Continuous Performance Test Performance Research Articles

Emotional Problems Suppress Disorder/Performance Associations in Adult ADHD Assessment

Issues related to Attention Deficit Hyperactivity Disorder (ADHD) are commonly assessed using a combination of indicators, including patient report and performance on cognitive tasks. The current study investigates the potential that emotional problems may suppress the relationship between objective continuous performance test (CPT) results and ADHD symptoms in a sample of 53 young adults referred to an outpatient clinic for cognitive evaluations, 26 of whom met diagnostic criteria for ADHD. Data indicate that emotional problems and continuous performance represent unique elements of adult ADHD, whether assessed via interview or self-report. Results also indicate that emotional problems do suppress CPT–ADHD relations, suggesting that failure to control for emotional problems may account, in part, for modest associations in the literature between CPT performance and other indicators of ADHD.

Construct Validity of Parent Ratings of Inhibitory Control

Recent literature has emphasized the need to examine executive functions (EF) in children using multiple sources, including both parent rating and performance-based measures. Computerized Go/No-Go tests, including commercially available continuous performance tests (CPTs), represent one of the most commonly used methods of assessing inhibitory control—a variable central to the executive function construct. We examined the relationship between parent ratings of inhibitory control and CPT performance in two mixed clinical samples. Experiment 1 examined 109 children ages 6–18 using the Behavior Rating Inventory of Executive Function (BRIEF; Gioia, Isquith, Guy, & Kenworthy, 2000) and the Conners' CPT-II (Conners, 2000). In this sample, ratings on the BRIEF Inhibit scale (mean T-score = 62.3) were significantly higher than the CPT-II commissions score (mean T-score = 50.7; p < .0001); and the BRIEF and CPT-II scores were not highly correlated (r = − .12). Experiment 2 examined a sample of 131 children ages 7–18 using the BRIEF and the Tests of Variables of Attention (TOVA; Greenberg, 1996). In this sample, parent ratings on the BRIEF Inhibit scale (mean T-score = 56.8) were similar to TOVA commissions scores (mean T-score = 58.6; p = .33), although still poorly correlated (r = −.02). Factor analyses exploring covariance between BRIEF scales CPT-II variables (Experiment 1) and between BRIEF and TOVA (Experiment 2) yielded similar findings. In both experiments, all eight BRIEF scales loaded on a single factor, with no overlap with either the CPT-II or the TOVA. In mixed outpatient clinical samples, the BRIEF appears to measure different elements of inhibitory control than those assessed by computerized continuous performance tests.

Relating Children's Attentional Capabilities to Intelligence, Memory, and Academic Achievement: A Test of Construct Specificity in Children with Asthma

The relationship between attention, intelligence, memory, achievement, and behavior in a large population (N = 939) of children without neuropsychologic problems was investigated in children with mild and moderate asthma. It was hypothesized that different levels of children's attentional capabilities would be associated with different levels of intellectual, memory, and academic abilities. Children ages 6–12 at the eight clinical centers of the Childhood Asthma Management Program (CAMP) were enrolled in this study. Standardized measures of child neuropsychological and behavioral performance were administered to all participants, with analyses examining both the developmental trajectory of child attentional capabilities and the associations between Continuous Performance Test (CPT) scores and intellectual functioning, and measures of memory, academic achievement, and behavioral functioning. Findings demonstrated that correct responses on the CPT increase significantly with age, while commission errors decrease significantly with age. Performance levels on the CPT were associated with differences in child intellectual function, memory, and academic achievement. Overall these findings reveal how impairments in child attention skills were associated with normal levels of performance on measures of children's intelligence, memory, academic achievement, and behavioral functioning, suggesting that CPT performance is a salient marker of brain function.

Intra-dimensional/extra-dimensional set-shifting performance in schizophrenia: Impact of distractors

