Right Frontal lobe lesion leads to
Correct Answer: Impaired left conjugate gaze
Description: (A) Impaired left conjugate gaze# Conjugate gaze refers to the eyes working in unison. A disorder of conjugate gaze means that patients are unable to look in certain directions with both eyes, such as upward, downward or laterally.> Centre for lateral conjugate gaze is seen in frontal lobe cortices & in occipital lobe cortices.> Frontal lobe centres for lateral conjugate gaze lie in the posterior aspect of frontal lobes.> They are quite close to the motor cortex and hence conjugate deviation of the eyes is seen in a number of paralytic strokes.> Frontal lobe centre for lateral conjugate gaze control voluntary conjugate eye movements to the opposite side. Teleologically, this makes sense: the left half of the brain "sees" space on the right side, therefore the left side of the brain controls movements of the right arm and leg, as well as eye movements to the right side.> In one side of frontal lobe centre destruction, as in a cerebral infarct, the tonic impulses from the opposite frontal lobe cause a deviation of the eyes towards the side of the lesion and patient looks to- wards the lesion and away from the paralyzed side.> Conjugate deviation occurs only in acute phase of an infarct and eventually the patient will recover, but there may be an intermediate stage where they are unable to move the eyes away from the lesion on command, yet able to follow an object to the opposite side.> Occipital lobe centre for lateral gaze control the ability of the eyes to follow an object to the opposite side.> In a patient with destruction of the right frontal centre but with an intact right occipital lobe centre cannot look to the left on command, but may be able to follow an object to the left.> If the patient is unable to follow a moving object, such as a finger, you can assess the occipital lobe centre by having them fixate on an immobile object while you move their head.> Remember! Lesions of occipital centre for lateral conjugate gaze are less common than lesions of frontal centre for lateral conjugate gaze.> Brainstem centre for lateral conjugate gaze are in the pons, very close to the sixth nerve nuclei.> The right frontal centre connects with the left pontine centre, and the left frontal centre with the right pontine centre. The left pontine centre controls lateral conjugate eye movement to the left, and the right pontine centre controls lateral conjugate eye movement to the right.> Thus, a patient who has a destruction of one pontine centre will look away from the lesion and towards the paralyzed side because of the unopposed action of the opposite pontine centre. Recovery of conjugate gaze after a brainstem lesion is unusual.
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