Pilot and Feasibility of MEMI for Chronic Traumatic Brain Injury

Deficits in memory and learning are hallmark to traumatic brain injury (TBI) and limit a person's ability to participate in medical care, benefit from therapy, maintain positive social relationships, and be successful at school or work. There has been limited progress in the last several decades in advancing functional memory outcomes after TBI, and constraints in the timing and context of the existing rehabilitation model may contribute. In memory rehabilitation, each opportunity to retrieve information strengthens that information in the neocortex, and is thus both an assessment and a learning opportunity. Increasing the contextual diversity of learning opportunities (i.e., in the daily lives and contexts of patients) may improve the rehabilitation potential of patients with TBI.

This study is a pilot and feasibility trial of MEMI as a technology-delivered intervention that extends memory assessment and treatment over time and space. We use a counterbalanced within-participant crossover design to examine MEMI's feasibility and acceptability in daily life and collect preliminary efficacy data as to how using MEMI in daily life affects long-term recall for participants with and without TBI. The study includes a group of adults with a chronic history of moderate-severe TBI and a demographically matched control group. Each participant uses MEMI for two weeks, each in a different condition:

• Blocked (Active Comparator) Condition: During one of the weeks, participants will complete their initial learning session on the target words, then immediately receive all of the exposures to each of the items in a single block. They do not complete any more retrieval sessions until one week later, when they complete a 15-minute test for their memory of all of the trained items.
• Spaced (MEMI Intervention) Condition: During the other week, participants complete their initial learning session, and the subsequent retrieval sessions are spaced out over the course of the week (two short retrieval sessions each day) using MEMI. Then, they complete a 15-minute test for their memory of all of the trained items at the end of the week.

This study addresses three aims:

Aim 1: To examine the real-world feasibility and acceptability of MEMI via user engagement and survey data.

Aim 2: To explore preliminary efficacy of spaced retrieval via MEMI to improve long-term word recall in individuals with and without chronic TBI.

Aim 3: To explore how a) spatial context and b) temporal context of exposures affect long- term word recall in people with and without chronic TBI.

Inclusion criteria

For participants with TBI:

• Moderate-severe TBI. All participants were determined to have a history of moderate-severe TBI upon joining the Vanderbilt Brain Injury Patient Registry. This determination was made based on the Mayo Classification Scale.
• All participants are at least 6 months post-injury at the time of study enrollment and thus exhibit chronic and stable neuropsychological profiles.
• Age ranging from 18-60, to rule out developmental TBI and limit influence of age-related cognitive decline.

For all participants:

• Oral and written language skills sufficient for the study tasks. This will be screened in the initial video conference contact with the participant, when consent is obtained.
• Participants must own a smartphone to access the Gorilla online behavioral experiment platform from their mobile phones.

Exclusion criteria

For participants with TBI:

• History of medical or neurological disease affecting the brain or language, before or after the qualifying TBI.

For non-injured comparison peers:

• History of neurological or cognitive disability, including TBI

For all participants:

• Any disability (e.g., vision impairment, hard of hearing, aphasia or other neurologic condition) that limits ability to read, type, or verbally communicate.
• Demonstrates inability to receive and respond to a text message after training by study personnel.