by A.H. Gazi, S. An, J.A. Sanchez-Perez, M. Chan, M. Nikbakht, D.J. Lin, S. Natarajan, K.A. Johnsen, J.D. Bremner, J. Hahn, O.T. Inan and C.J. Rozell
Abstract:
Objective: To develop a person-specific dy- namic modeling approach to quantify the time course of multiple peripheral markers of the autonomic nervous system (ANS) in response to acute stressors and potential stress-reducing interventions. Methods: We curated data (N=50 participants) from a double-blind, randomized, sham-controlled trial of non-invasive vagus nerve stimulation (nVNS) for posttraumatic stress disorder (PTSD). For each participant, a multi-input, multi-output, linear state space model (SSM) was trained on ∼3500 s of cardiovascular and respiratory marker time series data and tested for predictive validity on ∼2000 s of held-out data. The inputs to each SSM indicated the presence or absence of potential stressors (e.g., traumatic memories) and interventions (e.g., nVNS or sham stimu- lation). We analyzed the SSMs’ step responses to each input and compared the responses to real data. We then simulated the effects of just-in-time nVNS delivered during a traumatic memory. Results: The SSMs outperformed baseline forecasting methods on held-out data (P<.05). Responses to nVNS were in the opposite direction of responses to traumatic memories, with neutral conditions (included for comparison) remaining in between. For participants with PTSD, just-in-time nVNS attenuated–and briefly reversed–the response to traumatic memories along the principal axis of variance, which explained ∼50% or more variance and mirrored expected ANS changes. Just-in-time sham stimu- lation produced no attenuation. Conclusion: Our methods capture latent ANS dynamics during increasing and decreasing stress levels associated with traumatic memories and nVNS, respectively. Significance: Traumatic memories can cause pathological stress responses during daily life that just-in-time non- invasive neuromodulation may potentially help mitigate.
Reference:
Modeling Latent Dynamics of the Autonomic Nervous System in Response to Trauma Recall and Non-Invasive Vagus Nerve StimulationA.H. Gazi, S. An, J.A. Sanchez-Perez, M. Chan, M. Nikbakht, D.J. Lin, S. Natarajan, K.A. Johnsen, J.D. Bremner, J. Hahn, O.T. Inan and C.J. Rozell. IEEE Transactions on Biomedical Engineering, January 2025. Under review
Bibtex Entry:
@article{gazi.25,
author = {Gazi, A.H. and An, S. and Sanchez-Perez, J.A. and Chan, M. and Nikbakht, M. and Lin, D.J. and Natarajan, S. and Johnsen, K.A. and Bremner, J.D. and Hahn, J. and Inan, O.T. and Rozell, C.J.},
title = {Modeling Latent Dynamics of the Autonomic Nervous System in Response to Trauma Recall and Non-Invasive Vagus Nerve Stimulation},
journal = {IEEE Transactions on Biomedical Engineering},
year = {2025},
month = jan,
abstract = {Objective: To develop a person-specific dy- namic modeling approach to quantify the time course of multiple peripheral markers of the autonomic nervous system (ANS) in response to acute stressors and potential stress-reducing interventions. Methods: We curated data (N=50 participants) from a double-blind, randomized, sham-controlled trial of non-invasive vagus nerve stimulation (nVNS) for posttraumatic stress disorder (PTSD). For each participant, a multi-input, multi-output, linear state space model (SSM) was trained on ∼3500 s of cardiovascular and respiratory marker time series data and tested for predictive validity on ∼2000 s of held-out data. The inputs to each SSM indicated the presence or absence of potential stressors (e.g., traumatic memories) and interventions (e.g., nVNS or sham stimu- lation). We analyzed the SSMs’ step responses to each input and compared the responses to real data. We then simulated the effects of just-in-time nVNS delivered during a traumatic memory. Results: The SSMs outperformed baseline forecasting methods on held-out data (P<.05). Responses to nVNS were in the opposite direction of responses to traumatic memories, with neutral conditions (included for comparison) remaining in between. For participants with PTSD, just-in-time nVNS attenuated–and briefly reversed–the response to traumatic memories along the principal axis of variance, which explained ∼50% or more variance and mirrored expected ANS changes. Just-in-time sham stimu- lation produced no attenuation. Conclusion: Our methods capture latent ANS dynamics during increasing and decreasing stress levels associated with traumatic memories and nVNS, respectively. Significance: Traumatic memories can cause pathological stress responses during daily life that just-in-time non- invasive neuromodulation may potentially help mitigate.},
note = {Under review}
}