Parietal Lobe Signs
Higher cortical dysfunction comprises a variety of disorders other than language problems, depending on the location of the lesion.
In sensory neglect or sensory inattention, the patient has intact sensation when tested unilaterally but when confronted by bilateral stimuli, ignores the affected side
|The medical student is testing to see that sensation is intact on each side, and then challenges both sides at the same time. A normal individual would notice both sides being touched; however a patient with sensory neglect would only notice one side whilst both are being touched. This patient does not have sensory neglect but does have right left disorientation where they think their left is right and vice versa.|
|In this example the patient can clearly identify visual field stimuli unilaterally, but neglects her left when presented with bilateral stimuli. This is testing for visual fields by confrontation. It is important that the doctor is at the same eye level as the patient.|
|Now the doctor assesses the same patient for sensory neglect. She has no sensation in the left upper limb (presumably related to her stroke), but does have some sensation in the distribution of the left and right facial nerves. She is able to demonstrate intact unilateral and bilateral facial sensation, thus excluding sensory neglect – even though she does have left sided visual neglect.|
Agnosia is the inability to familiar recognise objects.
The doctor first ensures that sensation is intact and that there is no sensory neglect. He then traces different numbers on her hand, which she is unable to identify reliably. This is an example of dysgraphesthesia, a form of agnosia.
|In this video, the doctor has already established that the patient has intact sensation. He asks the patient to identify two coins (a two pence piece and a pound coin) by touch alone. She is unable to do so, which is consistent with agnosia.|
Astereognosis is the inability to recognise numbers drawn on the hand.
Dyspraxia is the inability to perform tasks, despite having the necessary strength and sensation – for example, unable to dress in the absence of a hemiparesis (‘dressing apraxia'). It is a problem with processing information.