- Email: [email protected]
Negative but not positive symptoms are associated with impairment on an ecologically valid test of executive function
154 ASSESSING VISUAL MASKING IN SCHIZOPHRENIA WITH THE PARACONTRAST AND METACONTRAST PROCEDURES Y. Rassovsky,* M. E Green, K. H. Nuechterlein, B. Breitmeyer, J. Mintz Psychiatry and Biobehavioral Sciences, UCLA Neuropsychiatrie Institute, Los Angeles, CA, USA Schizophrenic patients consistently demonstrate performance deficits on visual masking procedures. In visual masking, the subject's ability to process a target stimulus is reduced by another stimulus (mask) presented either before (forward masking) or after (backward masking) the target. Visual masking occurs typically through a combination of mechanisms (referred to as interruption and integration). Previous attempts to isolate the mechanisms have included use of relatively weak (i.e., low-energy) masks. Perhaps the most effective way to isolate the masking mechanism is through the use of a mask that surrounds, but does not spatially overlap, the target. This procedure is cailed paracontrast (for forward masking) and metacontrast (for backward masking). Although this latter procedure is excellent for isolating the interruption process, it has not been used (to our knowledge) in schizophrenia, and has only been used once with schizotypic college students. The purpose of the present study was to examine visual processing with the paracoutrast/metacontrast procedure in schizophrenic patients. We compared the results in this procedure to those from a low-energy masking condition. The visual masking tasks were administered to 103 schizophrenia patients and 49 normal controls. Compared with controls, patients showed deficits in both paracontrast and metacontrast procedures. The masking deficits were comparable in magnitude for both components (no group by paracontrast/metaeontrast interaction). There was no group by condition interaction, indicating that the deficits were also comparable in magnitude in the paracontrast/metacontrast procedure and the low-energy masking condition. These results suggest that the paracontrast/metacontrast procedure is roughly as sensitive in detecting deficits in early visual processing among schizophrenics as the low-energy procedure, despite the fact that it does not involve any spatial overlap of target and mask. Furthermore, as these deficits appear to reflect vulnerability to schizophrenia, the ability of the paracontrast/metacontrast procedure to disentangle the mechanisms underlying the masking effect makes this procedure well suited for studying potential pathophysiological processes that might be involved in schizophrenia. Funding for this project came from NIMH grant MH-43292 to Dr. Green.
NEGATIVE BUT NOT POSITIVE SYMPTOMS ARE ASSOCIATED WITH IMPAIRMENT ON AN ECOLOGICALLY VALID TEST OF EXECUTIVE FUNCTION C. D. Rice,* E. Pomarol-Clotet, H. Boos, T. Manly, D. J. D o n e , E J. M c K e n n a
Psychology, University of HertJordshire, Hertfordshire, United Kingdom It has been proposed that negative symptoms are a manifestation of frontal lobe dysfunction in schizophrenia. However, studies attempting to relate negative symptoms to poor executive test performance have had conflicting findings. We administered the Hotel Test, an ecologically valid executive test, to 36 schizophrenic patients and 20 normal controls matched for age and estimated IQ. The test requires participants to work on a number of different tasks related to hotel
11. Psychology, Neuromanagement. It emphasises ability to monitor the time, switch between tasks and keep track of intentions. The schizophrenic patients consisted of prospectively recruited asymptomatic patients (N=12), patients with only positive symptoms (N=14) and patients with only negative symptoms (N=10). All patients were intellectually intact (WAIS-R IQ>80). Patients were also administered conventionai tests of executive function (Brixton and Hayting Tests, Cognitive Estimates Test, verbal fluency). Performance of the asymptomatic patients on the Hotel Test was not significantly impaired compared to the normal controls (tasks attempted-~.50, sd=l.00 Vs 4.95, sd=0.22; NS). Patients with positive symptoms showed marginal impairment (tasks attempted=4.57, sd=0.76 Vs 4.95, sd=0.22; p=0.053). Patients with negative symptoms were significantly impaired, however (tasks attempted=3.80, sd= 1.14 Vs 4.95, sd=0.22; p<0.001). Performance on the conventional executive tests did not distinguish the three patient groups. The results suggest that ecologically valid tests, such as the Hotel Test, may be sensitive to a type of executive dysfunction specifically linked to negative symptoms.