Background We sought to determine if a representative group of young chronic patients with schizophrenia would demonstrate selective impairments in set shifting processes of the CANTAB Intra-dimensional/extra-dimensional (IDED) task. We predicted that patients would have prominent difficulties with Compound Discrimination (C_D) (stage of the task in which irrelevant stimuli are introduced) and Extra-Dimensional Shifting (EDS) (stage of the task in which a new stimulus dimension must be attended) on the basis of the results of cortical hypodopaminergic states in subhuman primates (for C_D) and effects of dorsolateral prefrontal cortical lesions on set shifting and prior results in schizophrenia (for EDS). Methods We administered the IDED to 36 patients and 26 healthy controls. Additionally, we administered the Wisconsin Card Sorting Test (WCST), another test of set shifting, and a Continuous Performance Test (CPT) type task of attention to patients with schizophrenia in order to investigate which cognitive components accounted for performance difficulties at different stages of the IDED task. Results Patients had selective difficulties on C_D and EDS stages of the task. In schizophrenic patients early stages of the task involving the introduction and establishment of attentional set were correlated to CPT performance, while later set shifting stages were correlated with WCST categories attained. Conclusion We found evidence that patients with schizophrenia were susceptible to introduction of unreinforced irrelevant stimuli at the C_D stage, such that the previously rewarded target stimuli no longer held hegemony as a representation. This type of processing failure may reflect difficulties in stabilizing a representation and is consistent with effects of prefrontal hypodopaminergia in primates. Secondly, “survivors” of this stage experienced marked difficulties on EDS-stage, suggestive of classic prefrontal failures.

More severe sustained attention deficits in nonpsychotic siblings of multiplex schizophrenia families than in those of simplex ones

Sustained attention deficits measured by the Continuous Performance Test (CPT) have been proposed as an endophenotype of schizophrenia. However, little is known about whether sustained attention deficits in first-degree relatives of schizophrenic patients are associated with familial loading for schizophrenia. We examined 107 parents and 84 siblings of simplex schizophrenia families as well as 72 parents and 56 siblings of multiplex schizophrenia families, all nonpsychotic, using the Diagnostic Interview for Genetic Studies and two sessions of the CPT (undegraded and degraded). The effect of perceptual load was assessed using the residual of the regression of the degraded score on the undegraded one. Statistical models that can adjust for familial correlations were used to compare the CPT performance of relatives between the two types of families. Siblings from multiplex families exhibited worse performance on the degraded CPT and less proficiency in processing the perceptual load than those from simplex families. No such difference was observed for the parents on either CPT version. We concluded that sustained attention along with perceptual load processing is more impaired in the siblings of schizophrenic patients with high familial loading and that this finding might be useful for future genetic dissection of schizophrenia.

Effect of additional auditory and visual stimuli on continuous performance test (noise-generated CPT) in AD/HD children – usefulness of noise-generated CPT

The continuous performance test (CPT) is designed to measure sustained attention quantitatively. Several CPTs are used clinically. We have made changes to the conventional type of visual CPT, by displaying auditory and visual noise along with target or non-target stimuli. By influencing the recognition of the subjects in this way, the changes were intended to increase the sensitivity of detection of inattention and impulsiveness, to make CPT more useful for diagnosis, and to examine the effect of noise on AD/HD children during CPT performance. Its usefulness for AD/HD diagnosis and the reaction of AD/HD children to noise were examined using newly developed computer software. Using this CPT analysis, a significant difference was observed in all measurements, except mean reaction time, between the control and AD/HD groups, showing that it was useful as a supplementary diagnostic method for AD/HD, and was more useful in the younger age group than in the older age group, as the same for conventional CPTs. As compared to no-noise sessions, commission and omission errors both increased significantly in auditory and visual noise sessions. Thus, analyzing the changes in measurements during noise sessions will improve the diagnosis of inattention and combined AD/HD subtypes. Furthermore, it was suggested that analysis of the effects of noise on AD/HD children will benefit their handling in an educational environment. Since omission errors were decreased in AD/HD children by noise during the CPT performance as compared to the control group, noise may induce attention in AD/HD children. The present study presents new findings on the responses to noise of AD/HD children during the CPT.

Utility of a CPT in Diagnosing ADHD among a Representative Sample of High-Risk Children: A Cautionary Study

Continuous performance tests (CPTs) are widely used in the assessment and study of attention deficit hyperactivity disorder (ADHD). Although CPTs have reliably found differences between children with ADHD and normal controls, discriminating between children with ADHD and children with subclinical levels of behavioral or cognitive problems is a more clinically relevant and difficult endeavor. Additionally, most studies use convenience samples from clinical care settings that may not represent the ADHD population as a whole. The current study assessed the utility of a clinically used CPT, the Test of Variables of Attention (TOVA), in distinguishing between children with ADHD and children with subclinical levels of attention/behavior problems. Participants constituted a representative sample of elementary school students at high risk for ADHD, including 116 children with ADHD and 51 subclinical controls. Results found no significant differences between the ADHD and subclinical group on CPT variables, and CPT performance did not reliably predict group membership. Implications of the findings are discussed.

