Ebook: Electrophysiological Kinesiology

New technologies and recent findings in neuromotor control can provide useful tools to conceive new diagnosis procedures and to restore impaired motor functions. For this purpose the basic understanding of natural sensory-motor integration must be combined with the knowledge of neuromotor disorders and with the advanced technologies used in rehabilitation. This is an interdisciplinary problem that requires the contributions of different researchers working in complementary areas (neurophysiology, neurology, rehabilitation, bioengineering and advanced technology).

This approach is typical of the “International Society of Electrophysiology and Kinesiology (ISEK) which is a multidisciplinary organization composed of scientists from the already mentioned fields working in basic research as well as clinical application.

At the IX meeting held in Florence attended more than 400 people including the most outstanding scientists in this field, who provided the main recent results of their research. Therefore this book provides an interesting updating of research, developments and clinical applications going on the following topics: Neuromotor Control, Electromyography, Functional Electrical Stimulation (FES), Motor Unit Control, Neuromuscular Diseases, Rehabilitation, Muscle Fatigue, Kinesiology, Motion Analysis and Ergonomics.

I would like to express my gratitude to the Congress Board and to the ISEK Council for their contribution to the designing and organization of the meeting and special thanks to CE.S.P.RI, Carla Finocchiaro and Matilde Cordella for their enthusiasm and irreplaceable help.

Prof. Antonio Pedotti

Congress Chairman

Discrete movements of a limb about a single joint are a widely studied experimental paradigm for the investigation of voluntary movement. Never-the-less, the literature on this apparently “simple” task does not reveal a consensus on how such movements are controlled. Rather, a diversity of control rules exist, one of which must be selected depending upon specific aspects of the task. For example, movements that vary in distance appear to be controlled according to different rules from those that vary only in speed. Since natural movements as well as experimentally contrived ones usually vary from each other in several “parameters”, this appears to complicate the task of any central motor controller which is first, to select a control rule for a movement and then to apply it to the peripheral neuromuscular mechanisms.

In this paper, a computational procedure (program) will be defined that generates control signals for the motoneuron pools of agonist and antagonist muscles. This program can move a single-joint limb from one stationary position to another. The program accounts for moving different distances with different inertial loads and for the influence of different instructions concerning movement speed and accuracy. The model that generates these motor commands describes EMG patterns as well as force and kinematic trajectories which are consistent with much of the data found in the literature of these movements. The model is premised on the notion that kinematically defined tasks are accomplished by programming forces, based on only a few cognitively recognized kinematic and dynamic features of the task. Most of the features found in EMG and kinematic patterns can be considered consequences of the program’s algorithmic procedures rather than specifically planned features of those movements.

EMG data will be presented that illustrate the behavior of the motor system performing different kinds of single-joint elbow movements in the horizontal plane. These will be compared to the predictions obtained from the motor program equations solved on a computer. A high degree of correlation will be demonstrated between modeled and actual EMGs under diverse conditions.

It is rapidly becoming possible to reanimate a paralyzed limb by applying wellcontrolled electrical stimulation to multiple nerves and muscles. However, fitting the technology to a particular patient with a particular disability now requires a large number of measurements, observations and decisions that are beyond the capabilities of most clinical rehabilitation environments. Fortunately, there are parallel technological advances in four key supporting areas - noninvasive morphometry, motion analysis, graphical user interfaces, and automated kinetic analysis - that may make this problem tractable, but only if they can be harnessed into complete, user-friendly clinical systems.

Classically, the agranular frontal cortex of the monkey and man has been considered to be formed by two motor areas: the primary motor area and the supplementary motor area. Evidence is presented that this subdivision is inadequate and that the agranular frontal cortex is constituted of at least seven different cortical areas. One of them (Fl) corresponds to the primary motor cortex. Two areas are located on the mesial cortical surface (F3 or “SMA-proper” and F6 or “pre-SMA”), two form the superior sector of area 6 (F2 and F7), and two form the area 6 inferior sector (F4 and F5). It is suggested that these various areas play a different role in motor control and that some of them (e.g. F4 and F5) are mostly involved in transforming visual object properties into motor acts, some (e.g. F2) are involved in proprioceptive control and proprioceptive representation of arm movements and finally some (F6) in decisions about movement initiation.

Skin sympathetic reflexes need to be recorded from more than one site over the hand and foot if the quantitative measure is to be of significance. For this purpose the instrument must to be sensitive enough to detect variations of a fractional of a percent of skin impedance. Method: To support sympathetic investigation we have developed a system which combine the functionality of a battery of tests with the flexibility of a computer analysis environment based on a dual-channel self-balancing impedance reactometer. Measurement of skin sympathetic reflexes in 33 healthy subjects, aged under 50 yrs. was performed by noninvasive monitoring transient change in the skin impedance both in phase (resistive) and in quadrature (capacitive) on rest and after a stimulus. The procedure requires a placement of a pair of surface electrodes on the skin and application upon the subject an endogenous/ exogenous stimulus. 12 bit data resolution specially designed data acquisition card is used which converts the signals into digital form and transfers this to the computer IBM PC XT/AT data bus directly. The software developed for the system written in Pascal, displays the data on standard PC colour monitor in real time 1, 2 or 4 traces at a time. Results: An autonomic response is an extremely complex state of the subject and can be characterized by many parameters which may have both temporal and spatial dependencies. The sympathetic response signal to be recorded is superimposed on a background signal which may be orders of magnitude larger but constant during the recording time. The insertion of the self-balancing circuit into the detection electronics, the background signal is compensated, the sympathetic signal is not affected and could be detected with the highest sensitivity. Transient skin sympathetic response was 2.18 +/- 0.31 %/s at hand, 1.41 +/- 0.42 %/s at foot and 0.27 +/- 0.14 %/s in other site of the body. The potential of the system is currently investigated for on line diabetic foot analysis.