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Open AccessReview

Emotion Recognition, Empathy, or ToM? The Influence of Social Cognition on Communication in Traumatic Brain Injury

A Systematic Review

Published Online:May 19, 2022https://doi.org/10.1024/1016-264X/a000355

Abstract

Abstract: Communication disorders following traumatic brain injury have been attributed to social-cognitive dysfunctions. However, this relationship is not always clearly demonstrated in empirical research. This systematic review seeks to clarify the relationship by considering different subcomponents of social cognition and communication. The results show that, for the social-cognitive subcomponents of emotion recognition and empathy, evidence is available mainly for a relationship to global communication abilities. However, we did find a systematic relationship between Theory of Mind and individual aspects of pragmatics (i. e., the processing of irony/sarcasm, insincerity, indirect speech acts). To strengthen the evidence for the role of social-cognitive subcomponents concerning communication, future research could implement a core outcome set based on the present findings.

Emotionserkennung, Empathie oder ToM? Der Einfluss sozialer Kognition auf die kommunikative Kompetenz nach Schädel-Hirn-Trauma: Ein systematisches Review

Zusammenfassung: Kommunikationsstörungen nach Schädel-Hirn-Trauma werden zum Teil auf sozial-kognitive Dysfunktionen zurückgeführt. Ein eindeutiger Zusammenhang kann jedoch in empirischen Studien sowie Sekundärarbeiten nicht immer abgebildet werden. Um ein differenzierteres Bild dieses Bedingungsgefüges abzuleiten, erfolgt im vorliegenden systematischen Review eine Zusammenfassung empirischer Evidenz nach sozial-kognitiven und kommunikativen Subkomponenten. Für die sozial-kognitiven Subkomponenten Emotionserkennung und Empathie zeigte sich ein belastbarer Zusammenhang lediglich mit globalen Kommunikationsfähigkeiten. Für die Subkomponente Theory of Mind legen die Ergebnisse dagegen einen systematischen Einfluss auf spezifische pragmatische Aspekte nahe (insbesondere für die Verarbeitung von Ironie/Sarkasmus, Lüge und indirekte Sprechakte). Um diese Zusammenhänge zu stützen, wäre die Implementation eines Core Outcome Sets, das die hier dargelegten Erkenntnisse berücksichtigt, in zukünftigen Studien wünschenswert.

Introduction

Each year, approximately 69 million people worldwide suffer a traumatic brain injury (TBI) (Dewan et al., 2018). Children and young adults as well as adults over 70 are particularly affected (James et al., 2019). The resulting neuropathology is – depending on the type and extent of the external force – heterogeneous and can have long-term functional as well as psychosocial consequences for the affected person (Ponsford et al., 2014). TBI can result in (multi-)focal brain damage but frequently causes diffuse axonal injury (DAI; Wallesch & Kulke, 2017), which affects the integrity of white matter pathways and thus contributes to impaired neuronal connectivity in general (Hayes, Bigler & Verfaellie, 2016). Focal brain lesions after TBI are often concentrated throughout the frontotemporal brain regions, particularly in the ventromedial and orbital areas of the frontal lobe (Stuss, 2011).

Communication disorders after TBI, often referred to as cognitive-communication disorders (CCDs), are estimated to affect at least 60 % of sufferers (Norman et al., 2020; Ponsford et al., 2014). Despite the comparatively high number of people affected and the general awareness of the comprehensive psychosocial consequences (Tran et al., 2018), CCDs have not yet been sufficiently addressed in the research literature. CCDs are described as the result of a dysfunction of a complex interaction of various linguistic, emotional, physical, behavioral, psychosocial, and (social) cognitive factors (MacDonald, 2017), and are commonly differentiated from aphasia. Individuals with CCDs experience less difficulty in linguistic processing than in the context-appropriate use of language in everyday communication situations (McDonald, Togher & Code, 2014). Because communication behavior in general is often perceived as inadequate or inappropriate by conversation partners (Crewe-Brown, Stipinovich & Zsilavecz, 2011), CCDs are associated with negative vocational (Meulenbroek & Turkstra, 2016) and psychosocial outcome (Neumann et al., 2019; Tran et al., 2018). More particularly, impairments are observed in discourse and pragmatic language.

