The occipital The occipital lobes Occipital lobe - Mahidol University

23/06/54Color agnosiaA defect of color recognition which has avariety of forms, primarily an inability toname or discriminate between colors.The color name may be given in a qualified orconcrete form or a confabulation may occur.It sometimes accompanies alexia and aphasia.Usually results from a left occipital or occipitotemporallesion.Color agnosia (cont)It sometimes accompanies alexia andaphasia.Usually results from a left occipital oroccipitotemporal p lesion.NEUROPSYCHIATRY 139NEUROPSYCHIATRY 140Color agnosia (cont)Test:Matching names to colors and colorsto names, color sorting, arrangingshades of a color by intensity, coloringpictures appropriately,identificationof inappropriatelycolored objects.SimultanagnosiaThe inability to absorb more than one objector aspect of a visual stimulus at a time.This condition occurs with bilateral lesionsof the occipitoparietal region.When accompanied by incoordination ofocular movements, this defect is known asBalint's syndrome.NEUROPSYCHIATRY 141NEUROPSYCHIATRY 142Simultanagnosia (cont)TestHave patient attempt to draw a linearound shapes (circle, square,triangle),or write with eyes open, thenclosed (with Balint's syndrome, closingeyes improves handwriting)MetamorphopsiaObjects are correctly recognized but aresubjectively distorted.Lesions of the occipital lobe produce simplerdeficits, while parietal lesions tend toproduce intermediate effects, , and temporallesions are associated with more complexdisorders.Teleopsia objects appear small and at adistance.NEUROPSYCHIATRY 143NEUROPSYCHIATRY 14424