{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,11,5]],"date-time":"2026-11-05T20:51:24Z","timestamp":1793911884265,"version":"4.8.0"},"reference-count":24,"publisher":"Springer Science and Business Media LLC","issue":"1","license":[{"start":{"date-parts":[[2025,11,21]],"date-time":"2025-11-21T00:00:00Z","timestamp":1763683200000},"content-version":"tdm","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0"},{"start":{"date-parts":[[2025,11,21]],"date-time":"2025-11-21T00:00:00Z","timestamp":1763683200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0"}],"funder":[{"DOI":"10.13039\/501100000781","name":"European Research Council","doi-asserted-by":"publisher","award":["682756"],"award-info":[{"award-number":["682756"]}],"id":[{"id":"10.13039\/501100000781","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":["link.springer.com"],"crossmark-restriction":false},"short-container-title":["Sci Rep"],"abstract":"<jats:title>Abstract<\/jats:title>\n                  <jats:p>Cochlear implants (CIs) are among the most established neuromodulation devices, providing auditory perception through electrical stimulation of the auditory nerve. While conventional stimulation strategies rely on symmetric biphasic rectangular pulses, alternative pulse shapes may offer improvements in neural activation and energy efficiency-particularly for fully implantable CI systems where power consumption is a key limitation. In this study, we investigate the efficacy of anodic-first ramped biphasic pulse shapes compared to conventional anodic-first rectangular pulses, using a custom-designed fully implantable cochlear implant (FICI) system in an in vivo guinea pig model. Electrically evoked auditory brainstem responses (eABRs) were recorded in response to four charge-balanced waveform types: Rectangular, RampUp, RampDown, and RampLong. In this single-subject feasibility study, ramped waveforms elicited significantly larger eABR amplitudes, steeper input-output functions, and shorter latencies compared to rectangular pulses. Additionally, we characterized transmission efficiency across the electrode\u2013tissue interface by analyzing waveform spectra and their attenuation through a frequency-dependent medium model. After correcting for these medium-specific losses, in the anodic-first biphasic configuration, RampUp and RampLong pulses demonstrated up to 19\u201322% improvement in power efficiency relative to rectangular pulses at subthreshold response levels. These findings highlight the potential of ramped stimulation to reduce energy consumption without compromising-and in some cases enhancing-neural activation. Such improvements are especially valuable for fully implantable devices, supporting longer battery life and more sustainable stimulation strategies in next-generation CIs.<\/jats:p>","DOI":"10.1038\/s41598-025-25077-2","type":"journal-article","created":{"date-parts":[[2025,11,21]],"date-time":"2025-11-21T11:47:45Z","timestamp":1763725665000},"update-policy":"https:\/\/doi.org\/10.1007\/springer_crossmark_policy","source":"Crossref","is-referenced-by-count":2,"title":["Power\u2212efficient ramped stimulation in a fully implantable cochlear implant"],"prefix":"10.1038","volume":"15","author":[{"given":"Mert","family":"Do\u011fan","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ozlem","family":"Topcu","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Hasan","family":"Ulusan","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"M. Berat","family":"Yuksel","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"M. Birol","family":"U\u011fur","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Haluk","family":"K\u00fclah","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"297","published-online":{"date-parts":[[2025,11,21]]},"reference":[{"key":"25077_CR1","doi-asserted-by":"publisher","first-page":"115","DOI":"10.1109\/rbme.2008.2008250","volume":"1","author":"F-G Zeng","year":"2008","unstructured":"Zeng, F.