Background & Aims

Mechanical detection thresholds (MDT) are a part of assessing the somatosensory profile of an individual (Backonja et al., 2013). The normative range differs based on age, gender and measurement location. While there are multiple methods and devices that can be used (Magerl et al., 2010), standardized reference values following the widely used German Research Association for Neuropathic Pain (DFNS) protocol (Rolke, Baron, et al., 2006) exist only for OptiHair2, a fragile, high-end, and costly type of glass filament (Rolke, Magerl, et al., 2006). Nylon filaments are a less expensive and more robust, and could be a viable alternative to glass filaments (Pfau et al., 2020). In this study, we compared the glass filaments OptiHair2 with the Aesthesiometer II nylon filaments set regarding the DFNS standard data in healthy subjects and patients with polyneuropathy.

Methods

MDT was determined in randomized order using OptiHair2 glass filaments (0.25 mN to 512 mN) and Aesthesiometer II nylon filaments (0.63 mN to 235.36 mN) in healthy subjects and patients with suspected polyneuropathy to measure the sensitivity of both methods for the detection of polyneuropathy. Data were analysed by calculating arithmetic means, log-based standard deviations, medians, ranges, percentages, and Z-values following DNFS-procedure (Rolke, Baron, et al., 2006). Additionally, we used Shapiro-Wilk-test, t-test or the non-parametric Wilcoxon-signed-rank-test, the Pearson correlation coefficient test to compare statistically, and Bland-Altman plots for visual representation of agreement.

Results

30 healthy adults aged 22-62 (20 female, age 32 ±14.69), 10 healthy children aged 9-15 years (5 female, age 13 ±1.87) and 15 patients with suspected polyneuropathy aged 35-86 years (8 female, age 55 ±11.51) were included in the study. Healthy subjects were tested in three body sites (cheek, hand, foot) and patients in two body sites (hand, foot).
There were significant correlations between Aesthesiometer II and OptiHair2 for healthy adults (r= 0.83, p<0.001; r=0.75, p<0.001), children (r=0.77, p<.001; r=0.74, p=0.01), and patients (r=0.68, p=0.01; r=0.84, p<0.001) alone and combined (r=0.80, p<.001; r=0.88, p<0.001) for the hand and foot, respecitively. Compared to OptiHair2, measured mechanical detection thresholds were increased in Aesthesiometer II in healthy subjects on the cheek and hand, but not in the feet and hand of patients. Bland-Altman plots visually showed systematically elevated values of Aesthesiometer II in patients, but less so in healthy subjects’ values.

Conclusions

In conclusion, low MDT value ranges (in cheek and hand of healthy subjects) show systematically too high values for Aesthesiometer II compared to Opti Hair 2. Currently, we cannot recommend Aesthesiometer II monofilaments as an equal peer to OptiHair2 filaments when applying the DFNS protocol.

References

Backonja, M. “Misha, Attal, N., Baron, R., Bouhassira, D., Drangholt, M., Dyck, P. J., Edwards, R. R., Freeman, R., Gracely, R., Haanpaa, M. H., Hansson, P., Hatem, S. M., Krumova, E. K., Jensen, T. S., Maier, C., Mick, G., Rice, A. S., Rolke, R., Treede, R.-D., … Ziegler, D. (2013). Value of quantitative sensory testing in neurological and pain disorders: NeuPSIG consensus. PAIN, 154(9). https://journals.lww.com/pain/fulltext/2013/09000/value_of_quantitative_sensory_testing_in.41.aspx
Magerl, W., Krumova, E. K., Baron, R., Tölle, T., Treede, R.-D., & Maier, C. (2010). Reference data for quantitative sensory testing (QST): Refined stratification for age and a novel method for statistical comparison of group data. PAIN, 151(3). https://journals.lww.com/pain/fulltext/2010/12000/reference_data_for_quantitative_sensory_testing.11.aspx
Pfau, D. B., Haroun, O., Lockwood, D. N., Maier, C., Schmitter, M., Vollert, J., Rice, A. S. C., & Treede, R.-D. (2020). Mechanical detection and pain thresholds: Comparability of devices using stepped and ramped stimuli. PAIN Reports, 5(6). https://journals.lww.com/painrpts/fulltext/2020/12000/mechanical_detection_and_pain_thresholds_.14.aspx
Rolke, R., Baron, R., Maier, C., Tolle, T. R., Treede, R. D., Beyer, A., Binder, A., Birbaumer, N., Birklein, F., Botefur, I. C., Braune, S., Flor, H., Huge, V., Klug, R., Landwehrmeyer, G. B., Magerl, W., Maihofner, C., Rolko, C., Schaub, C., … Wasserka, B. (2006). Quantitative sensory testing in the German Research Network on Neuropathic Pain (DFNS): Standardized protocol and reference values. Pain, 123(3), 231–243. https://doi.org/10.1016/j.pain.2006.01.041
Rolke, R., Magerl, W., Campbell, K. A., Schalber, C., Caspari, S., Birklein, F., & Treede, R.-D. (2006). Quantitative sensory testing: A comprehensive protocol for clinical trials. European Journal of Pain, 10(1), 77–77. https://doi.org/10.1016/j.ejpain.2005.02.003

Presenting Author

Jan D. Wandrey

Poster Authors

Jan D. Wandrey

Dr. med.

Charité-Universitätsmedizin Berlin, Department of Anaesthesiology and Intensive Care

Lead Author

Annika Reinecke

University Hospital of Pediatrics and Adolescent Medicine, Ruhr-University Bochum; Bochum, Germany

Lead Author

Andrea Westermann

Dr. med.

Department of Pain Medicine, BG University Hospital Bergmannsheil, Ruhr-University Bochum, Germany

Lead Author

Thomas Lücke

Prof. Dr. med.

University Hospital of Pediatrics and Adolescent Medicine, Ruhr-University Bochum; Bochum, Germany

Lead Author

Christoph Maier

Prof. Dr.

University Hospital of Pediatrics and Adolescent Medicine, Ruhr-University Bochum; Bochum, Germany

Lead Author

Jan Vollert

University of Exeter

Lead Author

Lynn Eitner

Dr. med.

University Hospital of Pediatrics and Adolescent Medicine, Ruhr-University Bochum; Bochum, Germany

Lead Author

Topics

  • Specific Pain Conditions/Pain in Specific Populations: Neuropathic Pain - Peripheral