Long pulse stimulation in its application in everyday clinical practice still represents a challe... more Long pulse stimulation in its application in everyday clinical practice still represents a challenge for many therapists and clinicians. It is often unclear how the intervention setup, in particular the parameters pulse width, frequency and amplitude, can influence muscle morphology. In addition, the cause of damage to the lower motoneuron can have multiple reasons and is not anatomically located at the same site. Given the large heterogeneity, it is essential to know the current options and limitations in order to carry out a targeted treatment. A retrospective data analysis of n=128 patients, seen at the Swiss Paraplegic Centre (SPC) in 2022, shows a broad variability in manifestation of lower motoneuron damage. Treatment examples based on different causes of lower motoneuron damage are shown and corresponding stimulation programmes are assigned, as well as the expected results in terms of stimulation duration, volume and configuration.
<p>The peak-to-peak amplitudes of the first (A) and second responses (B) of the same subjec... more <p>The peak-to-peak amplitudes of the first (A) and second responses (B) of the same subject as in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0147479#pone.0147479.g001" target="_blank">Fig 1</a> are illustrated in the three body positions (red: supine, cyan: standing, dark blue: prone) as a function of the applied stimulation intensity for all muscle groups. Second responses were largest in prone position. The threshold intensity was lowest while standing.</p
Here, we present a multi-channel data acquisition system designed to record bio-electrical signal... more Here, we present a multi-channel data acquisition system designed to record bio-electrical signals. The hardware concept is modularand consists of front-end acquisition modules and a synchronization module. The raw data streams are analyzed and stored on a personal computer or a single-board computer, which enables complex decisions and control algorithms even in real-time applications.
Seven paraplegic Functional Electrical Stimulation (FES) experienced users volunteered to test a ... more Seven paraplegic Functional Electrical Stimulation (FES) experienced users volunteered to test a newly developed eight channel stimulation system. The goal was to discover the influence of various stimulation parameters on the gait quality. As additional task the usability should be improved and simplified as much as possible. Commercially available hydrogel electrodes were attached to quadriceps and gluteus muscles to achieve hip and knee extension, to peroneal nerve to elicit flexion reflex and later also to adductor muscles. All patients were positive about the handling of the stimulation system. Especially the wireless remote control was highly approved. First results demonstrate the importance of an amplitude ramp during stimulation onset (0.1-0.4 s) resulting in a smooth and more "natural" movement. For an adequate step length and walking speed the timing of quadriceps and peroneal nerve stimulation at the end of the swing phase are crucial. Experienced patients with a higher walking speed require a short swing phase and an overlap of quadriceps decay and peronaeus onset (0-0.2 s). Activation of the adductor muscles reduces knee abduction and lead to a better knee trajectory during standing up and better leg movement during the swing phase. Patients can perform 15-25 steps per minute with a step length of 20-30 cm. The walking distance until exhaustion or muscle fatigue occurs is 4-60 m. The analysis of the used stimulation sequences brought up guidelines for a fast and effective parameter optimization procedure.
The International Journal of Artificial Organs, 1995
Functional Electrical Stimulation (FES) requires information on the stimulated muscle for adjustm... more Functional Electrical Stimulation (FES) requires information on the stimulated muscle for adjustment of the stimulation current, avoidance of muscle fatigue during the conditioning period and long term follow-up. Several applications of chronical FES are in clinical practice, but a system for direct registration of muscle activity under FES still does not exist. In six sheep the right Latissimus Dorsi Muscle (LDM) and Thoracodorsal Nerve were exposed. Stimulation electrodes were applied to each nerve and 3 EMG-applied sensing electrodes were placed into each LDM. The LDM tendon was connected to a force transducer. Burst stimulation was applied and the amplitude was increased from 0 to 4 mA in steps from burst to burst. EMG (M-wave) was amplified and recorded continuously via modified instrumentation amplifier, oscilloscope and tape recorder. Isometric muscle tension was recorded using force transducer, AID interface and PC. Continuous EMG-recording was performed in all cases. Simultaneous recording of muscle tension and EMG revealed a close correlation (Irl=0.95, p < 0.0001) between muscle strength and amplitude of the Mwave. Continuous recording of the EMG seems to be a reliable method for direct monitoring of the stimulated muscle. Three intramuscular electrodes can provide enough information to monitor FES induced muscle activity.
