Sensory Integration Balance Deficits in Complex mTBI: Can Early Initiation of Rehabilitation with Wearable Sensor Technology Improve Outcomes?

Developing a novel feedback system using wearable sensors to provide physical therapists with realtime information about quality of head and trunk movement during exercise could improve patient rehabilitation practices.

Mild traumatic brain injury (mTBI) is common both in civilian and military populations and can be debilitating if symptoms do not resolve after injury. Balance problems are one of the most common complaints after sustaining an mTBI and often prevent people from returning to their previous quality of life. However, clear guidelines are currently lacking on when to initiate physical therapy rehabilitation and it is unclear if early physical therapy is beneficial.

It is believed that the underlying problem of imbalance results from damage to parts of the brain responsible for interpreting sensory information for balance control. It is hypothesized that retraining the brain early, as opposed to months after injury, to correctly interpret sensory information will improve recovery. It is also believed this retraining is limited when rehabilitation exercises are performed incorrectly, and that performance feedback from wearable sensors, can improve balance rehabilitation.

There are three of objectives of this research:

  1. To determine how the timing of rehabilitation affects outcomes after mTBI;
  2. To determine if home monitoring of balance exercises using wearable sensors improves outcomes;
  3. To develop a novel feedback system using wearable sensors to provide the physical therapist with information, in real-time during training, about quality of head and trunk movements during prescribed exercises.

A total of 83 participants were recruited and screened with 53 meeting inclusion criteria. At the project’s conclusion, 29 subjects had completed the rehabilitation intervention with 9 still receiving rehabilitation. Seven completed a 6-month follow up test after their rehabilitation with 19 subjects still waiting for 6-month follow up testing. In terms of outcomes, the following was learned.

Balance: Balance impairments are a common complaint after mTBI. Preliminary analysis of postural sway data indicated that sway in the mediolateral plane while performing the modified Balance Error Scoring System (mBESS; Figure 1) becomes less variable over time and following rehabilitation. No changes occurred from baseline to post rehabilitation using the clinical subjective scoring of balance coordination across the mBESS testing conditions (top numbers across Figure 1). Objective measures of postural sway and balance impairments using sensors are needed to quantify subtle changes in balance outcomes otherwise undetected by clinical evaluations.

Figure 2. Visual spatial ability assessed by the Automated Neuropsychological Assessment Metric (ANAM) match to sample task reaction time between baseline and post rehabilitation sessions.

Cognition: Cognitive dysfunction is common following mTBI and preliminary results indicated that cognitive function improves over time and following rehabilitation (Figure 2). Cognition was assessed using the Automated Neuropsychological Assessment Metric (ANAM). The ANAM assessed simple reaction time, processing speed, visual memory, working memory, and visual-spatial ability. Participants improved their visual spatial processing ability (assessed by the match to sample task reaction time) following rehabilitation (Figure 2) and were within a normative range (indicated by the orange lines).

Symptoms: Initial results indicated improvement in symptoms over time for the participants in the study. Preliminary qualitative assessment of descriptive data also suggests a decrease in the dizziness handicap inventory (DHI) total score following rehabilitation.

Preliminary retest-reliability analysis of wearable sensors measuring head movement: Eighteen healthy controls were tested at three different time points on a series of conditions involved in the rehabilitation program. A total of eight different conditions were tested:

  • 2 Standing Balance: horizontal and vertical, eyes closed

  • 2 Vestibular-Ocular Reflex: horizontal and vertical, eyes fixated while head moves

  • 2 Visual Motion Sensitivity: horizontal and vertical, eyes and head move together

  • 2 Walking (dynamic) Balance: horizontal and vertical, eyes and head move together

Participants wore an inertial sensor on their forehead and sternum, reflecting what is used during the rehabilitation program. One of the research team’s physical therapists instructed participants which condition to perform for 30 seconds. For each trial, the two measures collected were the rotational velocity and range of motion (RoM) for the forehead and sternum in the primary movement axis.

This work was done by Dr. Laurie King (PI); Dr. Lucy Parrington; Dr.Kody Campbell; and Shelby Martin of Oregon Health & Science University and the Veteran Affairs Portland Health Care System for the Army Medical Research and Materiel Command. For more information, download the Technical Support Package below. ARL-0237

This Brief includes a Technical Support Package (TSP).
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Sensory Integration Balance Deficits in Complex mTBI: Can Early Initiation of Rehabilitation with Wearable Sensor Technology Improve Outcomes?

(reference ARL-0237) is currently available for download from the TSP library.

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