{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,4]],"date-time":"2026-07-04T01:13:26Z","timestamp":1783127606693,"version":"3.54.6"},"reference-count":28,"publisher":"MDPI AG","issue":"2","license":[{"start":{"date-parts":[[2024,1,19]],"date-time":"2024-01-19T00:00:00Z","timestamp":1705622400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"German Federal Ministry of Education and Research (BMBF)","award":["FKZ 13GW0486"],"award-info":[{"award-number":["FKZ 13GW0486"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>Transcutaneous spinal cord stimulation (tSCS) provides a promising therapy option for individuals with injured spinal cords and multiple sclerosis patients with spasticity and gait deficits. Before the therapy, the examiner determines a suitable electrode position and stimulation current for a controlled application. For that, amplitude characteristics of posterior root muscle (PRM) responses in the electromyography (EMG) of the legs to double pulses are examined. This laborious procedure holds potential for simplification due to time-consuming skin preparation, sensor placement, and required expert knowledge. Here, we investigate mechanomyography (MMG) that employs accelerometers instead of EMGs to assess muscle activity. A supervised machine-learning classification approach was implemented to classify the acceleration data into no activity and muscular\/reflex responses, considering the EMG responses as ground truth. The acceleration-based calibration procedure achieved a mean accuracy of up to 87% relative to the classical EMG approach as ground truth on a combined cohort of 11 healthy subjects and 11 patients. Based on this classification, the identified current amplitude for the tSCS therapy was in 85%, comparable to the EMG-based ground truth. In healthy subjects, where both therapy current and position have been identified, 91% of the outcome matched well with the EMG approach. We conclude that MMG has the potential to make the tuning of tSCS feasible in clinical practice and even in home use.<\/jats:p>","DOI":"10.3390\/s24020634","type":"journal-article","created":{"date-parts":[[2024,1,19]],"date-time":"2024-01-19T03:33:41Z","timestamp":1705635221000},"page":"634","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":9,"title":["Targeting Transcutaneous Spinal Cord Stimulation Using a Supervised Machine Learning Approach Based on Mechanomyography"],"prefix":"10.3390","volume":"24","author":[{"ORCID":"https:\/\/orcid.org\/0009-0000-7750-1469","authenticated-orcid":false,"given":"Eira Lotta","family":"Spieker","sequence":"first","affiliation":[{"name":"Department of Neurology, Charit\u00e9\u2013Universit\u00e4tsmedizin Berlin, Charit\u00e9platz 1, 10117 Berlin, Germany"},{"name":"Control Systems Group, Technische Universit\u00e4t Berlin, Einsteinufer 17, 10587 Berlin, Germany"},{"name":"SensorStim Neurotechnology GmbH, c\/o TU Berlin, Einsteinufer 17, 10587 Berlin, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0002-2765-8729","authenticated-orcid":false,"given":"Ardit","family":"Dvorani","sequence":"additional","affiliation":[{"name":"Control Systems Group, Technische Universit\u00e4t Berlin, Einsteinufer 17, 10587 Berlin, Germany"},{"name":"SensorStim Neurotechnology GmbH, c\/o TU Berlin, Einsteinufer 17, 10587 Berlin, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5527-9895","authenticated-orcid":false,"given":"Christina","family":"Salchow-H\u00f6mmen","sequence":"additional","affiliation":[{"name":"Department of Neurology, Charit\u00e9\u2013Universit\u00e4tsmedizin Berlin, Charit\u00e9platz 1, 10117 Berlin, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9768-5143","authenticated-orcid":false,"given":"Carolin","family":"Otto","sequence":"additional","affiliation":[{"name":"Department of Neurology, Charit\u00e9\u2013Universit\u00e4tsmedizin Berlin, Charit\u00e9platz 1, 10117 Berlin, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Klemens","family":"Ruprecht","sequence":"additional","affiliation":[{"name":"Department of Neurology, Charit\u00e9\u2013Universit\u00e4tsmedizin Berlin, Charit\u00e9platz 1, 10117 Berlin, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-0965-7530","authenticated-orcid":false,"given":"Nikolaus","family":"Wenger","sequence":"additional","affiliation":[{"name":"Department of Neurology, Charit\u00e9\u2013Universit\u00e4tsmedizin Berlin, Charit\u00e9platz 1, 10117 Berlin, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-0865-4418","authenticated-orcid":false,"given":"Thomas","family":"Schauer","sequence":"additional","affiliation":[{"name":"Control Systems Group, Technische Universit\u00e4t Berlin, Einsteinufer 17, 10587 Berlin, Germany"},{"name":"SensorStim Neurotechnology GmbH, c\/o TU Berlin, Einsteinufer 17, 10587 Berlin, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2024,1,19]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"481","DOI":"10.1089\/neu.2019.6588","article-title":"Transcutaneous spinal cord stimulation induces temporary attenuation of spasticity in individuals with spinal cord injury","volume":"37","author":"Hofstoetter","year":"2020","journal-title":"J. Neurotrauma"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"2633","DOI":"10.1523\/JNEUROSCI.2374-19.2020","article-title":"Cortical and subcortical effects of transcutaneous spinal cord stimulation in humans with tetraplegia","volume":"40","author":"Benavides","year":"2020","journal-title":"J. Neurosci."