Memory for Conversation in Traumatic Brain Injury: A Feasibility Study and Preliminary Findings.

PURPOSE: Despite common clinical complaints about memory for conversation after traumatic brain injury (TBI), the nature and severity of this deficit are unknown. In this research note, we report feasibility and preliminary data from a new conversation memory study protocol. METHOD: Participants in this feasibility study were 10 pairs, each including an adult with chronic, moderate-to-severe TBI and their chosen familiar conversation partner. The experiment began with a naturalistic conversation between participants with TBI and their conversation partners. After a filled delay, participants next completed verbal recall for the conversation, which we transcribed and coded for their accuracy relative to the original conversation. Participants also read chosen statements from their original conversation and predicted what each partner would remember in a week. One week later, participants completed a posttest about who said each of the chosen statements, allowing direct comparison to their predictions. RESULTS: We successfully collected conversation memory data from all 10 pairs, suggesting that this protocol is feasible for future study. In this preliminary sample, people with TBI and their conversation partners did not differ in the accuracy of their recall for the conversation about 20 min after it occurred. When asked to predict their partner's delayed memory, conversation partners were less accurate than participants with TBI because they underestimated how much their partners with TBI would remember. CONCLUSION: Measuring memory for conversation in TBI is feasible and may advance the characterization of cognitive-communication impairment in TBI, and its heterogeneity, in everyday contexts. SUPPLEMENTAL MATERIAL: https://doi.org/10.23641/asha.25927513.

Attentional Orienting and Disfluency-Related Memory Boost Are Intact in Adults With Moderate-Severe Traumatic Brain Injury.

PURPOSE: Traumatic brain injury (TBI) is associated with a range of cognitive-communicative deficits that interfere with everyday communication and social interaction. Considerable effort has been directed at characterizing the nature and scope of cognitive-communication disorders in TBI, yet the underlying mechanisms of impairment are largely unspecified. The present research examines sensitivity to a common communicative cue, disfluency, and its impact on memory for spoken language in TBI. METHOD: Fifty-three participants with moderate-severe TBI and 53 noninjured comparison participants listened to a series of sentences, some of which contained disfluencies. A subsequent memory test probed memory for critical words in the sentences. RESULTS: Participants with TBI successfully remembered the spoken words (b = 1.57, p < .0001) at a similar level to noninjured comparison participants. Critically, participants with TBI also exhibited better recognition memory for words preceded by disfluency compared to words from fluent sentences (b = 0.57, p = .02). CONCLUSIONS: These findings advance mechanistic accounts of cognitive-communication disorder by revealing that, when isolated for experimental study, individuals with moderate-severe TBI are sensitive to attentional orienting cues in speech and exhibit enhanced recognition of individual words preceded by disfluency. These results suggest that some aspects of cognitive-communication disorders may not emerge from an inability to perceive and use individual communication cues, but rather from disruptions in managing (i.e., attending, weighting, integrating) multiple cognitive, communicative, and social cues in complex and dynamic interactions. This hypothesis warrants further investigation.

Sleep Disruption Persists and Relates to Memory Disability After Traumatic Brain Injury: A Cross-Sectional Study of Adults in the Chronic Phase of Injury.

