Delayed Memory Task Research Articles

Acute Yohimbine Increases Laboratory-Measured Impulsivity in Normal Subjects

State-dependent changes in impulsivity may be related to norepinephrine. To examine possible relationships between norepinephrine and acute changes in impulsivity, we measured effects of yohimbine, which increases norepinephrine release by blocking alpha-2 noradrenergic receptors, on laboratory-measured impulsivity in healthy subjects without psychiatric or substance-use disorders. Impulsivity was assessed using the Immediate and Delayed Memory Tasks (IMT-DMT), derived from the Continuous Performance Test, before and after placebo or two doses of yohimbine, given 4 days apart. Blood pressure was monitored, and psychiatric symptoms were measured using self-rated visual analog scales. Yohimbine was associated with a dose-related increase in impulsive IMT commission errors, with an increase of > 50% relative to baseline at the higher dose. The activation factor of the Internal State Scale was increased at the same dose. These results are consistent with increased impulsivity in normal subjects given yohimbine, possibly related to increased norepinephrine.

Reduced Anterior Corpus Callosum White Matter Integrity is Related to Increased Impulsivity and Reduced Discriminability in Cocaine-Dependent Subjects: Diffusion Tensor Imaging

Brain imaging studies find evidence of prefrontal cortical dysfunction in cocaine-dependent subjects. Similarly, cocaine-dependent subjects have problems with behaviors related to executive function and impulsivity. Since prefrontal cortical axonal tracts cross between hemispheres in the corpus callosum, it is possible that white matter integrity in the corpus callosum could also be diminished in cocaine-dependent subjects. The purpose of this study was to compare corpus callosum white matter integrity as measured by the fractional anisotropy (FA) on diffusion tensor imaging (DTI) between 18 cocaine-dependent subjects and 18 healthy controls. The Barratt Impulsiveness Scale (BIS-11) and a continuous performance test: the Immediate and Delayed Memory Task (IMT/DMT) were also collected. Results of the DTI showed significantly reduced FA in the genu and rostral body of the anterior corpus callosum in cocaine-dependent subjects compared to controls. Cocaine-dependent subjects also had significantly higher BIS-11 scores, greater impulsive (commission) errors, and reduced ability to discriminate target from catch stimuli (discriminability) on the IMT/DMT. Within cocaine dependent subjects there was a significant negative correlation between FA in the anterior corpus callosum and behavioral laboratory measured impulsivity, and there was a positive correlation between FA and discriminability. The finding that reduced integrity of anterior corpus callosum white matter in cocaine users is related to impaired impulse control and reduced ability to discriminate between target and catch stimuli is consistent with prior theories regarding frontal cortical involvement in impaired inhibitory control in cocaine-dependent subjects.

Laboratory Measured Behavioral Impulsivity Relates to Suicide Attempt History

The purpose of this study was to examine the relationship between laboratory behavioral measured impulsivity (using the Immediate and Delayed Memory Tasks) and suicidal attempt histories. Three groups of adults were recruited, those with either: no previous suicide attempts (Control, n = 20), only a single suicide attempt (Single, n = 20), or multiple suicidal attempts (Multiple, n = 10). As hypothesized, impulsive responses increased with the number of suicide attempts (Control < Single < Multiple). This study helps to demonstrate how laboratory behavioral measures of impulsivity can be used to discriminate groups based on suicidal histories among samples not currently exhibiting significant suicidal behaviors.

P300 Event-Related Potential Amplitude and Impulsivity in Cocaine-Dependent Subjects

Previous studies report reduced amplitude of the P300 event-related potential in cocaine-dependent individuals. Cocaine dependence is also associated with increased impulsivity, possibly due to deficits in cognitive function that are associated with reduced P300 amplitude. In the current study, the relationship between cocaine dependence, impulsivity, and P300 amplitude were examined. An auditory oddball event-related potential task along with self-report (Barratt Impulsiveness Scale version 11) and behavioral laboratory (Immediate and Delayed Memory Task) measures of impulsivity were assessed in healthy controls (n = 14) and subjects who met DSM-IV criteria for current cocaine dependence (n = 17). P300 amplitude was reduced and self-reported and behavioral laboratory impulsivity scores were elevated among the cocaine-dependent group compared to controls. There was a positive correlation between the questionnaire and behavioral laboratory measures of impulsivity, and a negative correlation between impulsivity measures and P300 amplitude. The correlation between self-reported impulsivity scores and P300 amplitude remained after taking into account the number of childhood conduct disorder symptoms. This study supports the hypothesis that the basic neurophysiology responsible for the P300 amplitude in cocaine-dependent individuals is associated with impulsivity independent of a history of childhood conduct disorder symptoms.

