Iowa Gambling Task Performance in Parkinson Disease Patients with Impulse Control Disorders

Systematic Review and Meta-Analyses of Word Production Abilities in Dysfunction of the Basal Ganglia: Stroke, Small Vessel Disease, Parkinson's Disease, and Huntington's Disease

Clinical populations with basal ganglia pathologies may present with language production impairments, which are often described in combination with comprehension measures or attributed to motor, memory, or processing-speed problems. In this systematic review and meta-analysis, we studied word production in four (vascular and non-vascular) pathologies of the basal ganglia: stroke affecting the basal ganglia, small vessel disease, Parkinson's disease, and Huntington's disease. We compared scores of these clinical populations with those of matched cognitively unimpaired adults on four well-established production tasks, namely picture naming, category fluency, letter fluency, and past-tense verb inflection. We conducted a systematic search in PubMed and PsycINFO with terms for basal ganglia structures, basal ganglia disorders and language production tasks. A total of 114 studies were included, containing results for one or more of the tasks of interest. For each pathology and task combination, effect sizes (Hedges' g) were extracted comparing patient versus control groups. For all four populations, performance was consistently worse than that of cognitively unimpaired adults across the four language production tasks (p-values < 0.010). Given that performance in picture naming and verb inflection across all pathologies was quantified in terms of accuracy, our results suggest that production impairments cannot be fully explained by motor or processing-speed deficits. Our review shows that while language production difficulties in these clinical populations are not negligible, more evidence is necessary to determine the exact mechanism that leads to these deficits and whether this mechanism is the same across different pathologies.

Differences in Learning and Persistency Characterizing Behavior in Chronic Pain for the Iowa Gambling Task: Web-Based Laboratory-in-the-Field Study

Background

Chronic pain is a significant worldwide health problem. It has been reported that people with chronic pain experience decision-making impairments, but these findings have been based on conventional laboratory experiments to date. In such experiments, researchers have extensive control of conditions and can more precisely eliminate potential confounds. In contrast, there is much less known regarding how chronic pain affects decision-making captured via laboratory-in-the-field experiments. Although such settings can introduce more experimental uncertainty, collecting data in more ecologically valid contexts can better characterize the real-world impact of chronic pain.

Objective

We aim to quantify decision-making differences between individuals with chronic pain and healthy controls in a laboratory-in-the-field environment by taking advantage of internet technologies and social media.

Methods

A cross-sectional design with independent groups was used. A convenience sample of 45 participants was recruited through social media: 20 (44%) participants who self-reported living with chronic pain, and 25 (56%) people with no pain or who were living with pain for <6 months acting as controls. All participants completed a self-report questionnaire assessing their pain experiences and a neuropsychological task measuring their decision-making (ie, the Iowa Gambling Task) in their web browser at a time and location of their choice without supervision.

Results

Standard behavioral analysis revealed no differences in learning strategies between the 2 groups, although qualitative differences could be observed in the learning curves. However, computational modeling revealed that individuals with chronic pain were quicker to update their behavior than healthy controls, which reflected their increased learning rate (95% highest–posterior-density interval [HDI] 0.66-0.99) when fitted to the Values-Plus-Perseverance model. This result was further validated and extended on the Outcome-Representation Learning model as higher differences (95% HDI 0.16-0.47) between the reward and punishment learning rates were observed when fitted to this model, indicating that individuals with chronic pain were more sensitive to rewards. It was also found that they were less persistent in their choices during the Iowa Gambling Task compared with controls, a fact reflected by their decreased outcome perseverance (95% HDI −4.38 to −0.21) when fitted using the Outcome-Representation Learning model. Moreover, correlation analysis revealed that the estimated parameters had predictive value for the self-reported pain experiences, suggesting that the altered cognitive parameters could be potential candidates for inclusion in chronic pain assessments.

Conclusions

We found that individuals with chronic pain were more driven by rewards and less consistent when making decisions in our laboratory-in-the-field experiment. In this case study, it was demonstrated that, compared with standard statistical summaries of behavioral performance, computational approaches offered superior ability to resolve, understand, and explain the differences in decision-making behavior in the context of chronic pain outside the laboratory.

