Inhibitory Control Test Research Articles

Executive Functions in Pathologic Gamblers Selected in an Ecologic Setting

Recent studies have reported deficits in measures of decision making in pathologic gamblers (PGs) suggesting an involvement of the prefrontal cortex in the pathophysiology of this disorder. As only 7% to 12% of PGs are thought to seek treatment, most of the studies have relied on few specifically selected groups of PGs recruited from psychiatric units who were undergoing or seeking treatment and therefore their results are poorly representative of the general PG population. The present study compared decision making and executive functions among 11 PGs who were selected from an ecologic setting and 11 healthy controls. The PG group selected fewer advantageous cards on a decision-making task, the Iowa Gambling Task, and made more commission errors on the Go-No Go task, a test of inhibitory control, compared with controls. The impairments in decision making are similar to those previously reported in individuals with prefrontal lesions and treatment-seeking PGs. PGs also presented impairment in tasks of inhibitory control suggesting an involvement of the prefrontal cortex in the pathophysiology of pathologic gambling (PG). The deficits in decision making and inhibition of irrelevant information observed in this study may have distinct but additive effects upon the development of PG behavior.

Minimal hepatic encephalopathy matters in daily life

Minimal hepatic encephalopathy is a neuro-cognitive dysfunction which occurs in an epidemic proportion of cirrhotic patients, estimated as high as 80% of the population tested. It is characterized by a specific, complex cognitive dysfunction which is independent of sleep dysfunction or problems with overall intelligence. Although named "minimal", minimal hepatic encephalopathy (MHE) can have a far-reaching impact on quality of life, ability to function in daily life and progression to overt hepatic encephalopathy. Importantly, MHE has a profound negative impact on the ability to drive a car and may be a significant factor behind motor vehicle accidents. A crucial aspect of the clinical care of MHE patients is their driving history, which is often ignored in routine care and can add a vital dimension to the overall disease assessment. Driving history should be an integral part of care in patients with MHE. The lack of specific signs and symptoms, the preserved communication skills and lack of insight make MHE a difficult condition to diagnose. Diagnostic strategies for MHE abound, but are usually limited by financial, normative or time constraints. Recent studies into the inhibitory control and critical flicker frequency tests are encouraging since these tests can increase the rates of MHE diagnosis without requiring a psychologist. Although testing for MHE and subsequent therapy is not standard of care at this time, it is important to consider this in cirrhotics in order to improve their ability to live their life to the fullest.

Is the inhibitory control test as accurate as standard psychometric testing for diagnosing hepatic encephalopathy?

Is the inhibitory control test as accurate as standard psychometric testing for diagnosing hepatic encephalopathy?

Navigation skill impairment: Another dimension of the driving difficulties in minimal hepatic encephalopathy

Patients with minimal hepatic encephalopathy (MHE) have attention, response inhibition, and working memory difficulties that are associated with driving impairment and high motor vehicle accident risk. Navigation is a complex system needed for safe driving that requires functioning working memory and other domains adversely affected by MHE. The aim of this study was to determine the effect of MHE on navigation skills and correlate them with psychometric impairment. Forty-nine nonalcoholic patients with cirrhosis (34 MHE+, 15 MHE-; divided on the basis of a battery of block design, digit symbol, and number connection test A) and 48 age/education-matched controls were included. All patients underwent the psychometric battery and inhibitory control test (ICT) (a test of response inhibition) and driving simulation. Driving simulation consisted of 4 parts: (1) training; (2) driving (outcome being accidents); (3) divided attention (outcome being missed tasks); and (4) navigation, driving along a marked path on a map in a "virtual city" (outcome being illegal turns). Illegal turns were significantly higher in MHE+ (median 1; P = 0.007) compared with MHE-/controls (median 0). Patients who were MHE+ missed more divided attention tasks compared with others (median MHE+ 1, MHE-/controls 0; P = 0.001). Similarly, accidents were higher in patients who were MHE+ (median 2.5; P = 0.004) compared with MHE- (median 1) or controls (median 2). Accidents and illegal turns were significantly correlated (P = 0.001, r = 0.51). ICT impairment was the test most correlated with illegal turns (r = 0.6) and accidents (r = 0.44), although impairment on the other tests were also correlated with illegal turns. Patients positive for MHE have impaired navigation skills on a driving simulator, which is correlated with impairment in response inhibition (ICT) and attention. This navigation difficulty may pose additional driving problems, compounding the pre-existing deleterious effect of attention deficits.

