Reduced temporal organization of narrative recall in adults with moderate-severe traumatic brain injury

Narrative discourse impairments are well documented in individuals with moderate-severe traumatic brain injury (TBI). Studies of narrative discourse (i.e., story generation, story retelling) in this population have frequently focused on impairment of semantic relations across utterances and the larger discourse context (e.g., cohesion, coherence, story grammar). Less attention has been given to the temporal organization of narrative retelling in TBI. We applied temporal contiguity analyses, a technique traditionally used to characterize temporal organization of free recall of wordlists, to quantify the temporal organization of participants' story retellings with respect to the order in which the narrator originally presented the story details. We also conducted a parallel analysis of temporal contiguity of wordlist recall using data from the Rey Auditory Verbal Learning test. Participants with moderate-severe TBI and non-injured peers demonstrated above chance temporal organization and a tendency to make short transitions in the forward direction when recalling items in both the narrative recall and wordlist recall task. However, these effects were significantly reduced in the TBI group. Overall, their free recall performance was less temporally clustered, and they were more likely to make larger jumps between story details (or words in the wordlist recall task) than their non-injured peers when recalling stories. Examining free recall at multiple timepoints revealed that while repetition (i.e., multiple presentations of the wordlist) increased temporal organization of recall, long delays (i.e., one week) decreased temporal organization for both the TBI and non-injured groups. We propose that reduced temporal organization of narrative recall in individuals with moderate-severe TBI is linked to impairments in the declarative relational memory system. In line with retrieved-context models of free recall, memory disruption not only impacts the total number of story details recalled, but also the ability to use temporal context to encode and retrieve items in a sequentially organized way.