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Fernandez, K. A.

https://orcid.org/0000-0002-3231-9003

Mayo Clinic

Mayo Clinic

Citations 10

Off-target effects of percutaneous epidural spinal cord and dorsal root ganglion stimulation with task-specific training on lower urinary tract function in individuals with chronic spinal cord injury
Soong, Christina, Veith, Daniel D. , Gill, Megan L., Block, Julie B., Fernandez, K. A., Linde, Margaux B. , Mills, Candee J. , Scrabeck, Tyson L., Jahanian, Omid, Grahn, Peter J. , Zhao, Kristin D., Fernandez, K. A. , Solinsky, Ryan , Fernandez, K A , Beck, Lisa A. , Asp, Anders J , Jahanian, Omid , Solinsky, Ryan

The Journal of Spinal Cord Medicine | August 20, 2026 | Volume: No volume available | Issue: No issue available | Pages: 1-12

10.1080/10790268.2026.2703371 Get It

Percutaneous spinal stimulation to enhance gait and alleviate functional impairments in multiple sclerosis: A pilot study
Jahanian, Omid , Asp, Anders J., Gill, Megan L., Veith, Daniel D. , Fernandez, K. A. , Hogen, Cecilia A., Mills, Candee J. , Thoreson, Andrew R. , Grahn, Peter J. , Fernandez, Katrina A, Tobin, W Oliver , Fernandez, K A , Jahanian, Omid , Asp, Anders J., Solinsky, Ryan , Kaufman, Kenton R. , Zhao, Kristin D. , Tobin, W. Oliver

Multiple Sclerosis Journal – Experimental, Translational and Clinical | April 29, 2026 | Volume: 12 | Issue: 2 | Pages: No page available

10.1177/20552173261432301 Get It

Objective To evaluate the feasibility and potential efficacy of percutaneous spinal stimulation (epidural stimulation, ES) combined with task-specific training to reduce spasticity and improve gait and balance in individuals with progressive multiple sclerosis (MS). Methods Two men with progressive MS (EDSS 6.5) underwent ES lead implantation targeting the lower spinal cord, followed by one month of rehabilitation involving 12 ES-assisted training sessions. Assessments included instrumented gait analysis, Modified Ashworth Scale (MAS), pendulum test, and static balance testing performed at baseline, and at end of the study with ES-Off and ES-On conditions. Results Participant 1, with spastic hemiparetic gait, demonstrated improved lower extremity joint kinematics and muscle activation during gait, reduced knee extensor spasticity, and enhanced functional movement patterns with ES-On. Participant 2, with significant paraparesis and minimal spasticity, showed limited gait changes but experienced marked improvements in static balance, particularly under eyes-closed conditions. No adverse events were reported. Conclusion This pilot study demonstrates the feasibility and tolerability of ES paired with task-specific training in progressive MS. Participant-specific responses were observed, including improvements in gait kinematics, neuromuscular activation, spasticity, or balance; however, spatiotemporal gait parameters did not improve. These preliminary findings highlight response heterogeneity and the need for individualized ES parameter tuning. Trial registry name and URL: https://clinicaltrials.gov/study/NCT06019611
Therapy-specific motoneuron activation with epidural and dorsal root ganglion stimulation in spinal cord injury
Anders, Jennifer , Gill, Megan L., Fernandez, K. A. , Veith, Daniel D. , Linde, Margaux B. , Mills, Candee J. , Thoreson, Andrew R. , Hagedorn, Jon, Bendel, Mark A. , Iqbal, Rayyan A. , Grahn, Peter J. , Asp, Anders J , Fernandez, K A , Hagedorn, Jon M, Sayenko, Dimitry G , Solinsky, Ryan , Grahn, Peter J , Hagedorn, Jonathan M. , Bendel, Mark A., Sayenko, Dimitry G. , Solinsky, Ryan , Zhao, Kristin D.

