FES for Tremor Suppression
(Tremor Trial)
Recruiting in Palo Alto (17 mi)
Age: 18+
Sex: Any
Travel: May Be Covered
Time Reimbursement: Varies
Trial Phase: Academic
Recruiting
Sponsor: North Carolina State University
Must not be taking: Neuromuscular junction drugs
Disqualifiers: Muscle weakness, Infection, Neuromuscular disorders, others
No Placebo Group
Trial Summary
What is the purpose of this trial?This trial uses ultrasound imaging to study and understand hand tremors. It aims to help people with tremor disorders by accurately identifying involuntary muscle movements. The study includes both people with tremors and those without.
Do I need to stop my current medications for the trial?
The trial does not specify if you need to stop your current medications, but it excludes those using medications that affect the neuromuscular junction. It's best to discuss your specific medications with the trial coordinators.
What data supports the effectiveness of the treatment for tremor suppression using ultrasound imaging and electrical stimulation?
Research shows that ultrasound imaging can effectively visualize muscle activity and changes, which helps in monitoring and adjusting electrical stimulation for muscle strengthening and motor restoration. This suggests that combining ultrasound with electrical stimulation could be beneficial for controlling tremors by providing real-time feedback and personalized treatment adjustments.
12345Is functional electrical stimulation (FES) safe for humans?
Research on functional electrical stimulation (FES) for tremor suppression shows it can be used safely in humans, with studies indicating it effectively reduces tremors in conditions like essential tremor and Parkinson's disease. However, there are practical limitations, such as controlling only one pair of muscles at a time, which may restrict its use to certain types of tremors.
678910How does the FES treatment for tremor suppression differ from other treatments?
FES (Functional Electrical Stimulation) is unique because it uses electrical impulses to stimulate muscles, which can help suppress tremors by enabling controlled muscle movements. Unlike other treatments that might rely on medication or surgery, FES directly targets muscle activity and can be adjusted in real-time to manage muscle fatigue, making it a non-invasive and adaptable option for tremor management.
1231112Eligibility Criteria
This trial is for people aged 40-90 with Parkinson's Disease or tremor conditions, who have a rest tremor in their upper extremities. The tremor must be significant and re-emergent when holding a posture. Participants should not have other neuromuscular disorders, essential tremor, be on certain medications, or have muscle weakness.Inclusion Criteria
I am between 40 and 90 years old.
I experience involuntary shaking in one or both of my arms.
Criterion: You must have a specific type of tremor that occurs when you hold an object, and it should start with a delay and grow in strength over a few seconds. The tremor should not be caused by anxiety, stress, cold temperature, or fatigue. We will give you time to relax before the test to help reduce these factors.
+2 more
Exclusion Criteria
I have muscle weakness in my arm with tremors.
You have existing nerve or brain disorders.
I have been diagnosed with essential tremor by a specialist.
+2 more
Trial Timeline
Screening
Participants are screened for eligibility to participate in the trial
2-4 weeks
Treatment
Participants undergo ultrasound imaging and functional electrical stimulation to analyze and suppress tremors
3 years
Follow-up
Participants are monitored for safety and effectiveness after treatment
4 weeks
Participant Groups
The study tests how well ultrasound imaging combined with electrical stimulation can identify and suppress hand tremors versus current methods like medication or surgery. It aims to differentiate between voluntary movements and involuntary tremors for better treatment strategies.
2Treatment groups
Experimental Treatment
Group I: Tremor GroupExperimental Treatment4 Interventions
Individuals with either parkinson's disease or essential tremor will be recruited in this group
Group II: Able Body GroupExperimental Treatment4 Interventions
Individuals with no disorders will be recruited in this group
Find a Clinic Near You
Research Locations NearbySelect from list below to view details:
Engineering Building IIIRaleigh, NC
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Who Is Running the Clinical Trial?