OBJECTIVE: To examine sleep disruption in chronic traumatic brain injury (TBI) across 3 aims: (1) to examine differences in self-reported sleep disruption between adults with and without a chronic history of TBI; (2) to query reported changes in sleep after TBI; and (3) to explore the relationship between self-reported sleep disruption and memory failures in daily life. SETTING: Community-dwelling participants completed self-report sleep and memory surveys as part of their participation in a larger patient registry. PARTICIPANTS: This study included 258 participants, and half (n = 129) of them have a chronic history of moderate-severe TBI (mean time since injury is 5.1 [SD 6.5] years). DESIGN: We report descriptive statistics from this matched cross-sectional study on sleep in the chronic phase of injury. We also used planned Wilcoxon ranked-sum tests and exploratory correlations to examine the relationships of sleep disruption with TBI diagnosis, injury chronicity, and memory. MAIN MEASURES: We used the Pittsburgh Sleep Quality Index to measure sleep disruption and the Epworth Sleepiness Scale to measure daytime sleepiness. Participants answered questions about postinjury sleep and responded to the Everyday Memory Questionnaire as a measure of memory failures in daily life. RESULTS: Individuals with TBI had significantly higher rates of sleep disruption than those without TBI, as measured by the Pittsburgh Sleep Quality Index but not on the Epworth Sleepiness Scale. Sleep disruption in TBI manifested more in sleep quality than quantity. Half of the participants with TBI reported a negative change in sleep postinjury. In an exploratory analysis, sleep disruption was related to memory failure in daily life in the TBI sample. CONCLUSIONS: Sleep disruption persists long after TBI but may be under-recognized in people with chronic TBI. Given that sleep is critical for memory and rehabilitation outcomes well into the chronic phase of injury, steps to improve the identification and management of sleep disruption are needed. Key words:chronic, memory, sleep, traumatic brain injury.

Does Facebook Use Provide Social Benefits to Adults with Traumatic Brain Injury?

Drawing on the social compensation hypothesis, this study investigates whether Facebook use facilitates social connectedness for individuals with traumatic brain injury (TBI), a common and debilitating medical condition that often results in social isolation. In a survey (N = 104 participants; n = 53 with TBI, n = 51 without TBI), individuals with TBI reported greater preference for self-disclosure on Facebook (vs. face-to-face) compared to noninjured individuals. For noninjured participants, a preference for Facebook self-disclosure was associated with the enactment of relational maintenance behaviors on Facebook, which was then associated with greater closeness with Facebook friends. However, no such benefits emerged for individuals with TBI, whose preference for Facebook self-disclosure was not associated with relationship maintenance behaviors on Facebook, and did not lead to greater closeness with Facebook friends. These findings show that the social compensation hypothesis has partial utility in the novel context of TBI, and suggest the need for developing technological supports to assist this vulnerable population on social media platforms.

Memory and Traumatic Brain Injury: Assessment and Management Practices of Speech-Language Pathologists.

PURPOSE: Memory impairments are among the most commonly reported deficits and among the most frequent rehabilitation targets for individuals with traumatic brain injury (TBI). Memory and learning are also critical for rehabilitation success and broader long-term outcomes. Speech-language pathologists (SLPs) play a central role in memory management for individuals with TBI across the continuum of care. Yet, little is known about the current practice patterns of SLPs for post-TBI memory disorders. This study aims to examine the clinical management of memory disorders in adults with TBI by SLPs and identify opportunities to improve post-TBI memory outcomes. METHOD: SLPs from across the continuum of care were recruited to complete an online survey. The survey assessed key practice areas specific to memory and memory disorders post-TBI, including education and training, knowledge and confidence, and assessment and treatment patterns. RESULTS: Surveys from 155 SLPs were analyzed. Results revealed that TBI-specific training remains low in the field. Respondents varied in their practice patterns in assessing and treating memory disorders. Most SLPs do not appear to have access to appropriate standardized assessments to measure unique forms of memory. Respondents also reported a range of barriers and opportunities to advance memory outcomes following TBI and provided suggestions of areas in which they would like to see more basic and clinical research. CONCLUSIONS: These findings establish a baseline of the current practices for clinical management of memory impairment in adults with TBI by SLPs. Improved opportunities for clinician training, the development of a single tool to assess multiple forms of memory, better access to existing memory assessments, and implementation of evidence-based interventions promise to lead to improved memory outcomes for individuals with TBI.

Keeping track of who knows what in multiparty conversation despite severe memory impairment.