Journal of Neurophysiology | April 11, 2026 | Volume: 135 | Issue: 5 | Pages: 1220-1230

10.1152/jn.00438.2025 Get It

Epidural and dorsal root stimulation have emerged as promising therapies to restore function after spinal cord injury. However, how each modality uniquely or jointly engages spinal circuits remains unclear. To address this, we analyzed leg electromyography (EMG) responses to epidural stimulation (ES) and dorsal root ganglia stimulation (DRGS) delivered to the lumbosacral cord in the same individuals.
Increased symptomatic autonomic dysfunction is associated with greater cardiovascular endothelial dysfunction following spinal cord injury
Pramanik, Bishoy, Fernandez, K. A., Seidel‐Miller, Kim, Park, Andrew, Solinsky, Ryan, Fernandez, K. A. , Solinsky, Ryan , Solinsky, Ryan , Fernandez, K A

PM&R | December 25, 2025 | Volume: 18 | Issue: 7 | Pages: 716-722

10.1002/pmrj.70069 Get It

Abstract Background Individuals with spinal cord injury (SCI) are known to have high rates of cardiovascular disease that have traditionally been attributed to inability to engage in adequate intensity exercise. However, individuals with SCI also commonly experience instability in blood pressure. Blood pressure fluctuations are known to contribute to cardiovascular disease in other conditions, though this relationship in SCI is unknown. Objective To evaluate correlations between a clinical history of symptomatic blood pressure instability and objective evidence of vascular endothelial dysfunction in individuals with SCI. Design Case control. Setting Academic medical center. Participants Twenty‐four individuals with SCI, 14 uninjured controls of matched age, gender, and body mass index. Interventions Not applicable. Main Outcome Measures Symptomatic blood pressure instability was measured by the Autonomic Dysfunction Following SCI (ADFSCI) survey. Vascular endothelial dysfunction was quantified by ultrasound recordings of brachial flow mediated dilation following 5 minutes of forearm arterial occlusion. Results Total ADFSCI scores were significantly higher in individuals with SCI compared to controls (41.0 vs. 9.0, p = .002). Both percentage of brachial flow mediated dilation and consensus recommended allometrically scaled percentage of flow mediated dilation were significantly less in individuals with SCI ( p < .001 for both), demonstrating greater vascular dysfunction. More symptoms of blood pressure instability on the ADFSCI survey were correlated with more objective evidence of vascular dysfunction ( R 2 = 0.24, p = .03) for individuals with SCI. This relationship was not seen in uninjured controls. Conclusions In individuals with SCI, more severe symptoms of blood pressure instability are significantly correlated with more severe vascular endothelial dysfunction, making management of orthostatic hypotension and autonomic dysreflexia both high potential, modifiable risk factors for individuals with SCI to mitigate cardiovascular disease.
Percutaneous Spinal Cord Stimulator Enables Novel Clonus Biomarker and Management in Persons With Spinal Cord Injury and Multiple Sclerosis: An Exploratory Study
Asp, Anders J., Gill, Megan L., Veith, Daniel D. , Fernandez, K. A. , Mills, Candee J. , Thoreson, Andrew R. , Bendel, Markus A. , Zhao, Kristin D. , Grahn, Peter J. , Solinsky, Ryan J, Trentadue, Taylor P , Fernandez, K A , Asp, Anders J., Jahanian, Omid , Hagedorn, Jonathan M. , Solinsky, Ryan , Tobin, W. Oliver

Topics in Spinal Cord Injury Rehabilitation | September 24, 2025 | Volume: 31 | Issue: 2 | Pages: 114-124