Inhibitory deficits in attention-deficit/hyperactivity disorder are independent of basic processing efficiency and IQ

A substantial proportion of children with attention-deficit/hyperactivity disorder (ADHD) show deficits on inhibitory control tests. However, questions remain about (i) the extent of these deficits across different inhibitory domains, (ii) their relationship to deficits in non-executive processes and (iii) whether they extend into adolescence. Seventy-seven children and adolescents with ADHD and 50 non-ADHD controls completed three inhibitory tasks, a simple two choice RT task (2CR) and an IQ assessment. ADHD was moderately associated with deficits on all tasks (effect sizes d=0.5-0.9). Deficits were equally marked in childhood and adolescence. Inhibitory deficits were not associated with IQ and, although reduced substantially, remained significant after performance on a simple reaction time task was controlled for statistically. In highlighting the significant, but limited, role of inhibitory deficits in ADHD, these results are consistent with recent accounts that emphasize the neuropsychological heterogeneity of this condition.

Verbal fluency dysfunction in euthymic bipolar patients: A controlled study

ObjectiveTo study the executive functioning in euthymic bipolar patients in comparison to healthy controls and to examine the relationship between neuropsychological deficits and clinical variables. MethodsTwenty-five euthymic bipolar patients and 31 controls underwent a battery of executive tasks including mental flexibility, inhibitory control and verbal fluency tests. ResultsThere were no significant differences between bipolar patients and controls in relation to mental flexibility and inhibitory control. However, patients performed worse than controls on verbal fluency tests. Poor performances on the Stroop Test and the Hayling and Brixton Tests — part A were associated to lifetime occurrence of psychotic symptoms, prior number of episodes, and previous hospitalizations. ConclusionsIn our study, only verbal fluency tests differentiated bipolar euthymic patients from healthy controls. Patients who showed deficits in information processing speed and inhibitory control had more episodes and hospitalizations and lifetime occurrence of psychotic symptoms.

The Role of Cognitive Control in Cocaine Dependence

While hedonic and reward-related processes are central to drug use and dependence, this article focuses on the contribution that cognitive processes may make to addiction. In particular, attention is drawn to those processes involved in exercising control over behavior as drug dependence is characterized by risky, impulsive behavior. Functional neuroimaging implicates prefrontal deficits in cocaine dependence with an emerging picture of cocaine users having attentional biases towards drug-related stimuli, poor performance in laboratory tests of inhibitory control, and compromised monitoring and evaluation of their behavior. Combined, these deficits may contribute to the continuation of use in dependent individuals and may qualify as important targets for therapeutic interventions.

Buprenorphine—A review of its role in neuropathic pain

The use of opioids for the treatment of neuropathic pain remains somewhat controversial, since earlier studies indicate that neuropathic pain is generally less responsive to pure micro-opioid analgesia. A growing body of evidence now suggests that different opioids affect different pain pathways, and emerging data support the possibility of a role for buprenorphine in the management of neuropathic pain. This article reviews the preclinical and clinical data for the role of buprenorphine in the treatment of neuropathic pain. Literature searches were carried out using PubMed (1988 to September 2006). Search terms included buprenorphine and neuropathic pain, as well as neuropathy, painful neuropathy, hyperalgesia, and allodynia. Clinical studies and case studies were included. Several assays, including the formalin, cold tail flick, and diffuse noxious inhibitory control tests, have revealed buprenorphine's potential efficacy in various pain types. These findings seem to support hypotheses regarding its unique analgesic mechanisms as compared with pure micro-opioids. The exact mechanism of this analgesic efficacy remains unknown. Preclinical assessments of buprenorphine demonstrate its sustained antihyperalgesic effect in several models of neuropathic pain. These findings are supported in clinical studies of oral, intrathecal, intravenous, and transdermal buprenorphine. Furthermore, these studies have demonstrated that, despite there being a ceiling effect for respiratory depression, no relevant analgesic ceiling effect is found with buprenorphine. Further studies are certainly warranted to identify the clinical neuropathic syndromes that are most sensitive to buprenorphine treatment, and to compare buprenorphine with other opioids in head-to-head trials of neuropathic pain.

