(Kiosk 3) The Dual-lesion Hypothesis of Confabulation Demonstrated in a Patient with Severe Traumatic Brain Injury (TBI) Complicated by Post-traumatic Seizures

Case Diagnosis: A 67-year-old woman with mild residual cognitive symptoms following a severe TBI presenting with new-onset confabulation following delayed post-traumatic seizures.

Case Description: In 2018, the patient sustained a severe TBI while biking, resulting in bilateral frontal lobe and right temporal contusions as well as subarachnoid and intraventricular hemorrhage. She subsequently experienced mild difficulties with short term memory and processing speed, but remained fully independent with activities of daily living. In 2022, she presented to the hospital with new onset seizures, with a brain MRI showing restricted diffusion involving the right medial temporal lobe. The patient later presented for an outpatient physiatry follow-up complaining of worsening memory.

Discussion: During confabulation, an individual fills memory lapses with false memories that they believe to be true. The dual-lesion hypothesis of confabulation postulates that damage to the prefrontal structures and areas that support memory function precipitate confabulation as opposed to amnesia, as in the former, the hippocampus remains at least partially intact. The patient’s bilateral frontal lobe contusions from her 2018 TBI along with her medial temporal lobe changes following her seizure would fulfill the hypothesis. Rehabilitation for confabulation may involve re-orientation strategies, self-monitoring and time awareness training, and use of external memory aides such as daily diaries and calendars.

Setting: Outpatient

Assessment/Results: The patient and her husband provided numerous examples of new-onset memory difficulties, such as believing that she was moved to a different room while in the hospital, gave a nurse flowers, made new dinner plans, etc. suggestive of confabulation. On beside Montreal Cognitive Assessment (MOCA), she scored 25/30 with all points lost on delayed recall, though all items were subsequently recognized with category or multiple choice cues.

Conclusion: This case of a 67-year-old woman with a history of severe TBI presenting with marked confabulation following delayed post-traumatic seizures supports the validity of the dual-lesion hypothesis of confabulation.