Language use has long been understood to be tailored to the intended addressee, a process termed audience design. Audience design is reflected in multiple aspects of language use, including adjustments based on the addressee's knowledge about the topic at hand. In group settings, audience design depends on representations of multiple individuals, each of whom may have different knowledge about the conversational topic. A central question, then, concerns how these representations are encoded and retrieved in multiparty conversation where successful conversation requires keeping track of who knows what. In the present research, we probe the biological memory systems that are involved in this process of multiparty audience design. We present the results of two experiments that compare language use in persons with bilateral hippocampal damage and severe declarative memory impairment (amnesia), and demographically matched neurotypical comparison participants. Participants played a game in which they discussed abstract images with one partner in conversation, and then discussed the images again with the same partner or with a new partner in a three-party conversation. Neurotypical participants' language use reflected newly formed representations of which partner was familiar with which images. Participants with amnesia showed evidence of partner-specific audience design in multiparty conversation but it was attenuated, especially when success required rapid alternations between representations of common ground. The findings suggest partial independence of the formation and use of partner-specific representations from the hippocampal-dependent declarative memory system and highlight the unique contributions of the declarative memory system to flexible and dynamic language use.

Intact moral decision-making in adults with moderate-severe traumatic brain injury.

Background and aim: Deficits in decision-making are a common consequence of moderate-severe traumatic brain injury (TBI). Less is known, however, about how individuals with TBI perform on moral decision-making tasks. To address this gap in the literature, the current study probed moral decision-making in a sample of individuals with TBI using a widely employed experimental measure. Methods/hypothesis: We administered a set of 50 trolley-type dilemmas to 31 individuals with TBI and 31 demographically matched, neurotypical comparison participants. We hypothesized that individuals with TBI would be more likely to offer utilitarian responses to personal dilemmas than neurotypical peers. Results: In contrast to our hypothesis, we observed that individuals with TBI were not more likely to offer utilitarian responses for personal dilemmas. Conclusion: Our results suggest that moral decision-making ability is not uniformly impaired following TBI. Rather, neuroanatomical (lesion location) and demographic (age at injury) characteristics may be more predictive of a disruption in moral decision-making than TBI diagnosis or injury severity alone. These results inform the neurobiology of moral decision-making and have implications for characterizing patterns of spared and impaired cognitive abilities in TBI.

Self-Reported Symptoms of Vertigo and Imbalance Are Prevalent Among Adults With Chronic Moderate-Severe Traumatic Brain Injury: A Preliminary Analysis.

PURPOSE: Dizziness and imbalance are common symptoms during the acute phase of traumatic brain injury (TBI). However, there is evidence to suggest that these symptoms persist into the chronic phase of injury. Few prospective studies have examined the frequency and type of dizziness and imbalance in adults with chronic moderate-severe TBI. The aim of this preliminary analysis was to investigate the prevalence of these symptoms in adults with chronic moderate-severe TBI. METHOD: Twenty-four adults with chronic moderate-severe TBI and a group of 19 age-, sex-, and education-matched noninjured comparison participants were recruited. Self-reported dizziness and imbalance were measured using a modified version of a standard case history form. Significant associations between group (TBI group or noninjured comparison [NC] participants) and self-reports of dizziness, imbalance, and related symptoms (endorsed "yes" or "no") were explored. RESULTS: The TBI group most reported lightheadedness (75%), vertigo (38%), and imbalance and/or falling (46%). The most common related symptom reported by the TBI group was headache (63%) and nausea (46%). Significant associations revealed that the TBI group responded "yes" in higher percentages than the NC group across all categories (dizziness, imbalance, and related symptoms). There were no statistically significant relationships among dizziness, imbalance, or headache symptoms within the TBI group. CONCLUSIONS: These preliminary findings suggest that dizziness and imbalance are prevalent in adults with chronic moderate-severe TBI. Persistent vertiginous symptoms may point to an underlying vestibular impairment. However, further research is needed to characterize vestibular function in chronic moderate-severe TBI.

Memory for social media images following traumatic brain injury.