Inhibitory Control Test Is a Simple Method to Diagnose Minimal Hepatic Encephalopathy and Predict Development of Overt Hepatic Encephalopathy

To compare inhibitory control test (ICT), a simple/rapid test of attention, to a standard psychometric battery (SPT) to diagnose minimal hepatic encephalopathy (MHE) and predict development of overt hepatic encephalopathy (OHE) in cirrhotic patients. Fifty nonalcoholic cirrhotics and 50 age/educational-status-matched controls were given ICT and SPT in the same sitting. Performance impaired beyond two standard deviations of controls was considered MHE in cirrhotics. ICT results (lure/target response and lures/person) were compared between controls and cirrhotics and within cirrhotics with/without MHE. Receiver-operating characteristic analysis was used to study ICT for MHE diagnosis. Twenty subjects were administered SPT and ICT twice to assess test-retest reliability. All cirrhotics were followed routinely for the development of OHE. Cirrhotics performed worse than controls on SPT and ICT. Using SPT, 39 cirrhotics had MHE. ICT was administered faster than SPT (15 vs 37 min). Cirrhotics with MHE had significantly higher lure (28%vs 3%) and lower target response (91%vs 96%) compared with those without MHE. Lure/person >5 had 90% sensitivity/specificity for MHE diagnosis. AUC for receiver-operating characteristic for lures alone was 95.8%. Lure and target responses were highly correlated (r= 0.9) between sessions showing high test-retest reliability. Five (10%) patients developed OHE on f/u of 26 +/- 10 months; all five had been diagnosed with MHE using ICT and SPT. None of the five patients with discordant results on SPT and ICT developed OHE. ICT has good sensitivity/specificity for MHE diagnosis, is reliable and is equivalent to SPT for predicting OHE development.

Profile of executive deficits in cocaine and heroin polysubstance users: common and differential effects on separate executive components

Structure of executive function was examined and we contrasted performance of substance dependent individuals (polysubstance users) and control participants on neuropsychological measures assessing the different executive components obtained. Additionally, we contrasted performance of polysubstance users with preference for cocaine vs heroin and controls to explore possible differential effects of the main substance abused on executive impairment. Two groups of participants were recruited: abstinent polysubstance users and controls. Polysubstance users were further subdivided based on their drug of choice (cocaine vs heroin). We administered to all participants a comprehensive protocol of executive measures, including tests of fluency, working memory, reasoning, inhibitory control, flexibility, and decision making. Consistent with previous models, the principal component analysis showed that executive functions are organized into four separate components, three of them previously described: updating, inhibition, and shifting; and a fourth component of decision making. Abstinent polysubstance users had clinically significant impairments on measures assessing these four executive components (with effect sizes ranging from 0.5 to 2.2). Cocaine polysubstance users had more severe impairments than heroin users and controls on measures of inhibition (Stroop) and shifting (go/no go and category test). Greater severity of drug use predicted poorer performance on updating measures. Executive functions can be fractionated into four relatively independent components. Chronic drug use is associated with widespread impairment of these four executive components, with cocaine use inducing more severe deficits on inhibition and shifting. These findings show both common and differential effects of two widely used drugs on different executive components.

Inhibitory attentional control in patients with frontal lobe damage

The performance of a group of frontal lobe lesion and a group of frontal lobe dementia patients was compared with the performance of their respective matched normal control groups on two tests of inhibitory attentional control—the stop-signal reaction time task and a negative priming task. Both patient groups responded significantly slower than their respective normal control groups, but they showed only marginally significant selective impairments on the measures of inhibition. The data suggest that the specific inhibitory processes evaluated by these two tests are, in general, spared in patients with focal frontal lobe lesions or frontal lobe degeneration.

