Winnie Jensen

Aalborg University

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Ken Yoshida

Indiana University – Purdue University Indianapolis

Ernest Nlandu Kamavuako

King's College London

Thomas Stieglitz

University of Freiburg

Dario Farina

Imperial College London

Kristian Rauhe Harreby

Aalborg University

Silvestro Micera

Scuola Superiore Sant'Anna

Romulus Lontis

Aalborg University

Tim Boretius

University of Freiburg

David Guiraud

Université de Montpellier

Thomas Sinkjær

Aalborg University

Cooperative Institutions

Aalborg University

Scuola Superiore Sant'Anna

Faculty (United Kingdom)

Imperial College London

University of Freiburg

Aalborg University Hospital

Istituti di Ricovero e Cura a Carattere Scientifico

Centre National de la Recherche Scientifique

Università Cattolica del Sacro Cuore

Piaggio (Italy)

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Simultaneous and Proportional Force Estimation in Multiple Degrees of Freedom From Intramuscular EMG

IEEE Transactions on Biomedical Engineering (2012)

Ernest Nlandu Kamavuako Kevin Englehart Winnie Jensen D. Farina

This letter investigates simultaneous and proportional estimation of force in 2 degree-of-freedoms (DoFs) from intramuscular electromyography (EMG). Intramuscular EMG signals from three able-bodied subjects were recorded along with isometric forces in multiple DoF from the right arm. The association between five EMG features and force profiles was modeled using an artificial neural network. Correlation coefficients between the measured and the estimated forces were 0.85 ± 0.056 and 0.88 ± 0.05 without and with post processing, respectively. The results showed that force can be estimated in 2 DoFs with high accuracy and that the degree of performance depended on the force function (task) to be estimated.

10.1109/tbme.2012.2197210

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Citations (60)

In vivo implant mechanics of single-shaft microelectrodes in peripheral nervous tissue

Winnie Jensen Ken Yoshida Ulrich Hofmann

The VSAMUEL consortium developed silicon-based, electrode arrays (referred to as ACREO electrodes), that may one day provide a highly selective neural interface for neuroscience or neural prosthesis applications. We previously reported on the successful insertion into brain tissue. In the present work, we investigated the feasibility of implanting the ACREO electrodes into peripheral nerve. We compared the implant mechanics of single shaft silicon ACREO electrodes (25 times 38 times 15000 mum) and conventional tungsten needle electrodes (50mum diameter). Experimentally measured implant forces were measured in vivo (1 acute rabbit, 2 mm depth, 2 mm/s velocity). The force required for the tungsten electrode to first penetrate the perineurium was in average 7.4 plusmn 3.9 mN, whereas the maximum force the electrode had to withstand during the entire insertion/retraction was 11.3 plusmn 2.8 mN. It was not possible to facilitate perpendicular insertion of the ACREO electrode without breaking it. The critical buckling force of the ACREO electrode was theoretically estimated to 1-4 mN, which proved consistent with the experimentally measured break force (5.1 plusmn 2.1 mN). Bending moment analysis showed that tungsten could withstand ultimate stresses 4-10 times higher than our silicon-based electrodes. Before the ACREO electrodes can be safely used for peripheral and spinal cord implants we recommend to shorten and thicken the probes to increase their mechanically strength.

10.1109/cne.2007.369596

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Citations (10)

Use of Sample Entropy Extracted from Intramuscular EMG Signals for the Estimation of Force

IFMBE proceedings (2011)

Ernest Nlandu Kamavuako Dario Farina Winnie Jensen

Sample entropy

Sample (material)

10.1007/978-3-642-21683-1_31

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Citations (6)

Measurement of intrafascicular insertion force of a tungsten needle into peripheral nerve

Winnie Jensen Ken Yoshida T. Malina Ulrich Hofmann

Microfabricated silicon array structures, such as those being developed by the VSAMUEL consortium may one day provide inexpensive yet highly selective chronically implanted interfaces to the peripheral nervous system. In the present study we examined the feasibility of implanting such microelectrodes into peripheral nerve tissue by characterizing the mechanical forces required for implantation. We conducted in-vitro implantation experiments into excised rabbit peripheral nerve with electrosharpened tungsten needles similar in dimension to the VSAMUEL probes. A needle was manually advanced through the epineurium and perineurium using a micro-manipulator. The force applied to the needle during the insertion process was measured using a custom built force detection device. We found that a force greater than 2 mN was necessary to insert the needle. Clear dimpling of the nerve surface was also observed prior to penetration.