10.46292/sci24-00070 Get It

Background: Spasticity is common in spinal cord injury (SCI) and multiple sclerosis (MS), and it can manifest as repeated, rhythmic muscle contractions called clonus. The spontaneous nature of clonus can disrupt independent performance of activities of daily living and negatively impact overall health and quality of life. Objectives: To quantify biomarkers of clonus and explore management of clonus in individuals with SCI or progressive MS using epidural spinal cord stimulation (ES) or dorsal root stimulation (DRS). Methods: Four male participants were included in this case series study: 3 with SCI and 1 with MS. All participants underwent temporary percutaneous ES lead placement over the dorsolateral thoracolumbar region of the spinal cord. Participants with SCI were also implanted with DRS leads at the L4 dorsal root. Clonus was elicited mechanically at the ankle while recording electromyography of the soleus muscle synchronized to direct spinal cord field potential recordings from ES and DRS percutaneous leads. Results: Clonus was evident as a prominent band (5-8 Hz) in recordings from ES leads, DRS leads, soleus muscle, and accelerometry. In 4 participants, percutaneous spinal stimulation reduced median clonus duration and cycle count. Clonus was immediately suppressed upon activation of spinal cord stimulation, and the suppression persisted even when clonus was reinitiated after turning off the stimulation. Conclusion: The use of objective biomarkers, including spinal cord potentials, to quantify clonus in real time combined with the immediate and reversible effects of stimulation highlight the potential of neuromodulation as a therapeutic tool for managing clonus. These data demonstrate preliminary efficacy of ES and DRS for clonus monitoring and treatment in 4 participants.
ISNCSCI Exam Changes Following Spinal Cord Stimulation
Veith, Daniel D. , Gill, Megan L., Mills, Candee J. , Asp, Anders J., Fernandez, K. A. , Zhao, Kristin D. , Grahn, Peter J. , Solinsky, Ryan J, Trentadue, Taylor P , Fernandez, K A , Solinsky, Ryan , Beck, Lisa A., Asp, Anders J., Jahanian, Omid

Topics in Spinal Cord Injury Rehabilitation | August 22, 2025 | Volume: 31 | Issue: 3 | Pages: 68-76

10.46292/sci25-00017 Get It

Objectives: To describe changes in the International Standards for Neurological Classification of Spinal Cord Injury (ISNCSCI) exam in sublesional motor and sensory domains following short-term epidural electrical stimulation of lumbosacral spinal segments in individuals with spinal cord injury (SCI). Methods: Twenty individuals with SCI underwent implantation of percutaneous epidural spinal cord stimulation followed by stimulation parameter optimization and 10-12 sessions of stimulation-enabled motor training. Pre-/postintervention ISNCSCI exams were compared to determine changes in motor/sensory scores for regions within 3 levels of the neurological level of injury (NLI) and caudal to this, with subanalyses per motor/sensory complete versus incomplete baseline status. Results: Individuals with motor complete SCI gained 6% ± 3% of available motor points within 3 levels of NLI and 1% ± 0% of motor points caudal to this ( P = .08). Motor incomplete individuals gained 9% ± 22% of available motor points within 3 levels of NLI and lost 4% ± 7% of motor points caudal to this ( P = .63). Following stimulation, changes in motor scores with potential high functional impact occurred in 3 individuals (5 total muscle groups with conversion from baseline <3/5 strength to ≥3/5 at completion). Individuals with sensory complete SCI had fewer sensory gains within 3 levels of NLI (6%) compared to those with sensory incomplete SCI (30%, P = .02). Discussion: Spinal cord stimulation after SCI rapidly induces changes in both motor and sensory domains that are retained after stimulation is removed. These changes primarily occur within 3 levels of the NLI and occur to a greater degree in those with incomplete SCI.
Percutaneous epidural spinal cord stimulation immediately reduces clonus in an individual with multiple sclerosis
Anders, Jennifer , Jahanian, Omid , Gill, Megan L., Veith, Daniel D. , Fernandez, K. A. , Mills, Candee J. , Thoreson, Andrew R. , Larson, C. W., Sagen, Jessica, Grahn, Peter J. , Zhao, Kristin D. , Asp, Anders J , Fernandez, K A , Larson, Carol M, Sagen, Jessica A., Tobin, W Oliver , Trentadue, Taylor P , Jahanian, Omid , Larson, Carol M, Tobin, W. Oliver