PRIMARY OBJECTIVE: An emerging body of research examines the role of computer-mediated communication in supporting social connection in persons with traumatic brain injury (TBI). We examine the cognitive impacts of engaging with images posted to social media for persons with moderate-severe TBI. RESEARCH DESIGN: Prior work shows that after viewing social media posts, adults have better memory for posts when they generate a comment about the post. We examined if persons with TBI experience a memory benefit for commented-upon social media images similar to non-injured comparison participants. METHODS AND PROCEDURES: 53 persons with moderate-to-severe TBI and 52 non-injured comparison participants viewed arrays of real social media images and were prompted to comment on some of them. After a brief delay, a surprise two-alternative forced choice recognition memory test measured memory for these images. MAIN OUTCOMES AND RESULTS: Persons with TBI remembered social media images at above-chance levels and experienced a commenting-related memory boost much like non-injured comparison participants. CONCLUSIONS: These findings add to a growing literature on the potential benefits of social media use in individuals with TBI and point to the benefits of active engagement for memory in social media contexts in TBI.

Measurement of Sleep in Chronic Traumatic Brain Injury: Relationship Between Self-report and Actigraphy.

OBJECTIVE: To examine the relationship between self-report and actigraphy measurement of sleep in people with and without traumatic brain injury (TBI) by addressing 2 aims: (1) to assess the relationship between self-report and actigraphy for sleep quantity in people with and without TBI; and (2) to explore how self-report and actigraphy capture sleep quality in TBI. SETTING: Participants completed the study over 2 weeks in their own homes. They wore activity monitors, day and night, throughout the experiment and completed morning sleep diaries while interacting with an experimenter on videoconference. PARTICIPANTS: This project was embedded in a larger study on sleep and word learning in 100 adults: 50 with chronic, moderate-severe TBI and 50 demographically matched noninjured peers. Of the 100 participants who completed the larger study, 92 participants (45 with TBI and 47 noninjured peers) had sufficient actigraphy data for inclusion in the current study. DESIGN: We used multilevel linear regression models and correlation analyses to assess how well participants' self-report corresponded to actigraphy measurement of sleep. MAIN MEASURES: Actigraphy measures included nightly sleep duration and nighttime wakeups. Sleep diary measures included self-reported nightly sleep duration, nighttime wakeups, sleep quality, and morning fatigue. RESULTS: People with and without TBI did not differ in the relationship between self-reported and actigraphy measurement of sleep quantity. Performance on a neuropsychological memory assessment did not correlate with the difference in self-reported and actigraphy-measured sleep in the TBI group. Sleep characteristics that were measured by actigraphy did not predict subjective experiences of sleep quality or fatigue. CONCLUSIONS: Short-term self-report diaries capture accurate information about sleep quantity in individuals with TBI and may support self-report of other daily habits. Future research is needed to identify reliable metrics of sleep quality, and how they relate to other domains such as memory and mood, in the chronic phase of TBI.

Facial affect recognition in context in adults with and without TBI.

Introduction: Several studies have reported impaired emotion recognition in adults with traumatic brain injury (TBI), but studies have two major design features that limit application of results to real-world contexts: (1) participants choose from among lists of basic emotions, rather than generating emotion labels, and (2) images are typically presented in isolation rather than in context. To address these limitations, we created an open-labeling task with faces shown alone or in real-life scenes, to more closely approximate how adults with TBI label facial emotions beyond the lab. Methods: Participants were 55 adults (29 female) with moderate to severe TBI and 55 uninjured comparison peers, individually matched for race, sex, and age. Participants viewed 60 photographs of faces, either alone or in the pictured person's real-life context, and were asked what that person was feeling. We calculated the percent of responses that were standard forced-choice-task options, and also used sentiment intensity analysis to compare verbal responses between the two groups. We tracked eye movements for a subset of participants, to explore whether gaze duration or number of fixations helped explain any group differences in labels. Results: Over 50% of responses in both groups were words other than basic emotions on standard affect tasks, highlighting the importance of eliciting open-ended responses. Valence of labels by participants with TBI was attenuated relative to valence of Comparison group labels, i.e., TBI group responses were less positive to positive images and the same was true for negative images, although the TBI group responses had higher lexical diversity. There were no significant differences in gaze duration or number of fixations between groups. Discussion: Results revealed qualitative differences in affect labels between adults with and without TBI that would not have emerged on standard forced-choice tasks. Verbal differences did not appear to be attributable to differences in gaze patterns, leaving open the question of mechanisms of atypical affect processing in adults with TBI.

