Neglect dyslexia: A matter of "good looking"

Brain-damagedpatientswithright-sidedunilateralspatialneglect(USN)oftenmakeleft-sidederrorsin
reading singlewordsorpseudowords(neglectdyslexia,ND).Weproposethatbothleftneglectandlow
fixation accuracyaccountforreadingerrorsinneglectdyslexia.
EyemovementswererecordedinUSNpatientswith(ND+) andwithout(ND) neglectdyslexiaand
in amatchedcontrolgroupofrightbrain-damagedpatientswithoutneglect(USN). UnlikeND and
controls, ND+ patients showedleftlateralizedomissionerrorsandadistortedeyemovementpatternin
both areadingaloudtaskandanon-verbalsaccadictask.Duringreading,thetotalnumberof fixations
waslargerinthesepatientsindependentofvisualhemispace,andmost fixations wereinaccurate.
Similarly,inthesaccadictaskonlyND+ patients wereunabletoreachthemovingdot.Athird
experimentaddressedthenatureoftheleftlateralizationinreadingerrordistributionbysimulating
neglect dyslexiainND patients. ND and USN patients hadtoperformaspeededreading-at-
threshold taskthatdidnotallowforeyemovements.Whenstimulusexplorationwasprevented,ND
patients, butnotcontrols,producedapatternoferrorssimilartothatofND+ with unlimitedexposure
time (e.g.,left-sidederrors).
WeconcludethatneglectdyslexiareadingerrorsmayariseinUSNpatientsasaconsequenceofan
additional andindependentdeficit unrelatedtotheorthographicmaterial.Inparticular,thepresenceof
an alteredoculo-motorpattern,preventingtheautomaticexecutionofthe fine saccadiceyemovements
involvedinreading,uncovers,inUSNpatients,theattentionalbiasalsoinreadingsinglecentrally
presentedwords.