Human Finger Movements Research Articles

人間の指による操り動作計測システムの開発

Measurement system for manipulative motion of human fingers is presented. A human subject wears several clip-on devices on the back of the fingers. Each device has a short stem extending outward from a finger with a light emitter at its end. A stereo vision system measures the three dimensional positions of the light emitters. The positions and the orientations of the fingers are calculated from the light emitters' positions using a kinematic model of the fingers. The protruding stems on the back of the fingers reduce occlusion caused by other fingers. Selection of the stem length, calibration method, and two examples of measurement of manipulation are presented. The overall accuracy of the system was 0.3 to 0.8 mm.

二本指マイクロハンド用操作デバイスの開発とその制御

We have proposed a concept of two-fingered micro hand, and designed and built a two-fingered micro hand based on parallel mechanisms. In this paper we mainly discuss a master device to control the two-fingered micro hand and a strategy for effective operation. We observed actual human finger motions and designed a master device and a operation strategy suitable for the two-fingered micro hand. By using the developed device, we could obtain good performance of micro manipulation.

Sensory feedback contributes to early movement-evoked fields during voluntary finger movements in humans

Neuromagnetic field changes accompanying voluntary movement in humans (`movement-evoked fields' or MEFs) were recorded over the scalp using a whole-head MEG system during the performance of self-paced finger movements in order to determine the contribution of sensory feedback to the generation of these brain responses. It was found that cooling the subject's arm resulted in delays of 8 ms or more in the latency of the early movement-evoked field component (MEFI). These delays were attributed to increases in conduction times in the afferent pathways as confirmed by electrically evoked somatosensory responses and suggest a peripheral origin of the MEFI. In a second experiment, we demonstrated the effects of sensory input to the contralateral hand during a simple button pressing task in 4 subjects. The results indicated that responses over the hemisphere ipsilateral to the side of movement which resembled previously reported ipsilateral MEFs can be elicited by the spread of mechanical stimulation to opposite side of the body when a mechanical trigger is used. These experiments provide further evidence that early movement-evoked fields produced by unilateral finger movements are observed primarily over the contralateral somatosensory cortex and represent sensory feedback to the somatosensory cortex from the periphery.

Synchronization of human finger movements: delays and sex differences with isotonic 'antiphase' motion.

The interval between the operation of two Morse keys, or the moments at which fingers touched or broke contact with electrical conductors, has been measured, the subjects making the movements as synchronously as possible. The data obtained deal with timings when two fingers flexed or extended together ('in phase') and when one finger extended whilst the other flexed ('antiphase'). For antiphase movements of the index fingers with the conductors, flexion usually occurred before extension so there was 'overlap'. Statistically, this period was greater in women and unusually high values were found in one subject with mild cerebral palsy. Overlap was not found using the keys. Using conductors, the timing of antiphase movements for the index and middle fingers of the right and left hand showed overlap again. No significant relationships were found with handedness. When the conductors were placed above the fingers, and the contact was thus with the dorsum, extension took place before flexion: both fingers were extended for a while, with overlap occurring again. The significance of these findings for the understanding of motor control is discussed.

Development of noninvasive measurement techniques for the human brain

This paper proposes optical topography using near-infrared light as a new noninvasive measurement method for higher brain function. The brain activity accompanying human finger movement is measured by the proposed method. By static optical topography, the activation, of the primary motor area in connection with contralateral finger movement side is observed, which is consistent with established knowledge, and indicates the validity of the proposed method. By using dynamic optical topography, the hemodynamic changes accompanying the activation of the brain function are temporally and spatially analyzed. As a result, the change of the blood volume in the neighborhood of the motor area as a whole is observed at the start and immediately after the movement, as a characteristic event in common to both ipsilateral and contralateral finger movements. The increase of the local blood volume in the primary motor area is observed in the movement period as a characteristic event of the finger movement on the contralateral side. Near-infrared optical topography is a practical noninvasive method of measurement for the higher brain function, which has high portability and can be used in various environments. © 1997 Scripta Technica, Inc. Electron Comm Jpn Pt 3, 80(4): 42–50, 1997