Discourse impairments involve impaired organization of content in terms of cohesion and coherence (Coelho, 2007; Coelho, Grela, Corso, Gamble & Feinn, 2005; Marini, Zettin, Bencich, Bosco & Galetto, 2017) and/or reduced communicative efficiency (Galetto, Andreetta, Zettin & Marini, 2013). Pragmatic difficulties in TBI become evident in the context-inappropriate reception and use of language, such as in the interpretation of indirect speech acts (e. g., lies, irony, sarcasm; Arcara et al., 2020; Zimmermann, Gindri, de Oliveira & Fonseca, 2011). Furthermore, difficulties in communication behavior, such as difficulties in turn-taking (Murphy, Huang, Montgomery & Turkstra, 2015), or in the social appropriateness of communication (Togher & Hand, 1998) have been described.

Recently, the literature has become especially focused on the relationship between social-cognitive dysfunctions and CCDs in TBI. Social cognition is described as a multidimensional construct encompassing several processes that enable the adequate perception, analysis, and interpretation of social cues (e. g., emotions, needs, intentions; Frith & Frith, 2007). In general, social-cognitive processes help to understand and predict the behavior of others as well as to adjust one’s own behavior accordingly and are thus essential to interacting effectively (McDonald, Honan, Kelly, Byom & Rushby, 2014). Functional neuroimaging studies demonstrate that the neuroanatomical substrates of social-cognitive functions are chiefly located in the ventromedial and orbital frontal brain regions (e. g., Schurz, Radua, Aichhorn, Richlan & Perner, 2014), which are also primarily affected in TBI. However, the circuits involving these structures as well as subcortical structures, such as the amygdala, striatum, insula, and corpus callosum (Lieberman, 2007; McDonald Rushby, Dalton, Allen & Parks, 2018), are also considered relevant.

The influence of social-cognitive skills on communication competence seems intuitive: The speaker must continuously consider the intentions and needs of the communication partner(s) (McDonald, Honan et al., 2014). Successful communication thus requires the perception of both nonverbal and verbal cues as well as their interpretation – against the background of one’s own experiential knowledge and the situational context (McDonald, Honan et al., 2014). Consequently, the influence of social-cognitive abilities on communication competence is considered globally in several cognitive-linguistic theoretical approaches (MacDonald, 2017; Turkstra & Politis, 2017).

However, empirical evidence for the association of (social) cognition and communication is not always conclusive (Turkstra & Politis, 2017). A systematic meta-analysis by Rowley, Rogish, Alexander and Riggs (2017) focused on social cognition and pragmatic language comprehension in particular and demonstrated only a moderate correlative relationship. Turkstra and Politis (2017) assumed methodological reasons may lie behind this unclear association: (Social) cognitive functions in standardized test procedures are often operationalized as sum scores, though these tests actually assess more than one construct. Additionally, research has thus far tended to synthesize existing empirical evidence globally, neglecting the complexity of both the social cognition and communication domains. Social cognition has three subcomponents, namely, emotion recognition, empathy, and Theory of Mind (ToM), which are principally distinguished from each other theoretically and empirically (McDonald, 2013; Stietz, Jauk, Krach & Kanske, 2019). But there has been no systematic review of the social-cognitive subcomponents relevant to communication and how they impact communication competence. This systematic review, therefore, derives a more clearly differentiated picture of the specific association between the subcomponents of social cognition and communication competencies.

Social Cognitive Subcomponents and Communication

Despite the lack of consensus on the definition of social cognition (Baars & Gage, 2010), we can distinguish between three main subcomponents of social cognition: emotion recognition, empathy, and ToM (McDonald, 2013; McDonald, Gowland et al., 2014). These are also described either as “emotional” or “hot“ social-cognitive processes (i. e., emotion recognition, affective empathy), or as “cognitive“ or “cold“ social-cognitive processes (i. e., cognitive empathy, ToM) (McDonald, 2013). Depending on the location and extent of the lesion, individuals with TBI can experience difficulties in all three subcomponents.