Decision making in Parkinson's disease: An analysis of the studies using the Iowa Gambling Task

In Parkinson's disease (PD) impairments in decision making can occur, in particular because of the tendency toward risky and rewarding options. The Iowa Gambling Task has been widely used to investigate decision processes involving these options. The task assesses the ability to manage risk and to learn from feedback. The present paper aims at critically examining those studies in which this task has been administered to PD patients, in order to understand possible anomalies in patients' decision processes and which variables are responsible for that. A meta‐analysis has been conducted as well. Features of the task, sociodemographic and clinical aspects (including daily drugs intake), cognitive conditions and emotional disorders of the patients have been taken into account. Neural correlates of decision‐making competences were considered. It emerged that PD patients show a trend of preference toward risky choices, probably due to an impairment in anticipating the unrewarding consequences or to an insensitiveness to punishment. The possible role played by dopamine medications in decision making under uncertain conditions, affecting basal ganglia and structures involved in the limbic loop, was discussed. Attention has been focused on some aspects that need to be investigated in further research, in order to delve into this issue and promote patients' quality of life.

Decision making under ambiguity and risk in adolescent-onset schizophrenia

OBJECTIVE

Numerous studies have identified impaired decision making (DM) under both ambiguity and risk in adult patients with schizophrenia. However, the assessment of DM in patients with adolescent-onset schizophrenia (AOS) has been challenging as a result of the instability and heterogeneity of manifestations. The Iowa Gambling Task (IGT) and Game of Dice Task (GDT), which are frequently used to evaluate DM respectively under ambiguity and risk, are sensitive to adolescents and neuropsychiatric patients. Our research intended to examine the performance of DM in a relatively large sample of patients with AOS using the above-mentioned two tasks. We also aimed to take a closer look at the relationship between DM and symptom severity of schizophrenia.

METHODS

We compared the performance of DM in 71 patients with AOS and 53 well-matched healthy controls using IGT for DM under ambiguity and GDT for DM under risk through net scores, total scores and feedback ration. Neuropsychological tests were conducted in all participants. Clinical symptoms were evaluated by using Positive and Negative Syndrome Scale (PANSS) in 71 patients with AOS. Pearson's correlation revealed the relationship among total score of DM and clinical and neuropsychological data.

RESULTS

Compared to healthy controls, patients with AOS failed to show learning effect and had a significant difference on the 5th block in IGT and conducted more disadvantageous choices as well as exhibited worse negative feedback rate in GDT. Apart from DM impairment under risk, diminished DM abilities under ambiguity were found related to poor executive function in AOS in the present study.

CONCLUSIONS

Our findings unveiled the abnormal pattern of DM in AOS, mainly reflected under the risky condition, extending the knowledge on the performance of DM under ambiguity and risk in AOS. Inefficient DM under risk may account for the lagging impulse control and the combined effects of developmental disease. In addition, our study demonstrated that the performance on IGT was related to executive function in AOS.

Is there a Neurobiological Rationale for the Utility of the Iowa Gambling Task in Parkinson's Disease?

Up to 23% of newly diagnosed, non-demented, Parkinson’s disease (PD) patients experience deficits in executive functioning (EF). In fact, EF deficits may occur up to 39-months prior to the onset of motor decline. Optimal EF requires working memory, attention, cognitive flexibility, and response inhibition underlying appropriate decision-making. The capacity for making strategic decisions requires inhibiting imprudent decisions and are associated with noradrenergic and dopaminergic signaling in prefrontal and orbitofrontal cortex. Catecholaminergic dysfunction and the loss of noradrenergic and dopaminergic cell bodies early in PD progression in the aforementioned cortical areas likely contribute to EF deficits resulting in non-strategic decision-making. Thus, detecting these deficits early in the disease process could help identify a significant portion of individuals with PD pathology (14–60%) before frank motor impairment. A task to evaluate EF in the domain of non-strategic decision-making might be useful to indicate the moderate loss of catecholamines that occurs early in PD pathology prior to motor decline and cognitive impairment. In this review, we focus on the potential utility of the Iowa Gambling Task (IGT) for this purpose, given significant overlap between in loss of dopaminergic and noradrenergic cells bodies in early PD and the deficits in catecholamine function associated with decreased EF. As such, given the loss of catecholamines already well-underway after PD diagnosis, we evaluate the potential utility of the IGT to identify the risk of therapeutic non-compliance and a potential companion approach to detect PD in premotor stages.

