Metacognitive Function in Moderate to Severe Traumatic Brain Injury

Amadon, G., Weis, L., & Chiou, K. Author

08/01/2020 Added

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This project aims to understand metacognitive functioning following a traumatic brain injury.

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[00:00:00.000]Hi, my name is Lauren Weis, and I'm Grace Amadon. Today we are going to
[00:00:06.219]talk about metacognitive functioning in
[00:00:08.575]moderate to severe traumatic brain injury.
[00:00:13.443]Traumatic Brain Injury, or TBI, is an injury
[00:00:15.837]to the brain that is caused by a hit or jolt to
[00:00:18.295]the head that can result in physical, physiological, and/or cognitive deficits.
[00:00:23.030]These injuries account for 2.5 million emergency department visits and 56,800
[00:00:29.045]deaths every year in the United States.
[00:00:31.680]Self-awareness is a cognitive domain that is negatively affected after TBI. Impairments in self-awareness
[00:00:38.592]resulting from a TBI can be detrimental to rehabilitation engagement and functional outcomes.
[00:00:44.214]One specific facet of self-awareness is metacognition,
[00:00:48.400]which refers to one’s awareness of their own thought processes, or their ability to “think about thinking”.
[00:00:53.653]Metacognition can be further broken down into two domains: metacognitive knowledge and metacognitive experience.
[00:01:00.710]Metacognitive knowledge is one’s general knowledge of their ability to perform a task, such as “I am a good speller.”
[00:01:08.148]Metacognitive experience is an individual’s ability to monitor and evaluate their current, ongoing performance on a task.
[00:01:16.154]For example, someone is able to catch a spelling mistake in the midst of spelling a word out loud.
[00:01:23.062]Metacognitive experience can be measured through judgements of learning (JoL) which are predictions of performance,
[00:01:29.794]and retrospective confidence judgements (RCJ) which are ratings of confidence in the accuracy of one’s performance.
[00:01:37.235]Metacognitive accuracy is determined by comparing one’s own self report to their objective performance.
[00:01:44.573]This can be done by measuring metacognitive bias and metacognitive sensitivity.
[00:01:49.339]Bias measures errors of over or under confidence, whereas sensitivity is the discrepancy between one’s reported confidence and their objective accuracy.
[00:01:59.326]The effects of a traumatic brain injury on metacognition are not fully understood.
[00:02:04.516]Therefore, the purpose of this study was to better understand metacognitive functioning in individuals with moderate to severe TBI.
[00:02:11.829]Knowing this, we predict that individuals who have sustained a traumatic brain injury
[00:02:16.902]will show poor metacognitive accuracy,
[00:02:19.019]as evidenced by low values of metacognitive sensitivity.
[00:02:22.774]To perform this study, 18 adults with moderate to severe traumatic brain injury were recruited from the community; however,
[00:02:30.056]seven (7) of those participants were excluded due to errors in data collection.
[00:02:34.094]This resulted in a sample size of 11 participants.
[00:02:37.215]The demographics, showing the age, education, gender, time since injury, and participant ethnicities are shown to the right.
[00:02:44.484]Each participant completed three (3) runs of a metacognitive paradigm, consisting of 12 true trials
[00:02:51.732]where metacognitive judgements were collected and 4 foil trials, for a total of 16 trials per run.
[00:02:58.624]Foil trials were used intermittently as a distraction to avoid
[00:03:02.929]response bias and increase reliability of responses.
[00:03:05.788]These foil trials asked participants questions such as
[00:03:10.226]"How tired are you?" or "are you paying attention?"
[00:03:12.077]Individuals were presented a meta-working memory paradigm and asked
[00:03:16.024]to identify a target stimulus and assess their future and past performance.
[00:03:21.571]Future performance was indicated by judgements of learning,
[00:03:25.055]and past by retrospective confidence judgements.
[00:03:29.377]The paradigm, shown on the bottom left of the poster, was presented on a computer using a series of slides.
[00:03:35.721]The first slide showed a target stimulus with shapes in various locations.
[00:03:40.057]Participants were instructed to remember the shapes and their locations.
[00:03:44.258]Participants were then asked to provide a JoL response by rating how confident
[00:03:49.689]they would be in identifying the correct target stimulus.
[00:03:52.620]Individuals were presented with four options on the screen
[00:03:57.295]and asked to identify the target stimulus they had just viewed at the
[00:04:01.511]beginning of the trial.
[00:04:03.549]Finally, participants reported a retrospective confidence judgement by
[00:04:07.666]rating how confident they were that their response was correct on a Likert
[00:04:11.231]scale of 1-4, with 1 being low confidence, and 4 being high confidence.
[00:04:16.008]For the purpose of this study, we focused on RCJ in order to monitor
[00:04:22.255]metacognitive bias and sensitivity.
[00:04:24.787]The two measures of metacognitive accuracy that we used and calculated