Emotion Recognition

Approximately 30 % of individuals with TBI experience deficits in emotion recognition (Rigon, Turkstra, Mutlu & Duff, 2018). Studies report difficulties in the interpretation of static emotions (i. e., pictures of facial emotion) as well as impairments in the interpretation of dynamic stimuli (i. e., videos) (Babbage et al., 2011). Deficits are particularly evident in the processing of negative emotions (Rosenberg, McDonald, Dethier, Kessels & Westbrook, 2014). Patients may also experience difficulties in processing vocal emotion, that is, inferring the emotional state of a person by interpreting prosodic cues (Ietswaart, Milders, Crawford, Currie & Scott, 2008).

Empathy

Empathy encompasses an emotional and a cognitive component: Whereas emotional empathy means emotionally resonating with the feelings of another person, even if these differ from one’s own, cognitive empathy is described as the cognitive processing of another individual’s emotional state (Shamay-Tsoory, Aharon-Peretz & Perry, 2009). Yet the term “cognitive empathy” is often used inconsistently regarding the concept of ToM (see below), for example, it is used by some interchangeably with the term “affective ToM” (Dvash & Shamay-Tsoory, 2014), while for others, ToM is considered to be an essential prerequisite for cognitive empathy (Shamay-Tsoory, 2015). In a study by de Sousa et al. (2011), 70 % of the individuals with severe TBI rated their empathic abilities as limited.

Disorders related to the recognition and expression of both emotion and empathy are associated with difficulties in social interaction (Wauters & Marquardt, 2019), resulting in serious consequences for psychosocial functioning and intact intimate relationships (Douglas, 2017; de Sousa et al., 2011).

Theory of Mind

McDonald (2013) refers to ToM as a subcomponent of “cold“ social cognition: It describes the ability to explain one’s own behavior as well as the behavior of others, including thoughts, intentions, beliefs, and desires, and to compare the other person’s point of view with one’s own. The literature extensively described difficulties in ToM after TBI (Martín-Rodríguez & León-Carrión, 2010). McDonald, Gowland et al. (2014) view ToM as having “a clear potential relation to communication skills” to communicate information that is adequate in quality, quantity, and manner.

The Present Study

The inconclusive empirical evidence regarding the association between social-cognitive abilities and communicative competence in individuals with TBI motivates this attempt to derive a more differentiated view of the relationship by analyzing empirical evidence in view of social-cognitive subcomponents (emotion recognition, empathy, and ToM). Consequently, this systematic review examines corresponding empirical evidence based on the following research questions:

  1. 1
    Which subcomponents of the communication and social cognition domains are addressed?
  2. 2
    Which subcomponents of social cognition are associated statistically with subcomponents of communication?

Method

The design of this systematic review was based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines (Page et al., 2021).

Sources and Syntax

The systematic database search was conducted on 15 February 2021 in the following databases: Medline, PsycInfo, ERIC, and Academic Search Complete. The search strategy included three main clusters of search terms: Population (“traumatic brain injur*” OR TBI OR “closed head injur*”), social cognition and its subcomponents (“social cognit*” OR “theory of mind” OR ToM OR empath* OR emotion* OR “social percept*”) as well as communication and its subcomponents (communicat* OR “cognitive communicat*” OR pragmatic* OR discours* OR “social communicat*” OR “subtle language*” OR “subtle communicat*” OR “high* level language*” OR “high* order language” OR “complex language” OR “cognitive linguistic” OR “cognitive language”).

The search terms were applied to title, abstract, and keywords in all databases. An example of the query syntax can be found in the electronic supplementary material [ESM] 1.

Study Selection

The eligibility criteria were as follows:

  1. 1
    The study reports empirical data and has been published in a peer-reviewed, scientific journal in English.
  2. 2
    The study includes a defined group of individuals with TBI (age ≥ 18 years).
  3. 3
    The communication abilities of individuals with TBI were assessed with a standardized test procedure or with an experimental task/paradigm.
  4. 4
    The social-cognitive abilities of individuals with TBI were assessed with a standardized test procedure or with an experimental task/paradigm.

The study examines an association (relationship/influence) between the performances in the assessments outlined under Points 3 and 4 above.

No restrictions were placed on the publication date. We assigned assessments to a domain-specific subcomponent according to the author’s definition. If this information was not available, the authors of this paper made the assignment after reviewing the assessment.

