The frequency and reliability of cortical activity using a novel strategy to present pressure pain stimulus over the lumbar spine

doi:10.1016/j.jneumeth.2014.10.010

Journal of Neuroscience Methods

Volume 239, 15 January 2015, Pages 108-113

https://doi.org/10.1016/j.jneumeth.2014.10.010 Get rights and content

Highlights

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Novel MR compatible pressure algometry.
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High frequency of individuals showed cortical activity within the primary somatosensory cortex, insula and anterior cingulate cortex.
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Good to excellent run-to-run reliability for peak-voxel activity.
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Fair to excellent run-to-run reliability for cluster-size.
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Potential limitation is stimulus-presentation related artifacts.

Abstract

Background

The blocked stimulus presentation strategy, in fMRI study designs, is an important means to study brain function related to a particular stimulus. Specifically, applying pressure stimuli perceived as painful to different anatomical regions has been used to improve our understanding of central sensitization, which is an important clinical phenomenon in chronic pain.

New method

This paper introduces a novel MR-compatible device used to apply pressure pain stimuli to the lumbar spine of 13 subjects in the supine position. We present the frequency of individuals and within-subject reliability of cortical activity in the following brain regions: the primary somatosensory cortex, insula and anterior cingulate cortex bilaterally.

Results

Using the novel MR-compatible device, a high frequency of individuals showed cortical activity within the a priori brain regions. There was good to excellent run-to-run reliability for peak voxel, while cluster size was less reliable. We found a higher than expected association between stimulus presentation and movement artifacts.

Comparison with existing method(s)

Unlike previous methods, the current strategy can apply pressure stimuli to subjects over the lumbar spine while they lay supine. Previous methods required subjects to lay prone.

Conclusions

This strategy could be used for evaluating pressure stimuli related central sensitization associated with back pain.

Section snippets

Study design

This paper describes a novel MR-compatible device that was used to apply pressure pain stimuli to the lumbar spine of subjects in the supine position. The frequency and reliability estimates of BOLD responses were secondary analyses of pooled data from a pilot-fMRI project. That project examined cortical responses to “moderate” pressure pain stimuli applied to the lumbar spine with the MR-compatible device.

Participants

Thirteen participants (six females; average age ± standard deviation 42.5 ± 10.5 years) were

Frequency of individual-level ROI activation

Table 2 shows the frequency of individuals demonstrating cortical activity within the six a priori brain regions, the mean peak voxel T-score and the mean cluster size around the peak voxel. Frequency of individuals showing activity ranged from 84.6% to 100%. The left primary somatosensory cortex activity was found in all 13 subjects, while both the left anterior cingulate and insular cortices had 11 of the 13 subjects. Cortical activity within all of the brain regions was found in 11 or the 13

Summary of results

The present study describes a psychophysical test procedure using pressure stimuli to the lumbar spine while the subject is supine within the MR environment. Using this approach, we found a high frequency of individuals demonstrating activity within the ACC, INS, and SI bilaterally. At the group-level we found activity within the bilateral SI and right INS. The consistency of cluster size activity and peak voxel t-scores across three consecutive fMRI runs were “fair” reliability was found for

Conclusion

Our results show a promising methodology with some limitations. There was a high frequency of individuals demonstrating cortical activity within the bilateral primary somatosensory cortex, left insular cortex and bilateral anterior cingulate cortex. Further, we found that there was good to excellent within session, scan-to-scan consistency of peak-voxel T-scores for each of the brain regions. The reliability of the cluster-size around the peak-voxel was poor to good, and not as consistent as

Acknowledgements

We would like to thank Dorain L. Savino for her assistance. The primary study was funded through grants from: the Rochester Center for Brain Imaging – URMC Dean Slattery's Pilot Fund; the Central NY Research Corporation Bridge & Seed Fund; and the New York Chiropractic College Bridge & Seed Fund. CWG received funding from the National Center for Complementary and Alternative Medicine (NCCAM) (F32 AT007729-01A1) and NCMIC Foundation while writing this manuscript. MDB received funding from NCCAM (

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Cited by (2)

Demonstration and validation of a new pressure-based MRI-safe pain tolerance device
2016, Journal of Neuroscience Methods
Citation Excerpt :
There is currently no standardized way of administering pressure-based pain in the neuroimaging literature. Using Magnetic Resonance Imaging (MRI), pressure has been administered to the lower back (Gay et al., 2015), foot (Petre et al., 2008), jaw (Shaefer et al., 2001), and thumbnail (Cole et al., 2010). The devices used to administer pressure in these studies are either specifically designed for one piece of anatomy (i.e., the lower back for Gay et al., 2015) or not described in enough detail to replicate for future studies.
One of the barriers to studying the behavioral and emotional effects of pain using functional Magnetic Resonance Imaging (fMRI) is the absence of a commercially available, MRI-compatible, pressure-based algometer to elicit pain. The present study sought to address this barrier through creation and validation of a novel MRI-safe apparatus capable of delivering incremental, measurable amounts of pressure inside a scanning bore.
We introduced an MR-safe device used to administer pressure-based pain. To test against a commercially available, MRI-incompatible algometer (AlgoMed), 199 participants reported their pain tolerance for both devices. A second experiment tested the validity of pressure-based pain in an MRI environment by comparing brain activation with established neural networks for pain. 10 participants performed an identical procedure to test for pain tolerance while being scanned in a 7T MRI scanner.
Results support the validity and reliability of our novel device. In Study 1, pain tolerance with this device was strongly correlated with pain tolerance as measured by a commercially available algometer (r = 0.78). In Study 2, this device yielded BOLD activation within the insula (BA 13) and anterior cingulate gyrus (BA 24); as pressure increased, activation in these areas parametrically increased.
These findings correspond to other studies using thermal, electrical, or mechanical pain applications. Behavioral and functional data demonstrate that this new device is a valid method of administering pressure-related pain in MRI environments.
Our novel MRI-safe device is a valid instrument to measure and administer pressure-based pain.
Neuroimaging Assessment of Pain
2022, Neurotherapeutics

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Clinical NeuroscienceThe frequency and reliability of cortical activity using a novel strategy to present pressure pain stimulus over the lumbar spine