Neural correlates of lumbar tactile acuity in patients with non-specific low back pain and healthy controls – an MRI study
Bibliographic record
Abstract
Background Tactile acuity is defined as the skin’s ability to discriminate spatial patterns of stimulation. The two-point discrimination (TPD) threshold is commonly used to assess tactile acuity in non-specific low back pain (nsLBP) [ 1 ]. Another approach, the two-point estimation (TPE) task [ 2 ], is more time-efficient and, therefore potentially suitable for clinical use. The TPD is closely linked to functional and structural reorganisation in the primary somatosensory cortices (S1) [ 3 ] [ 4 ], yet studies on neural correlates of TPE are lacking. This study aims to identify potential associations between outcomes of lumbar TPE and TPD and resting-state functional connectivity (rsFC) and structural connectivity (SC) of the S1 region. Methods Preliminary data from the ongoing cross-sectional ‘PREDICT-LBP’ (PRedictive Evidence Driven Intelligent Classification Tool for Low Back Pain) study [ 5 ] are analysed. Whole-brain resting-state functional MRI (voxel size: 3mm isotropic; TE: 30; TR: 2500; acquisition time: 8:12min) and diffusion-weighted MRI (voxel size: 2mm isotropic, TE: 90; TR: 10000; 105 directions in 3 shells, b: 1000/1800/2500) are acquired with a 3T Philips Achieva MR system, providing rsFC and SC, respectively. MRI data processing is performed according to literature standards [ 6 ] [ 7 ]. To obtain SC, the deterministic tractography algorithm ‘SD_Stream’ from MRtrix3 [ 8 ] is performed to reconstruct white matter streamlines. To parcellate the brain into subregions, we use the ‘Brainnetome’ atlas [ 9 ] for both SC and rsFC. The lumbar TPD and TPE are measured at spinal level L4 with a digital calliper according to established protocols [ 2 ] [ 10 ]. The correlation of both SC and rsFC of the S1 region and the measures of tactile acuity are investigated using FDR-corrected univariate testing. Results We have currently (August 2023 – June 2024) acquired data from 155 participants (111 with nsLBP and 44 healthy controls). Visual quality control and processing of MRI data is ongoing and preliminary results will be presented at FSPT 2024. We hypothesize similar findings in neural correlates of TPE and TPD.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.000 |
| Insufficient payload (model declined to judge) | 0.003 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".