North Carolina State UniversityLead Sponsor
University of North Carolina, Chapel HillCollaborator
References
Ultrasound myography: application in nerve conduction velocity assessment and muscle cooling. [2019]A new application of ultrasound for studying muscle twitch induced by electrical stimulation is described and some preliminary results are presented. The method, called "ultrasound myography" (UMG), uses Doppler ultrasound to measure muscle movement velocity. The Doppler signals were measured simultaneously with the electromyography (EMG) signals from the thenar muscle of a healthy subject. Averaged EMG and full-wave rectified UMG responses to repeated electrical stimuli were measured after cooling of the hand and adaptation to room temperature. Latency times over the wrist of cold hands adapted to a surrounding temperature of 8 degrees C were 4.5 ms and 16.9 ms for the EMG and averaged rectified UMG responses, respectively. Both latency times decreased considerably after 1 h adaptation to a room temperature of 21 degrees C:20% for the EMG response and 35% for the UMG response. The conduction velocities of the median nerve in the forearm determined by both methods yield comparable results. The results of both methods are discussed. It is concluded that UMG possibly offers a new method in clinical practice for the assessment of nerve conduction velocities in the forearm, and basically is a new simple-to-use technique for noninvasive analysis of deep biomechanical processes.
Using Portable Ultrasound to Monitor the Neuromuscular Reactivity to Low-Frequency Electrical Stimulation. [2021]Neuromuscular electrical stimulation (NMES) is useful for muscle strengthening and for motor restoration of stroke patients. Using a portable ultrasound instrument, we developed an M-mode imaging protocol to visualize contractions elicited by NMES in the quadriceps muscle group. To quantify muscle activation, we performed digital image processing based on the Teager-Kaiser energy operator. The proposed method was applied for 35 voluntary patients (18 women and 17 men), of 63.8 ± 14.1 years and body mass index (BMI) 30.2 ± 6.70 kg/m2 (mean ± standard deviation). Biphasic, rectangular electric pulses of 350 µs duration were applied at two frequencies (60 Hz and 120 Hz), and ultrasound was used to assess the sensory threshold (ST) and motor threshold (MT) amplitude of the NMES signal. The MT was 23.4 ± 4.94 mA, whereas the MT to ST ratio was 2.69 ± 0.57. Linear regression analysis revealed that MT correlates poorly with body mass index (R2 = 0.004) or with the thickness of the subcutaneous adipose tissue layer that covers the treated muscle (R2 = 0.013). Our work suggests that ultrasound is suitable to visualize neuromuscular reactivity during electrotherapy. The proposed method can be used in the clinic, enabling the physiotherapist to establish personalized treatment parameters.
Ultrasound Echogenicity-based Assessment of Muscle Fatigue During Functional Electrical Stimulation. [2022]The rapid onset of muscle fatigue during functional electrical stimulation (FES) is a major challenge when attempting to perform long-term periodic tasks such as walking. Surface electromyography (sEMG) is frequently used to detect muscle fatigue for both volitional and FES-evoked muscle contraction. However, sEMG contamination from both FES stimulation artifacts and residual M-wave signals requires sophisticated processing to get clean signals and evaluate the muscle fatigue level. The objective of this paper is to investigate the feasibility of computationally efficient ultrasound (US) echogenicity as a candidate indicator of FES-induced muscle fatigue. We conducted isometric and dynamic ankle dorsiflexion experiments with electrically stimulated tibialis anterior (TA) muscle on three human participants. During a fatigue protocol, we synchronously recorded isometric dorsiflexion force, dynamic dorsiflexion angle, US images, and stimulation intensity. The temporal US echogenicity from US images was calculated based on a gray-scaled analysis to assess the decrease in dorsiflexion force or motion range due to FES-induced TA muscle fatigue. The results showed a monotonic reduction in US echogenicity change along with the fatigue progression for both isometric (R2 =0.870±0.026) and dynamic (R2 =0.803±0.048) ankle dorsiflexion. These results implied a strong linear relationship between US echogenicity and TA muscle fatigue level. The findings indicate that US echogenicity may be a promising computationally efficient indicator for assessing FES-induced muscle fatigue and may aid in the design of muscle-in-the-loop FES controllers that consider the onset of muscle fatigue.
Neuromuscular Ultrasound: A New Tool in Your Toolbox. [2019]Neuromuscular ultrasound is a rapidly evolving technique for diagnosing, monitoring and facilitating treatment of patients with muscle and nerve disorders. It is a portable point-of-care technology that is non-invasive, painless and without ionizing radiation. Ultrasound can visualize muscle texture alterations indicating dystrophy or denervation, changes in size and anatomic continuity of nerve fascicles, and its dynamic imaging capabilities allow capturing of contractions and fasciculations. Ultrasound can also provide real-time guidance for needle placement, and can sometimes make a diagnosis when electromyography is not tolerated or not informative anymore. This review will focus on the technical and practical aspects of ultrasound as an imaging technique for muscles and nerves. It will discuss basic imaging principles, hardware and software setup, and provide examples of ultrasound use for visualizing muscle and nerve abnormalities with accuracy and confidence. The review is intended as a practical "how-to" guide to get started with neuromuscular ultrasound in daily practice.