Effects of Cigarette Smoking on Spatial Working Memory and Attentional Deficits in Schizophrenia

Cigarette smoking rates in schizophrenia are higher than in the general population. To determine whether cigarette smoking modifies cognitive deficits in schizophrenia and to establish the role of nicotinic acetylcholine receptors (nAChRs) in mediating cigarette smoking-related cognitive enhancement. Neuropsychological assessments were performed at smoking baseline, after overnight abstinence, and after smoking reinstatement across 3 separate test weeks during which subjects were pretreated in a counterbalanced manner with the nonselective nAChR antagonist mecamylamine hydrochloride (0, 5, or 10 mg/d). Twenty-five smokers with schizophrenia and 25 control smokers. Outpatient mental health center. Visuospatial working memory (VSWM) and Continuous Performance Test (CPT) scores. In smokers with schizophrenia and control smokers, overnight abstinence led to undetectable plasma nicotine levels and an increase in tobacco craving. While abstinence reduced CPT hit rate in both groups, VSWM was only impaired in smokers with schizophrenia. Smoking reinstatement reversed abstinence-induced cognitive impairment. Enhancement of VSWM and CPT performance by smoking reinstatement in smokers with schizophrenia, but not the subjective effects of smoking, was blocked by mecamylamine treatment. Cigarette smoking may selectively enhance VSWM and attentional deficits in smokers with schizophrenia, which may depend on nAChR stimulation. These findings may have implications for understanding the high rates of smoking in schizophrenia and for developing pharmacotherapies for cognitive deficits and nicotine dependence in schizophrenia.

Norms of performance of sustained attention among a community sample: Continuous Performance Test study

The Continuous Performance Test (CPT) is a widely used measure of sustained attention, which is a preferred tool for assessing various mental functions. A well-established norm for CPT is essential when choosing a suitable threshold for classifying individuals as either case (CPT impairment) or non-case. The CPT performance of 900 adults who were randomly chosen from a community survey was measured to establish the norms for subgroups with different gender, age, and educational levels. The results revealed that age and educational level are significantly associated with the performance sensitivity (d') of CPT. Male subjects perform better than female subjects. Seventeen percent of the subjects scored higher on the masked CPT than on the unmasked CPT. Subjects who could not finish the masked CPT had the characteristics of older age and fewer years of education. When classifying a patient as case or non-case, his/her CPT performance should be considered relative to the norms for his/her gender, age, and educational levels.

Age-related decrements in performance on a brief continuous performance test

Research has revealed age-related decrements in performance on a variety of attention-related tasks, including sustained attention, selective attention, and inhibition tasks (e.g., [Armstrong, C. (1997). Selective versus sustained attention: A continuous performance test revisited. Clinical Neuropsychologist, 11(1), 18–33; Chao, L. L. & Knight, R. T. (1997). Prefrontal deficits in attention and inhibitory control with aging. Cerebral Cortex, 7(1), 63–69; Deaton, J. E., & Parasuraman, R. (1993). Sensory and cognitive vigilance: Effects of age on performance and subjective workload. Human Performance, 6(1), 71–97]). The continuous performance test (CPT) is a well-recognized measure of sustained attention and impulsivity [Riccio, C. A., Reynolds, C. R., & Lowe, P. (2001). Clinical applications of continuous performance tests: Measuring attention and impulsive responding in children and adults. New York: John Wiley & Sons, Inc.]. In the following study, the influence of age on CPT performance was assessed. Thirty-two healthy adults (age 19–82) completed a brief K–A version of the CPT under “clear” and “noisy” trial conditions. Under both conditions, participants’ accuracy on the CPT task decreased with age. In both conditions, the number of commission errors (including false alarms) increased significantly as age increased. This relationship differed with omission errors, as age accounted for a significant proportion of variance in omission errors under the noisy condition alone. Overall, this study provides evidence for age-related differences in performance on a brief CPT, particularly for deficits in selective response inhibition.

Attention deficits in bipolar disorder: a comparison based on the Continuous Performance Test

Although attentional deficits measured by Continuous Performance Tests (CPTs) have been observed in patients with bipolar disorder, their relationship with clinical state is not well understood. The identical pairs Continuous Performance Test (CPT-IP) shows particular promise as a measure sensitive to trait abnormalities in attentional function. In this study, the CPT-IP was administered to 27 patients with bipolar disorder (22 type I, 5 type II) and 25 demographically matched healthy comparison subjects, in order to assess the presence and nature of attentional deficits as a function of mood symptoms. Results showed significantly impaired CPT performance in bipolar patients compared with healthy subjects. Patients made fewer hits ( p < 0.01), were slower to respond ( p < 0.007), and had poorer discrimination ( p < 0.05) and bias ( p < 0.006) than comparison subjects. Severity of mania and depression was not correlated with any of the CPT measures. Our findings suggest that attentional dysfunction may be a trait deficit associated with bipolar illness. However, within-subjects longitudinal studies examining fluctuations in performance over time are needed.

