Exoskeleton Rehabilitation on TBI

Study Design and Setting

This is an observational, retrospective, chart review cohort study of patients from a private single rehabilitation hospital. Study approval was granted by the local Institutional Review Board and conformed to the Declaration of Helsinki and the US Federal Policy for the Protection of Human Subjects. Due to the retrospective nature of the study, a full waiver of authorization under the Health Insurance Portability and Accountability Act (1996) was submitted by the study team and approved by the Institutional Review Board.

Participants

Inclusion and Exclusion criteria: Subjects in the TBI group included patients who suffered a TBI and who used the EKSO® bionic exoskeleton during their rehabilitation treatment from 01/01/2017 to 04/30/2020. Subjects in the CVA group included all patients in the hospital that used the EKSO® during their rehabilitation process during the same period of the patients in the TBI group. Patients were excluded if their injury type was outside the scope of the current study. The registered nurse at the rehabilitation facility identified the patients based on the inclusion criteria, and this was verified by the doctor in physical therapy who oversees the rehabilitation hospital patient population. Approval and implementation of the EKSO® bionic device at the hospital commenced in 2014 for patients that suffered a CVA and spinal cord injury. Main indications for the use of the EKSO® during rehabilitation included a height range between 1.56 to 1.9 meters and a patient's weight equal to or less than 100kg. Stable blood pressure was required, with the ability to follow one to two steps commands, and the patient should also have demonstrated a normal range of motion in hips, knees, and ankles.

Variables

Demographic factors considered in this study were age at the time of admission into the rehabilitation facility (measured in years), and patient's sex (males or females). Ethnicity was self-reported and collected in the study, but it was not considered as a covariate since the vast majority of our cohort was of Hispanic origin. The overrepresentation of Hispanics/Latinos in the current cohort responds to the demographic distribution of the area the hospital serves. The investigators collected information related to the impairment type produced by the CVA, and for the TBI; investigators collected the abbreviated injury scale (ASI) to determine the injury severity score (ISS).

The change in FIM score from admission to discharge was used as the primary outcome for this study. The FIM score evaluates the ability of the patient in day-to-day functions within three (3) major categories: self-care, mobility, and communication. To explore whether the use of EKSO® facilitates the improvement in mobility and communication, investigators also explored the motor FIM and social interaction FIM, problem-solving FIM, and memory FIM. In parallel to FIM, investigators evaluated how the length of stay in the facility affected the outcomes.

Data sources/measurements

Variables collected in this study were retrospectively obtained from the patient's electronic medical chart. All information presented in this study was part of the patient's standard of care. No additional intervention or data collection instrument was implemented. The standard of care of the patient is as follows: all potentially eligible candidates were identified and cleared by the physician with subsequent patient education regarding the use of the EKSO®. For the use of the exoskeleton during the rehabilitation process, signed informed consent was obtained from either the patient or designated family member, depending on the status of the patient. Data obtained during the active use of the exoskeleton was visualized in the screen of the EKSO® (time active, steps taken, etc.) and subsequently recorded in each patient's paper chart. This paper was then scanned and uploaded into the patient's electronic chart under his/her progress notes. The therapy technicians helped in the data recording process. All available data related to EKSO use for CVA and TBI at our facility were included in the current study. The primary goal of the data analysis was to gather preliminary comparative outcomes that could guide us into designing larger-controlled studies.

Reduction of Bias

To minimize selection bias in the current study, investigators used all patients that were clinically determined by the attending physician to meet the criteria for exoskeleton rehabilitation. Patients were included in the chart review regardless of the number of sessions of exoskeleton use. All therapist and nurses at our facility have been certified to use the FIM assessment tool and the data is entered using the Uniform Data System for Medical Rehabilitation (https://www.udsmr.org/) software integrated within the hospital medical record platform. The main data extractor in the study (A.M.) is the site expert for data management within the Uniform Data System. Quality of the data was verified by the lead doctor in Physical Therapy (M.E.A.). None of the patients that used exoskeleton in rehabilitation had missing data during the time period used for the current study and all patients in the cohort completed the recommended therapeutic program and were successfully discharged from the hospital.

Exoskeleton use protocol

The EKSO GT® was operated by a Licensed Physical Therapist who was certified to control the device. The device is only approved to be used in a clinical setting. For the purposes of this study, four different modes were utilized to engage and challenge the patients: Pre-Gait, First Step, Pro Step Plus, and 2 Free. Pre-Gait Mode focused on the following metrics to facilitate movement and active participation: bilateral weight shifting in standing with biofeedback, mini squats, and stationary unilateral lower extremity advancement. The First Step mode allowed the therapist to be in full control of all movement. The therapist triggered the initiation and execution of each step reciprocally with the push of a button. In the Pro Step Plus mode, there was an appropriate weight shift either done independently by the patient or facilitated by the therapeutic handling of the physical therapist. The patient was given the opportunity to initiate each step; the EKSO® device completed any incomplete steps. The most advanced mode is called 2 Free. This mode was used to challenge the patient across the continuum as they progress. The patient was responsible for initiating and executing each step. The therapist programmed resistance unilaterally or bilaterally to the lower extremities to increase the demand for the activity.

Statistical methods

Descriptive statistics for the entire study population were generated. Normally distributed continuous variables were described with means and standard deviations, medians and ranges were used for non-normally distributed variables, and frequencies and column percentages summarized categorical variables. Differences in demographic and clinical characteristics between the two treatment groups were evaluated using Student t-test for independent samples for normally distributed continuous variables, Mann-Whitney U test for non-normally distributed continuous variables, and Fisher exact test for categorical variables. To test for the difference between the CVA and TBI groups in respect to socio-demographic and treatment measurements, paired t-test or Wilcoxon signed-rank test for continuous variables and Chi-square test/Fisher exact test for categorical variables were used. Shapiro-Wilk test for normality was conducted to determine the normality of the continuous variables' distributions. Linear regression analyses were carried out to evaluate the associations of each of the outcome variables with age, sex, and length of hospital stay, and with the injury groups (CVA and TBI) variable. All statistical tests were two-sided and were performed at a significance level of 0.05. All statistical analyses were conducted using SAS 9.4 (SAS Institute, Inc, Cary, North Carolina, USA.).