-G., Rebscher, S., Harrison, W., Sun, X. & Feng, H. Cochlear implants: System design, integration, and evaluation. IEEE Rev. Biomed. Eng. 1, 115\u2013142. https:\/\/doi.org\/10.1109\/rbme.2008.2008250 (2008).","journal-title":"IEEE Rev. Biomed. Eng."},{"key":"25077_CR2","doi-asserted-by":"publisher","DOI":"10.1038\/s44172-024-00275-4","author":"H Ulusan","year":"2024","unstructured":"Ulusan, H. et al. A full-custom fully implantable cochlear implant system validated in vivo with an animal model. Commun. Eng. https:\/\/doi.org\/10.1038\/s44172-024-00275-4 (2024).","journal-title":"Commun. Eng."},{"key":"25077_CR3","doi-asserted-by":"publisher","DOI":"10.1088\/1741-2560\/7\/4\/046009","volume":"7","author":"A Wongsarnpigoon","year":"2010","unstructured":"Wongsarnpigoon, A. & Grill, W. M. Energy-efficient waveform shapes for neural stimulation revealed with a genetic algorithm. J. Neural Eng. 7, 046009. https:\/\/doi.org\/10.1088\/1741-2560\/7\/4\/046009 (2010).","journal-title":"J. Neural Eng."},{"key":"25077_CR4","doi-asserted-by":"publisher","first-page":"1504","DOI":"10.1109\/tvlsi.2019.2898873","volume":"27","author":"H Ulusan","year":"2019","unstructured":"Ulusan, H., Chamanian, S., Ilik, B., Muhtaroglu, A. & Kulah, H. Fully implantable cochlear implant interface electronics with 51.2-$$\\mu$$ w front-end circuit. IEEE Trans. Very Large Scale Integr. VLSI Syst. 27, 1504\u20131512. https:\/\/doi.org\/10.1109\/tvlsi.2019.2898873 (2019).","journal-title":"IEEE Trans. Very Large Scale Integr. VLSI Syst."},{"key":"25077_CR5","doi-asserted-by":"publisher","first-page":"371","DOI":"10.1080\/00016480410031084","volume":"124","author":"RM Bonnet","year":"2004","unstructured":"Bonnet, R. M., Frijns, J. H., Peeters, S. & Briaire, J. J. Speech recognition with a cochlear implant using triphasic charge-balanced pulses. Acta Otolaryngol. 124, 371\u2013375. https:\/\/doi.org\/10.1080\/00016480410031084 (2004).","journal-title":"Acta Otolaryngol."},{"key":"25077_CR6","doi-asserted-by":"publisher","first-page":"1268","DOI":"10.1097\/mao.0000000000002398","volume":"40","author":"K Braun","year":"2019","unstructured":"Braun, K., Walker, K., S\u00f6rth, W., L\u00f6wenheim, H. & Tropitzsch, A. Triphasic pulses in cochlear implant patients with facial nerve stimulation. Otol. Neurotol. 40, 1268\u20131277. https:\/\/doi.org\/10.1097\/mao.0000000000002398 (2019).","journal-title":"Otol. Neurotol."},{"key":"25077_CR7","doi-asserted-by":"publisher","DOI":"10.1016\/j.heares.2023.108741","volume":"432","author":"J de Nobel","year":"2023","unstructured":"de Nobel, J., Kononova, A. V., Briaire, J. J., Frijns, J. H. & B\u00e4ck, T. H. Optimizing stimulus energy for cochlear implants with a machine learning model of the auditory nerve. Hear. Res. 432, 108741. https:\/\/doi.org\/10.1016\/j.heares.2023.108741 (2023).","journal-title":"Hear. Res."},{"key":"25077_CR8","doi-asserted-by":"publisher","first-page":"187","DOI":"10.1007\/s10162-013-0440-x","volume":"15","author":"D Ramekers","year":"2014","unstructured":"Ramekers, D. et al. Auditory-nerve responses to varied inter-phase gap and phase duration of the electric pulse stimulus as predictors for neuronal degeneration. J. Assoc. Res. Otolaryngol. 15, 187\u2013202. https:\/\/doi.org\/10.1007\/s10162-013-0440-x (2014).","journal-title":"J. Assoc. Res. Otolaryngol."},{"key":"25077_CR9","doi-asserted-by":"publisher","DOI":"10.1038\/s41598-020-60181-5","author":"CA Navntoft","year":"2020","unstructured":"Navntoft, C. A., Marozeau, J. & Barkat, T. R. Ramped pulse shapes are more efficient for cochlear implant stimulation in an animal model. Sci. Rep. https:\/\/doi.org\/10.1038\/s41598-020-60181-5 (2020).","journal-title":"Sci. Rep."