Intact speech-gesture integration in narrative recall by adults with moderate-severe traumatic brain injury.

PURPOSE: Real-world communication is situated in rich multimodal contexts, containing speech and gesture. Speakers often convey unique information in gesture that is not present in the speech signal (e.g., saying "He searched for a new recipe" while making a typing gesture). We examine the narrative retellings of participants with and without moderate-severe traumatic brain injury across three timepoints over two online Zoom sessions to investigate whether people with TBI can integrate information from co-occurring speech and gesture and if information from gesture persists across delays. METHODS: 60 participants with TBI and 60 non-injured peers watched videos of a narrator telling four short stories. On key details, the narrator produced complementary gestures that conveyed unique information. Participants retold the stories at three timepoints: immediately after, 20-min later, and one-week later. We examined the words participants used when retelling these key details, coding them as a Speech Match (e.g., "He searched for a new recipe"), a Gesture Match (e.g., "He searched for a new recipe online), or Other ("He looked for a new recipe"). We also examined whether participants produced representative gestures themselves when retelling these details. RESULTS: Despite recalling fewer story details, participants with TBI were as likely as non-injured peers to report information from gesture in their narrative retellings. All participants were more likely to report information from gesture and produce representative gestures themselves one-week later compared to immediately after hearing the story. CONCLUSION: We demonstrated that speech-gesture integration is intact after TBI in narrative retellings. This finding has exciting implications for the utility of gesture to support comprehension and memory after TBI and expands our understanding of naturalistic multimodal language processing in this population.

Emotion recognition of faces and emoji in individuals with moderate-severe traumatic brain injury.

BACKGROUND: Facial emotion recognition deficits are common after moderate-severe traumatic brain injury (TBI) and linked to poor social outcomes. We examine whether emotion recognition deficits extend to facial expressions depicted by emoji. METHODS: Fifty-one individuals with moderate-severe TBI (25 female) and fifty-one neurotypical peers (26 female) viewed photos of human faces and emoji. Participants selected the best-fitting label from a set of basic emotions (anger, disgust, fear, sadness, neutral, surprise, happy) or social emotions (embarrassed, remorseful, anxious, neutral, flirting, confident, proud). RESULTS: We analyzed the likelihood of correctly labeling an emotion by group (neurotypical, TBI), stimulus condition (basic faces, basic emoji, social emoji), sex (female, male), and their interactions. Participants with TBI did not significantly differ from neurotypical peers in overall emotion labeling accuracy. Both groups had poorer labeling accuracy for emoji compared to faces. Participants with TBI (but not neurotypical peers) had poorer accuracy for labeling social emotions depicted by emoji compared to basic emotions depicted by emoji. There were no effects of participant sex. DISCUSSION: Because emotion representation is more ambiguous in emoji than human faces, studying emoji use and perception in TBI is an important consideration for understanding functional communication and social participation after brain injury.

The growing gap: A study of sleep, encoding, and consolidation of new words in chronic traumatic brain injury.

Word learning is an iterative and dynamic process supported by multiple neural and cognitive systems. Converging evidence from behavioral, cellular, and systems neuroscience highlights sleep as an important support for memory and word learning over time. In many lab-based word learning experiments, participants encode and subsequently retrieve newly learned words in a single session. These designs are inadequate to capture the full dynamic word learning process, making them less ecologically valid. Single timepoint studies also limit investigation of the role of behavioral and lifestyle factors, like sleep, in supporting word learning over time. Adults with a history of traumatic brain injury (TBI), who commonly exhibit deficits in the memory systems that support word learning and report concomitant sleep disturbance, provide a unique opportunity to examine the link between memory, sleep, and word learning. Here we examined word learning over time and the influence of sleep on short- and long-term word recall in 50 adults with chronic moderate-severe TBI and 50 demographically matched neurotypical peers. We used a randomized within-participant crossover design to assess immediate encoding of new words and the consolidation of those words over time across intervals that did or did not involve sleep. Participants completed this study over the course of two weeks in their own homes to capture the iterative, dynamic process of real-world word learning. We also measured sleep in free living conditions using actigraphy throughout the experiment. Participants with TBI exhibited a word learning deficit that began at encoding and persisted across time. Critically, this deficit grew over the course of the week. The performance gap between groups was larger at the 1-week post-test than the immediate post-test, suggesting deficits in both encoding and consolidation of new words in individuals with TBI. Participants with and without TBI remembered more words when they slept after learning. Ecologically valid research designs that examine the relationship between memory, sleep, and word learning over time promise to advance mechanistic accounts of word learning and improve the long-term retention of new words in individuals with and without brain injury.

