Impaired neural drive in patients with low back pain
File(s)
Accepted version
Author(s)
Chiou, SY
Shih, YF
Chou, LW
McGregor, AH
Strutton, PH
Type
Journal Article
Abstract
Background
Control of trunk movement relies on the integration between central neuronal circuits and peripheral skeletomuscular activities and it can be altered by pain. There is increasing evidence that there are deficits within the central nervous system controlling the trunk muscles in people with low back pain (LBP). However, it is unclear how LBP impacts upon neural drive to back muscles at different levels of voluntary contraction. Therefore, the purpose of this study was to investigate if neural drive is impaired in these patients.
Methods
Seventeen patients with LBP and 11 healthy controls were recruited. Bilateral electromyographic (EMG) recordings were obtained from the erector spinae (ES) muscles at two vertebral levels (T12 and L4). Participants performed a series of brief isometric back extensions (50–100% maximum voluntary contraction – MVC), during which transcranial magnetic stimulation was delivered. The size of the evoked (superimposed) twitch was measured using dynamometry.
Results
The size of the superimposed twitch decreased linearly with increasing contraction strength in the controls; however, this linear relationship was not observed in the patients. Additionally, patients had larger superimposed twitches and longer time‐to‐peak amplitudes during MVCs than those observed in controls. Furthermore, patients had lower MVC and root‐mean‐square EMG activity of ES muscles during MVCs.
Conclusions
A decline of central neural drive to the back muscles at high level of voluntary contraction was observed in patients with LBP. These results suggest that it might be pertinent to include neuromuscular facilitation programmes and therapeutic exercise utilizing high voluntary contractions for patients with LBP.
Control of trunk movement relies on the integration between central neuronal circuits and peripheral skeletomuscular activities and it can be altered by pain. There is increasing evidence that there are deficits within the central nervous system controlling the trunk muscles in people with low back pain (LBP). However, it is unclear how LBP impacts upon neural drive to back muscles at different levels of voluntary contraction. Therefore, the purpose of this study was to investigate if neural drive is impaired in these patients.
Methods
Seventeen patients with LBP and 11 healthy controls were recruited. Bilateral electromyographic (EMG) recordings were obtained from the erector spinae (ES) muscles at two vertebral levels (T12 and L4). Participants performed a series of brief isometric back extensions (50–100% maximum voluntary contraction – MVC), during which transcranial magnetic stimulation was delivered. The size of the evoked (superimposed) twitch was measured using dynamometry.
Results
The size of the superimposed twitch decreased linearly with increasing contraction strength in the controls; however, this linear relationship was not observed in the patients. Additionally, patients had larger superimposed twitches and longer time‐to‐peak amplitudes during MVCs than those observed in controls. Furthermore, patients had lower MVC and root‐mean‐square EMG activity of ES muscles during MVCs.
Conclusions
A decline of central neural drive to the back muscles at high level of voluntary contraction was observed in patients with LBP. These results suggest that it might be pertinent to include neuromuscular facilitation programmes and therapeutic exercise utilizing high voluntary contractions for patients with LBP.
Date Issued
2014-07-01
Date Acceptance
2013-10-20
Citation
European Journal of Pain, 2014, 18 (6), pp.794-802
ISSN
1090-3801
Publisher
Wiley
Start Page
794
End Page
802
Journal / Book Title
European Journal of Pain
Volume
18
Issue
6
Copyright Statement
© 2013 European Pain Federation ‐ EFIC®. This is the peer reviewed version of the following article, which has been published in final form at https://onlinelibrary.wiley.com/doi/full/10.1002/j.1532-2149.2013.00428.x. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions.
Identifier
http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000335460300007&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=1ba7043ffcc86c417c072aa74d649202
Subjects
Science & Technology
Life Sciences & Biomedicine
Anesthesiology
Clinical Neurology
Neurosciences
Neurosciences & Neurology
TRANSCRANIAL MAGNETIC STIMULATION
CORTICAL VOLUNTARY ACTIVATION
HUMAN KNEE EXTENSORS
TWITCH INTERPOLATION
HUMAN MUSCLES
LUMBAR SPINE
SURFACE EMG
TRUNK
QUESTIONNAIRE
INTERFERENCE
Publication Status
Published
Date Publish Online
2013-11-27