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1186\/s12984-020-00682-6","article-title":"Supporting front crawl swimming in paraplegics using electrical stimulation: A feasibility study","volume":"17","author":"Wiesener","year":"2020","journal-title":"J. Neuroeng. Rehabil."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"202","DOI":"10.1179\/2045772313Y.0000000149","article-title":"Modification of spasticity by transcutaneous spinal cord stimulation in individuals with incomplete spinal cord injury","volume":"37","author":"Hofstoetter","year":"2014","journal-title":"J. Spinal Cord Med."},{"key":"ref_5","doi-asserted-by":"crossref","unstructured":"Taylor, C., McHugh, C., Mockler, D., Minogue, C., Reilly, R.B., and Fleming, N. (2021). Transcutaneous spinal cord stimulation and motor responses in individuals with spinal cord injury: A methodological review. PLoS ONE, 16.","DOI":"10.1371\/journal.pone.0260166"},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"582","DOI":"10.1080\/10790268.2021.2000200","article-title":"Transcutaneous spinal cord stimulation effects on spasticity in patients with spinal cord injury: A systematic review","volume":"46","author":"Alashram","year":"2023","journal-title":"J. Spinal Cord Med."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"103009","DOI":"10.1016\/j.msard.2021.103009","article-title":"Transcutaneous spinal cord stimulation improves postural stability in individuals with multiple sclerosis","volume":"52","author":"Roberts","year":"2021","journal-title":"Mult. Scler. Relat. Disord."},{"key":"ref_8","doi-asserted-by":"crossref","unstructured":"Hofstoetter, U.S., Freundl, B., Lackner, P., and Binder, H. (2021). Transcutaneous spinal cord stimulation enhances walking performance and reduces spasticity in individuals with multiple sclerosis. Brain Sci., 11.","DOI":"10.3390\/brainsci11040472"},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"637","DOI":"10.1109\/TNSRE.2010.2054112","article-title":"Stimulation of the human lumbar spinal cord with implanted and surface electrodes: A computer simulation study","volume":"18","author":"Ladenbauer","year":"2010","journal-title":"IEEE Trans. Neural Syst. Rehabil. Eng."},{"key":"ref_10","doi-asserted-by":"crossref","unstructured":"Hofstoetter, U.S., Freundl, B., Binder, H., and Minassian, K. (2019). Recovery cycles of posterior root-muscle reflexes evoked by transcutaneous spinal cord stimulation and of the H reflex in individuals with intact and injured spinal cord. PLoS ONE, 14.","DOI":"10.1371\/journal.pone.0227057"},{"key":"ref_11","doi-asserted-by":"crossref","unstructured":"Salchow-H\u00f6mmen, C., Schauer, T., M\u00fcller, P., K\u00fchn, A.A., Hofstoetter, U.S., and Wenger, N. (2021). Algorithms for Automated Calibration of Transcutaneous Spinal Cord Stimulation to Facilitate Clinical Applications. J. Clin. Med., 10.","DOI":"10.3390\/jcm10225464"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"691","DOI":"10.1016\/j.clinbiomech.2014.04.003","article-title":"Mechanomyography and muscle function assessment: A review of current state and prospects","volume":"29","author":"Ibitoye","year":"2014","journal-title":"Clin. Biomech."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"9489","DOI":"10.3390\/s140609489","article-title":"Novel Pseudo-Wavelet function for MMG signal extraction during dynamic fatiguing contractions","volume":"14","author":"Sepulveda","year":"2014","journal-title":"Sensors"},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"327","DOI":"10.1007\/s00421-002-0655-8","article-title":"Upper trapezius muscle mechanomyographic and electromyographic activity in humans during low force fatiguing and non-fatiguing contractions","volume":"87","author":"Madeleine","year":"2002","journal-title":"Eur. J. Appl. Physiol."