Skeletal muscle ultrasound. [2022]Muscle ultrasound is a convenient technique to visualize normal and pathological muscle tissue as it is non-invasive and real-time. Neuromuscular disorders give rise to structural muscle changes that can be visualized with ultrasound: atrophy can be objectified by measuring muscle thickness, while infiltration of fat and fibrous tissue increases muscle echo intensity, i.e. the muscles become whiter on the ultrasound image. Muscle echo intensity needs to be quantified to correct for age-related increase in echo intensity and differences between individual muscles. This can be done by gray scale analysis, a method that can be easily applied in daily clinical practice. Using this technique, it is possible to detect neuromuscular disorders with predictive values of 90%. Only in young children and metabolic myopathies the sensitivity is lower. Ultrasound is a dynamic technique and therefore capable of visualizing normal and pathological muscle movements. Fasciculations can easily be differentiated from other muscle movements. Ultrasound appeared to be even more sensitive in detecting fasciculations compared to Electromyography (EMG) and clinical observations, because it can visualize a large muscle area and deeper located muscles. With improving resolution and frame rate it has recently become clear that also smaller scale spontaneous muscle activity such as fibrillations can be detected by ultrasound. This opens the way to a broader use of muscle ultrasound in the diagnosis of peripheral nerve and muscle disorders.
Attenuation of pathological tremors by functional electrical stimulation. II: Clinical evaluation. [2019]In this study we evaluated a technique for tremor suppression with functional electrical stimulation (FES), the technical details of which were described in the previous paper. Three groups of patients were investigated: those with essential tremor, parkinsonian tremor, and cerebellar tremor associated with multiple sclerosis. In each group, tremor was attenuated by significant amounts (essential tremor: 73%; parkinsonian tremor: 62%; cerebellar tremor: 38%). These attenuations were in good accord with predictions based on the dynamic analyses and filter designs derived in the previous paper. With filters "tuned" to the lower mean tremor frequency encountered in the cerebellar patients, more attenuation was possible in this group as well. We identified some practical limitations in the clinical application of the technique in its present form. The most important was that in daily use, only one antagonist pair of muscles can realistically be controlled. At first sight, this restricts the usefulness of the system to patients with single-joint tremors. However, the concomitant use of mechanical orthoses may broaden the scope of application.
Augmented visual feedback counteracts the effects of surface muscular functional electrical stimulation on physiological tremor. [2021]Recent studies suggest that surface muscular functional electrical stimulation (FES) might suppress neurological upper limb tremor. We assessed its effects on upper limb physiological tremor, which is mainly driven by mechanical-reflex oscillations. We investigated the interaction between FES and augmented visual feedback, since (a) most daily activities are performed using visual cues, and (b) augmented visual feedback exacerbates upper limb tremor.
Attenuation of pathological tremors by functional electrical stimulation. I: Method. [2022]In this study we explored the possibility of suppressing pathological tremors using closed-loop functional electrical stimulation (FES) to activate the tremorogenic muscles out-of-phase. A displacement signal monitored with a transducer was filtered so as to be "tuned" to the tremor frequency at the wrist or elbow. The filtered signal was used to amplitude-modulate the electrical stimulation. The design process was based on measurements of the open-loop frequency response characteristics of the forearm and hand to stimulation of the elbow and wrist flexors and extensors in a number of subjects. These data allowed us to identify closed-loop configurations, which attenuated 2-5 Hz tremors substantially, while only minimally attenuating functional movements in the 0-1 Hz range. There was a fairly delicate balance between efficacy and the risk of instability. However, designs were identified that offered enough tremor suppression and adequate immunity to muscle/load variations for the technique to be considered seriously for clinical application.
Study on the elbow movement produced by functional electrical stimulation (FES). [2019]Functional electrical stimulation (FES)-induced movements of the upper extremity using the electromyography (EMG)-based stimulation data, which were created on the basis of EMG analysis of elbow flexion and extension in a normal human subject, were examined. As a result of the FES to the elbow flexors and extensors in another normal subject, smooth and reproducible elbow flexion and extension were controlled. This result seems to indicate not only an advantage of EMG-based stimulation data in the FES but also a great potential of FES as a new technique for the functional anatomy of the human extremities.