Developmental amnesia and its relationship to degree of hippocampal atrophy

Two groups of adolescents, one born preterm and one with a diagnosis of developmental amnesia, were compared with age-matched normal controls on measures of hippocampal volume and memory function. Relative to control values, the preterm group values showed a mean bilateral reduction in hippocampal volume of 8-9% (ranging to 23%), whereas the developmental amnesic group values showed a reduction of 40% (ranging from 27% to 56%). Despite equivalent IQ and immediate memory scores in the two study groups, there were marked differences between them on a wide variety of verbal and visual delayed memory tasks. Consistent with their diagnosis, the developmental amnesic group was impaired relative to both other groups on nearly all delayed memory measures. The preterm group, by contrast, was significantly impaired relative to the controls on only a few memory measures, i.e., route following and prospective memory. We suggest that early hippocampal pathology leads to the disabling memory impairments associated with developmental amnesia when the volume of this structure is reduced below normal by approximately 20-30% on each side. Whether this is a sufficient condition for the disorder or whether abnormality in other brain regions is also necessary remains to be determined.

Validation of the Immediate and Delayed Memory Tasks in Hospitalized Adolescents with Disruptive Behavior Disorders

This study explores concurrent and criterion validity of a Continuous Performance Test, the Immediate and Delayed Memory Tasks (IMT/DMT). Concurrent validity was examined through comparison with collateral measures of impulsivity, while criterion validity was assessed by comparison of groups with differing levels of impulsive behavior, those with and without disruptive behavior disorders (DBD). DBDs in the DSM-IV include conduct disorder and oppositional defiant disorder, which are both largely characterized by impulsive behaviors. We compared group performance on the IMT/DMT and several collateral measures of impulsivity between adolescent controls (n = 22) and psychiatric inpatients with a DBD diagnosis (n = 22). Data collected indicated that (1) DBD patients emitted more commission errors; (2) commission errors, but not correct detections, were significantly correlated with collateral measures of impulsivity, and (3) in posthoc comparisons, those DBD patients with histories of physical fighting emitted the greatest number of commission errors, followed by DBD nonfighters, and then controls. Similar group performance differences were observed for collateral impulsivity measures. This study supports the use of commission error rates on the Immediate and Delayed Memory Tasks as a behavioral measure of impulsivity. With further development, objective measures like these may prove useful in clinical assessment procedures and in monitoring treatment outcome.

Commission error rates on a continuous performance test are related to deficits measured by the Benton Visual Retention Test.

This study is one in a series investigating the relationship between impulsive behavior on a Continuous Performance Test (i.e., the Immediate and Delayed Memory Task) and other cognitive deficits measured by clinical instruments. Forty-two adolescents were selected for two groups, controls and hospitalized patients with disruptive behavior disorders. Each adolescent completed the Immediate and Delayed Memory Task and the Benton Visual Retention Test. Our main findings were that, even when controlling for IQ, the Immediate and Delayed Memory Task commission errors were associated with adverse Benton performance, but only in the patient group. These results may be explained by a shared association between processes of impulsivity and other deficits of executive control that may interfere with successful performance of the Benton.

Familial Transmission of Continuous Performance Test Behavior: Attentional and Impulsive Response Characteristics

Continuous Performance Tests (CPTs) provide information on attentional processing and impulsive behavior. The results of previous research that used self-report measures have provided evidence for familial transmission (through genetic and/or environmental influences) of impulsive characteristics. The authors of the present study examined whether the impulsive behavioral parameters that are measured by the CPT also share familial relationships. The researchers asked 26 healthy parent-adolescent pairs to complete the Immediate and Delayed Memory Tasks (IMT/DMT; D. M. Dougherty, 1999; D. M. Dougherty, D. M. Marsh, & C. W. Mathias, 2002), a modified CPT (B. A. Cornblatt, N. J. Risch, G. Faris, D. Friedman, & L. Erlenmeyer-Kimling, 1988; H. E. Rosvold, A. Mirsky, I. Sarason, E. D. Breansome, Jr., & L. H. Beck, 1956), and the Barratt Impulsiveness Scale (BIS; J. H. Patton, M. S. Stanford, & E. S. Barratt, 1995), a self-report measure. The main findings can be summarized as follows: (a) commission errors (but not correct detections) on the IMT and DMT were correlated between parents and their adolescent children, (b) adolescents emitted a higher proportion of commission errors than did their parents, and (c) self-reported impulsivity (i.e., BIS) was correlated with commission errors for parents, but not for adolescents. The findings of this study support the use of an objective behavioral measure of impulsivity to assess familial relationships of impulsivity.

