1. What is the central question?
What social and emotional deficits are present following traumatic brain injury? What neural correlates are seen with these processes?
2. What did you do?
● An analysis of legacy data on a large cohort of TBI patients was conducted to re- assess the concept of “frontal” behaviour using quantitative neuroimaging methods.
● A newly developed diffusion imaging technique that allows for more quantitative and biologically meaningful analysis of in vivo brain structure was conducted on a subset of patients from the previous analysis. These results were correlated with measures of dysexecutive function.
● These patients were followed up to test a social reward discounting paradigm.
● A battery of digital tasks was developed (available on tablets, smartphones, web) to assess wellbeing, and test performance on emotional recognition and metacognitive
abilities.
3. Why did you do it?
● Some behaviours are described as being "frontal" in nature. This mostly follows from famous case studies such as that of Phineas Gage. Here I quantitatively analysed data from 102 patients with frontal lesions and compared them to patients without frontal lesions and controls, looking at effects of white matter damage independent of focal damage.
● New imaging techniques and analyses allow us to investigate brain microstructure with improved sensitivity, helping us better understand real-world behaviour and function.
● Aspects of social behaviour, such as decision evaluation, may fall under executive functioning. Additionally, apathy has previously been found to be an issue in TBI patients through self-report and caregiver reports. Further objective assessments were aimed at exploring apathy in relation to social decision making in more detail.
● Little has been done in TBI patients to understand social and emotional deficits post- injury, despite being commonly reported issues. Digital assessments make it easier and more reliable to collect data both in the clinic and remotely and to track performance/wellbeing over time.
4. What happened?
● Non-lesion patients show similar behavioural deficits to those with focal lesions. This can be partially explained through results from quantitative diffusion imaging, which show damage in the brain independent of focal lesions.
● Advanced imaging techniques appear to be more sensitive when relating to cognitive performance.
● Apathy did not appear to be a factor in explaining patient behaviour. However, it seems patients did not distinguish between self and other, and may be more sensitive to reward than controls.
● Patients performed indicated some difficulty with emotional processing and reported lower levels of wellbeing compared to controls.
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● Patients were impaired on metacognition for processing speed but not emotional processing.
5. What do the results mean in theory?
● Developing techniques in quantitative imaging may prove more reliable than traditional visual inspection in identifying damage present following TBI.
● TBI can lead to deficits in social cognitive functioning. Patients may show signs of executive dysfunction, for instance by not incorporating all available information, leading to inappropriate decision making.
● Digital assessments of social cognitive function and wellbeing are feasible ways to investigate patients’ behaviour and state.
● Metacognition could be fractionated across cognitive domains, with TBI patients overestimating performance in some domains but not others.
6. What do the results mean in practice?
● Quantitative MRI measures, including multi-modal assessments of volume, diffusion, and neurochemistry, should be performed on patients with head injuries.
● More attention should be given to emotional and social issues following discharge, as this may have an impact on rehabilitation engagement, personal relationships and return to work.
● Special consideration should be given to seemingly well patients if they show signs of executive dysfunction, as this may lead to long-term impairments in social cognition.
● Digital assessments can be flexibly adapted to assess patients’ performance, either in
the clinic or at home. This would allow longitudinal monitoring of cognitive functioning that individuals may be struggling with.
7. What is the key benefit for the readers?
● Compared to lesion localisation, newer quantitative MRI methods are better-suited to inform our understanding of individual cognitive functioning.
● Application of a new multi-shell diffusion imaging technique shows that it has potential in investigating the neural correlates of social functioning in TBI patients
● Deficits in social cognition and emotional processing after TBI are highlighted and
investigated, informing a largely neglected area of brain injury research with
important consequences in treatment and rehabilitation.
● Introduction of novel digital and remote assessments, which are reliable and flexible
methods of evaluation that should be further explored and implemented in practice.
8. What remains unresolved?
As TBI is a heterogeneous disorder, development of neuroimaging measures and evaluation of the neural correlates are needed in order to identify the many disrupted paths that may lead to similar behavioural output. This could be done using a disconnection framework with analysis from multi-modal imaging. Additionally, social cognition and emotional processing is a complex area. Development of assessments, ecological validation and replication are required.