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PubMed1990

[Effects of vibration and noise on the reproductive function in experimental animals].

Experimental animal studies of the reproduction function were performed under prolonged vibration and noise conditions. For 4 months and 5 days male white rats were exposed to 4-hour noise and vibration effect in a noise-protected chamber. The correlated vibration velocity index was 5.07.10(-2) m/s. The permanent wide range noise level reached 92 dBA. It was established that: in a long-term experiment, vibration and noise affected the reproduction function in male white rats; in a combined vibration and noise action, marked changes in the reproduction function were revealed, and in the noise exposition alone, the function changes were not so vivid.

Animals↗
PubMed1990

Effects of whole-body vibration on short-term memory.

An experiment has been conducted to investigate the effects of whole-body vibration on cognitive performance independent of the direct mechanical action of vibration on vision and manual control. Sixteen subjects completed a short-term memory task (memory scanning) during exposure to 16 Hz sinusoidal whole-body vibration at four magnitudes: 0, 1.0, 1.6, and 2.5 ms-2 r.m.s. The results show a detrimental effect of vibration on performance when measured by mean reaction time (p less than 0.001) and number of attentional lapses (p less than 0.01). Response errors rose significantly during the 1.0 ms-2 r.m.s. condition alone. The data suggest that vibration disrupts central cognitive mechanisms utilized during the processing of information in short-term memory, although compensatory cognitive procedures may exist to minimise these effects.

Adolescent↗
PubMed1990

Effects of whole-body vibration waveform and display collimation on the performance of a complex manual control task.

An experiment is described in which two independent groups of eight subjects each performed a combined continuous and discrete tracking task during exposure to vertical whole-body vibration. Both groups received sinusoidal and random vibration at preferred third-octave centre frequencies of 0.5-10 Hz. One group performed the task with the display collimated by a convex lens. Without the collimation, performance was disrupted by both types of vibration at all vibration frequencies; collimation removed the disruption at frequencies above 1.6 Hz. There were differences in the effects of random and sinusoidal vibration at 2.0 and 2.5 Hz, suggesting that compensatory eye movements were assisting performance during exposure to the predictable sinusoidal motion. The results show that continuous control performance was disrupted by visual interference at frequencies above 1.6 Hz; closed-loop system transfer functions showed that visual interference increased the phase lags which impaired control performance. Possible mechanisms explaining the disruption in performance at lower frequencies are discussed.

Adolescent↗
PubMed1989

[Evaluation of digital vibration threshold for asymptomatic ulnar neuropathy in patients with carpal tunnel syndrome].

Quantitative assessment of vibration threshold at 125 Hz of index and little finger tips together with measurements of median and ulnar sensory nerve conduction velocity (SNCV) was performed for 25 limbs of 15 patients with carpal tunnel syndrome (CTS), 25 limbs of 13 disease controls with neurological symptoms similar to CTS and the nearly same number of limbs of normal controls. There was no significant difference in ulnar SNCV among 3 groups. However, ulnar SNCV at wrist was significantly reduced in patients with CTS as compared with normal value. In 17 limbs with CTS, vibration threshold of index finger tips was significantly increased, and 8 of those limbs were found to have concomitant increase of vibration threshold of little finger tips. Most of patients with increase of vibration threshold of both index and little finger tips were those who used to expose to repetitive mechanical stimuli at the wrist in their occupation. It was concluded that digital vibration threshold is simple to measure yet sensitive enough to detect asymptomatic ulnar neuropathy in CTS.

Adult↗
PubMed1988

The left ventricular vibration mode in the ventricular transfer function method and at the moment of the first heart sound.

Several investigators have aimed to clarify the patient's left ventricular (LV) physical properties by free vibration analysis of heart sound. Recently we have developed a transfer function (TF) method to calculate the LV viscoelasticity. To clarify whether this TF method and a clinical first heart sound (1 HS) analysis are based on the identical ventricular vibration mode analysis, we examined (1) the visualized LV vibration image in the TF method and (2) the quantitative relationship between the peak frequency of the 1 HS spectrum and that of TF curve in the early and late phase of the 1 HS. Isolated isovolumic potassium arrested canine left ventricles were used to visualize the vibration mode in describing the TF (N = 2). Examination of stroboscopically illuminated, slow-motion images revealed the oscillation of the ventricle to be of mode 2 behavior. To analyze the quantitative relation between the TF method and 1 HS analysis we used ten open-chest dogs. The correlation was good (r = 0.917) when the peak frequency of the TF curve at the early phase of the 1 HS was compared to the peak frequency of the 1 HS. We concluded that both the TF method and 1 HS analysis were based on the common, second-order ventricular vibration mode. Therefore, some information on the ventricular physical properties suggeted by the TF method could also be included in the clinical data obtained by 1 HS analysis.

