Stability of the head in pitch (neck flexion-extension): Studies in normal subjects and patients with axial rigidity

1989 ◽  
Vol 4 (3) ◽  
pp. 233-248 ◽  
Author(s):  
Michael Gresty
Keyword(s):  
Normal Subjects ◽  
Neck Flexion ◽  
Flexion Extension

scholarly journals Manual Tracking Performance in Patients with Cerebellar Incoordination: Effects of Mechanical Loading

1990 ◽  
Vol 17 (3) ◽  
pp. 275-285 ◽  
Author(s):  
Betty-Lynn Morrice ◽  
Werner J. Becker ◽  
J.A. Hoffer ◽  
Robert G. Lee
Keyword(s):  
High Velocity ◽  
Time Lag ◽  
Normal Subjects ◽  
Elastic Stiffness ◽  
Tracking Performance ◽  
Cerebellar Hemisphere ◽  
Manual Tracking ◽  
Improve Performance ◽  
Oscilloscope Screen ◽  
Flexion Extension

ABSTRACT:Manual tracking performance was studied in five patients with cerebellar incoordination due to unilateral cerebellar hemisphere lesions. The subjects were required to track a target on an oscilloscope screen by moving a cursor controlled by flexion-extension movements of the wrist. In comparison to normal subjects, the cerebellar patients, using their clinically affected arm, demonstrated irregular tracking patterns with inappropriate accelerations and decelerations, numerous high velocity peaks of movement, and an increased time lag between the cursor and the target.The addition of a viscous load provided by feeding back wrist velocity to a torque motor coupled to the apparatus resulted in significant improvement in tracking performance and suppression of the high velocity peaks. Increasing elastic stiffness by feeding back wrist position or inertial load by adding weights to the hand did not improve performance on this task. It is proposed that a hypotonic cerebellar limb behaves like an underdamped mechanical system. The addition of viscous loads helps restore more normal damping during voluntary movements of the arm.

EMG-Based Interface for Position Tracking and Control in VR Environments and Teleoperation

1997 ◽  
Vol 6 (3) ◽  
pp. 282-291 ◽  
Author(s):  
Srikanth Suryanarayanan ◽  
Narender P. Reddy
Keyword(s):  
Elbow Joint ◽  
Joint Angle ◽  
Intelligent System ◽  
Normal Subjects ◽  
Surface Emg ◽  
Position Tracking ◽  
Emg Signal ◽  
Human Movements ◽  
Flexion Extension ◽  
And Control

Position tracking and control using bioelectric signals are emerging as promising techniques. Surface electromyographic (EMG) signals are being researched for tracking human movements, direct proportional control of teleoperators, and object manipulation in VR environments. This study investigates the use of surface EMG to track elbow joint angle during flexion-extension of the arm applied to control of a virtual environment or an anthropomorphic telemanipulator. An intelligent system based on neural networks and fuzzy logic has been developed to use the processed surface EMG signal and predict the joint angle. The intelligent system has been tested on normal subjects performing flexion-extension of the arm of various angles and at several speeds. The joint angles predicted by the intelligent system were input to a computer-simulated model of an elbow manipulator. Preliminary results show the average root mean squared (RMS) error between the actual elbow joint angle measured with a goniometer and the joint angle reproduced by the robot model to be less than 20%. The technique of using EMG as an interface for tracking and direct biocontrol has great potential in VR and telemanipulation.

scholarly journals Motion Characteristics of Subclinical Tremors in Parkinson’s Disease and Healthy Subjects

2021 ◽  
Author(s):  
PING YI CHAN ◽  
ZAIDI MOHD RIPIN ◽  
Sanihah Abdul Halim ◽  
Wan Nor Arifin ◽  
Ahmad Shukri Yahya ◽  
...  
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Inertial Sensors ◽  
Frequency Dispersion ◽  
Normal Subjects ◽  
Peak Frequency ◽  
Distal Segment ◽  
Full Spectrum ◽  
Flexion Extension ◽  
Motion Characteristics

Abstract The Parkinson’s disease tremor characteristics reported previously are not applicable to the full spectrum of severity. The characteristics of high- and low-amplitude tremors differ in signal regularity and frequency dispersion, which indicates that characterization should be studied in separate severity. The subclinical tremor of Parkinson’s disease is close to physiological tremor, yet their distinctive features are still undetermined. This study aims to determine joint motion characteristics that are unique to subclinical Parkinson’s disease tremors. The tremors were characterized by four hand–arm motions based on displacement and peak frequencies. The rest and postural tremors of 63 patients and 62 normal subjects were measured with inertial sensors. The baseline was established from normal tremors, and the joint motions were compared within and between the two subject groups. Displacement analysis shows that pronation–supination and wrist abduction–adduction are the most and least predominant tremor motions respectively, for both Parkinson’s disease and normal tremors. However, the subclinical Parkinson’s disease has significant greater in amplitude and peak frequency in specific predominant motions as compared to normal tremor. The flexion-extension of normal postural tremor increases in frequency from proximal to distal segment, which is explainable by mechanical oscillation. This characteristic is also observed in patients but with amplification in wrist and elbow joints. The contributed distinctive characteristics of subclinical tremors provide clues on the physiological manifestation that is a result of the neuromuscular mechanism of Parkinson’s disease.

