Balint Syndrome: The Challenges of Simultagnosia, Optic Ataxia and Ocular Apraxia

In the sudden onset of visual challenges, a 63-year-old woman finds herself unable to perceive the entirety of a picture, instead describing fragmented details, and struggling with the once-fluid precision of grasping objects. This example highlights the severe effects of Balint syndrome, a brain disorder that impairs visual-spatial skills.
Frederika Malichová

Frederika Malichová

Neuroscientist at the University Of Cambridge.

An image of an eye inside on top of a brain.

What is Balint syndrome?

Balint syndrome is a rare neurological disorder, typically resulting from bilateral damage to the posterior parietal and occipital lobes of the brain [1].

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The occipital lobe, specifically, is involved in visual processing, and damage to this area can lead to disorders of visuospatial skills, such as those seen in Balint's syndrome [2].

The posterior parietal cortex plays a critical role in multimodal spatial integration and in the fusion of different coordinates into a unified representation of space [2] .

Damage to specific functional modules in the posterior parietal cortex for reaching, saccades, grasp, attention, and state estimation in the posterior parietal cortex can result in various aspects of Balint's syndrome [3].

Balint syndrome can be caused by various factors such as trauma, infarctions, infections, tumours, and certain neurodegenerative disorders like atypical Alzheimer's disease 2 [4].

Interestingly, the syndrome was first described by Rudolf Balint in 1909, and it was postulated that the symptoms were due to a lack of coordination between sensory input and motor output [4].

In some cases, no underlying cause can be identified to explain the brain atrophy.

Symptoms of Balint's Syndrome

Despite these visual-spatial challenges, patients with Balint syndrome typically maintain intact memory, language, and cognition.

The Balint syndrome is characterized by three main symptoms:

Simultanagnosia

Simultanagnosia is a disorder of visual perception where individuals struggle to identify multiple items in a visual scene simultaneously or to visualize more than one object in the visual field at a time.

It is often associated with difficulty in recognizing global structures while preserving perception of local detail.

Simultanagnosia patients can enumerate up to 2-3 elements as efficiently as healthy individuals, a phenomenon known as "subitizing".

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Optic Ataxia

Patients with optic ataxia struggle to reach accurately for objects, particularly when they are presented in peripheral vision.

Optic ataxia is characterized by an impaired visual control of the direction of arm reaching to a visual target, accompanied by defective hand orientation and grip formation.

It is related to the dysfunction in the occipito-parietal stream of the visual brain.

Additionally, individuals experience a failure to reach an object with one hand but can do so with the other, indicating a disruption in visually guided hand movements [5].

Ocular Apraxia

Ocular motor apraxia, also known as congenital ocular motor apraxia (COMA), is a rare condition manifesting as a deficit in visual scanning, reflecting the difficulty in voluntarily moving the eyes to scan the visual.

It is characterized by a defect or absence of voluntary and optically induced horizontal saccadic movements. These are rapid eye movements that allow the eyes to quickly shift focus between different points in the visual field.

In individuals with ocular motor apraxia, these movements are impaired, leading to difficulties in directing the gaze horizontally.

This condition often presents with compensatory head movements or thrusts on attempted lateral gaze [6].

Treatment of Balint's Syndrome

Rehabilitation strategies constitute the cornerstone of Balint syndrome
management [7,8,9]. These encompass a multifaceted approach:

  1. Compensatory Strategies: Patients learn techniques to work around their deficits, such as turning their heads for more effective environmental scanning or utilizing verbal cues to aid visual recognition.
  2. Remediation Exercises: Tailored activities target specific deficits associated with Balint syndrome. Visuoperceptual retraining exercises, for instance, aim to improve visual perceptual deficits.
  3. Transfer of Learned Skills: The application of acquired skills to real-world situations is vital. Functional programs are designed to provide rehabilitation in contexts meaningful to the patient. However, the effectiveness of these strategies varies based on the individual's condition and the underlying cause of the syndrome. In cases where visual perceptual rehabilitation proves ineffective, cognitive remediation may be necessary.

Studies suggest that while compensatory strategies generally prove beneficial, restorative training yields mixed results.

Balint syndrome, with its intricate dance of neurological factors, underscores the importance of tailored and adaptive rehabilitation strategies to enhance the quality of life for those navigating the complexities of visual-spatial dysfunction.

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Disclaimer

This article does not offer health advice. Always consult a medical professional regarding your condition.

Frederika Malichová

Frederika Malichová

Frederika is a postgraduate researcher at the University of Cambridge, where she investigates new biomarkers for Frontotemporal Dementia and other tauopathies. Her research has been published at prestigious conferences such as the Alzheimer’s Association International Conference 2023. She obtained her BSc in Biomedical Sciences from UCL, where she worked closely with the UK Dementia Research Institute.