Animals↗
PubMed1989

[The effect of whole-body vibration on the electrical activity and oxidative metabolism in different brain structures].

Chronic experiments on rabbits were performed to study the bioelectric activity, oxygen consumption and succinate dehydrogenase (DG) activity in different parts of the cortex and subcortex (mesencephalic reticular formation, lateral vestibular nucleus, thalamus posteroventrolateral nucleus), as well as the compound electric activity of the neck muscles, and rythm adoption. The phase character and different vibration sensitivity of the brain structures depending on the duration of vibration were revealed. At the initial phase, the following vibration effects were examined: reaction of activation on encephalogram, growing EMG and DG activity, increased oxygen consumption, and rythm adoption high frequency shifting. Prolonged vibration caused a vivid violation of the intracentral correlation between the cortex and subcortex. Correlation was also identified between electric activity and the brain structures' oxidation metabolism against the vibration dynamics levels.

Animals↗
PubMed1988

Intensity judgments of vibrations in the X axis, Z axis, and X-plus-Z axes.

Seated subjects matched their perceptions of the intensity of X-axis, Z-axis, or X-plus-Z vibrations, by adjusting the intensity of a sinusoidal, 5 Hz, Y-axis response vibration. Stimuli were sinusoidal at 3.2, 5, and 8 Hz. For each frequency there were six vibration conditions (X axis alone, Z axis alone, or both axes together with 0 degree, 90 degrees, 180 degrees, or 270 degrees phase angles between them) each presented at each of two acceleration levels (0.15 and 0.25 G.R.M.S.). Results showed that Y-axis response accelerations for the dual-axis stimuli were greater than those for either one of their X-axis or Z-axis components. This occurred for both acceleration levels and for all three frequencies. However, the pattern of results indicated that response acceleration varied significantly as a function of the combination of phase angle and frequency. This is in contrast to results from a previous experiment, involving Y-plus-Z axis stimuli, which showed that the effects of phase angle were minimal at all three frequencies. Apparently phase angle, in combination with frequency, plays a significant role for X-plus-Z vibrations, but not for Y-plus-Z vibrations.

Acceleration↗
PubMed1988

Vibration in textile mills.

The vibration in nine halls of the six weaving mills was measured in 1978-80. The measurements were taken at regular intervals in the working area of the weavers, which was the wooden support attached to the machine or the floor of the textile mill. The accelerometer was mounted with screws onto the working area, and all vibration samples were analyzed immediately, in situ. The vibration of the floor was tangent to or exceeded slightly the "reduced comfort boundary" specified in International Standard ISO 2631/1 (1985) only in the areas where the floor was not against the ground. The greatest amount of vibration occurred on the supports which had been attached to the machines. On these supports the vibration in places exceeded the "fatigue-decreased proficiency boundary."

Finland↗
PubMed1987

Clinical neurological methods in the diagnosis of the hand-arm vibration syndrome.

Methods for assessing neurological disturbances in the diagnosis of the hand-arm vibration syndrome are described. The clinical examination should comprise a careful history of symptoms and vibration exposure and a consideration of neurological signs known to be associated with vibration exposure. There is as yet no etiologic diagnostic method for vibration-induced neurological lesions. The best method is a relevant clinical examination as described, in combination with a quantitative assessment of sensory modalities (such as the vibration perception threshold) and an electroneuromyographic test.

Arm↗
PubMed1986

Comparative effects of whole-body vibration on sensorimotor performance achieved with a mini-stick and a macro-stick in force and position control modes.

The aim of this investigation was to assess the performance of subjects in a target recentering task, performed under both normal and vibration conditions. A conventional helicopter stick and an arm-side controller were used in both position and force control modes. The task was designed to simulate instrument flying. The results showed that in the no-vibration situation, the highest performance was achieved in the force control mode and little difference was observed between the two sticks. They also showed that vibration impaired the velocity control of the performance. It is suggested that the subject might be switching over from a visual and arm afferent and efferent control in the no-vibration situation, to a visual control only under vibration condition. From this study, it appears that the more efficient stick to execute the designed task is the mini-stick operating in the force control mode.