Advantage for emotional words in immediate and delayed memory tasks: could it be explained in terms of processing capacity?

Emotional stimuli are better remembered and recognized than neutral ones. This advantage for emotional stimuli has been repeatedly obtained when testing long-term retention. However, there are contradictory results concerning retention of emotional information when short retention intervals are used. The aim of the present study was, on the one hand, to test the effect of retention interval on memory for emotional stimuli (Experiment 1). The results showed that emotional information is better remembered than neutral information in both immediate and delayed memory tests, suggesting that the advantage for emotional information is not limited to long retention intervals. On the other hand, I tried to test the proposals made by Christianson and Nilsson (1984) and Bower (1992). These authors suggested that the advantage for emotional stimuli could be explained as emotional stimuli spending more processing capacity during acquisition, thus rendering less capacity available to encode simultaneously presented information (Experiments 2 and 3). Results showed that concurrent presentation of emotional stimuli did not inhibit the recall of neutral stimuli. These findings do not seem to support the proposals of Christianson and Nilsson (1984) and Bower (1992). According to these results, some mechanisms other than a greater spending of processing capacity have to be involved in the advantage for emotional information in memory.

Reliability estimates for the immediate and delayed memory tasks.

The Immediate and Delayed Memory Tasks are variations of the Continuous Performance Test. While previous research with the tasks has focused on group performance across multiple blocks and sessions, reliability estimates have not been established. We estimated reliability (1) between blocks of a single testing session (N=106), (2) across four sessions within a single testing day (N=20), and (3) across sessions on four consecutive testing days (N=20). Analyses indicated that the primary variable of interest, i.e., commission of errors, showed acceptable reliability within and across testing periods.

Immediate and delayed memory tasks: a computerized behavioral measure of memory, attention, and impulsivity.

The Immediate and Delayed Memory Task (IMT/DMT), a variant of the Continuous Performance Test (CPT), is a new software package designed to be a flexible research tool for the study of attention, memory, and impulsivity. This package allows researchers to determine the design to be used during a testing session and to manipulate many of the parameters. It features two components: the IMT and the DMT, both of which present sequential 2- to 7-digit stimuli with variable presentation rates and intertrial intervals. Subjects respond to identically matched stimuli presented consecutively, spanning a brief period of time (IMT), or to stimuli spanning a greater period of time (during which intervening stimuli to be ignored appear; DMT). Task complexity can be adjusted to suit applications for both children and adults. Preliminary studies have demonstrated that these laboratory tasks are sensitive to group differences, produce stable baselines of performance, and are sensitive to drug-induced performance decrements.

Comparisons of women with high and low trait impulsivity using behavioral models of response-disinhibition and reward-choice

Two types of behavioral models of impulsive behavior, response-disinhibition/attentional and reward-choice response models, were used to compare women grouped by high (Impulse+, n=43) and low (Impulse−, n=43) self-reported impulsive behavior on the Eysenck I 7 Questionnaire. Two of the four different tasks tested were response-disinhibition/attentional models; these included the Immediate and Delayed Memory Task and the GoStop Task. The other two tasks were based on the reward-choice model of impulsivity and included the Single Key Impulsivity Paradigm and the Two-Choice Reward Task. Of particular interest was whether commission errors (response-disinhibition/attentional paradigms) or a preference for smaller–sooner rewards over larger–later rewards (reward-choice) would differ between the groups. Participants completed one session of each task in a single day. The most significant findings were that the Impulse+ group had: (1) elevated commission errors; (2) lower stimulus discriminability (between target and catch stimuli); and (3) poorer response inhibition to a stop signal. Responding on the response-disinhibition/attentional tasks distinguished between the impulsivity groups while the reward-choice tasks did not. These results demonstrate that women who report higher levels of trait impulsivity respond in a manner consistent with previous studies examining impulsive behavior.