Word Learning as a Window to Memory and Rehabilitation Outcomes in Traumatic Brain Injury.

PURPOSE: The purpose of this viewpoint is to advocate for increased study of word learning abilities and word learning interventions in traumatic brain injury (TBI). METHOD: We describe the word learning process and the unique opportunities afforded by studying each component and stage. Building on discussions at the 2022 International Cognitive-Communication Disorders Conference, we describe how word learning may underlie a variety of functional outcomes after TBI, making it a promising target for rehabilitation. Finally, we discuss principles that may guide study in this critical area to advance outcomes after TBI for children and adults. RESULTS: Word learning is a dynamic and iterative process taking place over time and in multiple stages. Thus, studying word learning affords the opportunity to parse the relative contributions of multiple memory systems to different phases and components of the process. However, single-timepoint designs are insufficient to capture the full word learning process, which occurs over time and across contexts. Word learning also presents an opportunity to assess the contributions of behavioral and lifestyle factors (e.g., sleep and exercise) to different memory phases. Understanding these interactions could drive clinical interventions aimed at improving memory through manipulable external behaviors. CONCLUSIONS: Word learning is key to success in functional spheres across the life span. The importance of words to daily life remains after TBI, even as the memory systems that support word learning are disrupted. The empirical study of word learning and rehabilitation of word learning deficits in TBI presents a promising new direction in understanding the breadth of neurogenic cognitive-communication disorders and an opportunity to explore a potential driver of functional outcome and impactful rehabilitation target.

Facebook Experiences of Users With Traumatic Brain Injury: A Think-Aloud Study.

BACKGROUND: A critical gap in our knowledge about social media is whether we can alleviate accessibility barriers and challenges for individuals with traumatic brain injury (TBI), to improve their social participation and health. To do this, we need real-time information about these barriers and challenges, to design appropriate aids. OBJECTIVE: The aim of this study was to characterize the ways people with TBI accessed and used social media websites and understand unique challenges they faced. METHODS: We invited 8 adults with moderate to severe TBI to log onto their own Facebook page and use it as they regularly would while thinking aloud. Their comments were recorded and transcribed for qualitative analysis. We first analyzed participants' utterances using a priori coding based on a framework proposed by Meshi et al to classify adults' motives for accessing social media. We next used an open coding method to understand the challenges that people with TBI faced while using Facebook. In other words, we analyzed participants' needs for using Facebook and then identified Facebook features that made it challenging for them to meet those needs. RESULTS: Participants used all categories of codes in the framework by Meshi et al and provided detailed feedback about the Facebook user interface. A priori coding revealed 2 dimensions that characterized participants' Facebook use: whether they were active or passive about posting and self-disclosure on Facebook and their familiarity and fluency in using Facebook. The open coding analysis revealed 6 types of challenges reported by participants with TBI, including difficulty with language production and interpretation, attention and information overload, perceptions of negativity and emotional contagion, insufficient guidance to use Facebook, concerns about web-based scams and frauds, and general accessibility concerns. CONCLUSIONS: Results showed that individuals with TBI used Facebook for the same reasons typical adults do, suggesting that it can help increase social communication and reduce isolation and loneliness. Participants also identified barriers, and we propose modifications that could improve access for individuals with brain injury. On the basis of identified functions and challenges, we conclude by proposing design ideas for social media support tools that can promote more active use of social media sites by adults with TBI.

Mediators, Moderators, and Covariates: Matching Analysis Approach for Improved Precision in Cognitive-Communication Rehabilitation Research.