Adult↗
PubMed1986

[The value of thermographic tests in the diagnosis of the vascular vibration syndrome].

With the aim of testing the usefulness of static thermography for the diagnosis of the vibration syndrome with the AGA-680 Medical apparatus, 111 patients treated in the clinic for suspected vibration syndrome and 25 patients with the idiopathic Raynaud's syndrome have been examined. The vibration syndrome was found in 70 patients, basing on complex multispecialist examinations with no thermovisual evaluation. Ischaemic symptoms were found thermographically in 63 subjects (56%), the rates being the same for the vibration syndrome and non-diagnosed occupational disease groups. The highest sensitivity was that of the isotonic capillary test (100%) and pallesthesiometry (88.2%), whereas thermometry and capillaroscopy exhibited lower sensitivity (78.1% and 71.5%, respectively), the lowest sensitivities being those of static thermography (56%) and coolness test (31.8%). The highest correlation between the thermographic pathology and the results of the other tests was that relating to pallesthesiometry and isotopic capillary test. No temperature range characteristic for the vibration syndrome or parallelism of clinical and thermovisual evaluations has been found.

Adult↗
PubMed1977

[Vibration of the uterine arteries during pregnancy in cows].

A clinical examination was carred out via the rectum to follow up the initial moment of vibration as established on the medium and rear uterine arteries in a total of 410 cows of the Bulgarian Brown breed by groups of first to eighth pregnancy. The vibration of the uterine arteries may serve as a good clinical sign to determine the age of the fetus. The following more important conclusions were drawn: 1. The uterine arteries start vibrating as pointed below: a. uterina media--in the pregnant horn from the 93rd to the 142nd day (on the 122.2 +/- 0.57 day); in the unpregnant horn from the 167th to the 210th day (on the 188.2 +/- 0.54 day, on an average); a. uterina caudalis--in the pregnant horn from the 200th to the 248th day (222.6 +/- 0.54 day, on an average); in the opposite horn from the 235th to the 279th day (256.7 +/- 0.55, on an average). 2. The initial moment of vibration of the uterine arteries is dependent on the number of previous births. 3. Closest to the average values are those established at the fourth and fifth pregnancy. At the previous pregnancy periods vibration starts earlier, and at the following ones--later.

Animals↗
PubMed1978

Vibration influence on control of single motor unit activity.

Effects of vibratory stimulation and maximal isometric contraction on a fine motor control task were evaluated in 17 human subjects. Electromyographic audiovisual feedback cues derived from two fine-wire bipolar electrodes, inserted to a depth of 12 and 6 mm respectively, were used to train the subjects to isolate a motor unit in the extensor carpi radialis brevis muscle. A specially designed compressed air driven vibrator providing vibratory stimulation with an amplitude of 2 mm and a frequency range of 120-160 cycles per second was applied to the muscle tendon. A significant decrease was found in the subjects; ability to isolate the pretest motor unit during and after continuous and interrupted periods of vibration and following a maximal isometric contraction of the extensor carpi radials brevis muscle. Individual variations in the subjects' responses to the forms of application of the vibratory stimulus, electrode preference and feedback specificity were observed. Results suggest that marked spatial recruitment of motor units, brought into action by the vibration stimulus or by the maximal isometric contraction, interfered with inhibitory mechanisms necessary to achieve isolation and control of a single motor unit. A therapeutic application of vibration, based on the marked spatial recruitment observed during and after vibration, is proposed for muscle reeducation.

Action Potentials↗
PubMed1984

[Vibration hazards in quarry workers].