A COMPARISON OF IMPLICIT A N D EXPLICIT N O N V E R B A L MEMORY IN SCHIZOPHRENIC PATIENTS A N D THEIR FIRST-DEGREE RELATIVES O. Robles,* T. A. Blaxton, J. M. Gold, A. N. Kakoyannis, H. A d a m i , G. K. T h a k e r
Schizophrenia Related Disorders, Maryland Psychiatric Research Center, Baltimore, MD, USA This study evaluated whether episodic memory performance in schizophrenic patients and their first degree relatives varies as a function of retrieval mode. Two sets of 35 non-nameable visuospatial designs assessing nonverbal memory yet different in their retrieval modality (yes/no recognition vs. repetition priming pleasant/unpleasant determination), were used. Methods were the same for both explicit and implicit encoding sessions. Subjects were presented 35 abstract designs, one at a time, and were asked to decide whether they had more than one horizontal line. During the retrieval phase subjects viewed 70 designs (35 previously presented items intermixed with 35 non studied items). In the explicit memory test individuals were asked to decide whether the current stimulus had been previously presented, by answering yes or no. In the implicit memory test, participants were required to decide whether the current stimulus was pleasant or unpleasant. Unlike explicit tasks, implicit tests do not require reference to the prior study episode. Subject groups tested included schizophrenic patients, first degree relatives with and without schizophrenia spectrum personality (SSP), and community subjects with and without SSE Preliminary data indicate that both ill probands and their SSP relatives have impaired performance in explicit memory, when compared to the other groups. Both of these groups showed poorer discriminability (lower d', calculated from a combination of the number of hits and false alarms) and gave more liberal responses (lower [3, increasing the rate of false alarms to maximize hits). On the other hand, when implicit performance was assessed, all the groups (including patients) showed evidence of priming (calculated from a combination of the number of pleasant responses obtained for studied items and non-studied items) with no significant differences among them. The impairments observed in schizophrenic patients and their SSP relatives on the yes/no recognition task, do not appear to generalize to the test of implicit memory. Supported by NARSAD, and a pre-doctoral scholarship from the Basque Government, Spain.
International Congress on Schizophrenia Research 2003
NEGATIVE BUT NOT POSITIVE SYMPTOMS ARE ASSOCIATED WITH IMPAIRMENT ON AN ECOLOGICALLY VALID TEST OF EXECUTIVE FUNCTION C. D. Rice,* E. Pomarol-Clotet, H. Boos, T. Manly, D. J. D o n e , E J. M c K e n n a
Psychology, University of HertJordshire, Hertfordshire, United Kingdom It has been proposed that negative symptoms are a manifestation of frontal lobe dysfunction in schizophrenia. However, studies attempting to relate negative symptoms to poor executive test performance have had conflicting findings. We administered the Hotel Test, an ecologically valid executive test, to 36 schizophrenic patients and 20 normal controls matched for age and estimated IQ. The test requires participants to work on a number of different tasks related to hotel
11. Psychology, Neuromanagement. It emphasises ability to monitor the time, switch between tasks and keep track of intentions. The schizophrenic patients consisted of prospectively recruited asymptomatic patients (N=12), patients with only positive symptoms (N=14) and patients with only negative symptoms (N=10). All patients were intellectually intact (WAIS-R IQ>80). Patients were also administered conventionai tests of executive function (Brixton and Hayting Tests, Cognitive Estimates Test, verbal fluency). Performance of the asymptomatic patients on the Hotel Test was not significantly impaired compared to the normal controls (tasks attempted-~.50, sd=l.00 Vs 4.95, sd=0.22; NS). Patients with positive symptoms showed marginal impairment (tasks attempted=4.57, sd=0.76 Vs 4.95, sd=0.22; p=0.053). Patients with negative symptoms were significantly impaired, however (tasks attempted=3.80, sd= 1.14 Vs 4.95, sd=0.22; p<0.001). Performance on the conventional executive tests did not distinguish the three patient groups. The results suggest that ecologically valid tests, such as the Hotel Test, may be sensitive to a type of executive dysfunction specifically linked to negative symptoms.
A COMPARISON OF IMPLICIT A N D EXPLICIT N O N V E R B A L MEMORY IN SCHIZOPHRENIC PATIENTS A N D THEIR FIRST-DEGREE RELATIVES O. Robles,* T. A. Blaxton, J. M. Gold, A. N. Kakoyannis, H. A d a m i , G. K. T h a k e r
Schizophrenia Related Disorders, Maryland Psychiatric Research Center, Baltimore, MD, USA This study evaluated whether episodic memory performance in schizophrenic patients and their first degree relatives varies as a function of retrieval mode. Two sets of 35 non-nameable visuospatial designs assessing nonverbal memory yet different in their retrieval modality (yes/no recognition vs. repetition priming pleasant/unpleasant determination), were used. Methods were the same for both explicit and implicit encoding sessions. Subjects were presented 35 abstract designs, one at a time, and were asked to decide whether they had more than one horizontal line. During the retrieval phase subjects viewed 70 designs (35 previously presented items intermixed with 35 non studied items). In the explicit memory test individuals were asked to decide whether the current stimulus had been previously presented, by answering yes or no. In the implicit memory test, participants were required to decide whether the current stimulus was pleasant or unpleasant. Unlike explicit tasks, implicit tests do not require reference to the prior study episode. Subject groups tested included schizophrenic patients, first degree relatives with and without schizophrenia spectrum personality (SSP), and community subjects with and without SSE Preliminary data indicate that both ill probands and their SSP relatives have impaired performance in explicit memory, when compared to the other groups. Both of these groups showed poorer discriminability (lower d', calculated from a combination of the number of hits and false alarms) and gave more liberal responses (lower [3, increasing the rate of false alarms to maximize hits). On the other hand, when implicit performance was assessed, all the groups (including patients) showed evidence of priming (calculated from a combination of the number of pleasant responses obtained for studied items and non-studied items) with no significant differences among them. The impairments observed in schizophrenic patients and their SSP relatives on the yes/no recognition task, do not appear to generalize to the test of implicit memory. Supported by NARSAD, and a pre-doctoral scholarship from the Basque Government, Spain.
International Congress on Schizophrenia Research 2003