Images of the Twenty-First Century. Proceedings of the Annual International Engineering in Medicine and Biology Society
On the basis of experiences gained in clinical applications of functional electrostimulation of n... more On the basis of experiences gained in clinical applications of functional electrostimulation of nerves with implantable stimulation units, 20-channel implants fabricated in thick-film technology and using gate array circuits were developed. Extracorporal power supply and adjustment of stimulation parameters are accomplished by using a versatile microprocessor-based device that can be attached to the belt of the patient. The device (12*4*6 cm) can program and supply two implants. The supply unit consists of a CMOS microcomputer (80C51) with 32-kb EPROM (electrically programmable read-only memory), a 32-kB RAM (random access memory), an eight-channel ADC (analog-to-digital converter), a watchdog, a real-time clock, an acoustic signal, an eight-character display, and an RS232 link to communicate with a PC either directly or through a modem.<<ETX>>
Neuromuscular electrical stimulation (NMES) is a widely used technique for clinical diagnostic, t... more Neuromuscular electrical stimulation (NMES) is a widely used technique for clinical diagnostic, treatment, and research. Normally, it applies charge-balanced biphasic pulses, which several publications have reported to be less efficient than monophasic pulses. A good alternative is the use of interphase intervals (IPI) on biphasic pulses that allows to achieve similar responses than those evoked by monophasic stimulation. This study analyzes the enhancing mechanism of the IPI and provides guidelines on how to optimize the IPI in order to reduce secondary effects such as the electrode corrosion. The tibial nerve was excited by NMES biphasic pulses with different IPI durations and polarities. Then, the elicited responses were recorded on the soleus muscle via electromyography. When cathodic-first pulses were applied, the responses increased proportionally to the IPI until the duration of 250 µs, where the increase saturated at 30% of the original amplitude. The responses evoked during...
Purpose of review The Purpose of this review is to outline and explain the therapeutic use of ele... more Purpose of review The Purpose of this review is to outline and explain the therapeutic use of electrical spinal cord stimulation (SCS) for modification of spinal motor output. Central functional stimulation provides afferent input to posterior root neurons and is applied to improve volitional movements, posture and their endurance, control spasticity, and improve bladder function or perfusion in the lower limbs. Clinical accomplishments strongly depend on each individual's physiological state and specific methodical adaptation to that physiological state. Recent findings Effectiveness of this neuromodulory technique for changing motor control after spinal cord injury (SCI) continues to be explored along with the underlying mechanisms of its effect in people with complete and incomplete spinal cord injuries. There are extensive studies of tonic and rhythmical activity elicited from the lumbar cord as well as data demonstrating augmentation of residual volitional activity. Recent studies have focused on verifying if and how SCS can modify features of neurocontrol in ambulatory spinal cord patients.
The Influence of New Technology on Medical Practice, 1988
Functional neural stimulation (FNS) for the locomotion of paraplegic patients is effected by mean... more Functional neural stimulation (FNS) for the locomotion of paraplegic patients is effected by means of surface electrodes (Kralj et al., 1981; Jaeger, 1983; Petrofsky and Phillips, 1983), intramuscular percutaneous electrodes (Marsolais et al., 1984) or stimulation of the peripheral nerve (Brindley et al., 1978; Thoma et al., 1983).
Long pulse stimulation in its application in everyday clinical practice still represents a challe... more Long pulse stimulation in its application in everyday clinical practice still represents a challenge for many therapists and clinicians. It is often unclear how the intervention setup, in particular the parameters pulse width, frequency and amplitude, can influence muscle morphology. In addition, the cause of damage to the lower motoneuron can have multiple reasons and is not anatomically located at the same site. Given the large heterogeneity, it is essential to know the current options and limitations in order to carry out a targeted treatment. A retrospective data analysis of n=128 patients, seen at the Swiss Paraplegic Centre (SPC) in 2022, shows a broad variability in manifestation of lower motoneuron damage. Treatment examples based on different causes of lower motoneuron damage are shown and corresponding stimulation programmes are assigned, as well as the expected results in terms of stimulation duration, volume and configuration.
<p>The peak-to-peak amplitudes of the first (A) and second responses (B) of the same subjec... more <p>The peak-to-peak amplitudes of the first (A) and second responses (B) of the same subject as in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0147479#pone.0147479.g001" target="_blank">Fig 1</a> are illustrated in the three body positions (red: supine, cyan: standing, dark blue: prone) as a function of the applied stimulation intensity for all muscle groups. Second responses were largest in prone position. The threshold intensity was lowest while standing.</p
Here, we present a multi-channel data acquisition system designed to record bio-electrical signal... more Here, we present a multi-channel data acquisition system designed to record bio-electrical signals. The hardware concept is modularand consists of front-end acquisition modules and a synchronization module. The raw data streams are analyzed and stored on a personal computer or a single-board computer, which enables complex decisions and control algorithms even in real-time applications.
Seven paraplegic Functional Electrical Stimulation (FES) experienced users volunteered to test a ... more Seven paraplegic Functional Electrical Stimulation (FES) experienced users volunteered to test a newly developed eight channel stimulation system. The goal was to discover the influence of various stimulation parameters on the gait quality. As additional task the usability should be improved and simplified as much as possible. Commercially available hydrogel electrodes were attached to quadriceps and gluteus muscles to achieve hip and knee extension, to peroneal nerve to elicit flexion reflex and later also to adductor muscles. All patients were positive about the handling of the stimulation system. Especially the wireless remote control was highly approved. First results demonstrate the importance of an amplitude ramp during stimulation onset (0.1-0.4 s) resulting in a smooth and more "natural" movement. For an adequate step length and walking speed the timing of quadriceps and peroneal nerve stimulation at the end of the swing phase are crucial. Experienced patients with a higher walking speed require a short swing phase and an overlap of quadriceps decay and peronaeus onset (0-0.2 s). Activation of the adductor muscles reduces knee abduction and lead to a better knee trajectory during standing up and better leg movement during the swing phase. Patients can perform 15-25 steps per minute with a step length of 20-30 cm. The walking distance until exhaustion or muscle fatigue occurs is 4-60 m. The analysis of the used stimulation sequences brought up guidelines for a fast and effective parameter optimization procedure.