Measuring impulsivity in Parkinson's disease: a correlational and structural neuroimaging study using different tests

BACKGROUND AND PURPOSE

Impulsivity is an aspect of personality and a major component of multiple neuropsychiatric conditions. In Parkinson's disease, it has been associated with the expression of impulse control disorders, a highly prevalent non-motor complication. Even though multiple tests of impulsivity have been used in this context, the impact of test choice has not been addressed. The aim was to evaluate whether different impulsivity measures in Parkinson's disease share substantial inter-scale and anatomical correlations or rather mirror different underlying phenomena.

METHODS

In a consecutive sample of 89 Parkinson's disease patients without impulse control disorders, four common tests were evaluated assessing different aspects of impulsivity: impulsiveness trait, decisions under implicit risk with and without losses, and delay discounting. Correlations among test scores were analysed and each score was used as a regressor in a set of grey matter volume (GMV) voxel-based morphometry analyses to explore their brain structural correlates.

RESULTS

No significant correlations were found between the different impulsivity tests. Furthermore, their structural brain correlates were divergent. Impulsiveness trait appeared to be associated with lower GMV in dorsal-lateral prefrontal cortices, implicit risk (with losses) with higher GMV in the left nucleus accumbens and lower left insular GMV, implicit risk (without losses) with higher GMV in the left lingual gyrus and lower GMV in the gyri recti and delay discounting with higher GMV in the left nucleus accumbens.

CONCLUSIONS

In Parkinson's disease, different impulsivity measures reflect very dissimilar behavioural and brain structural correlates. Our results suggest that parkinsonian impulsivity is not a unitary phenomenon but rather a heterogeneous entity.

Behavioral and Neuroanatomical Account of Impulsivity in Parkinson's Disease

Impulse control disorder (ICD) is a major non-motor complication of Parkinson's disease (PD) with often devastating consequences for patients' quality of life. In this study, we aimed to characterize the phenotype of impulsivity in PD and its neuroanatomical correlates.

Methods: Thirty-seven PD patients (15 patients with ICD, 22 patients without ICD) and 36 healthy controls underwent a neuropsychological battery. The test battery consisted of anxiety and depression scales, self-report measures of impulsivity (Barratt scale and UPPS-P), behavioral measures of impulsive action (Go/No-Go task, Stop signal task) and impulsive choice (Delay discounting, Iowa gambling task), and measures of cognitive abilities (working memory, attention, executive function). Patients and controls underwent structural MRI scanning.

Results: Patients with ICD had significantly higher levels of self-reported impulsivity (Barratt scale and Lack of perseverance from UPPS-P) in comparison with healthy controls and non-impulsive PD patients, but they performed similarly in behavioral tasks, except for the Iowa gambling task. In this task, patients with ICD made significantly less risky decisions than patients without ICD and healthy controls. Patients without ICD did not differ from healthy controls in self-reported impulsivity or behavioral measurements. Both patient groups were more anxious and depressive than healthy controls. MRI scanning revealed structural differences in cortical areas related to impulse control in both patient groups. Patients without ICD had lower volumes and cortical thickness of bilateral inferior frontal gyrus. Patients with ICD had higher volumes of right caudal anterior cingulate and rostral middle frontal cortex.