Titles identified in the database search were exported to citation software (Citavi 5.0). After removing duplicates, we first screened all remaining titles by title/abstract to determine whether they met inclusion criteria 1 to 4 and then included the studies that met these criteria in the full-text analysis, which served to verify inclusion criteria 1 to 5. The process is outlined in Figure 1. Study eligibility was determined independently by two reviewers (JQ, CK). We assessed the quality of studies using the Appraisal Tool for Cross-Sectional Studies (AXIS; Downes, Brennan, Williams & Dean, 2016; for more detail see ESM 2).

Figure 1 Study selection flowchart.

Data Extraction Strategy

We conducted a full-text analysis of the studies included using a data extraction form, extracting the following information from the final set of articles: sample characteristics (sample size, sex distribution, age), study aim, results, assessment procedures used (standardized/experimental), and the statistical procedure used to analyze the relationship/influence of social cognition on communication.

Results

Study Selection

The systematic database search resulted in a total of 450 articles; two additional records had been identified through other sources. After removing the duplicates, we scanned the title and abstract of the 253 remaining articles for relevance based on the predetermined inclusion criteria. This first screening resulted in a total of 48 articles. We examined the full text of these records in more detail and found a total of 17 studies that met the inclusion criteria and that were then subjected to further analysis. For more details, see Figure 1.

Study Characteristics

The characteristics of the studies analyzed are presented in ESM 3. Average sample size was M = 24.82 (SD = 9.97). All studies except one (n = 16) focused on individuals with medium to severe TBI; the remaining study included participants with mild to medium TBI. Participants were on average 36.6 years old (SD = 5.48), and the average time post-onset was 6.97 years (SD = 4.68).

Subcomponents of Social Cognition and Communication

Eight of the 17 studies focused on more than one subcomponent of social cognition. Most studies identified examined ToM (14 out of 17), 8 of the 17 studies investigated emotion recognition, and only 2 studies looked at empathy.

Regarding communication, 5 studies examined global communication competence (self-/proxy-rating), 8 out of the 17 studies focused on pragmatics (reception/production), and 4 studies investigated discourse (reception/production).

Associations Between Social Cognition and Communication

The more detailed analysis presented below focuses on the aforementioned individual social-cognitive subcomponents, namely, emotion recognition, empathy, and ToM, and their association with both global communication abilities and with the two subcomponents of communication, pragmatics and discourse. Studies that included empirical evidence on more than one subcomponent were listed for each component.

Overall, the studies revealed significant associations between each of the three subcomponents of social cognition, i. e., emotion recognition, empathy, and ToM, and global communication abilities as well as the subcomponents of communication, pragmatics and discourse. Fifteen of the 17 studies reported a statistically significant association between social-cognitive abilities and communicative competencies.

Emotion Recognition

For the subcomponent of emotion recognition, 4 studies (out of a total of 8 studies, all surveys of significant others/independent raters) provided positive evidence for an association with global communication abilities (McDonald, Flanagan, Martin & Saunders, 2004; Milders, Ietswaart, Crawford & Currie, 2008; Rigon et al., 2018; Watts & Douglas, 2006). One study could not establish a significant relationship between emotion recognition and global communication, i. e., self-perceived communication problems (Saxton, Younan & Lah, 2013). Three studies investigated an association with pragmatic aspects but could not confirm a significant relationship (McDonald & Flanagan, 2004; McDonald, Fisher, Flanagan & Honan, 2015; McDonald, Fisher & Flanagan, 2016). For an overview see ESM 4.

Empathy

The subcomponent of empathy was investigated in two studies: Saxton et al. (2013) identified a significant correlation between self-perceived empathy and a subdomain of a self-rating measure that focuses on “communication problems.” The subdomain of empathy significantly related with communication problems was “perspective-taking.” McDonald et al. (2015) did not establish a unique contribution of emotional empathy to sincerity detection. For more details, see ESM 5.

Theory of Mind

For ToM, the social-cognitive subcomponent most frequently investigated; 11 out of 14 studies demonstrated an association with communication. Most evidence was found for a specific connection between ToM and aspects of pragmatics: 6 out of 7 studies demonstrated a significant association, in particular with the processing of irony/sarcasm, insincerity, and indirect speech acts. Four studies examined an association between ToM and discourse (reception/production). Two of these were able to provide clear evidence for a relationship; the other two, however, were not. In summary, 3 out of 14 studies failed to demonstrate an association between ToM and communication abilities. For an overview, see ESM 6.