Multiple Sclerosis Journal | July 28, 2025 | Volume: 32 | Issue: 1 | Pages: 144-147

10.1177/13524585251357143 Get It

Clonus is a disabling symptom of upper motor neuron dysfunction in patients with multiple sclerosis (MS). We report immediate termination of mechanically evoked clonus by epidural lumbosacral spinal cord stimulation (ES) in a 58-year-old man with secondary progressive MS. This observation was captured during training using video and skin surface electromyography of soleus muscle activity. ES immediately reduced mechanically evoked clonus duration and cycle count compared to trials without stimulation, as determined by a Kruskal–Wallis test ( p < 0.05, n = 2–3 trials), and reverted to baseline status when stimulation was off.
Prevalence of autonomic dysreflexia during spinal cord stimulation after spinal cord injury
Veith, Daniel D. , Anders, Jennifer , Gill, Megan L., Fernandez, K. A. , Mills, Candee J. , Linde, Margaux B. , Zhao, Kristin D. , Grahn, Peter J. , Asp, Anders J , Fernandez, K A , Grahn, Peter J , Solinsky, Ryan , Trentadue, Taylor P , Jahanian, Omid , Beck, Lisa A. , Solinsky, Ryan

Journal of Neurophysiology | September 25, 2024 | Volume: 132 | Issue: 5 | Pages: 1371-1375

10.1152/jn.00343.2024 Get It

Spinal cord stimulation for motor recovery after spinal cord injury is a popular research intervention, though off-target effects are a concern. Using continual blood pressure and heart rate recordings during passive spinal cord stimulation parameter testing, we identified frequent episodes of autonomic dysreflexia that were rarely associated with symptoms. This presents a previously unrecognized risk of spinal cord stimulation and appropriate vigilance in targeted monitoring is urged to maintain participant safety.
Functional outcomes and participants’ perspectives during short-term application of spinal stimulation in individuals with spinal cord injury
Veith, Daniel D. , Gill, Megan L., Whitmarsh, Crystal L., Fernandez, K. A. , Linde, Margaux B. , Asp, Anders J., Mills, Candee J. , Bendel, Mark A. , Grahn, Peter J. , Zhao, Kristin D. , Trentadue, Taylor P , Fernandez, K A , Beck, Lisa A. , Asp, Anders J.

The Journal of Spinal Cord Medicine | August 22, 2024 | Volume: 48 | Issue: 6 | Pages: 978-989

10.1080/10790268.2024.2383377 Get It

Automatic detection of calcium phosphate deposit plugs at the terminal ends of kidney tubules
Fernandez, K. A. , Korinek, Mark, Camp, Jon J. , Holmes, David R. , Fernandez, Katrina, Camp, Jon, Lieske, John, Fernandez, K A , Lieske, John C.

Healthcare Technology Letters | October 11, 2019 | Volume: 6 | Issue: 6 | Pages: 271-274

10.1049/htl.2019.0086 Get It

Kidney stones are a common urologic condition with a high amount of recurrence. Recurrence depends on a multitude of factors the incidence of precursors to kidney stones, plugs, and plaques. One method of characterising the stone precursors is endoscopic assessment, though it is manual and time‐consuming. Deep learning has become a popular technique for semantic segmentation because of the high accuracy that has been demonstrated. The present Letter examined the efficacy of deep learning to segment the renal papilla, plaque, and plugs. A U‐Net model with ResNet‐34 encoder was tested; the Letter examined dropout (to avoid overtraining) and two different loss functions (to address the class imbalance problem. The models were then trained in 1666 images and tested on 185 images. The Jaccard‐cross‐entropy loss function was more effective than the focal loss function. The model with the dropout rate 0.4 was found to be more effective due to its generalisability. The model was largely successful at delineating the papilla. The model was able to correctly detect the plaques and plugs; however, small plaques were challenging. Deep learning was found to be applicable for segmentation of an endoscopic image for the papilla, plaque, and plug, with room for improvement.