Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “VIBRATION”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,729 records · Page 96Linked to original sources
PubMed1976

The response of alpha-motoneurons of different size to stretch and vibration of extensor muscles after injection of 5-hydroxytryptophan in spinal cats.

1. Vibration of the GS muscle at 100/sec, and the peak-to-peak amplitude of about 100 mu, produced slight reflex activity of homonymous and heteronymous alpha-motoneurons in the spinal, unanesthetized cat. 2. Intravenous injection of the 5-HT precursor 5-HTP (25 mg/kg, L-form) performed in the spinal preparation facilitated the responses of single extensor alpha-motoneurons to both vibration and stretch of the corresponding muscle. The 5-HT antagonist methysergide (0-5 mg/kg i. v.) blocked almost completely the facilitation of the vibration and stretch induced motoneuronal discharges produced by 5-HTP in the spinal cat, indicating that the facilitation was 5-HT specific. 4. A comparison of the types of alpha-motoneurons participating in the reflex responses elicited by the different stimuli in the spinal cat following injection of 5-HTP showed that both small-tonic and large-phasic alpha-motoneurons take part in both stretch and vibration reflexes. 5. It is concluded that the alpha-motoneuron pool of the GS muscle represents an homogenous population, no matter what kind of synaptic drive is used for its activation, and that the susceptibility of a motoneuron to discharge depends on the amount of the afferent excitatory input rather than on the modalities of sensory stimulation.

5-Hydroxytryptophan↗
PubMed2001

Dentist's hand symptoms and high-frequency vibration.

The paper discusses characteristics of mechanical vibration as well as the mechanisms of vibration syndrome. Analysis of the relationship between the high-frequency vibration and the typical symptoms in the hands of the dentists is presented. Suggestions have been offered on how to limit exposure to vibration in the hands of dentists

Carpal Tunnel Syndrome↗
PubMedDate not supplied

[Effects of vibration on contents of micronuclei in polychromatophilic erythrocytes of the rat bone marrow].

The paper presents data on the impact of vibration (32 Hz) on spontaneous mutagenesis in mammals. Higher counts of micronuclei were found in the bone marrow polychromophilic red blood cells in rats on day 5 of exposure to vibration, there was a reduction in their counts by day 20 and their recovery by day 30, and their steady-state decrease within 30 days after vibration discontinuation. The involvement of emotional stress in the mechanism of antimutagenic action of vibration is considered.

Animals↗
PubMed1995

The effects of whole-body vibration on human biodynamic response.

The objective of vibration research at the Armstrong Laboratory includes the expansion and improvement of the measurement, quantification, analysis, and modeling of human vibration response. The driving-point impedance and transmissibility techniques have been expanded and are rigorously applied in the research efforts. Driving-point impedance is defined as the ratio between the transmitted force and input velocity at the point of load application. Transmissibility is typically defined as the ratio between the acceleration level measured at some location on the body and the input acceleration at the seat. These two ratios are used to assess the magnitude and frequency location of resonance behaviors where maximum motions occur in the body. From these data, analytical models are developed which can simulate the motions and coupling behaviors, and predict the stiffness and damping characteristics of the affected anatomical structures. The ultimate goal of the research is to provide new and improved data and modeling capability for revising exposure standards and for developing equipment design guidelines and criteria for improving tolerance and reducing physiological consequences. This paper describes the results of recent studies conducted to identify the biodynamic behavior of major anatomical structures affected by seated whole-body vibration, to develop an analytical model for simulating human vibration response, and to apply the model to evaluate the effects of seat cushion materials on the transmission/attenuation pathways.

Acceleration↗
PubMed1997

Experimental study on biodynamic response to vibration in human and animals.

In order to study the characteristics of human dynamic response to vibration, 56 subjects were exposed to vibration on X, Y and Z axes. It showed that there were two resonance peaks of most local parts of the human body. The curves of transmissibility are essentially the same in all the subjects. It was found that resonance frequencies of the human body decreased with increase of G levels of vibration. These characteristics were also proved in animals. Using three-level artificial neural network, common reflective relation of the resonance frequency with height and weight of the human body and exciting acceleration were obtained. The above findings might be applicable to studies of vibration ergonomics.

Acceleration↗
PubMed1999

[The combined effect of noise and vibration on intelligibility of Chinese syllables].

Objective. The changes of auditory effect on Chinese single syllables uttered by talker under combined condition of noise and vibration were investigated. Method. The intelligibility tests were made under three conditions (quiet, 0 dB and -6 dB S/N ratios). The utterances were recorded under combined factors of noise and vibration, single factor of noise or vibration, and the control condition. Result. As compared with control group, the decrease of speech intelligibilities in combined factors groups was significant. It also occurred in most cases as compared with the single factors groups. It showed that combined effects played greater roles as S/N decreased in listening environment. As S/N was -6 dB, the intelligibilities were less than 70 percent. Conclusion. The speech production will be changed under noise and vibration, and the changes will deteriorate communication, especially in adverse listening environment. The results have important implications for communication in aerospace and military environments.

