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

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.

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.