NCT03705676

Unraveling Back Pain Chronicity: an EMG and EEG Study

Unraveling the Puzzle of Back Pain Chronicity: an Integrative Perspective on Sensorimotor Control and Maladaptive Cognitive Processes

• Status: Completed
• Phase: N/A
• Study type: Interventional
• Enrollment: 107 (actual)
• Sponsor: University Ghent · Academic / Other
• Sex: All
• Age: 18 Years – 45 Years
• Healthy volunteers: Accepted

Summary

This study aims at examining the influence of both threat of experimentally induced pain and clinical low back pain (LBP) on trunk motor control on the one hand and brain activity related to movement preparation on the other hand. Therefore, 3 groups are studied: healthy controls, people with recurrent LBP, and people with chronic LBP. A comparison in electromyography (EMG) of the trunk muscles and electroencephalography (EEG) activity between the 3 groups will be made in 2 conditions: a control condition without experimental pain on 1 test day, and a fear condition with experimental pain on another test day. In both conditions a motor control task will be performed and muscle and brain activity will be measured during each motor control task. It is hypothesised that motor control will be different between the 3 groups in both conditions, i.e. delayed trunk muscle onset in LBP groups compared with controls. With regards to the brain activity, it is expected that preparation for movement will also be delayed in the LBP groups. Furthermore, it is expected that the fear condition will entail differences in both EMG and EEG within each group.

Detailed description

March 2017 - April 2018. 30 healthy participants, 30 recurrent and 30 chronic LBP patients all aged 18-45 and of both genders were tested for 2 conditions on 2 separate days, i.e. a control condition (C) on 1 test day; a fear (F) condition consisting out of threat (T) and no threat trials (NT) on another test day. The order of test days was randomized. 1 block of 240 rapid arm movements (RAM) with the dominant arm was performed per condition, while electroencephalography (EEG) of the brain and surface electromyography (sEMG) of the Internal Oblique/Transversus Abdominis, External Oblique, Multifidus and Iliocostalis Lumborum pars Thoracis muscles were measured bilaterally. sEMG of the Anterior Deltoid muscle of the dominant arm was also measured. This RAM was used to induce an internal perturbation to the postural balance of subjects and is an often used task in the study of trunk motor control. Midway the RAM block, the participants got a short intermission of 90 seconds seated rest. Both conditions consisted of a warning cue (colored dot on a screen) followed by a go cue (arrow indicating either an upwards or downwards rapid arm movement) or a no-go cue ('STOP') and 12 seconds rest before the next trial. Harmless vibrotactile stimuli were always administered to the low back region during the appearance of the warning cue. During the C, a white warning cue was presented (safe cue), meaning that the RAM would never be accompanied by a painful electrocutaneous stimulus in that condition. During the F a safe (no threat) or a threatening warning cue could be presented (50-50%); in 25% of the trials after the threatening cue an electrocutaneous stimulus was given to the lower back region; the trials after the no threat cue were never accompanied with painful stimuli. The intensity of the electrocutaneous stimulus was self-determined by participants through a staircase paradigm and was administered by a digitimer system. At the beginning of each test day several questionnaires were also administered to control for psychological factors and physical activity, i.e. Central Sensitization Index (CSI), Hospital Anxiety and Depression Scale (HADS), Tampa Scale for Kinesiophobia (TSK), Pain Catastrophizing Scale (PCS), Pain Vigilance and Awareness Questionnaire (PVAQ), Roland-Morris Disability Questionnaire (RMDQ), International Physical Activity Questionnaire (IPAQ) and a general questionnaire regarding socio-demographic information and history of complaints. Furthermore, complaint specific questionnaires were also administered, but only for the clinical populations (RLBP and CLBP) Statistical analysis will be performed to assess whether and to what extent both threat and LBP might influence motor control as measured with EMG during RAM. Furthermore, the effect of both on cortical movement preparation and somatosensory processing will also be assessed based on the EEG measurements.

Conditions

• Low Back Pain

Interventions

Type	Name	Description
BEHAVIORAL	Rapid Arm Movements	240 trials of RAM in either a forward (50%) or backward (50%) shoulder flexion direction and back to neutral as fast as possible, with maintaining extension in the elbow. Visual cues (arrows) indicated the movement direction.
DEVICE	Unpleasant stimulus	An unpleasant, but harmless, electrocutaneous stimulus is administered to the low back region in 25% of the threat trials during the fear condition. Due to a conditioning phase before testing, participants know to expect this stimulus after the presentation of a warning cue related to the fear trials (either pink or blue dot dependent on randomization).
DEVICE	Vibrotactile stimulus	In all trials, during the presentation of the warning cue, a vibrotactile stimulus is administered to the low back region. This stimulus is used to evoke somatosensory evoked potentials (SEP) measured with EEG during the movement-preparation phase.

Timeline

• Start date: 2017-03-03
• Primary completion: 2018-04-17
• Completion: 2018-04-17
• First posted: 2018-10-15
• Last updated: 2023-12-18

Locations

1 site across 1 country: Belgium