Toddler temperament, cognition and caregiver interaction predict impulsive functioning

(2002) Journal of Child Psychology and Psychiatry 43, 435; Olson SL, Bates JE, Sandy JM, Schilling EM. . Early and developmental precursors of impulsive and inattentive behaviour: from infancy to...

To go or not to go: inhibitory control in ‘hard to manage’ children

AbstractThis study is an age‐7 follow‐up of 40 children who at age 4 were identified as ‘hard to manage’ and were compared to 40 age and sex matched typically developing peers on a set of simple, manually administered executive function tasks. At age 4, the ‘hard to manage’ group showed marked deficits in inhibitory control and planning, but showed intact set‐shifting and working memory (Hughes et al., 1998). The present study assessed the continuity of executive function deficits among these ‘hard to manage’ children, using computerized tests of planning, working memory and set‐shifting (from the Cambridge Neuropsychological Test Automated Battery (CANTAB)) and a computerized Go‐No‐Go test of inhibitory control (from the Maudsley Attention and Response Suppression task battery (MARS)). In addition, real‐time observational ratings were made via a questionnaire checklist. Compared with controls, children in the ‘hard to manage’ group showed impaired inhibitory control but intact planning, working memory and set‐shifting. Observational ratings confirmed the group difference in inhibitory control, as the ‘hard to manage’ group showed significantly more perseverative errors and rule violations. These findings raise important methodological issues concerning effects of task format and highlight the importance of combining experimental and observational approaches to assessing problems in executive control. Copyright © 2002 John Wiley & Sons, Ltd.

Inhibitory control in adults with Attention-Deficit/Hyperactivity Disorder.

Children with Attention-Deficit/Hyperactivity Disorder (ADHD) have been found to be deficient in inhibitory control. The purpose of this study was to determine if adults with ADHD are also deficient in this domain. The performance of 18 adults with ADHD and 18 normal controls was compared on the Stop Signal Paradigm, which is a test of inhibitory control. The adults with ADHD performed more poorly on the Stop Signal Paradigm than did the normal controls. The ADHD subjects exhibited a longer latency to respond to the stop signal than did the control subjects. The individuals with ADHD tested in this study showed an inhibitory control deficit. The results suggest that a deficit in inhibitory control is central to ADHD.

Efectos de los psicoestimulantes en el desempeño cognitivo y conductual de los niños con un déficit de atención con hiperactividad subtipo combinado.

Many studies have shown the efficacy of methylphenidate in treating children with attention deficit and hyperactivity to reduce the main symptoms of the disorder and problems of behaviour: behaviour which is disruptive, antisocial, negative and aggressive. 1. Analyze the therapeutic effects of methylphenidate on the cognitive function of children with TDAH, combined subtype, evaluated by means of neuropsychological tests of attention and inhibitory control. 2. Determine the efficacy of methylphenidate in improving the basic symptoms of TDAH C according to the DSM 1V for parents and teachers, and their behaviour, evaluated by their teachers, in the combined subtype. The sample was made up of 48 children with TDAH C. 24 of these had been referred by paediatricians and received drug treatment with methylphenidate, 0.5 mg/kg once in the morning and once after lunch (TDAH C/CTF). The other group of 24 children with TDAH C were referred from their teachers to a school psychologist so that they followed the usual guidelines for orientation but not a systematically developed treatment (TDAH C/C or control group). RESULTS. In relation to the first objective the results were good for the TDAH C/CTF compared with the TDAH C/C group regarding the proportion of children who improved their results on neuropsychological testing of planning inhibitory control and attention. The differences between the two groups were statistically significant in the latent period of the reflexive impulsive test (MFF), arithmetic, cancellation of rhomboids and cancellation of numbers. Regarding the second objective, the improvement in the TDAH C/CTF group according to the teachers opinions were statistically significant with respect to attention, hyperactivity and impulsiveness, as compared with the control group. However, according to the parents assessment, although improvement was greater in both dimensions, the differences between the two groups did not reach statistical significance. Finally, the teachers observed greater improvement in the medicated group as compared to the control group regarding three variables: learning problems, antisocial conduct and failure to adapt to school. Overall, our results coincide with those of other excellent reviews, which have shown the effectiveness of methylphenidate in the treatment of cognitive and behaviour disorders in this group.