Corticospinal Function and Voluntary Movement

edited by Robert Porter and Roger Lemon, 428 pp., Oxford, Clarendon Press, 1993 (paperback issue 1995), $59.50 Neurologists easily recognize the pattern of weakness that results from injury to the corticospinal tract but are perhaps less familiar with how the corticospinal system functions normally to produce voluntary movements. Porter and Lemon's monograph, originally issued in hardback in 1993, summarizes and synthesizes a vast body of experimental data that examine the physiology and functional anatomy of the motor cortex. It focuses primarily on coordinated hand and finger movements in humans and primates. Although the book was written to be a successor to the 1977 monograph by Porter and Phillips …

Development of Welfare Robots Similar to Human Hands

A robot today is used at various industries. At its early stage first the robot had only one function but today it has many functions and also the intelligent robot is manufactured. This paper presents a robot hand system that has the same motions as human. This robot hand is designed to have three fingers that are a thumb, a indexfinger and a middle finger. And the robot hand system adjusted to the motions of human fingers is designed by two detective methods of the motions of human fingers.

Topography of Scalp-Recorded Motor Potentials in Human Finger Movements

Four distinct negative events were identified in the averaged, scalp-recorded EEGs of normal subjects before and after the onset of self-paced, voluntary finger movements; reaction-time movements and passive movements were also studied. These events are the peak of the negative slope (NS'), the initial slope of motor potential (isMP), the parietal peak of motor potential (ppMP), and the frontal peak of motor potential (fpMP). For self-paced movements, NS' and isMP occurred before the onset of electromyographic (EMG) activity, and ppMP and fpMP occurred after the onset of EMG activity. NS' had a wide distribution, covering the parietal region with slight contralateral predominance. The isMP mapped focally over the contralateral hand motor area on the scalp. The location of ppMP was similar to that of isMP. The fpMP was localized anterior and medial to motor cortex with a contralateral preponderance and possible location over the supplementary motor area. The isMP and fpMP also were identified in the recordings of reaction-time movements, but only the fpMP persisted in the recordings of passive movements. The isMP appears to reflect activation of the cortical cells in the hand area of motor cortex for the execution of voluntary movement, and the fpMP appears to reflect proprioceptive feedback from the periphery.

A computer-controlled torque motor

The authors describe an inexpensive intelligent controller for laboratory torque motors, or any other analogue positioning device. The instrument is based on a single-board microcomputer, and is programmed in the high-level language FORTH. It may be interfaced to a general purpose computer via one of two serial ports, and may also function as a stand-alone controller. The compact hardware, and the flexible software, also allow the controller to function as a general purpose remote data logger. Operation of the system to produce perturbing torques in studies of human finger movement is described.

Muscle activation patterns and kinetics of human index finger movements

1. The present study was conducted to determine whether dynamic interaction torques are significant for control of digit movements and to investigate whether such torques are compensated by specific muscle activation patterns. 2. Angular positions of the metacarpophalangeal (MP) and proximal interphalangeal (PIP) joints of the index finger in the flexion/extension plane were recorded with the use of planar electrogoniometers. Muscle activation patterns were monitored with the use of fine wire and surface electromyography of intrinsic and extrinsic finger muscles. 3. Dynamic interaction torques associated with index finger movements were large in relation to joint torques produced by muscles, especially in faster movements. The significance of dynamic interaction torques was demonstrated in model simulations of two-joint finger motion in response to joint torque inputs. Removal of interaction torques from the model inputs produced movements that differed greatly from digit motions produced by human subjects. 4. Electromyogram (EMG) and torque patterns associated with finger movements of different speeds indicated that muscle activity is necessary not only for producing motion at the joints but also to counteract segmental interaction torques. This was especially evident during movements that required voluntary maintenance of a constant MP joint angle during motion of the distal segment about the PIP joint. Under these conditions, muscle moments acting at the MP acted directly to counteract torques at the MP arising from motion at the PIP. 5. Neural mechanisms underlying control of index finger movement are discussed with reference to the implications of dynamic interaction torques. Potential control strategies include accurate programming of muscle activation patterns, appropriate use of motion-dependent peripheral afferent information, and control of the finger as a viscoelastic system through coactivation of flexor and extensor musculature. It is concluded that additional research incorporating study of motion in three dimensions and the use of mechanical models of the finger and related musculature is required to determine how interaction torques are compensated during finger motion.

