# Feasibility and usability of microinteraction ecological momentary assessment using a smartwatch in military personnel with a history of traumatic brain injury

## TL;DR

This study shows that using a smartwatch to track symptoms in real time is feasible and well-received by military personnel recovering from traumatic brain injury.

## Contribution

Demonstrates the feasibility and usability of smartwatch-based microinteraction ecological momentary assessment in military TBI patients.

## Key findings

- Completion and compliance rates were 80.1% and 77.4%, indicating high adherence to the miEMA protocol.
- Participants rated the smartwatch app as highly usable with a mean System Usability Scale score of 89.0.
- Adherence rates were comparable to civilian populations, suggesting miEMA is viable in military TBI rehabilitation.

## Abstract

Microinteraction Ecological Momentary Assessment (miEMA) addresses the challenges of traditional self-report questionnaires by collecting data in real time. The purpose of this study was to examine the feasibility and usability of employing miEMA using a smartwatch in military service members undergoing traumatic brain injury (TBI) rehabilitation.

Twenty-eight United States active duty service members with a TBI history were recruited as patients from a military outpatient TBI rehabilitation center, enrolled in either a 2-week or 3-week study arm, and administered miEMA surveys via a custom smartwatch app. The 3-week arm participants were also concurrently receiving cognitive rehabilitation. Select constructs evaluated with miEMA included mood, fatigue, pain, headache, self-efficacy, and cognitive strategy use. Outcome measures of adherence were completion (percentage of questions answered out of questions delivered) and compliance (percentage of questions answered out of questions scheduled). The Mobile Health Application Usability Questionnaire (MAUQ) and System Usability Scale (SUS) assessed participants’ perceptions of smartwatch and app usability.

Completion and compliance rates were 80.1% and 77.4%, respectively. Mean participant completion and compliance were 81.1% ± 12.0% and 78.1% ± 13.0%, respectively. Mean participant completion increased to 87.7% ± 8.8% when using an embedded question retry mechanism. Mean participant survey set completion was 69.8% ± 18.3% during the early morning but remained steady during the late morning/early afternoon (85.7% ± 12.8%), afternoon (86.2% ± 12.6%), and late afternoon/evening (85.0% ± 14.7%). The mean overall item score for the MAUQ was 6.3 ± 1.1 out of 7. The mean SUS score was 89.0 ± 7.2 out of 100 and mean SUS percentile ranking was 96.4% ± 8.4%.

Overall adherence was similar to previous studies in civilian populations. Participants rated the miEMA app and smartwatch as having high usability. These findings suggest that miEMA using a smartwatch for tracking symptoms and treatment strategy use is feasible in military service members with a TBI history, including those undergoing rehabilitation for cognitive difficulties.