Explorations of the Normal Neural Behavioral and Pathological Bases of Metacognition
试验速览
- 阶段
- 不适用
- 状态
- 已完成
- 发起方
- 入组人数
- 109
- 试验地点
- 3
- 主要终点
- Predecisional behavioral variables
研究概览
简要总结
Metacognition is the ability to introspect and report one's own mental states, or in other words to know how much one knows. It allows us to form a sense of confidence about decisions one makes in daily life, so one can commit to one option if our confidence is high, or seek for more evidence before commitment if our confidence is low. Although this function is crucial to behave adequately in a complex environment, confidence judgments are not always optimal. Notably, individuals with schizophrenia are prone to overconfidence in errors and underconfidence in correct answers. In schizophrenia, confidence is less correlated with performance compared to controls.
These aspects are held to be at the origin of delusions, disorganization, poor insight into illness and into cognitive deficit and poor social functioning.
Our study aims at identifying the cognitive and neural processes involved in metacognitive deficits in schizophrenia. Participants will perform metacognitive judgments on a low-level perceptual task (visual motion discrimination). Participants will do the first-order perceptual task by clicking on the correct answer with a mouse. During the first order task completion, the investigators will record several behavioral, physiological and neural variables. Then, participants will perform the metacognitive task with a visual analog scale.
The study will address four research questions:
- Q1: is schizophrenia associated with a decrease in metacognitive efficiency? Is the metacognitive deficit due to under- or over-confidence?
- Q2: is the metacognitive impairment reflected at a decisional level as measured by behavioral variables (mouse tracking and reaction times)?
- Q3: which physiological markers (EEG, skin conductance, heart rate) are predictors of metacognitive efficiency in individuals with schizophrenia and healthy controls?
- Q4: which clinical symptoms correlate with metacognitive deficits?
The investigators make several hypotheses related to the previous research questions:
- Q1: the investigators expect metacognitive deficits in schizophrenia, based on results from several studies using both qualitative and quantitative measures. The investigators will rule out that quantitative deficits are not confounded with impairments in type 1 performance, with a generalized cognitive deficit in schizophrenia (lower premorbid and current Intelligence Quotient (IQ), and deficits in executive functioning and particularly in planning and working memory abilities), with depression or with statistical flaws during analysis of confidence.
- Q2: the investigators expect behavioral cues (mouse tracking and reaction times) to be less correlated with confidence in patients vs. controls. The investigators thus make the hypothesis that the metacognitive deficit in schizophrenia may stem from an inability to integrate pre-decisional cues while performing an explicit metacognitive judgment.
- Q3: the investigators expect physiological cues (EEG with Error-Related Negativity, Lateralized Readiness Potential and alpha suppression, and arousal of the autonomic nervous system with skin conductance and heart rate ) to be less correlated with confidence in patients vs. controls.
- Q4: based on previous findings, the investigators expect that several clinical dimensions of schizophrenia may correlate with metacognitive performance. The metacognitive deficit would be greater for patients with high levels of positive and disorganized symptoms, and greater for patients with low levels of clinical and cognitive insight, and low levels of social functioning.
详细描述
SAMPLING PLAN
- Existing data Registration before the creation of data: As of the date of submission of this research plan for preregistration, the data have not yet been collected, created, or realized.
- Data collection procedures. Healthy volunteers will be recruited from the general population. Individuals with schizophrenia will be recruited from community mental health centers and outpatient clinics in the Versailles area and among the FACE-SZ (FondaMental Academic Centers of Expertise for Schizophrenia) cohort in Versailles. All participants will be naive to the purpose of the study, give informed consent in accordance with institutional guidelines and the Declaration of Helsinki, and receive a monetary compensation (10€ / h).
- Sample size Maximum of 50 healthy controls vs. 50 individuals with schizophrenia.
- Sample size rationale The estimated sample sizes allow testing effects of medium size between individuals with schizophrenia and healthy controls with a power of 0.8, based on one-sided two-sample t-test power calculation with Cohen's d = 0.5, α = 0.05. They allow measuring medium correlations within groups with a power of 0.7, based on approximate correlation-power calculation with r = 0.3, α = 0.05.
Sample sizes for electrophysiological recordings are based on previous a study, with 20 patients vs. 20 controls, resulting in 13 vs. 13 after outlier exclusion. 5. Stopping rule Optional stopping will be avoided by using sequential Bayes factor analyses. Data collection will stop whenever a critical comparison reaches the threshold of BF = 3 or BF = 1/3.
DESIGN PLAN 6. Study design The investigators will ask participants to discriminate the motion direction of a random dot kinetogram (type 1 task). They will use a mouse to indicate whether the dots were mostly moving rightward or leftward, by clicking on the side they think corresponds to a correct answer (red and blue circles, see Figure 1). The mouse trajectory corresponding to the type 1 task will be recorded and analyzed. Motion variance will be adapted for each subject before the experiment using a 1up/2down staircase, so to reach an average performance of 71%. An auditory feedback will be played if participants answer in more than 6s. On each trial, participants will then indicate on a visual analog scale the confidence in their response (type 2 task). The scale will range from 0% ("Certain my response is right") to 100% ("Certain my response is wrong"). The initial position of the cursor will always correspond to 50% confidence ("Uncertain of my response)". The experiment will consist in 10 blocks of 30 trials and last about 1h. 7. Randomization Motion direction (left or right) will be pseudo-randomized, with no more than 4 successive trials with the same direction.
ANALYSIS PLAN 8. Statistical models 8.1. Behavioral data All analyses will be performed with R, using notably the afex, BayesFactor, ggplot2, lme4, lmerTest, and effects packages. In all ANOVAs, degrees of freedom will be corrected using the Greenhouse-Geisser method.
研究设计
- 研究类型
- Observational
- 观察模型
- Case Control
- 时间视角
- Cross Sectional
入排标准
- 年龄范围
- 18 Years 至 65 Years（Adult, Older Adult）
- 性别
- All
- 接受健康志愿者
- 是
入选标准
- •DSM-V criteria for schizophrenia (Structured Clinical Interview for Disorders)
- •Normal or corrected-to-normal vision
排除标准
- •a moderate or severe substance used disorder within the past 6 months (DSM-V criteria)
- •current or prior history of untreated significant medical illness or of neurological illness
- •electroconvulsive therapy in the last three months
- •dyschromatopsia
结局指标
主要结局
Predecisional behavioral variables
时间窗: Repeated measures within a 2 hours long experiment
Reaction times and mouse trajectory parameters (motion entropy on the x-axis)
EEG markers
时间窗: Repeated measures within a 2 hours long experiment
Error-Related Negativity, Lateralized Readiness Potential and alpha suppression
Metacognitive performance
时间窗: Repeated measures within a 2 hours long experiment
Regression slope between accuracy and confidence, in a binomial mixed-effects model including appropriate covariates (variables that are significantly different between patients and controls, among the following: age, sex, education, premorbid and current IQ, executive performance with planning and working memory; and depression)
次要结局
- Positive symptoms of schizophrenia(One measure per subject, assessed during a 30 min long interview)
- Insight into illness(One measure per subject, assessed with a 10 min long autoquestionnaire)
- Disorganization symptoms of schizophrenia(One measure per subject, assessed during a 30 min long interview)
- Cognitive insight(One measure per subject, assessed with a 20 min long autoquestionnaire)
- social functioning(One measure per subject, assessed during a 20 min long interview)
- Metacognitive bias(Repeated measures within a 2 hours long experiment)
研究者
Dr Paul ROUX
Investigator coordinator
Versailles Hospital