Analyses of biomarkers for tremor using local field potentials recorded from deep brain stimulation electrodes in the thalamus.

Background: Deep brain stimulation (DBS) of the ventral intermediate nucleus (VIM) of the thalamus (TH) is an effective therapy for suppressing tremor. One of the critical challenges to optimizing VIM-DBS therapy is the lack of robust neural biomarkers that correlate well with tremor.

Objective: To quantify biomarkers for tremor using intraoperative TH local field potential (LFP) recorded from DBS electrodes.

Four-Year Follow-Up from a Prospective, Multicenter Study of Percutaneous 60-Day Peripheral Nerve Stimulation for Chronic Low Back Pain.

Introduction: Chronic low back pain (LBP) is a leading cause of healthcare expenditure and long-term disability associated with complex treatment challenges and the need for progressively invasive interventions. Percutaneous 60-day Peripheral Nerve Stimulation (PNS) is a minimally invasive neurostimulation treatment that has shown efficacy for chronic LBP, providing sustained improvements through 1 year of follow-up after treatment. The present work explores the long-term clinical outcomes of Percutaneous 60-day PNS for chronic LBP approximately 4 years after initial treatment.

Evoked potentials reveal neural circuits engaged by human deep brain stimulation.

Background: Deep brain stimulation (DBS) is an effective therapy for reducing the motor symptoms of Parkinson's disease, but the mechanisms of action of DBS and neural correlates of symptoms remain unknown.

Objective: To use the neural response to DBS to reveal connectivity of neural circuits and interactions between groups of neurons as potential mechanisms for DBS.

Methods: We recorded activity evoked by DBS of the subthalamic nucleus (STN) in humans with Parkinson's disease.

Effects of ramped-frequency thalamic deep brain stimulation on tremor and activity of modeled neurons.

Objective: We conducted intraoperative measurements of tremor to quantify the effects of temporally patterned ramped-frequency DBS trains on tremor.

Methods: Seven patterns of stimulation were tested in nine subjects with thalamic DBS for essential tremor: stimulation 'off', three ramped-frequency stimulation (RFS) trains from 130 → 50 Hz, 130 → 60 Hz, and 235 → 90 Hz, and three constant frequency stimulation (CFS) trains at 72, 82, and 130 Hz. The same patterns were applied to a computational model of the thalamic neural network.

Sensory percepts induced by microwire array and DBS microstimulation in human sensory thalamus.

Background: Microstimulation in human sensory thalamus (ventrocaudal, VC) results in focal sensory percepts in the hand and arm which may provide an alternative target site (to somatosensory cortex) for the input of prosthetic sensory information. Sensory feedback to facilitate motor function may require simultaneous or timed responses across separate digits to recreate perceptions of slip as well as encoding of intensity variations in pressure or touch.

Objectives: To determine the feasibility of evoking sensory percepts on separate digits with variable intensity through either a microwire array or deep brain stimulation (DBS) electrode, recreating "natural" and scalable percepts relating to the arm and hand.

Multiple Reflex Pathways Contribute to Bladder Activation by Intraurethral Stimulation in Persons With Spinal Cord Injury.

Objective: To measure the urodynamic effects of electrical co-stimulation of 2 individual sites in the proximal and distal urethra in persons with spinal cord injury (SCI). This work was motivated by preclinical findings that selective co-stimulation of the cranial urethral sensory nerve and the dorsal genital nerve, which innervate the proximal and distal portions of the urethra, respectively, increased reflex bladder activation and voiding efficiency.

Materials And Methods: Electrical co-stimulation of urethral afferents was conducted in persons with chronic SCI during urodynamics.

Optimized temporal pattern of brain stimulation designed by computational evolution.

Brain stimulation is a promising therapy for several neurological disorders, including Parkinson's disease. Stimulation parameters are selected empirically and are limited to the frequency and intensity of stimulation. We varied the temporal pattern of deep brain stimulation to ameliorate symptoms in a parkinsonian animal model and in humans with Parkinson's disease.

Short pauses in thalamic deep brain stimulation promote tremor and neuronal bursting.

Objective: We conducted intraoperative measurements of tremor during DBS containing short pauses (⩽50 ms) to determine if there is a minimum pause duration that preserves tremor suppression.

Methods: Nine subjects with ET and thalamic DBS participated during IPG replacement surgery. Patterns of DBS included regular 130 Hz stimulation interrupted by 0, 15, 25 or 50 ms pauses.

Measurement of evoked potentials during thalamic deep brain stimulation.

Background: Deep brain stimulation (DBS) treats the symptoms of several movement disorders, but optimal selection of stimulation parameters remains a challenge. The evoked compound action potential (ECAP) reflects synchronized neural activation near the DBS lead, and may be useful for feedback control and automatic adjustment of stimulation parameters in closed-loop DBS systems.

Objectives: Determine the feasibility of recording ECAPs in the clinical setting, understand the neural origin of the ECAP and sources of any stimulus artifact, and correlate ECAP characteristics with motor symptoms.

Investigation of deep brain stimulation mechanisms during implantable pulse generator replacement surgery.

Background: Direct testing of deep brain stimulation (DBS) mechanisms in humans is needed to assess therapy and to understand stimulation effects.

Objective: We developed an innovative paradigm for investigation of DBS on human movement disorders. Temporary connection to the DBS electrode during implantable pulse generator (IPG) replacement permitted analysis of novel patterns of stimulation on motor symptoms, which could enhance efficacy and improve battery life.

Improved efficacy of temporally non-regular deep brain stimulation in Parkinson's disease.

High frequency deep brain stimulation is an effective therapy for motor symptoms in Parkinson's disease. However, the relative clinical efficacy of regular versus non-regular temporal patterns of stimulation in Parkinson's disease remains unclear. To determine the temporal characteristics of non-regular temporal patterns of stimulation important for the treatment of Parkinson's disease, we compared the efficacy of temporally regular stimulation with four non-regular patterns of stimulation in subjects with Parkinson's disease using an alternating finger tapping task.

Tremor reduction and modeled neural activity during cycling thalamic deep brain stimulation.

Objective: The effectiveness of deep brain stimulation (DBS) depends on both the frequency and the temporal pattern of stimulation. We quantified responses to cycling DBS with constant frequency to determine if there was a critical on and/or off time for alleviating tremor.

Methods: We measured postural tremor in 10 subjects with thalamic DBS and quantified neuronal entropy in a network model of Vim thalamic DBS.