Comparison of Biofeedback Tools to Train the Transversus Abdominis Activation in Healthy Subjects

Summary

Introduction: Non specific low back pain (NSLBP) is a low back pain (LBP) that cannot be attributable to a known pathology. LBP has prevalence as high as 84%, making it a heavy burden for health services and society worldwide. Furthermore, LBP seems to be more prevalent as the population gets older, and is the cause of severe functional limitations. One of the treatment recommended for LBP is physical therapy. It has been shown that the trunk muscles usually maintain trunk stability by making a sequence of postural adjustment in advance of distal movement to prevent any loss of balance. However, in NSLBP, this motor control adjusting is lacking, and, furthermore, stays so even after the resolution of acute LBP, which could contribute to the recurrence of LBP. Physical therapy therefore addresses NSLBP by rehabilitating the timing and activation of trunk muscle, among other things. The importance of trunk musculature has been highlighted by many studies showing the feedforward contraction of the trunk muscles in anticipation of extremity movement. Those trunk muscles comprise the transversus abdominis (TrA) and lumbar multifidus (LM). Since those muscles create no movement, but rather an increase in abdominal pressure, it is thus often a complex contraction to teach. To help with that teaching, physical therapist may use one of the two feedback tools that exist to teach a TrA contraction, namely the pressure biofeedback unit (PBU) and rehabilitative ultrasound imaging (RUSI). Unfortunately, their efficiency to help with the teaching of TrA contraction is yet to be shown in an elderly population, and few studies compared their efficiency. Furthermore, even though the teaching of the TrA contraction must be followed by a translation of that skill in more functional position such as standing, no studies looked at the effect of the feedback in supine to the skill of TrA contraction in standing.

Objective: The principal aim of this study is thus to compare, throughout a healthy population of 60 to 80 years old, the immediate efficiency of adding PBU or RUSI to the TrA contraction teaching in supine. The secondary objectives are as follow: 1) to see if that teaching in supine can be translated by a better contraction of the TrA in standing, and if one of the two tools is superior in doing so and 2) to see if one tool favor a more specific contraction of TrA when compared to the other muscles of the lateral abdominal wall. The hypothesis is that the RUSI will prove superior to the PBU.

Method: This will be a single-blinded controlled laboratory study with randomization. The independent variables will be the group of randomization, either PBU or RUSI. The dependent variable will be the TrA contraction. To answer our objectives, forty (40) healthy people aged between 60 and 80 will be recruited. The subjects will be healthy with no current pain and no history of limiting LBP in the past year. Of those, 20 will be women. The randomization will be made in blocks to allow a good balance of the sex throughout the groups. Every subject's TrA contraction (principal outcome) will be measured before and after the intervention (immediate effect) with the RUSI (change of thickness between resting and contracting state) both in supine and standing. The intervention will consist of a 5-minute education on the trunk muscle and their role, a brief teaching of how to contract them properly and the use of the feedback tool used in their group. Will follow a training program of 15 contractions with the feedback tool (PBU vs RUSI). Descriptive analysis will be used to describe the subjects. The TRA activation ratio (AR) and preferential activation ratio (PAR) will be compared after the intervention with Wilcoxon signed rank tests for each subject first. The group's mean will then be compared, first for each age group, then for each feedback tool as a whole with the Wilcoxon rank sum test.

Impact: Age and LBP both influence the motor control and feedforward contraction of the trunk muscles. Since NSLBP is highly prevalent throughout the ages and cost a lot for the society, the identification of the best tool to help in teaching the TrA contraction is crucial. This project will provide the first steps to justify a bigger controlled study on NSLBP. Moreover, this project will familiarize the Canadian physical therapist society to the use of RUSI, a tool still seldom used in the clinic in Canada but highly promising.

Conditions

• Low Back Pain

Interventions

DEVICE

Real-time ultrasound imaging feedback

Participants will be taught about the anatomy of abdominal wall muscles and the general functioning of RUSI (5 mins). Then, they will be invited to take the supine position, knees flexed. The feedback will consist of an ultrasound image transmitted to a brightness (B)-mode. Participants will receive the necessary education to understand the image and the desired recruitment according to a standardized protocol. They will then be asked to perform 15 contractions held 10 seconds of the TrA with a visible thickening of the TrA on the RUSI monitor exceeding the measurement at rest (visible on the monitor). Forty-five seconds rest will be allowed between each contraction to avoid fatigue. Participants will have to watch the RUSI monitor during the 15 tests.

DEVICE

PBU feedback

Participants will receive the same instruction on the anatomy of abdominal wall muscles and general information about the PBU device. They will be invited to take the same position as for the RUSI group (supine, knees flexed). The feedback will be to visualize the intensity of pressure on the dial of a STABILIZER PBU (Chattanooga Group, Hixon, TN). Participants will receive the education necessary to understand the tool and the desired recruitment according to a standardized protocol. They will then be asked to perform 15 contractions of the TrA with a duration of 10 seconds while maintaining the constant pressure at 40 mmHg ± 2 mmHg. Forty-five seconds of rest will be allocated between each contraction. Participants will have to watch the PBU dial during the 15 tests.

Sponsors & Collaborators

• Université de Sherbrooke

  lead OTHER

Principal Investigators

• Nathaly Gaudreault, Ph.D · Université de Sherbrooke

• Guillaume Léonard, Ph.D · Université de Sherbrooke

Study Design

Allocation

RANDOMIZED

Purpose

TREATMENT

Masking

SINGLE

Model

PARALLEL

Eligibility

Min Age

60 Years

Max Age

80 Years

Sex

ALL

Healthy Volunteers

Yes

Timeline & Regulatory

Start

2017-12-01

Primary Completion

2018-07-31

Completion

2019-07-31

Countries

• Canada

Study Locations