Effects of Moderate and High Doses of Alcohol on Attention, Impulsivity, Discriminability, and Response Bias in Immediate and Delayed Memory Task Performance

Prior studies that examined the effects of alcohol on Continuous Performance Test (CPT) performance have resulted in inconsistent outcomes. Most studies that examined the effects of alcohol on concentrated attention tasks (like the CPT) found little effect of alcohol on performance measures, even when doses that exceeded 0.8 g/kg were used. One likely reason for these inconsistencies is the varying difficulty (and sensitivity) of the task used, and as a result, comparisons between studies are difficult. This study is one in a series that examines the effects of alcohol on attention by using a difficult version of the CPT (Immediate and Delayed Memory Task--IMT/DMT). Our purpose for these studies has been two-fold, examining the effects of alcohol (1) on concentrated attention (i.e., correct detections) and (2) on errors (i.e., commission errors) previously correlated with impulsive behaviors. The first is important because previous studies have shown little effect of alcohol on attention, and the second is important because commission errors have been related to impulsive behaviors. In the IMT/DMT, participants respond to a briefly displayed number when it is identical to the one displayed before it. The procedure includes immediate and delayed conditions where successive stimuli to be matched are delayed by 0.5 sec or by 3.5 sec. The three stimulus types included target (identical match), catch (four of five digits match), and filler (no match) stimuli. Twenty subjects completed this task after consuming either a placebo drink or a drink that contained 0.5 g/kg or 1.0 g/kg of alcohol on different days. The main findings were that (1) alcohol decreased the percentage of correct identifications of target stimuli; (2) alcohol increased the percentage of commission errors in relation to the number of correct target responses; and (3) alcohol decreased discriminability whereas response bias became more conservative. These results clearly demonstrated a time-course effect of the 1.0 g/kg alcohol dose on attention, impulsivity, discrimination, and response criteria when a variety of dependent measures are used.

Effects of Moderate and High Doses of Alcohol on Attention, Impulsivity, Discriminability, and Response Bias in Immediate and Delayed Memory Task Performance

Effects of Moderate and High Doses of Alcohol on Attention, Impulsivity, Discriminability, and Response Bias in Immediate and Delayed Memory Task Performance

A Comparison Between Adults With Conduct Disorder And Normal Controls on a Continuous Performance Test: Differences in Impulsive Response Characteristics

Continuous Performance Test (CPT) responding was compared between 15 adults with a history (childhood/adolescent) of Conduct Disorder (CD) and 15 normal controls. Of particular interest was whether response latencies and commission errors, which have been suggested to be measures of impulsivity, would differ between the groups. The CPT procedure used included two conditions: Immediate Memory Task and Delayed Memory Task (IMT/DMT; Dougherty et al., 1998). Both the IMT (0.5-s delay) and DMT (3.5-s delay with distracter stimuli at 0.5-s intervals) required the subject to respond if a briefly displayed number was identical to the one presented before it. Stimuli included target (identical match), catch (four of five digits matched), and novel (no match). Participants completed six 22-min testing sessions scheduled across a single day. The most significant findings were that the CD group (compared to the control group) had (a) elevated commission errors (responses to catch stimuli); (b) lower stimulus discriminability (between target and catch stimuli); and (c) shorter response latencies. These results are consistent with the few previous studies indicating that these parameters are related to impulsive behaviors.

Alcohol Increases Commission Error Rates for a Continuous Performance Test

Studying the effects of alcohol on Continuous Performance Test (CPT) performance was of interest for two reasons, i.e., (1) perhaps because of the ease of the task used in previous experiments, alcohol has not been found to impair performance, and (2) CPT commission errors (described below) have been related to impulsive behavior. In this study, the CPT featured both an Immediate Memory Task (IMT) and a more difficult Delayed Memory Task (DMT). We compared the performance of 18 subjects under both alcohol and placebo conditions, using a within-subject design. Both the IMT (0.5-sec delay) and the DMT (3.5-sec delay, with distracter stimuli at 0.5-sec intervals) required the subject to respond if a briefly displayed number was identical to the one presented before it. Stimuli included target (identical match), catch (4 of 5 digits matched), and novel (random number) stimuli. On 2 separate days, subjects performed between administrations of three hourly placebo drinks or three hourly drinks containing 0.20 g/kg of alcohol (producing peak breath alcohol concentrations of approximately 0.035%). The main finding was that alcohol consumption increased responses to catch stimuli (i.e., commission errors) in the DMT. In contrast, performance in the IMT (the easier task) was unaffected by alcohol. Commission errors measured during peak breath alcohol concentrations were significantly correlated with scores on the Barratt Impulsivity Scale for both the IMT and DMT. Discriminability (A') between target and catch stimuli was reduced by alcohol for the DMT only. These data indicate that even small amounts of alcohol can produce measurable changes in CPT performance parameters if the task is of sufficient difficulty and that commission errors can be increased by alcohol consumption.