ToM and Pragmatics

The influence of ToM skills on the reception or production of sarcasm was demonstrated in 2 studies (Channon, Pellijeff & Rule, 2005: first-order ToM → reception of sarcasm; Bosco et al., 2017; Bosco et al., 2018: first- & second-order ToM → production of sarcasm). However, this is contradicted by the results of Martin and McDonald (2005), who did not confirm a relationship between the comprehension of irony and ToM (second-order ToM).

Three studies found a relationship between ToM and the production (Bosco, Gabbatore, Angeleric, Zettin & Parola, 2018) and reception of insincere speech acts (Bosco, Parola, Sacco, Zettin & Angeleri, 2017; Bosco et al., 2018; Channon et al., 2005; McDonald et al., 2015).

Muller et al. (2010) and McDonald et al. (2015) identified a significant association between ToM and the reception of indirect speech acts. Muller et al. (2010) differentiated between nonverbal and verbal ToM tasks, and a significant correlation was found only for verbal ToM tasks (faux pas test, first-order, and second-order false belief tasks).

ToM and Discourse

Three studies examined the influence of ToM on discourse production abilities (Byom & Turkstra, 2012, 2017; McDonald, Gowland et al., 2014). In 2 of these studies, higher demands on ToM revealed limitations on several discourse analytic parameters. For example, Byom and Turkstra (2012) demonstrated that men with TBI had difficulty in adapting to the intimacy level of a conversation with known interlocutors compared to neurologically healthy controls. They analyzed the production of mental state terms (MST), i. e., words that refer to states of mind and indicate one’s own thoughts, feelings, or desires. McDonald, Gowland et al. (2014) revealed a somewhat more ambiguous picture: They observed no influence of ToM on productive discourse performance (number of correct details in picture description). The exception was a task with a high demand on inhibitory control in which the respondent had to inhibit their own self-perspective.

Regarding ToM and its association with discourse reception, McDonald, Gowland et al. (2014) described a relationship between second-order ToM and the processing of pragmatic inferences. Honan, McDonald, Gowland, Fisher & Randall (2015) failed to provide evidence for a direct relationship between second-order ToM skills and receptive discourse performance, though their study did provide evidence that working memory skills predicted discourse reception skills.

Discussion

The present systematic review provides a differentiated view of the association between social-cognitive abilities and communicative abilities in people with CCDs after TBI. In summary, we found significant associations between each of the three subcomponents of social cognition, i. e., emotion recognition, empathy, and ToM, and global communication abilities as well as discourse and pragmatic subcomponents. However, the number of studies as well as the clarity of the findings differed for the individual subcomponents. The results of the review point to a more global role of emotion recognition and empathy regarding communication interaction. In contrast, the analysis presented here suggests a systematic relationship between ToM and individual aspects of pragmatics, in particular the processing of irony/sarcasm, insincerity, and indirect speech acts.

Relationship Between Social Cognition and Communication

The overall results agree with existing cognitive-linguistic approaches that consider all three social-cognitive subcomponents (emotion recognition, empathy, and ToM) as relevant to successful communicative interaction (i. e., MacDonald, 2017; Turkstra & Politis, 2017). The following give detailed analyses of the individual subcomponents of social cognition.

Emotion Recognition

For the subcomponent of emotion recognition, 4 studies (out of a total of 8) provided positive evidence for an association with global communication abilities, while 3 studies did not support an association with pragmatics. This could lead to the assumption that impairments of “hot “social-cognitive processes become especially evident in everyday social interactive communication and play a less crucial role in cognitive pragmatic processes, such as in the interpretation of pragmatic inferences. This is supported by a review by Milders (2019), who identified strong empirical evidence for an association between emotion recognition and post-TBI social behavior. Most of the studies included that found a positive significant relationship between emotion recognition and communication subcomponents applied measures that assessed dynamic facial emotion recognition. Thus, a more systematic investigation of the influence of emotion recognition on communicative abilities in experimental, ecologically valid contexts would be desirable.