Sustained attention deficits in nonpsychotic relatives of schizophrenic patients: a recurrence risk ratio analysis

Background In nonpsychotic parents and siblings of schizophrenic patients, the recurrence risk ratios of sustained attention deficits, as measured by the continuous performance test (CPT), were examined with a series of cut-off points. Methods Among 116 parents and 95 siblings of 91 schizophrenic probands in northern Taiwan, both undegraded and degraded sessions of the CPT were administered. Subjects' signal detection sensitivity of CPT performance (d′) was standardized against a community sample without (unadjusted z score) or with (adjusted z score) adjustment for age, gender, and educational level. Results Differences in the risk ratios between the parents and siblings that were based on the unadjusted z scores of CPT d′ diminished markedly if the adjusted z scores were used. As the cut-off point in the adjusted z score decreased from −2.5 to −3.0, the risk ratio increased continually for both the undegraded (10.1–18.8 for parents, 10.0–16.7 for siblings) and degraded (12.4–102.7 for parents, 8.6–72.0 for siblings) test. Conclusions Stringent cut-off criteria of CPT deficits with adjustment for demographic features leads to recurrence risk ratios greater than those based on schizophrenia alone in both parents and siblings of schizophrenic patients.

Nonpatient CPT performance varying target frequency and interstimulus interval on five response measures

Studies of sustained attention using the Continuous Performance Test (CPT) often incorporate effortful processing conditions and different response measures. Difficulty of attentional effort and interrelationships among response measures, however, have not been well established particularly with normal populations. This study investigated three CPT tasks which varied in interstimulus interval and target frequency in 107 nonpatient adults. This report also examined five response measures ( d′, a measure of discriminability; In( β), a measure of response bias; reaction time; and omission and commission errors). Findings indicated that a high target frequency condition was more effortful than a short interstimulus interval condition on all response measures. Further, d′, omission errors, and commission errors differentiated the short interstimulus interval condition from baseline, but reaction time and In( β) did not. Participants with faster reaction times in the high target frequency condition had fewer omission errors but more commission errors; these relationships may have been mediated by response bias. This suggested that response measures were interrelated but nonredundant, and that these relationships were influenced by attentional effort and response bias.

Conversation with Conan Kornetsky.

Conversation with Conan Kornetsky.

Recall bias in patients with schizophrenia

Thirty patients with a DSM-III-R diagnosis of schizophrenia were assessed for severity of schizophrenic symptoms using the Brief Psychiatric Rating Scale (BPRS) and were tested on a Continuous Performance Test (CPT) and a smooth pursuit eye tracking task. Negative symptoms were significantly correlated with eye tracking impairment (r=0.43, p<0.01) and CPT deficits (r=0.67, p<0.001), but performance on neither task was correlated with positive symptoms. CPT performance and eye tracking performance were modestly correlated with each other (r=0.39, p<0.01) and CPT performance was found to be a stronger predictor of negative symptoms than eye tracking performance. These data indicate that neurocognitive markers of vulnerability to schizophrenia are associated with negative rather than positive symptoms.

Continuous performance test performance in a normative epidemiological sample.

A 14-min continuous performance test (CPT) requiring a high rate of responding was administered to a probability-weighted random sample of 816 9-17-year-old children drawn from a population of 17,117 children in an ongoing epidemiological and longitudinal study in Western North Carolina. Systematic main effects of improved performance with older age were found in this age range for all variables, including reaction time (RT), RT standard error, errors of omission, errors of commission, and signal detection parameters (d' and beta). Significant gender main effects included more impulsive errors, less variability, and faster RT by males, with no interactions between age and gender. There were no main effects of ethnicity or interactions of ethnicity with age and/or gender. Large main effects of interstimulus interval (ISI; 1, 2, or 4-s intervals) and time block were present for most CPT performance measures. The normative data from the CPT should provide a useful framework for interpreting similar data in future studies of child and adolescent psychopathology.

Relations between Continuous Performance Test performance measures and ADHD behaviors.