[00:04:30.080]for each individual were metacognitive bias and metacognitive sensitivity.
[00:04:33.645]Metacognitive bias measures whether the individual made any errors
[00:04:38.576]of over or underconfidence. RCJ scores were first converted from their Likert scale of one to four
[00:04:46.166]into percentages. Then, bias was calculated by subtracting
[00:04:50.221]the percent correct on the stimulus recognition task from the
[00:04:54.219]confidence rating. If this value is zero, the participant shows no bias.
[00:04:58.922]If the value is positive, the participant was overconfident, meaning their
[00:05:03.689]rating was higher than their actual accuracy.
[00:05:07.091]If the value is negative, the participant was underconfident,
[00:05:12.421]meaning their confidence rating was lower than their actual accuracy.
[00:05:14.076]Metacognitive sensitivity was measured using area under the curve analyses.
[00:05:19.759]This is determined by measuring the proportionality between
[00:05:23.013]concordant and discrepant confidence/accuracy responses.
[00:05:27.936]Concordant responses are when a person's confidence
[00:05:30.913]matches their accuracy, such as, they are confident when they are correct,
[00:05:34.392]or, they are not confident when they are incorrect. Discrepant responses are
[00:05:38.312]when the person's confidence rating does not match their accuracy,
[00:05:41.815]so they are not confident but they did answer correctly, or they answered incorrectly,
[00:05:47.022]yet they are confident. These values of AUC can range from 0.5 to one,
[00:05:52.187]with 0.5 representing a low level of metacognitive sensitivity
[00:05:56.568]or poor metacognitive awareness, and one represents a high level
[00:06:00.695]of metacognitive sensitivity, or high metacognitive awareness.
[00:06:04.440]So then, going into our results, based on that, we found that on average,
[00:06:11.361]participants with TBI were accurate in recognizing the correct target
[00:06:14.114]response 48.53 percent of the time. In terms of confidence, individuals with TBI
[00:06:20.403]presented an average rating of 2.24 on a Likert scale of 1-4. This 2.24 can be
[00:06:27.033]translated to an average percentage of 56.7 on a scale of one to 100.
[00:06:32.325]In terms of over/under confidence, we found that the over/under confidence
[00:06:38.541]bias value was 0.08, and because this value is positive, it means that
[00:06:43.177]participants were overconfident in their responses.
[00:06:46.930]And finally, the area under the curve value we found was 0.65. Because this
[00:06:52.583]value is closer to 0.5 than one, it indicates that there is a high
[00:06:55.929]degree of discrepancy between participant's confidence and accuracy
[00:07:00.114]ratings. This shows that individuals with TBI exhibit a low level of metacognitive
[00:07:03.973]sensitivity.
[00:07:06.787]Based on these results, we can conclude that individuals with TBI in this
[00:07:10.679]sample perform poorly on a working memory task. This is consistent with
[00:07:14.822]literature documenting working memory deficits following a TBI.
[00:07:18.742]In addition, participants were low to moderately confident in their responses.
[00:07:24.659]We also found that individuals with TBI tend to make errors of overconfidence,
[00:07:29.037]where they reported being confident in their answers, even when answering
[00:07:31.803]incorrectly.
[00:07:34.917]As discussed prior, we know that an area under the curve value closer
[00:07:38.184]to 0.5 than 1 demonstrates that individuals with TBI have a low level of
[00:07:42.857]metacognitive sensitivity. In this case, an AUC value of 0.65 shows that our
[00:07:48.955]sample had low sensitivity, however, the magnitude of this insensitivity is
[00:07:52.978]unclear because there was no control group for comparison.
[00:07:57.030]Further, without a control group, we cannot confirm that the low sensitivity
[00:08:00.967]was a result of the traumatic brain injury.
[00:08:04.609]In addition, the sample size of this study was also limited: The sample was
[00:08:08.279]predominantly male and seven participants were excluded from analysis
[00:08:11.974]due to errors in data collection, as we mentioned earlier.
[00:08:15.600]The use of neuroimaging in the future would allow a better understanding
[00:08:19.552]of the neural mechanisms involved in these metacognitive deficits that we
[00:08:23.942]found from the study. In addition, interventions aimed at improving
[00:08:27.776]metacognition can be developed. Going forward, the administration of this
[00:08:31.522]paradigm before and after intervention would allow researchers to compare
[00:08:36.784]results and determine effectiveness of the treatment.
[00:08:39.512]So our references are listed below and we would like to thank all of the people listed
[00:08:45.305]for their assistance.
[00:08:46.536]Finally, this research was sponsored by a research grant from the New Jersey
[00:08:49.287]Commission on Brain Injury Research awarded to Doctor Kathy Chiou.

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Metacognitive Function in Moderate to Severe Traumatic Brain Injury

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