Empathy

Empathy was the explicit focus in only a single study, which found an association with global pragmatic skills. Because of the limited number of studies, no further generalizations can be made. Given that empathy is considered principally to be a separate construct, and thus dissociated from ToM (Stietz et al., 2019), and to be relevant for successful communicative interactions (McDonald, Gowland et al., 2014), research that focuses explicitly on this subcomponent is needed.

ToM

Overall, the results of the analysis demonstrated a more specific role of ToM in the context of the reception and production of indirect speech acts (hints, irony/sarcasm, insincerity) and socially acceptable communication behavior.

Only 5 studies examined the causal influence of ToM on communicative competence (2 of which focused on the same sample). Three of these studies were able to demonstrate the influence of ToM on the identification of pragmatic inferences (lies, sarcasm, irony). The role of ToM in the context of these pragmatic abilities is also described for other neurological disorders, such as schizophrenia (Li et al., 2019). In contrast, McDonald, Gowland et al. (2014) confirmed the role of ToM on discourse production only for a task that demanded high inhibitory abilities. Honan et al. (2015) did not confirm a prediction of receptive discourse processing through ToM.

The two aforementioned studies, whose regression analytic approach failed to confirm an influence of ToM on communication parameters, concluded that executive functions and working memory significantly influence communicative performance. This leads to a discussion of the entire (social-) cognitive interplay contributing to a successful communication interaction. In their theoretical review, Martin and McDonald (2003) proposed both the social inference theory, which attributes pragmatic impairments to deficits in ToM, and the executive function theory, which relates executive dysfunctions to pragmatic deficits. The authors concluded that none of these theories can be generalized. Furthermore, several authors point out that, because of the neuropathological heterogeneity of acquired brain damage, different “disorder routes” may be assumed that may ultimately manifest clinically in comparable pragmatic or discourse impairments, i. e., in different “cognitive phenocopies” (Channon et al., 2005; Turkstra & Politis, 2017).

The discussion of the (social-)cognitive interplay underlying communication competence outlined above is intertwined with the question of the relative independence of the social-cognition construct from other cognitive processes. Evidence for a relationship linking social-cognition abilities with cognitive flexibility and executive functions in individuals with TBI was provided in some previous studies (e. g., Theadom et al., 2019), whereas other studies were unable to demonstrate correlations between social cognition and cognitive performance (e. g., Spikman, Timmerman, Milders, Veenstra & van der Naalt, 2012). This rather heterogeneous picture is also reflected in the study corpus analyzed in this paper: A portion of the studies also examined the association between social-cognitive processes and other neuropsychological parameters as a subsidiary outcome. Whereas some could not establish a dependence of ToM on executive functions (e. g., Bosco et al., 2017; Muller et al., 2010), others did (i. e., working memory performance; Honan et al., 2015; inhibition; McDonald, Gowland et al., 2014). The identification of the key influencing processes depends, in both contexts, largely on the comparability of empirical evidence, which is hampered by the variability across the measures applied as well as by the disagreement concerning the definition of the subcomponents of social cognition and communication.

Our analyses revealed heterogeneity across the social cognition and communication measures applied within the included studies. Concerning social-cognition measures, this can be illustrated, for example, in the assessment of emotion recognition: Whereas some measures use a video-based presentation of items in the context of communicative interaction (TASIT; McDonald, Flanagan, Rollins & Kinch, 2003), other, more traditional measures use static representations of facial emotions (Reading The Mind in The Eyes Test; Baron-Cohen, Wheelwright, Hill, Raste & Plumb, 2001). The observed heterogeneity agrees with several studies that point out the variability of social cognition assessments, such as ToM measures, both in their conceptualization (Milders, 2019; Wallis, Kelly, McRae, McDonald & Campell, 2021) and in their demand for linguistic skills (Byom & Mutlu, 2013; Muller et al., 2010). Depending on their conceptualization, the procedures seem to depict a different facet of the respective construct. This is supported by an imaging study by Khosdelazad et al. (2020) for different emotion recognition tests and is also described for various ToM tasks in Schurz et al. (2014).