The Conners' Continuous Performance Test (CPT) is a neuropsychological task that has repeatedly been shown to differentiate ADHD from normal groups. Several variables may be derived from the Conners' CPT including errors of omission and commission, mean hit reaction time(RT), mean hit RT standard error, d', and beta. What each CPT parameter actually assesses has largely been based upon clinical assumptions and the face validity of each measure (e.g., omission errors measure inattention, commission errors measure impulsivity). This study attempts to examine relations between various CPT variables and phenotypic behaviors so as to better understand the various CPT variables. An epidemiological sample of 817 children was administered the Conners' CPT. Diagnostic interviews were conducted with parents to determine ADHD symptom profiles for all children. Children diagnosed with ADHD had more variable RTs, made more errors of commission and omission, and demonstrated poorer perceptual sensitivity than nondiagnosed children. Regarding specific symptoms, generalized estimating equations (GEE) and ANCOVAs were conducted to determine specific relationships between the 18 DSM-IV ADHD symptoms and 6 CPT parameters. CPT performance measures demonstrated significant relationships to ADHD symptoms but did not demonstrate symptom domain specificity according to a priori assumptions. Overall performance on the two signal detection measures, d' and beta, was highly related to all ADHD symptoms across symptom domains. Further, increased variability in RTs over time was related to most ADHD symptoms. Finally, it appears that at least 1 CPT variable, mean hit RT, is minimally related to ADHD symptoms as a whole, but does demonstrate some specificity in its link with symptoms of hyperactivity.

CPT performance in major depressive disorder before and after treatment with imipramine or fluvoxamine

Numerous neuropsychological studies have reported deficits in cognitive and attentional functioning in depressed patients. However, there are limited data available about unmedicated depressed patients and the effects of antidepressant treatment on attentional performance. In this study, a Continuous Performance Test (CPT) was employed to evaluate the attentional performance of depressed inpatients during a drugfree period ( n=52) in comparison to healthy control subjects ( n=73). After 4 weeks of double-blind treatment with imipramine (TCA) or fluvoxamine (SSRI) at adequate plasma levels the CPT performance was studied again. We found that the unmedicated patients had a significantly impaired performance on all CPT parameters (reaction time, omission errors and commission errors) in comparison to the controls. None of the CPT parameters correlated with the severity of the depression or the level of psychomotor retardation. However, the CPT performance in the patient group was significantly related to subjective mood state (depression, tension). Double-blind treatment with imipramine or fluvoxamine resulted in an improvement of the CPT performance. In the imipramine treatment group the mean reaction time decreased significantly, and after treatment with fluvoxamine a significant decrease of the mean reaction time and the number of omission errors was detected. Both antidepressants induced a significant improvement of clinical state, but we did not find a relationship between the altered CPT performance and the changes on the clinical scales. Future studies should investigate other mechanisms underlying the improved attentional performance after treatment.

Relations Between Visual and Auditory Continuous Performance Tests in a Clinical Population: A Descriptive Study

Increased interest in auditory continuous performance tests (CPTs) exists despite the absence of a clear understanding about this procedure. The relation between auditory and visual CPTs and associations with IQ, achievement, and memory are evaluated in a referred sample of 634 children, ages 5.5 to 17.9. Age effects are found with CPT performance, regardless of modality. Total number correct or number of commissions correlations across tasks were greater than within-task number correct-number of commissions relations. The mean visual minus auditory correct difference score was 7.01; the mean commission difference score was -.85. Difference scores decreased with age and were not consistently related to other measures. Those with the lowest number correct on both CPTs (<25th percentile) were younger and had weaker short-term auditory memory and verbal learning skills; those falling in the problem quartile on commissions (>75th percentile) were younger and had poorer reading, verbal memory, and verbal learning. Total error scores (omissions + commissions) were inversely related to age. The auditory CPT has clinical utility, but other factors must be considered.

The continuous performance test: a window on the neural substrates for attention?

Attention is a complex process whose disturbance is considered a core deficit in a number of disorders [e.g., Attention Deficit Hyperactivity Disorder (ADHD), schizophrenia]. In 1956, Rosvold and colleagues [J. Consult. Psychol. 20 (1956) 343.] demonstrated that the continuous performance test (CPT) as a measure of sustained attention was highly sensitive to brain damage or dysfunction. These findings have been replicated with various populations and with various versions of the CPT. The CPT is now cited as the most frequently used measure of attention in both practice and research. Across studies, results are consistent with models of sustained attention that involve the interaction of cortical (frontal, temporal, parietal), subcortical (limbic, basal ganglia), and functional systems including the pathways between the basal ganglia, thalamus, and frontal lobes. Right hemisphere involvement (asymmetric response) is also evident across multiple studies. As such, the CPT demonstrates sensitivity to dysfunction of the attentional system whether this is due to diffuse or more focal damage/dysfunction or in conjunction with any specific disorder. CPT performance can be viewed as symptom specific (attentional disturbance), but it is not disorder specific (e.g., ADHD). Implications for neuropsychological interpretation of CPT results are presented.