Perineurium

Epineurium

Endoneurium

Peripheral Nervous System

10.1109/iembs.2001.1017459

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Citations (7)

From pulse width modulated TENS to cortical modulation: based on EEG functional connectivity analysis

Frontiers in Neuroscience (2023)

Armita Faghani Jadidi Winnie Jensen Ali Asghar Zarei Romulus Lontis S. Farokh Atashzar

Modulation in the temporal pattern of transcutaneous electrical nerve stimulation (TENS), such as Pulse width modulated (PWM), has been considered a new dimension in pain and neurorehabilitation therapy. Recently, the potentials of PWM TENS have been studied on sensory profiles and corticospinal activity. However, the underlying mechanism of PWM TENS on cortical network which might lead to pain alleviation is not yet investigated. Therefore, we recorded cortical activity using electroencephalography (EEG) from 12 healthy subjects and assessed the alternation of the functional connectivity at the cortex level up to an hour following the PWM TENS and compared that with the effect of conventional TENS. The connectivity between eight brain regions involved in sensory and pain processing was calculated based on phase lag index and spearman correlation. The alteration in segregation and integration of information in the network were investigated using graph theory. The proposed analysis discovered several statistically significant network changes between PWM TENS and conventional TENS, such as increased local strength and efficiency of the network in high gamma-band in primary and secondary somatosensory sources one hour following stimulation. Our findings regarding the long-lasting desired effects of PWM TENS support its potential as a therapeutic intervention in clinical research.

10.3389/fnins.2023.1239068

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Citations (1)

Referred Sensation Areas in Bilateral Upper Limb Amputee

2022 44th Annual International Conference of the IEEE Engineering in Medicine & Biology Society (EMBC) (2023)

Romulus Lontis Winnie Jensen

Phantom limb pain (PLP) following amputation considerably reduces the quality of life, given a difficult to treat pain of highly variate profile. The loss of sensory input induces a complex pattern of neuroplastic changes of the sensory neural pathways and their central projections. Referred sensation areas (RSAs) may occur on the stump as a consequence of amputation, providing a direct path towards the altered central sensory projections. Modulated electrical stimulation of RSAs was investigated in a long-term experiment in the case of a 62 years-old participant with bilateral upper limb amputation due to traumatic injury. RSAs were investigated using mechanical (vibration and pressure) and electrical stimuli over five sessions within a five weeks period. Further test of sensations induced by steady state and modulated electrical stimuli was performed during additional 4 sessions. Location and features of RSAs were highly dependent on the type of stimulus and time of delivery between sessions.Clinical Relevance— The case study presents a variety of types and locations of the sensation induced by electrical and mechanical stimuli that may eventually be used as artificially generated sensory input as individualized alternative form of therapy for PLP alleviation. Furthermore, possible multichannel stimulus delivery on RSAs on both arms and the cross-over effect of the bilateral amputation in perception of the induced sensation in the opposite phantom hand may be considered in dedicated design of an experimental setup that may possibly help investigation of mechanisms for PLP.

Sensation

Stimulus (psychology)

Phantom limb

Sensory stimulation therapy

10.1109/embc40787.2023.10340833

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Citations (1)

Simultaneous Modulation of Cortical Activity and Phantom Pain in a Patient with Brachial Plexus Injury

Ali Asghar Zarei S. Farokh Atashzar Winnie Jensen Armita Faghani Jadidi Romulus Lontis

