DeNeuro 2013 Abstracts


Short Papers
Paper Nr: 2
Title:

Computational Models of Populations of Motor Neurons

Authors:

Jakob L. Dideriksen and Dario Farina

Abstract: Two examples of applications of neuromechanical models are given, each highlighting different advantages of using simulations to support experimental tests. Both examples address pathological tremor; a common movement disorder related to several pathological conditions. The first example demonstrated how models can be applied to test the robustness of rehabilitation techniques when experimental data is sparse and when full parameter sensitivity analysis in patients is not feasible. Last, the sensitivity of internal physiological parameters on the motor output was assessed, for neuromuscular properties that cannot be measured experimentally.

Paper Nr: 3
Title:

Multi Channel Surface EMG - Detection and Conditioning

Authors:

M. Gazzoni and U. Barone

Abstract: The electromyogram is a compound signal comprising the electrical activity of the motor units activated asynchronously during voluntary muscle contractions. The temporal and spatial evolution of EMG can be sampled by surface electrodes. The basic principles and concepts about sEMG signal conditioning, spatial filtering, and spatial sampling are introduced and discussed.

Paper Nr: 4
Title:

On the Impact of Pathological Tremor Intensity on Noninvasive Characterization of Motor Unit Discharge Properties

Authors:

Petra Povalej Bržan, Vojko Glaser, Simon Zelič, Juan Álvaro Gallego, Juan Pablo Romero Muñoz and Aleš Holobar

Abstract: The impact of severity of pathological tremor on surface EMG decomposition was systematically assessed on eight essential tremor patients. The inertial data and surface EMG signals were concurrently recorded from wrist extensor and flexor muscles of both patients’ arms. The inertial recordings were segmented into different tremor cycles and the tremor amplitude was assessed in each tremor cycle. Surface EMG was decomposed by Convolution Kernel Compensation (CKC) technique in order to yield individual motor unit discharge patterns in each tremor cycle. Accuracy of EMG decomposition was assessed for each identified motor unit and was largely uncorrelated with tremor amplitude. In all the patients, the percentage of EMG energy identified by decomposition and the number of identified motor units were found to be positively correlated with tremor amplitude, though the correlation was relatively weak and not always significant. The results demonstrate that the CKC decomposition not only copes with moderate and severe tremor but also improves its performance with tremor intensity.

Paper Nr: 5
Title:

Motor Unit Properties and Underlying Determinants in Pathological Tremor

Authors:

J. A. Gallego, J. L. Dideriksen, A. Holobar, J. P. Romero, J. L. Pons, E. Rocon and D. Farina

Abstract: Pathological tremors are accepted to originate from the projection of supraspinal pathological oscillations to motor neurons that innervate the affected muscles. These oscillations interact with other neural mechanisms such as reflexes, and, together with the mechanical properties of the limb, determine the characteristics of the tremor. However, much is yet unknown about the exact mechanisms that mediate the different types of tremor, and how they interact. Given that the neural drive to muscle encodes information about all pathways that regulate movement, we are investigating the properties of motor unit activities in tremor patients and the factors that determine them as a means to further our understanding of the disorder. This paper presents a simulation study that supports our departure hypothesis (that tremor is a common cortical projection to the motor neuron pool), and first experimental evidences on a patient with essential tremor. The latter illustrate that the predictions derived from the model provide significant support for the analysis of real data, and demonstrate the potential of the analysis techniques here employed.

Paper Nr: 6
Title:

A Review of Methods to Characterize Motor Unit Firing Properties and Underlying Determinants

Authors:

J. L. Dideriksen, J. A. Gallego, F. Negro, A. Holobar and Dario Farina

Abstract: This paper reviews traditional and novel techniques for the characterization of motor unit firing properties and the determination of their underlying determinants.