Examinando por Autor "Goldstein, Jill"

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  • Publicación
    Acceso abierto
    Dose-Optimization of Respiratory-Gated Auricular Vagal Afferent Nerve Stimulation (RAVANS) for Blood Pressure Modulation in Hypertensive Patients
    (2019-09-05) Stowell, Jessica; Garcia, Ronald G.; Staley, Rachel; Sclocco, Roberta; Fisher, Harrison; Napadow, Vitaly; Goldstein, Jill; Barbieri, Riccardo
    The objective of this study was to determine the optimal frequency of respiratory-gated auricular vagal afferent nerve stimulation (RAVANS) for the modulation of blood pressure in hypertensive patients. Twelve hypertensive subjects (52.5±6.0 years, 8 females) underwent five randomized stimulation sessions, during which they received exhalatory-gated stimulation at frequencies of 2, 10, 25, and 100 Hz or sham stimulation. A continuous blood pressure signal was collected during a 30-minute stimulation period and a 10-minute recovery period using a Finometer device (Finapress Medical System, the Netherlands). LabChart (ADInstruments, Colorado Springs, CO, USA) was used to process and compute blood pressure responses. A significantly greater reduction of systolic blood pressure values during stimulation was observed in the 100 Hz session compared to sham (p=0.02). In addition, significant reductions in diastolic blood pressure (p=0.04) and mean arterial pressure (p=0.04) values were observed during RAVANS stimulation compared to baseline during the 100 Hz session. Evaluation of other stimulation frequencies did not reveal significant results. RAVANS exhibits a frequency-dependent effect on the modulation of arterial blood pressure levels of hypertensive subjects.
  • Publicación
    Acceso abierto
    Stimulus frequency modulates brainstem response to respiratory-gated transcutaneous auricular vagus nerve stimulation
    (2020-03-27) Sclocco, Roberta; Garcia, Ronald G.; Kettner, Norman W.; Fisher, Harrison P.; Isenburg, Kylie; Makarovsky, Maya; Stowell, Jessica A.; Goldstein, Jill; Barbieri, Riccardo; Napadow, Vitaly; Neurociencias
    Background: The therapeutic potential of transcutaneous auricular VNS (taVNS) is currently being explored for numerous clinical applications. However, optimized response for different clinical indications may depend on specific neuromodulation parameters, and systematic assessments of their influence are still needed to optimize this promising approach. Hypothesis: We proposed that stimulation frequency would have a significant effect on nucleus tractus solitarii (NTS) functional MRI (fMRI) response to respiratory-gated taVNS (RAVANS). Methods: Brainstem fMRI response to auricular RAVANS (cymba conchae) was assessed for four different stimulation frequencies (2, 10, 25, 100 Hz). Sham (no current) stimulation was used to control for respiration effects on fMRI signal. Results: Our findings demonstrated that RAVANS delivered at 100 Hz evoked the strongest brainstem response, localized to a cluster in the left (ipsilateral) medulla and consistent with purported NTS. A colocalized, although weaker, response was found for 2 Hz RAVANS. Furthermore, RAVANS delivered at 100 Hz also evoked stronger fMRI responses for important monoamine neurotransmitter source nuclei (LC, noradrenergic; MR, DR, serotonergic) and pain/homeostatic regulation nuclei (i.e. PAG). Conclusion: Our fMRI results support previous localization of taVNS afference to pontomedullary aspect of NTS in the human brainstem, and demonstrate the significant influence of the stimulation frequency on brainstem fMRI response.