Executive function in preschoolers: Links with theory of mind and verbal ability

Fifty preschool children (mean age 3:11 years) took part in an investigation of the relations between children's executive function performance, their understanding of mind and their language skills. The study demonstrates the feasibility of testing rudimentary executive function skills among preschoolers, using an original battery of tasks. The results were consistent with those from studies of older children (e.g. Welsh, Pennington & Groisser, 1991), in that three aspects of executive function were distinguished: working memory, attentional flexibility and inhibitory control. In addition, specific links were found between executive function and theory‐of‐mind performance, even when age and both verbal and non‐verbal ability were taken into account. In particular, children's deceptive abilities were closely related to success on tests of inhibitory control. The implications of these results for our understanding of deceit are discussed.

Assessment of Attention-Deficit Hyperactivity Disorder in Preschoolers

Twenty-six preschoolers, 13 with Attention-Deficit Hyperactivity Disorder (ADHD), and 13 without ADHD, were assessed with respect to the following: Psychosocial Functioning, Attention, Impulsivity, and Hyperactivity. Two new behavioral coding systems, a new test of inhibitory control, and a new test of vigilance were specifically designed for preschoolers to measure activity, impulsivity, and attention. Preschoolers with ADHD were rated by their parents as significantly more stressful to manage, less reinforcing, more demanding, less adaptable to change, and less compatible with the parent. Although family functioning was rated to be within the average range for both groups, mothers of preschoolers with ADHD rated themselves as exhibiting more symptoms of depression, and a sense of reduced parental competence. During structured tasks, preschoolers with ADHD more often grabbed materials, and required more frequent directives from an examiner. During unstructured tasks the preschoolers with ADHD more often played with a set of “off-limits toys”. Activity level, as well as squirming, did not reliably distinguish between the preschoolers with and without ADHD. Finally, preschoolers with ADHD, consistent with the school-age ADHD literature, committed significantly more errors of commission on a preschool vigilance task. Discussion focuses on the clinical validity of this protocol, the importance of assessing preschoolers with developmentally appropriate measures of attention and behavior, and of interpreting their profiles within a neurodevelopmental framework.

Mothers' singing to infants and preschool children

The current study explored private speech (PS), private singing, and humming in relation to executive function (EF). Fifty-eight children (4–8 years) were observed as they performed a selective attention task (SAT) and engaged in PS. In addition, their EF was measured with tests of cognitive flexibility (Dimensional Change Card Sorting Task), inhibitory control (Go-No Go, Head-Toes-Knees-Shoulders), and planning (Tower of London). Parents reported on child EF issues. Almost all (95%) participants engaged in PS. Nearly one third of the sample used private song, and children who sang engaged in more overt PS on average than children who did not sing. There were children who used little to no PS, but children who used more overt task-relevant speech typically also had lower inhibitory control and more parent-reported EF issues. Private singing was unassociated with EF. Directions for future research on PS and song are discussed.

Do nonclinical checkers exhibit deficits in cognitive control? Tests of an inhibitory control hypothesis

We tested the hypothesis that persons who engage in compulsive checking may do so to compensate for cognitive errors produced by deficient inhibitory control. In two experiments, undergraduates were classified by scores on the MOCI checking subscale as checkers or noncheckers. On self-report measures, checkers were significantly more depressed, more anxious, more prone to cognitive slips, and more likely to engage in obsessive-compulsive behaviors. However, checkers performed similarly to noncheckers on laboratory tests of inhibitory control of cognition. Checkers and noncheckers were equally able to (1) ignore distractors in a selective attention task, (2) suppress inappropriate word meanings in a sentence comprehension task, and (3) inhibit retrieval of to-be-forgotten items in a memory task. These results suggest that compulsive checking does not arise from failures of inhibitory control of cognition.