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Europa Medicophysica 1998 June;34(2):97-102

Copyright © 1998 EDIZIONI MINERVA MEDICA

language: English

Impaired processing in visual object recognition. A single case study

Granà A. ¹, Gattinoni F. ², Di Benedetto P. ²

¹ Department of Psychology, University of Trieste, Italy; ² Rehabilitation Center, Azienda Ospedaliera “Ospedali Riuniti”, Trieste, Italy

Object rec­og­ni­tion is a com­plex abil­ity ­which ­involves the inter­play of a num­ber of dif­fer­ent func­tion­al com­po­nents (e.g. ­size, orien­ta­tion, dif­fer­ent ­types of ­stored knowl­edge). In ­this ­paper we ­report the ­case of S.G., a ­brain-dam­aged ­patient ­whose vis­u­al ­object rec­og­ni­tion def­i­cit was ­assessed and eval­u­at­ed ­with ref­er­ence to the func­tion­al mod­el pro­posed by Riddoch and Humphreys (­BORB). According to the pro­posed frame­work, S.G. had no dif­fi­cul­ties in encod­ing or link­ing togeth­er pre-cat­e­gor­i­cal fea­tures of vis­u­al pro­cess­ing, nor in rec­og­nis­ing an ­object ­viewed ­from an unusu­al pros­pec­tive. Her abil­ity to ­retrieve func­tion­al char­ac­ter­is­tics and asso­ci­a­tions ­between relat­ed ­objects ­appeared to be ­well pre­served. By con­trast, S.G. ­failed in com­par­ing the ­shape of pre­sent­ed ­objects ­with the ­shape of ­known ­objects; her ­object draw­ing ­from mem­o­ry was ­poor as was her nam­ing. This def­i­cit was inter­pret­ed as an impair­ment at the lev­el of ­stored knowl­edge of ­shapes. An addi­tion­al def­i­cit in ­name retriev­al was detect­ed. The ­authors empha­sise the impor­tance of mak­ing ref­er­ence to a func­tion­al mod­el in ­order to eval­u­ate and inter­pret the pat­tern of ­acquired cog­ni­tive dis­or­ders in ­terms of a spe­cif­ic “func­tion­al ­lesion” of a sin­gle or mul­ti­ple com­po­nents of the cog­ni­tive ­system. For ­this pur­pose, ­both quan­ti­ta­tive and qual­ita­tive infor­ma­tion of pre­served and ­impaired capa­bil­ities ­must be tak­en ­into ­account.