Conclusions: Despite the presence of ICD as confirmed by both clinical follow-up and self-reported impulsivity scales and supported by structural differences in various neural nodes related to inhibitory control and reward processing, patients with ICD performed no worse than healthy controls in various behavioral tasks previously hypothesized as robust impulsivity measures. These results call for caution against impetuous interpretation of behavioral tests, since various factors may and will influence the ultimate outcomes, be it the lack of sensitivity in specific, limited ICD subtypes, excessive caution of ICD patients during testing due to previous negative experience rendering simplistic tasks insufficient, or other, as of now unknown aspects, calling for further research.

Functional inhibitory control dynamics in impulse control disorders in Parkinson's disease

BACKGROUND

Impulse control disorders related to alterations in the mesocorticolimbic dopamine network occur in Parkinson's disease (PD). Our objective was to investigate the functional neural substrates of reward processing and inhibitory control in these patients.

METHODS

Eighteen PD patients with impulse control disorders, 17 without this complication, and 18 healthy controls performed a version of the Iowa Gambling Task during functional magnetic resonance scanning under 3 conditions: positive, negative, and mixed feedback. Whole-brain contrasts, regions of interest, time courses, functional connectivity analyses, and brain-behavior associations were examined.

RESULTS

PD patients with impulse control disorders exhibited hyperactivation in subcortical and cortical regions typically associated with reward processing and inhibitory control compared with their PD and healthy control counterparts. Time-course analyses revealed that only PD patients with impulse control disorders exhibited stronger signal intensity during the initial versus final periods of the negative-feedback condition in bilateral insula, and right ventral striatum. Interestingly, hyperactivation of all the examined right-lateralized frontostriatal areas during negative feedback was positively associated with impulse control disorder severity. Importantly, positive associations between impulse control disorder severity and regional activations in the right insula and right inferior frontal gyrus, but not the right subthalamic nucleus, were mediated by functional connectivity with the right ventral striatum.

CONCLUSIONS

During a reward-based task, PD patients with impulse control disorders showed hyperactivation in a right-lateralized network of regions including the subthalamic nucleus that was strongly associated with impulse control disorder severity. In these patients, the right ventral striatum in particular played a critical role in modulating the functional dynamics of right-lateralized inhibitory-control frontal regions when facing penalties. © 2019 International Parkinson and Movement Disorder Society.

Nigrostriatal dopamine transporter availability, and its metabolic and clinical correlates in Parkinson's disease patients with impulse control disorders

PURPOSE

Previous studies in patients with Parkinson's disease (PD) and impulse control disorders (ICDs) have produced heterogeneous results regarding striatal dopamine transporter (DaT) binding and activity in the mesocorticolimbic network. Our aim here was to study the relationship between striatal DaT availability and cortical metabolism, as well as motor, behavioural and cognitive features of PD patients with ICD.

METHODS

In a group of PD patients with ICD (PD-ICD, n = 16) and 16 matched PD patients without ICD (PD-noICD, n = 16), DaT single-photon emission computed tomography (SPECT) imaging (DaTSCAN) was used to study DaT availability in predefined striatal volumes of interest (VOIs): putamen, caudate nucleus and ventral striatum (VS). In addition, the specific association of striatal DaT binding with cortical limbic and associative metabolic activity was evaluated by ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography (PET) in PD-ICD patients and investigated using statistical parametric mapping (SPM8). Finally, associations between DaT availability and motor, behavioural and cognitive features were assessed.

RESULTS

PD-ICD patients had a significantly lower DaT density in the VS than PD-noICD patients, which was inversely associated with ICD severity. Lower DaT availability in the VS was associated with lower FDG uptake in several cortical areas belonging to the limbic and associative circuits, and in other regions involved in reward and inhibition processes (p < 0.0001 uncorrected; k > 50 voxels). No significant results were observed using a higher conservative threshold (p < 0.05; FDR corrected). PD-ICD patients also displayed impairment in interference and attentional Stroop Task execution, and more anxiety, all associated with reduced DaT availability in the VS and caudate nucleus.

CONCLUSIONS

ICDs in PD patients are related to reduced DaT binding in the VS, which accounts for dysfunction in a complex cortico-subcortical network that involves areas of the mesolimbic and mesocortical systems, being associated with reward evaluation, salience attribution and inhibitory control processes.