and behavior.

What Is Neglect Syndrome?

Neglect Syndrome, also known as hemispatial neglect or unilateral neglect, is a condition where an individual fails to attend to stimuli on one side of their environment, despite having no primary sensory impairment on that side. For example, someone with left-sided neglect may not notice objects or people on their left side, even though their vision and hearing are intact. This lack of awareness can extend to motor functions as well. Patients may fail to move limbs on the affected side or even perceive them as absent. This condition typically arises from damage to the right hemisphere of the brain, which plays a critical role in spatial awareness and attention. When the right hemisphere is damaged, the brain's ability to process information from the left side is impaired. The prevalence of this condition in patients with right-sided strokes is quite high, ranging from 33% to 85%. While left-sided strokes can also result in neglect, it is less frequent.

Causes of Neglect Syndrome

Neglect Syndrome primarily occurs as a result of brain lesions, particularly those resulting from strokes. The right hemisphere of the brain, which governs perception from both sides of the body, is typically affected. However, the left hemisphere, while processing information from the right side, does not fully compensate for right-sided neglect in the same way that the right hemisphere compensates for left-sided neglect. The severity of neglect syndrome can be influenced by several factors, including the location and extent of brain damage. Age is another significant factor, with elderly individuals being more likely to develop this syndrome following a stroke than younger patients.

Pathophysiology: How Neglect Syndrome Develops

Neglect Syndrome is often considered within the broader category of visuospatial disorders, which includes conditions like optic ataxia. This condition results from damage to the occipital, parietal and frontal lobes of the brain, which are responsible for processing sensory information and orienting attention to spatial surroundings. Although basic sensory functions like vision and hearing remain intact, the brain struggles to integrate sensory information to form a coherent and holistic view of the environment, often ignoring one half of the world. The parietal, temporal, and frontal lobes are involved in maintaining spatial awareness and guiding attention toward significant stimuli. When the right hemisphere is damaged, the ability to perceive stimuli from the left side of the body and environment is compromised, leading to neglect of that side. This is particularly problematic when both sides are stimulated simultaneously, as the brain tends to prioritize the non-neglected side, further exacerbating the condition.

Symptoms of Neglect Syndrome

Neglect Syndrome manifests in a variety of ways, depending on the extent and location of the brain damage. Common symptoms, which can vary in severity, include:

• Visual neglect: Patients may fail to notice objects in their left or right visual field, despite having normal vision.
• Auditory neglect: Patients may ignore sounds coming from one side or fail to attend to auditory stimuli from that direction.
• Tactile neglect: Inability to respond to touch on one side of the body, often leading to a lack of awareness of their limbs.
• Motor neglect: This can involve difficulty initiating movements on the affected side, even when motor pathways are intact, or even the failure to recognize that their limbs exist, resulting in reduced use of that side of the body.

One of the characteristic signs of neglect syndrome is sensory extinction: if a person is simultaneously exposed to stimuli on both sides of the body, they may fail to notice the stimuli on the neglected side. Despite this, they often react appropriately when stimuli are presented solely to the neglected side. Another symptom is anosognosia, a lack of awareness of the deficit, where the patient denies or fails to recognize their neurological impairments.

Complications of Neglect Syndrome

Neglect Syndrome complicates recovery, especially after a stroke, as it can significantly hinder rehabilitation efforts. Patients often have difficulties with daily tasks, such as eating, dressing, or moving, because they fail to notice one side of their body or environment. This lack of awareness can also increase the risk of falls and injuries, as the affected individuals may not be conscious of obstacles or hazards in their surroundings. The syndrome can also significantly impact a person's emotional and psychological well-being. The frustration of not being able to perform everyday activities, combined with the lack of recognition of the disability, can lead to depression, anxiety, and increased dependence on caregivers. Social isolation often follows, as the individual's ability to participate in activities and communicate with others becomes limited.

Diagnosis of Neglect Syndrome

Neglect Syndrome is diagnosed through a combination of clinical observation and standardized neuropsychological testing. Early detection is critical, as it allows for timely interventions that can improve outcomes. Neurologists, neuropsychologists, and occupational therapists may assess patients through a series of tests designed to evaluate their ability to attend to stimuli on both sides of their environment and body. Common tests include:

• Clock-drawing task: A typical test where patients are asked to draw a clock face, often neglecting one side of the clock.
• Line bisection test: The patient is asked to mark the center of a line, but they may ignore the left half of it.
• Reading tasks: Patients might read only the first part of a sentence or skip words on one side of the page.
• Object recognition tests: The patient may fail to recognize objects on one side, even though they are capable of recognizing those on the unaffected side.

In addition to these behavioral tests, neuroimaging techniques, such as MRI or CT scans, are used to confirm the presence of brain lesions and identify the affected areas.

Treatment Options for Neglect Syndrome

While some individuals experience spontaneous recovery from neglect syndrome, particularly within the first few months after a stroke, targeted interventions are often necessary to facilitate improvement. Early intervention can help reduce the severity of symptoms and increase the likelihood of regaining full function.

Neuropsychological Rehabilitation

A multidisciplinary approach to rehabilitation is the cornerstone of treatment for neglect syndrome. Neuropsychological correction involves exercises designed to encourage patients to pay attention to the neglected side. These can include activities such as visual scanning training, where the patient is encouraged to shift their gaze toward the neglected side, and reading with the help of markers. Constraint-induced movement therapy (forcing the use of the affected side) and vestibular stimulation techniques are also used in some cases.

Psychological Support

Psychological support is essential for patients struggling with the emotional and psychological impacts of neglect syndrome. A psychologist may work with both the patient and their family to address emotional challenges and improve coping mechanisms. They may also help modify the patient's environment to better accommodate their sensory and motor deficits, such as by strategically placing objects on the neglected side to encourage interaction and awareness.

Physiotherapy and Medication

Occupational therapy and physiotherapy are important parts of treatment, particularly in restoring motor function, improving mobility, and promoting independence in activities of daily living. Techniques like transcranial magnetic stimulation, electrical stimulation, and biofeedback are sometimes used in the rehabilitation process. While research is ongoing, some medications, such as dopaminergic agents, may be considered to potentially promote recovery. However, there are currently no FDA-approved medications specifically for the treatment of neglect.

Prognosis and Prevention

The prognosis for patients with neglect syndrome depends on several factors, including the severity of the stroke, the age of the patient, and how early treatment is initiated. In many cases, significant improvement can be seen within three to six months, particularly in younger patients and with early intervention. However, if left untreated or if rehabilitation is delayed, the condition can persist and significantly hinder long-term functional recovery. Preventing neglect syndrome primarily involves reducing the risk of stroke through lifestyle modifications and medical management of risk factors. Maintaining a healthy lifestyle, managing blood pressure, cholesterol levels, and avoiding smoking are critical preventive measures. Regular check-ups and early detection of potential cardiovascular issues can help reduce the risk of stroke and its associated complications.

Conclusion

Neglect Syndrome is a challenging neurological disorder that requires a multi-disciplinary approach to treatment. Although it can significantly impact a patient's quality of life, early intervention and rehabilitation can greatly improve outcomes. Understanding the causes, symptoms, and treatment options for neglect syndrome can help patients, families, and healthcare providers work together to manage the condition and support recovery.