Vibration hazards were surveyed in a population of quarry workers using chipping hammers and to a lesser extent, rock drills. Sixty-nine male quarry workers, aged 49.1 +/- 8.7 and exposed to vibration for 16.4 +/- 5.1 years, were surveyed in 1981-82. They were exposed to vibration for about 2-4 hours per days, mainly under a piece-work pay system. They had a high prevalence of Raynaud's phenomenon (36.2%) and numbness in upper extremities (53.6%). It is considered that the high prevalence was mainly due to large vibration levels in chipping hammers and rock drills and long daily exposure time. The attacks of Raynaud's phenomenon were found predominantly in the left hand, which held chisels, whereas the restriction of motion in the elbow was predominantly in the right arm which pushed chipping hammers. The same 49 male quarry workers in this population were also surveyed in 1976-77 and the prevalence of their complaints between 1976-77 and 1981-82 was compared. The prevalence of Raynaud's phenomenon was the same, but the frequency of the attacks increased between the two periods. The prevalence of other complaints such as numbness, pain and chills in the upper extremities also increased. Between 1976-77 and 1981-82, the prevalence of Raynaud's phenomenon, numbness, and pain in the upper extremities increased in the population of quarriers exposed to vibration for above 2.6 hours per day and 200 days per year, or 600 hours per year. On the other hand, the prevalence of these complaints mostly decreased in the population of quarriers with less exposure.

Adult↗
PubMedDate not supplied

[Combined action of vibration and ionizing radiation on the body].

The effect of vibration on the development and outcome of radiation injury was studied and the efficacy of pharmacochemical and local protection was measured. The biological effect of the combined exposure was estimated by radiobiological and hematological methods. The animals were exposed to vibration with a frequency of 70, 700, 1500 Hz (during single and repeated exposures) and irradiation with X-rays, gamma-rays and protons at different doses. Vibration may exert a significant effect on the development and outcome of radiation injury of animals. The effect was that this factor was capable either of increasing or decreasing responses of the animal body to ionizing radiation. The direction and level of changes depended on the pattern and force of stimulation, time and sequence of action of factors, etc. The lymph tissue showed high sensitivity to vibration. The findings indicate that vibration may both enhance and diminish the efficacy of antiradiation pharmacochemical drugs.

Animals↗
PubMed1978

[Changes in energy metabolism in the tissues of animals subjected to the effects of constant and intermittent low frequency vibration].

The exposure of rats to 1 month continuous low-frequency vibration did not cause any changes in the brain adenylic fund and led to significant decrease in ATP content and total adenine nucleotides in the muscles of the extremities. For 3 months after the vibration there was a significant exhaustion of the brain and muscle adenylic fund. Under exposure to the interrupted vibration the state of adenine nucleotide system depended upon the duration of intervals limiting the continuous vibration effects. Under the vibration with the shortest intervals between each of the 30-minutes exposure there were no changes in the muscle and brain energy metabolism. 8- and 15-minute intervals for muscle adenine nucleotide and 8-minute interval for the brain proved to be unfavourable.

Adenosine Diphosphate↗
PubMed1981

Effect of body supination angle on subjective response to whole-body vibration.

Three experiments were conducted to evaluate the subjective symptomatology associated with various combinations of supination angle and vibration spectral composition. Sinusoidal, sum-of-sine, and random vibration were used in the first, second and third experiments, respectively. All exposure periods were 40 s and the supination angle was varied from 13-65 degrees. Subjective response was evaluated by means of a physical symptom survey incorporating a discomfort rating scale. For all three experiments, the results indicated a primary effect of supination angle was to shift the vibration-induced sensations across body regions. Small angles (nearly seated upright) were most often associated with stomach, abdomen, and head discomfort; large angles were most often associated with upper back, neck, and sacral discomfort. With respect to the calculated total-body response, results indicated a preference for the 30 degree supination angle for both complex vibration spectrums used and for all three sinusoidal frequencies. This findings suggests the existence of an optimal supination angle for comfort under vibration.

Humans↗
PubMed1981

[Intra-nasal distribution of aerosols with or without vibration].

Intra-nasal distribution of aerosol deposited with or without air flow vibration was investigated by the use of a cast of human nose. In order to analyze the effect of vibration on the particle deposition, the size distribution and the concentration of aerosol were simultaneously measured by an on-lined laser beam scattering particle counter. According to the experimental and the theoretical considerations, it was found that the vibration strongly affected on the motion of particles and then the aerosol particle was more widely and uniformly distributed in the nasal cavity by vibrating the air. This also caused the increasing of particle deposition efficiency and the changing the partial efficiency of each particle size in it. Judging from the above mentioned facts, it was considered that the vibration aerosol therapy would be an useful technique for nasal diseases as well as paranasal sinus diseases.

Aerosols↗