},{"key":"25077_CR10","doi-asserted-by":"publisher","DOI":"10.1177\/23312165211061116","author":"CA Navntoft","year":"2021","unstructured":"Navntoft, C. A., Landsberger, D. M., Barkat, T. R. & Marozeau, J. The perception of ramped pulse shapes in cochlear implant users. Trends Hear. https:\/\/doi.org\/10.1177\/23312165211061116 (2021).","journal-title":"Trends Hear."},{"key":"25077_CR11","doi-asserted-by":"publisher","DOI":"10.1177\/2331216515619763","author":"J Ballestero","year":"2015","unstructured":"Ballestero, J. et al. Reducing current spread by use of a novel pulse shape for electrical stimulation of the auditory nerve. Trends Hear. https:\/\/doi.org\/10.1177\/2331216515619763 (2015).","journal-title":"Trends Hear."},{"key":"25077_CR12","doi-asserted-by":"publisher","first-page":"250","DOI":"10.3390\/brainsci13020250","volume":"13","author":"E Partouche","year":"2023","unstructured":"Partouche, E., Adenis, V., Stahl, P., Huetz, C. & Edeline, J.-M. What is the benefit of ramped pulse shapes for activating auditory cortex neurons? an electrophysiological study in an animal model of cochlear implant. Brain Sci. 13, 250. https:\/\/doi.org\/10.3390\/brainsci13020250 (2023).","journal-title":"Brain Sci."},{"key":"25077_CR13","doi-asserted-by":"publisher","first-page":"227","DOI":"10.1088\/1741-2560\/4\/3\/008","volume":"4","author":"M Sahin","year":"2007","unstructured":"Sahin, M. & Tie, Y. Non-rectangular waveforms for neural stimulation with practical electrodes. J. Neural Eng. 4, 227\u2013233. https:\/\/doi.org\/10.1088\/1741-2560\/4\/3\/008 (2007).","journal-title":"J. Neural Eng."},{"key":"25077_CR14","doi-asserted-by":"publisher","first-page":"275","DOI":"10.1146\/annurev.bioeng.10.061807.160518","volume":"10","author":"SF Cogan","year":"2008","unstructured":"Cogan, S. F. Neural stimulation and recording electrodes. Annu. Rev. Biomed. Eng. 10, 275\u2013309. https:\/\/doi.org\/10.1146\/annurev.bioeng.10.061807.160518 (2008).","journal-title":"Annu. Rev. Biomed. Eng."},{"key":"25077_CR15","doi-asserted-by":"publisher","first-page":"171","DOI":"10.1016\/j.jneumeth.2004.10.020","volume":"141","author":"DR Merrill","year":"2005","unstructured":"Merrill, D. R., Bikson, M. & Jefferys, J. G. Electrical stimulation of excitable tissue: Design of efficacious and safe protocols. J. Neurosci. Methods 141, 171\u2013198. https:\/\/doi.org\/10.1016\/j.jneumeth.2004.10.020 (2005).","journal-title":"J. Neurosci. Methods"},{"key":"25077_CR16","doi-asserted-by":"publisher","DOI":"10.1038\/s41598-017-13671-y","author":"M Yip","year":"2017","unstructured":"Yip, M., Bowers, P., Noel, V., Chandrakasan, A. & Stankovic, K. M. Energy-efficient waveform for electrical stimulation of the cochlear nerve. Sci. Rep. https:\/\/doi.org\/10.1038\/s41598-017-13671-y (2017).","journal-title":"Sci. Rep."},{"key":"25077_CR17","doi-asserted-by":"publisher","DOI":"10.1002\/advs.202308277","author":"MB Yuksel","year":"2024","unstructured":"Yuksel, M. B., Atik, A. C. & Kulah, H. Piezoelectric multi?channel bilayer transducer for sensing and filtering ossicular vibration. Adv. Sci. https:\/\/doi.org\/10.1002\/advs.202308277 (2024).","journal-title":"Adv. Sci."},{"key":"25077_CR18","doi-asserted-by":"publisher","first-page":"214","DOI":"10.1109\/jssc.2014.2355822","volume":"50","author":"M Yip","year":"2015","unstructured":"Yip, M., Jin, R., Nakajima, H. H., Stankovic, K. M. & Chandrakasan, A. P. A fully-implantable cochlear implant soc with piezoelectric middle-ear sensor and arbitrary waveform neural stimulation. IEEE J. Solid-State Circuits 50, 214\u2013229. https:\/\/doi.org\/10.1109\/jssc.2014.2355822 (2015).","journal-title":"IEEE J. Solid-State Circuits"},{"key":"25077_CR19","doi-asserted-by":"publisher","first-page":"2965","DOI":"10.1109\/jssc.2006.884862","volume":"41","author":"PT Bhatti","year":"2006","unstructured":"Bhatti, P. T. & Wise, K. D. A 32-site 4-channel high-density electrode array for a cochlear prosthesis. IEEE J. Solid-State Circuits 41, 2965\u20132973. https:\/\/doi.org\/10.1109\/jssc.2006.884862 (2006).","journal-title":"IEEE J. Solid-State Circuits"},{"key":"25077_CR20","doi-asserted-by":"publisher","first-page":"1","DOI":"10.1007\/s10162-015-0545-5","volume":"17","author":"J Boulet","year":"2016","unstructured":"Boulet, J., White, M. & Bruce, I. C. Temporal considerations for stimulating spiral ganglion neurons with cochlear implants. J. Assoc. Res. Otolaryngol. 