The International Journal of Artificial Organs, 1995
Functional Electrical Stimulation (FES) requires information on the stimulated muscle for adjustm... more Functional Electrical Stimulation (FES) requires information on the stimulated muscle for adjustment of the stimulation current, avoidance of muscle fatigue during the conditioning period and long term follow-up. Several applications of chronical FES are in clinical practice, but a system for direct registration of muscle activity under FES still does not exist. In six sheep the right Latissimus Dorsi Muscle (LDM) and Thoracodorsal Nerve were exposed. Stimulation electrodes were applied to each nerve and 3 EMG-applied sensing electrodes were placed into each LDM. The LDM tendon was connected to a force transducer. Burst stimulation was applied and the amplitude was increased from 0 to 4 mA in steps from burst to burst. EMG (M-wave) was amplified and recorded continuously via modified instrumentation amplifier, oscilloscope and tape recorder. Isometric muscle tension was recorded using force transducer, AID interface and PC. Continuous EMG-recording was performed in all cases. Simultaneous recording of muscle tension and EMG revealed a close correlation (Irl=0.95, p < 0.0001) between muscle strength and amplitude of the Mwave. Continuous recording of the EMG seems to be a reliable method for direct monitoring of the stimulated muscle. Three intramuscular electrodes can provide enough information to monitor FES induced muscle activity.
Images of the Twenty-First Century. Proceedings of the Annual International Engineering in Medicine and Biology Society
On the basis of experiences gained in clinical applications of functional electrostimulation of n... more On the basis of experiences gained in clinical applications of functional electrostimulation of nerves with implantable stimulation units, 20-channel implants fabricated in thick-film technology and using gate array circuits were developed. Extracorporal power supply and adjustment of stimulation parameters are accomplished by using a versatile microprocessor-based device that can be attached to the belt of the patient. The device (12*4*6 cm) can program and supply two implants. The supply unit consists of a CMOS microcomputer (80C51) with 32-kb EPROM (electrically programmable read-only memory), a 32-kB RAM (random access memory), an eight-channel ADC (analog-to-digital converter), a watchdog, a real-time clock, an acoustic signal, an eight-character display, and an RS232 link to communicate with a PC either directly or through a modem.<<ETX>>
Neuromuscular electrical stimulation (NMES) is a widely used technique for clinical diagnostic, t... more Neuromuscular electrical stimulation (NMES) is a widely used technique for clinical diagnostic, treatment, and research. Normally, it applies charge-balanced biphasic pulses, which several publications have reported to be less efficient than monophasic pulses. A good alternative is the use of interphase intervals (IPI) on biphasic pulses that allows to achieve similar responses than those evoked by monophasic stimulation. This study analyzes the enhancing mechanism of the IPI and provides guidelines on how to optimize the IPI in order to reduce secondary effects such as the electrode corrosion. The tibial nerve was excited by NMES biphasic pulses with different IPI durations and polarities. Then, the elicited responses were recorded on the soleus muscle via electromyography. When cathodic-first pulses were applied, the responses increased proportionally to the IPI until the duration of 250 µs, where the increase saturated at 30% of the original amplitude. The responses evoked during...
Purpose of review The Purpose of this review is to outline and explain the therapeutic use of ele... more Purpose of review The Purpose of this review is to outline and explain the therapeutic use of electrical spinal cord stimulation (SCS) for modification of spinal motor output. Central functional stimulation provides afferent input to posterior root neurons and is applied to improve volitional movements, posture and their endurance, control spasticity, and improve bladder function or perfusion in the lower limbs. Clinical accomplishments strongly depend on each individual's physiological state and specific methodical adaptation to that physiological state. Recent findings Effectiveness of this neuromodulory technique for changing motor control after spinal cord injury (SCI) continues to be explored along with the underlying mechanisms of its effect in people with complete and incomplete spinal cord injuries. There are extensive studies of tonic and rhythmical activity elicited from the lumbar cord as well as data demonstrating augmentation of residual volitional activity. Recent studies have focused on verifying if and how SCS can modify features of neurocontrol in ambulatory spinal cord patients.
The Influence of New Technology on Medical Practice, 1988
Functional neural stimulation (FNS) for the locomotion of paraplegic patients is effected by mean... more Functional neural stimulation (FNS) for the locomotion of paraplegic patients is effected by means of surface electrodes (Kralj et al., 1981; Jaeger, 1983; Petrofsky and Phillips, 1983), intramuscular percutaneous electrodes (Marsolais et al., 1984) or stimulation of the peripheral nerve (Brindley et al., 1978; Thoma et al., 1983).
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