Adaptive band-pass filter (ABPF) for tremor extraction from inertial sensor data. [2010]Cancelling pathological tremor in everyday living activities may be possible with functional electrical stimulation (FES). One such feasible FES system with feedback from inertial sensors would rely on tremor estimates in real time. We present an adaptive band-pass filter (ABPF) that estimates tremor from volitional hand movement with zero-phase lag. The proposed algorithm is simple and easy to implement. Performance of the ABPF is compared to one popular well-established method for tremor extraction (weighted-frequency Fourier linear combiner, WFLC) using both synthetic data and data from inertial sensors, recorded in tremor patients during "finger to nose" task execution. The results were comparable, favoring ability of ABPF for faster adaptation, higher accuracy and robustness.
Ultrasound Echogenicity as an Indicator of Muscle Fatigue during Functional Electrical Stimulation. [2022]Functional electrical stimulation (FES) is a potential neurorehabilitative intervention to enable functional movements in persons with neurological conditions that cause mobility impairments. However, the quick onset of muscle fatigue during FES is a significant challenge for sustaining the desired functional movements for more extended periods. Therefore, a considerable interest still exists in the development of sensing techniques that reliably measure FES-induced muscle fatigue. This study proposes to use ultrasound (US) imaging-derived echogenicity signal as an indicator of FES-induced muscle fatigue. We hypothesized that the US-derived echogenicity signal is sensitive to FES-induced muscle fatigue under isometric and dynamic muscle contraction conditions. Eight non-disabled participants participated in the experiments, where FES electrodes were applied on their tibialis anterior (TA) muscles. During a fatigue protocol under either isometric and dynamic ankle dorsiflexion conditions, we synchronously collected the isometric dorsiflexion torque or dynamic dorsiflexion angle on the ankle joint, US echogenicity signals from TA muscle, and the applied stimulation intensity. The experimental results showed an exponential reduction in the US echogenicity relative change (ERC) as the fatigue progressed under the isometric (R2=0.891±0.081) and dynamic (R2=0.858±0.065) conditions. The experimental results also implied a strong linear relationship between US ERC and TA muscle fatigue benchmark (dorsiflexion torque or angle amplitude), with R2 values of 0.840±0.054 and 0.794±0.065 under isometric and dynamic conditions, respectively. The findings in this study indicate that the US echogenicity signal is a computationally efficient signal that strongly represents FES-induced muscle fatigue. Its potential real-time implementation to detect fatigue can facilitate an FES closed-loop controller design that considers the FES-induced muscle fatigue.
Sonomyography Analysis on Thickness of Skeletal Muscle During Dynamic Contraction Induced by Neuromuscular Electrical Stimulation: A Pilot Study. [2017]Neuromuscular electrical stimulation (NMES) that stimulates skeletal muscles to induce contractions has been widely applied to restore functions of paralyzed muscles. However, the architectural changes of stimulated muscles induced by NMES are still not well understood. The present study applies sonomyography (SMG) to evaluate muscle architecture under NMES-induced and voluntary movements. The quadriceps muscles of seven healthy subjects were tested for eight cycles during an extension exercise of the knee joint with/without NMES, and SMG and the knee joint angle were recorded during the process of knee extension. A least squares support vector machine (LS-SVM) LS-SVM model was developed and trained using the data sets of six cycles collected under NMES, while the remaining data was used to test. Muscle thickness changes were extracted from ultrasound images and compared between NMES-induced and voluntary contractions, and LS-SVM was used to model a relationship between dynamical knee joint angles and SMG signals. Muscle thickness showed to be significantly correlated with joint angle in NMES-induced contractions, and a significant negative correlation was observed between Vastus intermedius (VI) thickness and rectus femoris (RF) thickness. In addition, there was a significant difference between voluntary and NMES-induced contractions . The LS-SVM model based on RF thickness and knee joint angle provided superior performance compared with the model based on VI thickness and knee joint angle or total thickness and knee joint angle. This suggests that a strong relation exists between the RF thickness and knee joint angle. These results provided direct evidence for the potential application of RF thickness in optimizing NMES system as well as measuring muscle state under NMES.