What is Optic Ataxia?
“Ataxia” is a condition, which indicates lack of coordination in a body’s physiological processes. Optic Ataxia is a type of ataxia where the patient is not able to guide his/her hand towards an object with the help of visual information. Patients with Optic Ataxia are unable to move their hand to reach or grab an object by using vision. There is incoordination of hand movements and visual input leading to optic ataxia. Optic ataxia is nothing, but dyskinesia with eye to hand movements where the patient is not able to reach out and grab objects despite seeing them clearly.
Optic Ataxia is one of the characteristic features of Balint’s syndrome. Other examples of ataxia also include ataxic respiration where there is lack of coordination in respiratory movements.
Causes of Optic Ataxia
The cause of Optic Ataxia is thought to be damage to the posterior parietal lobe leading to disturbance in connections between the visual association cortex and pre-motor/motor cortex. The function of parietal lobe is integrating sensory information for formation of spatial sense and perception. The posterior region of the parietal lobe is responsible for combining and expressing information about the position of the body and relating it to movement. The visual association cortex is a part of posterior region of the brain, which is responsible for interpreting visual information and providing it with meaning. The pre-motor and motor cortex regions are present in anterior area of the brain and they are responsible for controlling motor functions.
The posterior parietal cortex has outputs that include spinal cord, pre-motor and pre-frontal cortex, brain stem motor pathways, cerebellum and basal ganglia.
Optic ataxia is often a component of Balint’s syndrome; however, the optic ataxia can also occur on its own in association with injuries to the superior parietal lobule. Balint’s syndrome is a condition symptom is Optic ataxia. In Balint’s syndrome, the patient is not able to voluntarily control his/her gaze.
Simultanagnosia is also a symptom of Balint’s syndrome where the patient is not able to recognize more than one objects that are shown at the same time.
Symptoms of Optic Ataxia
- Patient finds it is difficult or is unable to accurately reach and grab the objects that can be clearly seen.
- Patient has incoordination between hand movement and vision.
Treatment for Optic Ataxia
Treatment of optic ataxia depends on its underlying cause. Treatment can help in managing the effects of optic ataxia. Treatment, in most of the cases, is not able to completely relieve the patient’s optic ataxia. If the cause of optic ataxia is a single focal injury, then the recovery from optic ataxia will be better. If the cause of optic ataxia is a neurological degenerative condition, then treatment takes more time.
Treatment by training the perceptual skills helps in restoration of the damaged CNS system. Treatment also consists of medicines, occupational therapy and physical therapy.
- “Balint’s Syndrome: A Window into the Visible World” – Frontiers in Neurology [https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3961705/]
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- Dijkerman, H. C., McIntosh, R. D., & Milner, A. D. (2003). Prism adaptation of reaching movements in optic ataxia: comparing single and multiple target paradigms. Cortex, 39(4-5), 536-542. DOI: 10.1016/S0010-9452(08)70138-1
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