17, 1\u201317. https:\/\/doi.org\/10.1007\/s10162-015-0545-5 (2016).","journal-title":"J. Assoc. Res. Otolaryngol."},{"key":"25077_CR21","doi-asserted-by":"publisher","first-page":"331","DOI":"10.1002\/cne.10244","volume":"447","author":"CL Adamson","year":"2002","unstructured":"Adamson, C. L., Reid, M. A., Mo, Z., Bowne-English, J. & Davis, R. L. Firing features and potassium channel content of murine spiral ganglion neurons vary with cochlear location. J. Comp. Neurol. 447, 331\u2013350. https:\/\/doi.org\/10.1002\/cne.10244 (2002).","journal-title":"J. Comp. Neurol."},{"key":"25077_CR22","doi-asserted-by":"publisher","first-page":"4773","DOI":"10.1523\/jneurosci.4511-11.2012","volume":"32","author":"MA Rutherford","year":"2012","unstructured":"Rutherford, M. A., Chapochnikov, N. M. & Moser, T. Spike encoding of neurotransmitter release timing by spiral ganglion neurons of the cochlea. J. Neurosci. 32, 4773\u20134789. https:\/\/doi.org\/10.1523\/jneurosci.4511-11.2012 (2012).","journal-title":"J. Neurosci."},{"key":"25077_CR23","doi-asserted-by":"publisher","first-page":"477","DOI":"10.1146\/annurev.physiol.61.1.477","volume":"61","author":"LO Trussell","year":"1999","unstructured":"Trussell, L. O. Synaptic mechanisms for coding timing in auditory neurons. Annu. Rev. Physiol. 61, 477\u2013496. https:\/\/doi.org\/10.1146\/annurev.physiol.61.1.477 (1999).","journal-title":"Annu. Rev. Physiol."},{"key":"25077_CR24","doi-asserted-by":"publisher","DOI":"10.3389\/fnins.2022.823423","author":"L Zheng","year":"2022","unstructured":"Zheng, L., Feng, Z., Xu, Y., Yuan, Y. & Hu, Y. An anodic phase can facilitate rather than weaken a cathodic phase to activate neurons in biphasic-pulse axonal stimulations. Front. Neurosci. https:\/\/doi.org\/10.3389\/fnins.2022.823423 (2022).","journal-title":"Front. Neurosci."}],"container-title":["Scientific Reports"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.nature.com\/articles\/s41598-025-25077-2.pdf","content-type":"application\/pdf","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/www.nature.com\/articles\/s41598-025-25077-2","content-type":"text\/html","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/www.nature.com\/articles\/s41598-025-25077-2.pdf","content-type":"application\/pdf","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,11,21]],"date-time":"2025-11-21T11:47:46Z","timestamp":1763725666000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.nature.com\/articles\/s41598-025-25077-2"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2025,11,21]]},"references-count":24,"journal-issue":{"issue":"1","published-online":{"date-parts":[[2025,12]]}},"alternative-id":["25077"],"URL":"https:\/\/doi.org\/10.1038\/s41598-025-25077-2","relation":{},"ISSN":["2045-2322"],"issn-type":[{"value":"2045-2322","type":"electronic"}],"subject":[],"published":{"date-parts":[[2025,11,21]]},"assertion":[{"value":"30 June 2025","order":1,"name":"received","label":"Received","group":{"name":"ArticleHistory","label":"Article History"}},{"value":"17 October 2025","order":2,"name":"accepted","label":"Accepted","group":{"name":"ArticleHistory","label":"Article History"}},{"value":"21 November 2025","order":3,"name":"first_online","label":"First Online","group":{"name":"ArticleHistory","label":"Article History"}},{"order":1,"name":"Ethics","group":{"name":"EthicsHeading","label":"Declarations"}},{"value":"The authors declare no competing interests.","order":2,"name":"Ethics","group":{"name":"EthicsHeading","label":"Competing interests"}}],"article-number":"41323"}}