Brachial plexus injury may induce complete loss of sensation and motor control in parts of the affected arm, leading to phantom limb pain (PLP). PLP is associated with functional reorganization at the somatosensory cortex and alteration in the functional connectivity of the related pain brain areas. Several therapies have previously been suggested for PLP relief. Transcutaneous electrical nerve stimulation (TENS) is a non-invasive intervention used for pain relief and stroke rehabilitation. However, the underlying mechanism of TENS on cortical activity associated with PLP relief is not well-known. The effect of TENS (20Hz) intervention on somatosensory activity, cortical functional connectivity, and possible PLP reduction was investigated in this study in the case of a 55 year old subject with brachial plexus injury inducing complete paralysis below the elbow in the left arm. We recorded EEG data and the patient's pain level before and after the intervention. Somatosensory evoked potentials (SEPs) and functional connectivity between pain-related areas were assessed from EEG data. The results showed that the application of TENS suppressed somatosensory evoked potentials. In addition, the intervention enhanced the functional connectivity (a) between the primary somatosensory cortex and the anterior cingulate cortex (SI-ACC), also (b) between the primary somatosensory cortex and the medial prefrontal cortex (SI-MPC). Moreover, these results were associated with PLP reduction following TENS. We compared the results with our previous research on a large healthy population to assess the cortical changes.

Somatosensory evoked potential

Secondary somatosensory cortex

10.1109/ner52421.2023.10123824

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A method for monitoring intra-cortical motor cortex responses in an animal model of ischemic stroke

International Conference of the IEEE Engineering in Medicine and Biology Society (2006)

Winnie Jensen P.J. Rousche Terry C. Chiganos

Neuroplasticity is believed to play a key role in functional recovery after stroke. Neuroplastic effects can be monitored at the cellular level via e.g. neurotransmitter assessment, but these studies require sacrifice of the animal. FMRI can be used to assess functional neuronal performance, but the spatial and temporal resolution is far from the single cell level. The objective was to establish an effective method for short-term analysis of single and multi-unit electrophysiological function before, during and after stroke. We instrumented one rat with a 16-ch array in the primary motor cortex (100 mum wire diameter) to monitor cortical activity. A bipolar cuff electrode was implanted around the Ulnar nerve in the contralateral forelimb to provide a controlled electrical stimulus input to the sensory-motor system. A 3 mm diameter ischemic infarct was created immediately posterior to the electrode array by light activation of a photosensitive dye (Rose Bengal, 1.3 mg/100 mg body weight) at the cortical surface. M1 activity in response to the peripheral electrical stimulus was recorded before, during and after the cortical ischemic infarct. At 425 min following ischemic infarct the peak peri-stimulus time response had decreased to 30plusmn11% (electrodes placed 1.5 mm from the infarct core) of the activity before the ischemic onset. The mean response latency increased from 30.1plusmn4.5 ms (before infarct) to 40.6plusmn8.5 ms (at 425 min). This dynamic view of neuroplasticity may eventually assist in optimizing acute stroke therapies and optimize functional recovery further

Forelimb

Stimulus (psychology)

10.1109/iembs.2006.259218

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Citations (6)

Effect of initial joint position on nerve-cuff recordings of muscle afferents in rabbits

IEEE Transactions on Neural Systems and Rehabilitation Engineering (2001)

Winnie Jensen S.M. Lawrence Ronald Raymond Riso Thomas Sinkjær

The objective was to characterize nerve-cuff recordings of muscle afferents to joint rotation over a large part of the physiological joint range. This information is needed to develop control strategies for functional electrical stimulation (FES) systems using muscle afferent signals for sensory feedback. Five acute rabbit experiments were performed. Tripolar cuff electrodes were implanted around the tibial and peroneal divisions of the sciatic nerve in the rabbit's left leg. The electroneurograms (ENG) were recorded during passive ankle rotation, using a ramp-and-hold profile starting at seven different joint positions (excursion = 5 degrees, velocity = 10 degrees/s, initial positions 60 degrees, 70 degrees, 80 degrees, 90 degrees, 100%, 110 , and 120 ). The amplitude of the afferent activity was dependent on the initial joint position. The steady-state sensitivity of both nerve responses increased with increasing joint flexion, whereas the dynamic sensitivity increased initially but then decreased. The results indicate that recordings of the muscle afferents may provide reliable information over only a part of the physiological joint range. Despite this limitation, muscle afferent activity may be useful for motion feedback if the movement to be controlled is within a narrow joint range such as postural sway.

Functional electrical stimulation

Cuff

Common peroneal nerve

10.1109/7333.948454

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Citations (22)

Yohimbine for treatment of xylazine overdosing in a cat

Journal of the American Veterinary Medical Association (1985)

Winnie Jensen

10.2460/javma.1985.187.06.627

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Citations (0)