Turkstra and Politis (2017) criticize the frequent use in empirical studies of measures that are less ecologically valid and thus cannot map both (social-)cognitive and communicative-pragmatic skills closely onto everyday life. Our results show that studies demonstrating a significant association between social-cognitive subcomponents and communication subcomponents often applied a more ecologically valid social-cognition measure. This supports the call for applying ecologically valid test procedures in the context of CCDs in TBI. In short, when choosing a measure, the goal must be considered: When the point of interest is a basic theoretical question, e. g., the analysis of the (social-) cognitive framework of communication competence, a differentiated analysis that considers the cognitive and linguistic demands of the applied measure is inevitable (Muller et al., 2010). If, however, the goal is a clinical diagnosis that aims to map social-cognitive abilities as closely as possible to everyday life, then diagnostic procedures integrating the interplay of social cognition, memory, attention, and linguistic-communicative competencies are indicated. For both contexts – empirical research and clinical studies – we need a consensus on a core outcome set of measures used in both to improve comparability across studies.

In our analysis, we treated the three social-cognitive subcomponents as clearly delineated from each other, and we viewed each as internally consistent. Clinically, behaviorally, and neuroanatomically, there is evidence for both dissociation (Shamay-Tsoory et al., 2009; Stietz et al., 2019) and overlap (de Sousa et al., 2010) between these subcomponents. Additionally, the construct of empathy as a domain of social cognition and its intersection with ToM is yet to be empirically specified (Wallis et al., 2021). Given the lack of agreement on definitions as well as the heterogeneity in assessments, the clear delineation of constructs made in this study might have distorted results. Nevertheless, our analysis points to at least partial delineation of the constructs of emotion recognition, empathy, and ToM, as they each seem to play a specific role concerning communicative abilities.

Because of the limited number of studies that met the inclusion criteria, their research methodology (small sample size, potential selection bias, heterogeneous samples e. g., in terms of neuropathology, duration of posttraumatic amnesia as the sole indicator of the severity of injury; see also ESM 3), the heterogeneity of the subcomponents (only a few studies have looked at the same combination of social-cognitive and communication subcomponents), and measures, the conclusions made in this review should be considered with caution. Nevertheless, the evidence that currently exists can improve our understanding of CCDs after TBI. Because of the limited number of studies as well as the heterogeneity of assessment procedures used, we could perform no further analysis e. g., of the special role of first-order and second-order ToM. Additionally, we were unable to differentiate them regarding the cause, location, and severity of TBI or to time post-onset. These factors should be considered in future research.

Conclusion and Clinical Implications

Based on the present systematic review, the influence of social-cognitive abilities on communication competence in individuals with TBI can be assumed. Even though we could not identify a clear causal relationship between particular subcomponents of social cognition and particular subcomponents of communication because of the limited number of studies and the conceptual and methodological heterogeneity across studies, the present review does present converging evidence that “hot” social-cognitive abilities such as emotion recognition seem to play an important role in global social communication interaction, whereas “cold” social-cognitive abilities, namely ToM, seem to have a more specific influence on pragmatic abilities (i. e., processing of irony/sarcasm, insincerity, indirect speech acts). Further research is needed to strengthen these observations.

This review stresses the methodological heterogeneity in empirical research on the association between social cognition and communication. To improve comparability across studies and thus derive a clearer picture of the relationship between both domains, we need a consensus on a core outcome set of measures used in research focusing on social cognition and/or on communication with people with TBI. This has already been claimed elsewhere for social-cognition measures (Milders, 2019).

The results highlight the use of ecologically valid assessments in the diagnosis of CCDs after TBI. Diagnostic procedures should emphasize both constructs, social cognition and communication, including their intersection. This is already considered in assessments such as the TASIT or its German adaptation, the Basel Social Inference Test (BASIT; Jarsch, Bartsch et al., in press; Jarsch, Piguet et al., in prep.) and in a pilot study with individuals with TBI (Quinting, Jonas, Sollberger & Stenneken, 2022). Overall, the results motivate an interdisciplinary approach to neuropsychology and speech-language therapy in the diagnostic and therapeutic process with individuals with CCD after TBI, which is considered internationally, for example, in the Clinical Practice Guidelines for Cognitive Rehabilitation after TBI from the International Cognitive Working Group (INCOG; Togher et al., 2014).

Literature