PURPOSE: The dual goals of this tutorial are (a) to increase awareness and use of mediation and moderation models in cognitive-communication rehabilitation research by describing options, benefits, and attainable analytic approaches for researchers with limited resources and sample sizes and (b) to describe how these findings may be interpreted for clinicians consuming research to inform clinical care. METHOD: We highlight key insights from the social sciences literature pointing to the risks of common approaches to linear modeling, which may slow progress in clinical-translational research and reduce the clinical utility of our work. We discuss the potential of mediation and moderation analyses to reduce the research-to-practice gap and describe how researchers may begin to implement these models, even in smaller sample sizes. We discuss how these preliminary analyses can help focus resources for larger trials to fully encapsulate the heterogeneity of individuals with cognitive-communication disorders. RESULTS: In rehabilitation research, we study groups, but we use the findings from those studies to treat individuals. The most functional clinical research is about more than establishing only whether a given effect exists for an "average person" in the group of interest. It is critical to understand the active ingredients and mechanisms of action by which a given treatment works (mediation) and to know which circumstances, contexts, or individual characteristics might make that treatment most beneficial (moderation). CONCLUSIONS: Increased adoption of mediation and moderation approaches, executed in appropriate steps, could accelerate progress in cognitive-communication rehabilitation research and lead to the development of targeted treatments that work for more clients. In a field that has made limited progress in developing successful interventions for the last several decades, it is critical that we harness new approaches to advance clinical-translational research results for complex, heterogeneous groups with cognitive-communication disorders.

Evidence of Audience Design in Amnesia: Adaptation in Gesture but Not Speech.

Speakers design communication for their audience, providing more information in both speech and gesture when their listener is naïve to the topic. We test whether the hippocampal declarative memory system contributes to multimodal audience design. The hippocampus, while traditionally linked to episodic and relational memory, has also been linked to the ability to imagine the mental states of others and use language flexibly. We examined the speech and gesture use of four patients with hippocampal amnesia when describing how to complete everyday tasks (e.g., how to tie a shoe) to an imagined child listener and an adult listener. Although patients with amnesia did not increase their total number of words and instructional steps for the child listener, they did produce representational gestures at significantly higher rates for the imagined child compared to the adult listener. They also gestured at similar frequencies to neurotypical peers, suggesting that hand gesture can be a meaningful communicative resource, even in the case of severe declarative memory impairment. We discuss the contributions of multiple memory systems to multimodal audience design and the potential of gesture to act as a window into the social cognitive processes of individuals with neurologic disorders.

Temporal order memory impairments in individuals with moderate-severe traumatic brain injury.

INTRODUCTION: Temporal order memory is a core cognitive function that underlies much of our behavior. The ability to bind together information within and across events, and to reconstruct that sequence of information, critically relies upon the hippocampal relational memory system. Recent work has suggested traumatic brain injury (TBI) may particularly impact hippocampally mediated relational memory. However, it is currently unclear whether such deficits extend to temporal order memory, and whether deficits only arise at large memory loads. The present study assessed temporal order memory in individuals with chronic, moderate-severe TBI across multiple set sizes. METHOD: Individuals with TBI and Neurotypical Comparison participants studied sequences of three to nine objects, one a time. At test, all items were re-presented in pseudorandom order, and participants indicated the temporal position (i.e., first, second, etc.) in which each object had appeared. Critically, we assessed both the frequency and the magnitude of errors (i.e., how far from its studied position was an item remembered). RESULTS: Individuals with TBI were not impaired for the smallest set size, but showed significant impairments at 5+ items. Group differences in the error frequency did not increase further with larger set sizes, but group differences in error magnitude did increase with larger memory loads. Individuals with TBI showed spared performance for the first object of each list (primacy) but were impaired on the last object (recency), though error frequency was better for last compared to middle items. CONCLUSIONS: Our findings demonstrate that TBI results in impaired temporal order memory for lists as small as five items, and that impairments are exacerbated with increasing memory loads. Assessments that test only small set sizes may be insufficient to detect these deficits. Further, these data highlight the importance of additional, sensitive measures in the assessment of cognitive impairments in TBI.