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Mechanistic experimental pain assessment in computer users with and without chronic musculoskeletal pain.

Ge HY, Vangsgaard S, Omland Ø, Madeleine P, Arendt-Nielsen L - BMC Musculoskelet Disord (2014)

Bottom Line: There were no significant differences between groups neither in PPTs nor pain intensity induced by dynamic pressure algometry.No significant difference in PPT was observed in TA between groups.However, computer users with higher pain intensity and lower PPTs were found to have decreased efficiency in descending pain modulation.

View Article: PubMed Central - PubMed

Affiliation: Center for Sensory-Motor Interaction (SMI), Department of Health Science and Technology, Faculty of Medicine, Aalborg University, Fredrik Bajers Vej 7D, 9220 Aalborg, Denmark. LAN@hst.aau.dk.

ABSTRACT

Background: Musculoskeletal pain from the upper extremity and shoulder region is commonly reported by computer users. However, the functional status of central pain mechanisms, i.e., central sensitization and conditioned pain modulation (CPM), has not been investigated in this population. The aim was to evaluate sensitization and CPM in computer users with and without chronic musculoskeletal pain.

Methods: Pressure pain threshold (PPT) mapping in the neck-shoulder (15 points) and the elbow (12 points) was assessed together with PPT measurement at mid-point in the tibialis anterior (TA) muscle among 47 computer users with chronic pain in the upper extremity and/or neck-shoulder pain (pain group) and 17 pain-free computer users (control group). Induced pain intensities and profiles over time were recorded using a 0-10 cm electronic visual analogue scale (VAS) in response to different levels of pressure stimuli on the forearm with a new technique of dynamic pressure algometry. The efficiency of CPM was assessed using cuff-induced pain as conditioning pain stimulus and PPT at TA as test stimulus.

Results: The demographics, job seniority and number of working hours/week using a computer were similar between groups. The PPTs measured at all 15 points in the neck-shoulder region were not significantly different between groups. There were no significant differences between groups neither in PPTs nor pain intensity induced by dynamic pressure algometry. No significant difference in PPT was observed in TA between groups. During CPM, a significant increase in PPT at TA was observed in both groups (P < 0.05) without significant differences between groups. For the chronic pain group, higher clinical pain intensity, lower PPT values from the neck-shoulder and higher pain intensity evoked by the roller were all correlated with less efficient descending pain modulation (P < 0.05).

Conclusions: This suggests that the excitability of the central pain system is normal in a large group of computer users with low pain intensity chronic upper extremity and/or neck-shoulder pain and that increased excitability of the pain system cannot explain the reported pain. However, computer users with higher pain intensity and lower PPTs were found to have decreased efficiency in descending pain modulation.

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Related in: MedlinePlus

The pressure pain assessment sites and the rollers used for assessing muscle tenderness. Diagrams for pressure pain threshold (PPT) mapping in the neck-shoulder region (A) and in the elbow region (B) and the experimental set-up used for dynamic pressure algometry (C) showing a set of 8 rollers, the dynamic process, and the electronic visual analogue scale used to record pain ratings.
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Fig2: The pressure pain assessment sites and the rollers used for assessing muscle tenderness. Diagrams for pressure pain threshold (PPT) mapping in the neck-shoulder region (A) and in the elbow region (B) and the experimental set-up used for dynamic pressure algometry (C) showing a set of 8 rollers, the dynamic process, and the electronic visual analogue scale used to record pain ratings.

Mentions: The mapping procedure in the current study followed a previous protocol [14]. To locate the assessment sites concisely, a wax pencil was used to mark a grid describing the locations from where the pressure stimuli should be applied. The grid for pressure point recording was set using the C7-acromion distance d (mean: 180 mm) to compute the inter-distance in a 15 point geometrically shaped grid covering the upper trapezius muscle (Figure 2A). Adjacent PPT points were separated by 1/6 of d (approx. 30 mm) except between point 1 and 2 and point 3 and 4 where the horizontal distance was 1/7 of d. In addition, PPT at point 7 on the contralateral side was also measured. Similar to the position for grid preparation, the participants were placed in a prone position during recordings. This provided a comfortable resting position for the participants and accessibility for PPT recordings. The recording order was randomized between points going either column or row-wise and by starting either at outer points and going inward or at inner points and going outward to prevent temporal summation [14].Figure 2


Mechanistic experimental pain assessment in computer users with and without chronic musculoskeletal pain.