},{"key":"ref_15","doi-asserted-by":"crossref","unstructured":"Krueger, E., Scheeren, E.M., Nogueira-Neto, G.N., da SN Button, V.L., and Nohama, P. (September, January 28). A new approach to assess the spasticity in hamstrings muscles using mechanomyography antagonist muscular group. Proceedings of the 2012 Annual International Conference of the IEEE Engineering in Medicine and Biology Society, San Diego, CA, USA.","DOI":"10.1109\/EMBC.2012.6346364"},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"441","DOI":"10.1088\/0967-3334\/30\/5\/002","article-title":"Classification of the mechanomyogram signal using a wavelet packet transform and singular value decomposition for multifunction prosthesis control","volume":"30","author":"Xie","year":"2009","journal-title":"Physiol. Meas."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"2571","DOI":"10.1007\/s00421-014-2975-x","article-title":"Wavelet-based intensity analysis of the mechanomyograph and electromyograph during the H-reflex","volume":"114","author":"Armstrong","year":"2014","journal-title":"Eur. J. Appl. Physiol."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"107","DOI":"10.1002\/mus.25432","article-title":"Mechanomyographic responses during recruitment curves in the soleus muscle","volume":"56","author":"Miramonti","year":"2017","journal-title":"Muscle Nerve"},{"key":"ref_19","doi-asserted-by":"crossref","unstructured":"S\u00f6rnmo, L., and Laguna, P. (2005). Bioelectrical Signal Processing in Cardiac and Neurological Applications, Academic Press.","DOI":"10.1016\/B978-012437552-9\/50003-9"},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"676","DOI":"10.1113\/EP088401","article-title":"A brief contraction has complex effects on summation of twitch pairs in human adductor pollicis","volume":"105","author":"Smith","year":"2020","journal-title":"Exp. Physiol."},{"key":"ref_21","doi-asserted-by":"crossref","unstructured":"Freeman, S.R., and Durfee, W.K. (September, January 30). Twitch response of intact human tibialis anterior muscle to doublet stimulation at graded strengths. Proceedings of the 2006 International Conference of the IEEE Engineering in Medicine and Biology Society, New York, NY, USA.","DOI":"10.1109\/IEMBS.2006.260940"},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"221","DOI":"10.1002\/mus.21288","article-title":"Nonlinear twitch torque summation by motor units activated at M-wave and H-reflex latencies","volume":"40","author":"Dean","year":"2009","journal-title":"Muscle Nerve Off. J. Am. Assoc. Electrodiagn. Med."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"327","DOI":"10.1002\/mus.20700","article-title":"Posterior root\u2013muscle reflexes elicited by transcutaneous stimulation of the human lumbosacral cord","volume":"35","author":"Minassian","year":"2007","journal-title":"Muscle Nerve Off. J. Am. Assoc. Electrodiagn. Med."},{"key":"ref_24","doi-asserted-by":"crossref","unstructured":"Hofstoetter, U.S., Freundl, B., Binder, H., and Minassian, K. (2018). Common neural structures activated by epidural and transcutaneous lumbar spinal cord stimulation: Elicitation of posterior root-muscle reflexes. PLoS ONE, 13.","DOI":"10.1371\/journal.pone.0192013"},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"257","DOI":"10.1111\/j.1525-1594.2011.01213.x","article-title":"Can the human lumbar posterior columns be stimulated by transcutaneous spinal cord stimulation? A modeling study","volume":"35","author":"Danner","year":"2011","journal-title":"Artif. Organs"},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"557","DOI":"10.1007\/BF02524423","article-title":"Technical aspects of mechnomyography recording with piezoelectric contact sensor","volume":"36","author":"Watakabe","year":"1998","journal-title":"Med. Biol. Eng. Comput."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"046015","DOI":"10.1088\/1741-2552\/ace552","article-title":"Enhanced selectivity of transcutaneous spinal cord stimulation by multielectrode configuration","volume":"20","author":"Bryson","year":"2023","journal-title":"J. Neural Eng."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"2111","DOI":"10.1152\/jn.00454.2019","article-title":"Preferential activation of spinal sensorimotor networks via lateralized transcutaneous spinal stimulation in neurologically intact humans","volume":"122","author":"Calvert","year":"2019","journal-title":"J. Neurophysiol."}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/24\/2\/634\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,10]],"date-time":"2025-10-10T13:45:44Z","timestamp":1760103944000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/24\/2\/634"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2024,1,19]]},"references-count":28,"journal-issue":{"issue":"2","published-online":{"date-parts":[[2024,1]]}},"alternative-id":["s24020634"],"URL":"https:\/\/doi.org\/10.3390\/s24020634","relation":{},"ISSN":["1424-8220"],"issn-type":[{"value":"1424-8220","type":"electronic"}],"subject":[],"published":{"date-parts":[[2024,1,19]]}}}