A study of the range of motion of human fingers with application to anthropomorphic designs : Becker, J.C., and Thakor, N.V.IEEE Trans Biomed Engng, 1988, 35.2, 110–117

A study of the range of motion of human fingers with application to anthropomorphic designs : Becker, J.C., and Thakor, N.V.IEEE Trans Biomed Engng, 1988, 35.2, 110–117

A study of the range of motion of human fingers with application to anthropomorphic designs.

The multifingered human hand serves as a model for anthropomorphic manipulators and prosthetic devices. In order to better guide the design of these devices, a study of the range of motion of human fingers is presented. The role of tendons in the actions of human fingers is modeled and results of experimental studies on the range of motion of fingers in normal humans are presented. Further study of disabled hands illustrates constraints imposed by deficient tendon mechanisms. The basic investigations of normal and disabled hands guide the design of tendon-based actuators for mechanized fingers. The design of a prototype finger actuated by a shape-memory alloy material serving as a tendon is discussed.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

多自由度人間形人工の手の開発 : 5本指,腕の構成

Studies on artificial hands are done at many laboratories all over the world. The necessary functions for artificial hands hereafter may be dexterity, speediness, flexible handling, intelligence, and so forth. The playing of keyboards can be considered human activity which is highly dependent on these functions. This study aims to have an anthropomorphic robot play a keyboard (an electric organ in the first step of this study), with a focus on its degree-of-freedom mechanism and speediness, with the intent of developing artificial hands for more universal uses. The following three points are keys for the development of an anthropomorphic robot with the capability to play keyboards: 1) the integration of multiple degrees of freedom at the fingers, 2) the speed of finger and arm motions, and 3) the composition of a microcomputer system to control the mechanism for the multiple degrees of freedom. The design was to have 2 degrees of freedom for the thumb and 3 degrees for each finger, totalling 14 degrees, based on the analysis of motions of human fingers. As to finger driving units, it is impossible for actuators (DC sevomotors), which drive the multiple freedom mechanism, to be installed at the fingers. Therefore, actuators are installed in the body of the robot, and their power is transmitted through reduction gears to the fingers by wires and outer-wire tubes. Moreover, spring elements are introduced in the power transmission units to minimize the effects of friction forces between wires and outer-wire tubes on the responses of finger motions. Fingers are made of CFRP (Carbon Fiber Reinforced Plastics) to reduce the load on the arm. The experiments on a five-finger model have resulted in realization of 10 (Hz) tapping. In terms of an arm, the basic necessary data for design and control methods of an artificial arm were obtained through the analysis of human postures and of motions of the arm as a linking mechanism. The artificial arm is designed to be humanlike in size, shape, and functions, and to have 7 degrees of freedom including one redundant degree. Actuators are DC servomotors, sensors are velocity and position sensors, and the arm is made of CFRP, as are the fingers. Velocity and position control have enabled speedy, smooth motion of the arm. Concerning the computer system, a hierarchically structured multi-micro computer system has been composed, because total degrees of freedom are near to 50 when the degrees of freedom of four limbs are totalled. As a result, this robot system has realized the fluent play of tunes for beginners on a keyboard instrument.

An electrical sign of participation of the mesial ‘supplementary’ motor cortex in human voluntary finger movement

An electrical sign of participation of the mesial ‘supplementary’ motor cortex in human voluntary finger movement