Immediate versus delayed visual memory task performance among schizophrenic patients and normal control subjects

In an exploratory study, 10 schizophrenic patients and 10 normal control subjects performed immediate and delayed memory tasks, which were variants of previously developed continuous performance tests. Both tasks required participants to identify five-digit numbers which were repeated. Numbers were presented in series for 500 ms each and separated by a 500-ms time-out period. In the immediate memory task, subjects were to respond if a number was identical to the one that had immediately preceded it. The delayed memory task differed from the first task in that a longer delay (3.5 s) between stimuli was introduced, and during this delay distracter stimuli appeared. While normal control subjects performed accurately on both tasks (exceeding 80% correct detections), schizophrenic patients performed poorly, performing worse on the delayed memory task than on the immediate memory task. Rates of commission errors (responses made to similar, but not identical numbers) were nearly equal between groups on the immediate memory task, but on the delayed memory task normal control subjects made relatively more commission errors while schizophrenic patients made fewer commission errors. No differences in response latencies were observed between subject groups or tasks. This paradigm may prove useful in discriminating subtle differences in immediate and delayed memory capability among psychiatric populations and normal control subjects.

Immediate and Delayed Memory Tasks during FMRI of Schizophrenic and Normal Subjects

Immediate and Delayed Memory Tasks during FMRI of Schizophrenic and Normal Subjects

Verbal and visuo‐spatial memory Two clinical tests administered to a group of normal subjects

Abstract.— A group of 165 normal subjects were examined on two memory tests in clinical use, the Word Pairs Test and the Visual Gestalts Test. The purpose of the study was to establish norms with the variables of age, sex, and length of schooling being taken into consideration. During the learning phase a complex interaction between all three factors was found for the Word Pairs, whereas in the Visual Gestalts scores were only affected by age. In the delayed memory task used in both tests, age was again found to be the only significant factor. Using quartile scores, it was found that females performed better than males on the verbal test and vice versa on the visuo‐spatial test. Normative data are presented for three age groups. A significant decline in performance appeared in the age group 40–49 years. The data became more heterogenous with an increase in the age of the subjects.

子どもにおける空間表象の変換に及ぼす感覚一運動的手がかりの効果

The present study aimed mainly at demonstrating the effect of two different sensory-motor cues on trausformation of spatial representation in children. A simplified version of Piaget's “-mountainsexperiment” was undertaken here through experiments I and II.Experiment IThe subjects were 30 boys and 30 girls. They were ranged in age from 4 ; 8 to 6 ; 9. In place of three mountains three objects, i. e., a cube, a bowling pin, and a cylinder, were used. The experiment ran as follows ; the three experimental situations were put into practice.(A) To predict the object's locations of a covered landscape after having turned the turn-table for 180 degrees on which the objects were arranged.(B) To predict the object's locations of a covered landscape after a child removed around turntable for 180 degrees.(C) To identify object's locations (perspectives) from the opposite position, in which a doll stood.(The Piaget-type task)Generally, moving around himself was more effective on the transformation of image than turning the stimulus frame, and (C) was most difficultfor children. There were no significant differencesbetween younger and older children.Experiment IIThe subjects were 23 boys and 29 girls at the age of 7. In the pre-test, the same materials as Experiment I were used according to the Piaget-type procedure. Ss were divided into four homogeneous groups according to the pre-test score. Each group had different experience at the next interim test.Group I: After the subjects turned the table for 90 or 180 degrees and then observed each objects' location during 15 seconds, they turned the table back to the original position and then reconstructed what they had seen.Group II: After the subjects removed around the turn-table for 90 or 180 degrees and then observed each objects' locations during 15 seconds, they went back to their original place and then reconstructed what they had seen.Group III: Having verbalized right-left and before-behind relations from various positions, they predicted the perspective landscape from another visual point (doll's position).Group IV: The subjects had the smile task as Group III except for verbalization. It was a kind of delayed memory task for Group I and II. The results of the interim test were as follows. The score of Group I was the best of the four. The score of Group I was significantly better than that of Group II.Immediately after the interim test, the post-test (the same task as the pretest) was administered. Its results of it were as follows. Among four groups, only Group II showed significant progress from the pre-test to the post-test. It was interesting that only Group II that had no observational effect showed significant progress in the post-test,.In general, through the interim and post-test, verbalizing effect had not found, and there were no significant difference between Group III and Group IV. In conclusion, it was most effective for the child's experience to remove himself for 90or 180 degrees and confirm the sight by their own eyes in the interim test.