Ge HY, Vangsgaard S, Omland Ø, Madeleine P, Arendt-Nielsen L - BMC Musculoskelet Disord (2014)

The pressure pain assessment sites and the rollers used for assessing muscle tenderness. Diagrams for pressure pain threshold (PPT) mapping in the neck-shoulder region (A) and in the elbow region (B) and the experimental set-up used for dynamic pressure algometry (C) showing a set of 8 rollers, the dynamic process, and the electronic visual analogue scale used to record pain ratings.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4265505&req=5

Fig2: The pressure pain assessment sites and the rollers used for assessing muscle tenderness. Diagrams for pressure pain threshold (PPT) mapping in the neck-shoulder region (A) and in the elbow region (B) and the experimental set-up used for dynamic pressure algometry (C) showing a set of 8 rollers, the dynamic process, and the electronic visual analogue scale used to record pain ratings.
Mentions: The mapping procedure in the current study followed a previous protocol [14]. To locate the assessment sites concisely, a wax pencil was used to mark a grid describing the locations from where the pressure stimuli should be applied. The grid for pressure point recording was set using the C7-acromion distance d (mean: 180 mm) to compute the inter-distance in a 15 point geometrically shaped grid covering the upper trapezius muscle (Figure 2A). Adjacent PPT points were separated by 1/6 of d (approx. 30 mm) except between point 1 and 2 and point 3 and 4 where the horizontal distance was 1/7 of d. In addition, PPT at point 7 on the contralateral side was also measured. Similar to the position for grid preparation, the participants were placed in a prone position during recordings. This provided a comfortable resting position for the participants and accessibility for PPT recordings. The recording order was randomized between points going either column or row-wise and by starting either at outer points and going inward or at inner points and going outward to prevent temporal summation [14].Figure 2

Bottom Line: There were no significant differences between groups neither in PPTs nor pain intensity induced by dynamic pressure algometry.No significant difference in PPT was observed in TA between groups.However, computer users with higher pain intensity and lower PPTs were found to have decreased efficiency in descending pain modulation.

View Article: PubMed Central - PubMed

Affiliation: Center for Sensory-Motor Interaction (SMI), Department of Health Science and Technology, Faculty of Medicine, Aalborg University, Fredrik Bajers Vej 7D, 9220 Aalborg, Denmark. LAN@hst.aau.dk.

ABSTRACT

Background: Musculoskeletal pain from the upper extremity and shoulder region is commonly reported by computer users. However, the functional status of central pain mechanisms, i.e., central sensitization and conditioned pain modulation (CPM), has not been investigated in this population. The aim was to evaluate sensitization and CPM in computer users with and without chronic musculoskeletal pain.

Methods: Pressure pain threshold (PPT) mapping in the neck-shoulder (15 points) and the elbow (12 points) was assessed together with PPT measurement at mid-point in the tibialis anterior (TA) muscle among 47 computer users with chronic pain in the upper extremity and/or neck-shoulder pain (pain group) and 17 pain-free computer users (control group). Induced pain intensities and profiles over time were recorded using a 0-10 cm electronic visual analogue scale (VAS) in response to different levels of pressure stimuli on the forearm with a new technique of dynamic pressure algometry. The efficiency of CPM was assessed using cuff-induced pain as conditioning pain stimulus and PPT at TA as test stimulus.

Results: The demographics, job seniority and number of working hours/week using a computer were similar between groups. The PPTs measured at all 15 points in the neck-shoulder region were not significantly different between groups. There were no significant differences between groups neither in PPTs nor pain intensity induced by dynamic pressure algometry. No significant difference in PPT was observed in TA between groups. During CPM, a significant increase in PPT at TA was observed in both groups (P < 0.05) without significant differences between groups. For the chronic pain group, higher clinical pain intensity, lower PPT values from the neck-shoulder and higher pain intensity evoked by the roller were all correlated with less efficient descending pain modulation (P < 0.05).

Conclusions: This suggests that the excitability of the central pain system is normal in a large group of computer users with low pain intensity chronic upper extremity and/or neck-shoulder pain and that increased excitability of the pain system cannot explain the reported pain. However, computer users with higher pain intensity and lower PPTs were found to have decreased efficiency in descending pain modulation.

Show MeSH
Related in: MedlinePlus