A VIRTUAL Three-month Intervention Study of the Effects of a Smartphone Application (HippoCamera) on Memory in Teens and Young Adults With Down Syndrome

Individuals with Down syndrome exhibit a disproportionate deficit in hippocampally-dependent memory, including a particular difficulty remembering event-specific details of events from their own lives (i.e., autobiographical memory). In the proposed research, the investigators test the efficacy of a digital memory prosthetic-the HippoCamera application-in supporting this specific autobiographical memory in individuals with Down syndrome. In HippoCamera, participants are asked to record one event each day and replay up to five recorded events from prior days. This replay is curated by a research-based algorithm in HippoCamera that optimizes consolidation of these events over time. HippoCamera replay has been shown to enhance memory specificity in other populations with memory impairments, particularly those that stem from hippocampal disfunction. Specifically, memories that were replayed during the intervention were remembered with greater specificity than those that were just recorded and not replayed. The current research attempts to extend these findings by showing memory enhancements in a population with intellectual disabilities. Specifically, there are two independent aims:

Goal 1: Does using HippoCamera to record and replay daily events lead to greater memory specificity for the replayed events? To test the efficacy of HippoCamera in enhancing replayed memories, the current study compares memory for replayed and not replayed events in a sample of 40 individuals with Down syndrome. All participants enrolled in the study will take part in this intervention, allowing a within-subject comparison of replayed vs. not replayed events. This difference will be tested at two points: immediately (right after the 12-week intervention) and delayed (6 weeks after the 12-week intervention).

Goal 2: Does using HippoCamera to record and replay daily events help participants to develop memory-oriented strategies and behaviors that lead to global memory improvements?

It is possible that the greater benefit of HippoCamera is a global memory enhancement for all autobiographical memories in individuals who complete the intervention. To explore global memory benefits, the 40 participants will be pseudo-randomly assigned to one of two intervention groups (20 each in Groups A and B; pseudo-randomized to ensure matching of age, education, and baseline memory performance).

Critically, although all participants will eventually take part in the intervention, Group B will have a delayed start. In other words, all participants will complete the baseline memory test at the time of enrollment, then participants in Group A will immediately begin the intervention while participants in Group B will serve as a no-intervention control. At the end of Group A's 12-week intervention, both groups will complete a follow-up memory test.

Baseline-to-follow-up increases in memory specificity in Group A (i.e., intervention arm) will be compared to the same increases in Group B (i.e., control arm); greater increases in Group A could then be attributed to their enrollment in the 12-week intervention).

After serving as the control group for Group A's 12-week intervention, Group B will then begin the intervention.

Inclusion criteria

• Diagnosis of Down syndrome
• Daily access to a smart phone
• The ability to create and replay memories using HippoCamera with limited support from a guardian
• Informed consent obtained from parent or guardian (or participant, if legally independent)
• Informed verbal assent obtained from participant
• Ability to comprehend instructions, denoted by parent/guardian acknowledgment
• English as a primary written and spoken language
• Normal or corrected-to-normal vision and hearing
• All races/ethnicities and socio-economic statuses

Exclusion criteria

• Autism
• Non-native speaker of English (acquired after the age of 5)