Cerebral Achromatopsia Research Articles

OBSERVATIONS ON COLOUR AGNOSIA.

associated withfamiliar objects. He named thisdefect 'amnestic colourblindness' andregarded itas 'related toaphasia'. Lewandowsky (1908) described another case, andexplained thedefect asresulting froma'dissociation oftheideaofthecolour from thatoftheobject'. Sittig (1921) presented afuller casestudy ofa patient whohadsustained a left temporo-occipital shrapnel wound,resulting ina slight receptive butmarkedexpressive aphasia, as wellasaninability topick outcoloured woolsto correspond tonamedobjects ortonameappropriate objects whenshownacolour. Yethewasnotcolour blind andcould recognize colours previously shown tohim.He coulddetect pictures whichhadbeen deliberately wrongly coloured. A similar, though milder case appears tohavebeenthat ofHeilbronner (1906), whosepatient misnamed colours butwould correctly allocate objects tocolours, and'usually' colours toobjects. Goldstein andGelb(1918) saw intheir caseofcolour agnosia an'impairment ofthe categorical attitude' inrelation tocolours. Their patient wasreported only tobeabletoattach the exactly correct colour toanobject andnotonethat merely fell intotheright colour category. Lange (1936), reviewing thesubject, wasunable todecide whether colour agnosia isanaphasic manifestation oratruerecognition defect. Hedid, however, point outthatGoldstein andGelb's explanation would seemtobeapplicable tonocaseother thantheir own. Stengel (1948) reported twofurther cases, the first ofwhich hestudied ingreat detail. Thefurther casepresented belowresembles Stengel's case1in manyrespects. CASEREPORT

The Syndrome of Visual Alexia with Colour Agnosia

Cases showing alexia which is not part of a general visual agnosia or of a speech disorder (letter or word blindness, cécité verbale pure) are uncommon and deserve careful study for a variety of reasons. The conception of word blindness as loss of visual memories due to a localized cerebral lesion (Hinshelwood, 1917) has been challenged by later investigators who aimed at a more general analysis of impairment of cerebral functions. The application of the principles of Gestalt psychology has introduced new aspects into the study of word blindness. Investigations into acquired word blindness, apart from their psychological and neuro-pathological interest, are of value for the understanding of congenital word blindness which has been found to be a condition of considerable practical importance. It was the investigation of cases of acquired word blindness which led Hinshelwood to the first full description of the congenital disability.

PARTIAL CORTICAL BLINDNESS WITH PRESERVATION OF COLOR VISION

It is a fact long established by clinical observation and pathologic studies that cortical and subcortical lesions may give rise to dissociation of color perception from visual acuity, namely, loss of the former without impairment of the latter ; and it is well known that in impairment of vision, whether peripheral or central, the first to be lost and the last to be regained is the perception of color. In addition to this dissociation between color and light perception, other types of dissociation in the recognition and naming of various colors have been described. Paralleling the disturbances in the realms of speech and general sensation, distinction is made between color agnosia and loss of color vision. For instance, a patient may fail to recognize or distinguish colors and yet retain the memory of color. These dissociations and the pathologic and psychologic problems to which they give rise, and particularly