An In-Vivo Study of Normal Wrist Kinematics

1982 ◽  
Vol 104 (3) ◽  
pp. 176-181 ◽  
Author(s):  
R. B. Brumbaugh ◽  
R. D. Crowninshield ◽  
W. F. Blair ◽  
J. G. Andrews
Keyword(s):  
Reference Frame ◽  
Three Dimensional ◽  
Normal Subjects ◽  
Normal Group ◽  
In Vivo Study ◽  
Ulnar Deviation ◽  
Flexion Extension ◽  
The Common

The motion of the hand relative to a reference frame embedded in the radius is described using the screw displacement axis (SDA) concept. A three-dimensional sonic digitizer was utilized in a study of the dominant wrist of 15 normal subjects to determine the location and orientation of the SDAs based on the endpoints of flexion-extension motion (FEM) and radial-ulnar deviation (RUD) of the hand. The length of the common perpendicular between the SDAs of FEM and RUD was as large as 6 mm in some individuals; however, in some subjects the FEM SDA was distal of the RUD SDA while in others it was proximal. Considering the group of 15 subjects, the SDAs of FEM and RUD for the normal group nearly intersect in the head of the capitate in the neutrally positioned wrist and forearm.

scholarly journals Vestibulo-sympathetic reflex in patients with bilateral vestibular loss

2019 ◽  
Vol 127 (5) ◽  
pp. 1238-1244
Author(s):  
O. Kuldavletova ◽  
P. Denise ◽  
G. Quarck ◽  
M. Toupet ◽  
H. Normand
Keyword(s):  
Normal Subjects ◽  
Head Position ◽  
Neck Flexion ◽  
Vascular Effect ◽  
Vestibular Loss ◽  
Bilateral Vestibular Loss ◽  
Eyes Closed ◽  
Head Positions ◽  
Sympathetic Effect ◽  
Sensory Compensation

This study assessed cardiovascular control during head-down neck flexion (HDNF) in a group of patients suffering from total bilateral idiopathic vestibular loss (BVL) for 7 ± 2 yr. Nine adult patients (age 54 ± 6 yr) with BVL were recruited. Calf blood flow (CBF), mean arterial pressure (MAP), and heart rate (HR) were measured with subjects’ eyes closed in two lying body positions: ventral prone (VP) and lateral (LP) on the left side. Vascular resistance (CVR) was calculated as MAP/CBF. The HDNF protocol consisted in passively changing the head position: head up (HU)–head down (HD)–HU. Measurements were taken twice at each head position. In VP CBF significantly decreased in HD (3.65 ± 0.65 mL·min−1·100 mL−1) vs. HU (4.64 ± 0.71 mL·min−1·100 mL−1) ( P < 0.002), whereas CVR in VP significantly rose in HD (31.87 ± 6.93 arbitrary units) vs. HU (25.61 ± 6.36 arbitrary units) ( P < 0.01). In LP no change in CBF or CVR was found between the two head positions. MAP and HR presented no difference between HU and HD in both body positions. Age of patients did not significantly affect the results. The decrease in CBF of the BVL patients was similar to the decrease observed with the same HDNF protocol in normal subjects. This suggests a sensory compensation for the lost vestibular inputs that could originate from the integration of inputs from trunk graviceptors and proprioceptive and cutaneous receptors. Another possibility is that the HDNF vascular effect is evoked mostly by nonlabyrinthine sensors. NEW & NOTEWORTHY The so-called vestibulo-sympathetic reflex, as demonstrated by the head-down neck flexion (HDNF) protocol, is present in patients with total bilateral vestibular idiopathic loss, equally in young and old subjects. The origin of the sympathetic effect of HDNF is questioned. Moreover, the physiological significance of the vestibulo-sympathetic reflex remains obscure, because it acts in opposition to the orthostatic baroreflex. It may serve to inhibit the excessively powerful baroreflex.

Wavelet Analysis of Humans with Osteoarthritis

2016 ◽  
Vol 823 ◽  
pp. 155-160
Author(s):  
Daniela Tarniţă ◽  
Dan Marghitu ◽  
Nicolae Craciunoiu
Keyword(s):  
Wavelet Transform ◽  
Wavelet Analysis ◽  
Normal Subjects ◽  
Research Proposal ◽  
Kinematic Data ◽  
Osteoarthritis Knee ◽  
Flexion Extension

In this research proposal we want to develop from kinematic data, measures using thewavelets theory to characterize normal and osteoarthritis knee locomotion. The kinematic data of theradio-carpal flexion-extension angles were analyzed using the wavelet transform. The experimentaldata was acquired with a complex goniometer system. The detail energy for the level 5 is an importantfactor to characterize the osteoarthritis patients and normal subjects.

Auditory Selective Attention in Cerebral-Palsied Individuals

1985 ◽  
Vol 16 (4) ◽  
pp. 260-266 ◽  
Author(s):  
Lee Ann Laraway
Keyword(s):  
Selective Attention ◽  
White Noise ◽  
Normal Subjects ◽  
Auditory Selective Attention ◽  
Normal Individuals ◽  
Significant Difference

The purpose of this study was to determine whether there is a statistically significant difference between the auditory selective attention abilities of normal and cerebral-palsied individuals. Twenty-three cerebral-palsied and 23 normal subjects between the ages of 5 and 21 were asked to repeat a series of 30 items consisting of from 2 to 4 digits in the presence of intermittent white noise. Results of the study indicate that cerebral-palsied individuals perform significantly poorer than normal individuals when the stimulus is accompanied by noise. Noise was not a significant factor in the performance of the normal subjects regardless of age.

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