Comparison of the continuous performance test with and without working memory demands in healthy controls and patients with schizophrenia

The Penn Continuous Performance Test (PCPT), a measure of sustained visual attention developed for use in functional neuroimaging studies, was compare d with a standard CPT developed by Gordon Diagnostic Systems (GDS; Vigilanc e subtest). The PCPT and the GDS CPT were administered with a standard neur opsychological battery to 68 healthy adults to assess reliability and const ruct validity. The test had adequate internal consistency, and convergent v alidity was established through significant correlations between measures o f efficiency on the PCPT and the GDS CPT. With the exception of a significa nt correlation between efficiency measures on the GDS CPT and a measure of auditory sustained attention, neither version of the CPT correlated signifi cantly with other measures in the battery. Factor analysis showed that the PCPT loaded with the GDS CPT, In 39 patients with schizophrenia and 39 matc hed, healthy controls, equivalent impairment was evident on the two CPT tas ks. Neither version correlated significantly with symptom measurements. The se results support previous conclusions that sustained visual attention in schizophrenia is a core information processing deficit, not directly relate d to symptomatology. (C) 2001 Elsevier Science B.V. All rights reserved.