 PERGAMON Neuropsychologia 26 "0888# 492Ð409 9917!2821:88:,*see front matter Þ 0888 Elsevier Science Ltd[ All rights reserved[ PII]S9917!2821"87#99957!1 Delayed recognition memory in Parkinson|s disease] a role for working memory< Glenn T[ Stebbins a\ \ John D[ E[ Gabrieli a\b \ Francesca Masciari a \ Laura Monti a \ Christopher G[ Goetz a a Department of Neurological Sciences\ Rush Medical College\ Suite 349\ 0534 W[ Jackson\ Chicago\ IL 59501\ USA b Department of Psychology\ Stanford University\ USA Received 2 June 0886^ accepted 14 May 0887 Abstract Immediate and delayed recognition memory for words was examined in a sample of 05 non!demented patients with Parkinson|s disease and 05 normal control participants of equivalent age and educational attainment[ The patients\ relative to control participants\ had intact immediate but impaired delayed recognition memory performance[ Patients were also impaired on tests of free and cued recall\ working memory and a measure of psychomotor processing speed[ Processing speed was a signi_cant covariate for delayed recognition\ free and cued recall and working memory performance\ but not for immediate recognition performance[ These results suggest that the same cognitive processes which support performance on tests of recall and working memory also support performance on tests of delayed recognition[ Þ 0888 Elsevier Science Ltd[ All rights reserved[ Keywords] Cognition and basal ganglia^ Fronto!striatal memory system 0[ Introduction Non!demented patients with Parkinson|s disease "PD# show a variable pattern of performance on tests of declarative memory[ In many studies\ they are intact on recognition memory tests ð5\ 05\ 19\ 20\ 44Ł\ but impaired on tests of recall ð5\ 05\ 19\ 46Ð48Ł\ recall of temporal order ð09\ 19\ 31\ 45\ 52Ł\ recollection of source ð48Ł and self!ordered pointing ð19\ 39Ł[ The precise pattern of memory ability and disability varies across studies\ prob! ably due to variations in disease severity\ treatment and other factors "e[g[ Ref[ ð39Ł#[ Many studies\ however\ report a dissociation between intact recognition and imp! aired recall of items\ order or source[ The frequent dissociation between intact and impaired performance on declarative memory tests in PD patients contrasts with that of patients with amnesia or Alzh! eimer|s disease in whom performance on all tests of declarative memory is impaired "e[g[ Refs[ ð00\ 43Ł#[ The dissociation of performance on di}erent declarative memory tests in PD is\ however\ similar to that seen in patients with focal frontal!lobe lesions "e[g[ Refs[ ð10\ 15\ 16\ 26\ 28\ 30Ł# or other degenerative striatal diseases\  Corresponding author[ Tel[] ¦0!201!321!4922^ Fax] ¦0!201!321! 8221^ E!mail] gstebbinÝrpslmc[edu[ such as Gilles de la Tourette syndrome ð44Ł and Hunt! ington|s disease ð49Ł[ The frontal!lobes and striatum are highly interconnected ð0Ł and the common pattern of impaired recall and intact recognition in patients with damage to these structures suggest that the integrity of a fronto!striatal neural system is essential for recall but not for recognition[ It has been hypothesized that the pattern of declarative memory test performance in PD is due to impairments in the cognitive processes which support the development and utilization of strategic operations ð19Ł[ Strategic oper! ations require the manipulation of information in declarative memory\ rather than simply verifying the presence of information in declarative memory[ In this regard\ recognition memory tests require minimal stra! tegic operations because the participant is simply required to verify\ from among foils and recently pre! sented targets\ which stimuli had been previously enco! untered[ The determinant of performance is a non! strategic operation of externally guided search of memory[ In contrast\ recall tests do not require veri! _cation of externally presented targets and foil\ but rather require the reconstruction of the study episode[ Thus\ recall tests place a great demand upon strategic oper! ations because the participant must develop an internally generated strategy to guide memory search[