Aerospace Medicine↗
PubMed2002

Reduced sensory nerve conduction velocity of the distal part of the radial nerve among patients with vibration syndrome.

The present study was aimed at clarifying the effects of vibration syndrome (VS) on the distal part of the radial nerve, which is rarely affected by chronic entrapment. Thirty-one patients with VS due to previous exposure to vibration and 18 age-matched controls were examined for sensory nerve conduction velocities in the distal part of the radial nerve (SCV-DR) in the dorsal side of the hand. The patient group was divided into two subgroups, one of those with vibration-induced white finger (VWF) in the thumb or index finger where sensory nerves are innervated by the radial nerve (N = 21) and the other without VWF (N = 10). SCV-DR among the patients was significantly slower than in the controls (t = 3.55, p = 0.00138). The ANOVA of SCV-DR for the three groups showed F2, 46 = 5.25 (p = 0.0088). A significant difference was found between the controls and the VWF (+) group (p = 0.0233), but not between the controls and the VWF (-) group (p = 0.478) by multiple comparison using Scheffe's method. These findings suggest that VS affects the radial nerve with a direct vibration effect and/or a co-operative effect with direct circulatory disturbance manifested by VWF.

Action Potentials↗
PubMed1975

Effect of vibration on sulfomucopolysaccharide metabolism in the eye.

The metabolism of 35S sodium sulfate was studied in the eyes of guinea pigs and rabbits subjected to vibration. The investigations included determination of radioactivity of whole eyeballs of guinea pigs and in single eyeball tunics of rabbits, i.e., retina-choroid-sclera investigated jointly as a tissue complex, and cornea and lens studied separately, besides that, autoradiographic investigations were performed. The animals were subjected to a vertical, sinusoidal vibration of 42 Hz. frequency and 1 mm. amplitude. The duration of one exposure was three hours and they were repeated daily for three to six days. Incorporation of the isotope into the eyeballs of animals subjected to vibration was decreased and this decrease was related to the length of exposure suggesting that vibration changes the metabolism of sulfomucopolysaccharides in the eye.

Animals↗
PubMed1999

[Quantitative analysis of vocal fold vibration].

OBJECTIVE: To measure vocal fold vibration quantitatively and study the effects of gender and phonation mode. METHOD: The authors adopted a new computerized image analysis technique and EGG in 60 normal speakers, and the parameters of vocal fold vibration were measured and analyzed according to the loudness, pitch and gender. RESULT: With frequency increasing, CQ got smaller and OQ larger which expressed longer open phase. As intensity increased, the duration of open phase became shorter and the closing phase got relatively much shorter. Males had a longer closed phase than females. The closing duration appeared relatively shorter than opening duration in phonation. CONCLUSION: The quantitative measures of vocal fold vibration become feasible with modern computers and commercially available image analysis software. Certain features of vocal fold vibration vary with intensity variations, while others vary with gender or frequency variation.

Adolescent↗
PubMed2002

[Occupational exposure of whole-body vibration in Poland].

Occupational exposure to whole-body vibration may cause health risk. Thus it is important to know the sources of vibration and the number of exposed workers. The aim of the study was to evaluate the number of men and women exposed to whole-body vibration in Poland. The results of the study indicate that almost 50,000 workers are exposed to vibration exceeding the threshold limit values.

Adult↗
PubMed1992

[Changes in the auditory threshold of workers exposed to the combined action of noise and local vibrations].

Study is performed on the effect of noise and local vibrations during a combined effect and independently on the auditory threshold for 4 kHz. The audiometric data of 1242 workers from the textile industry, coal- and ore production are analysed. On the basis of precise assessment of the noise level and occupational exposure to noise and local vibrations are formed 4 groups: exposed to independent noise effect with intensity 90 and 100 db (spinners and dressmakers); exposed to combined effect of noise (91 and 103 db) and local vibrations, surpassing the maximum admissible norms respectively 2.5 and 3.5 times (miners of coal- and ore production). In view of the occupational exposure and standardization concerning age and length of service the audiograms of 248 persons are examined. The following is established: different rate of increase of the auditory threshold for 4 kHz depending on the intensity of the factors noise and local vibrations in conditions of independent and combined effect: positive correlation with the length of service in the changes of the auditory sensoriness; dynamics in the increase of the auditory threshold for 4 KHz.

Adult↗
PubMed1992

Comparison of two activity-controlled rate-adaptive pacing principles: acceleration versus vibration.

Activity-guided rate-adaptive pacing is currently the most widely used principle for rate adaptation. Broad experience has been gathered from several hundred thousand pacemakers that adjust the pacing rate according to vibrational forces detected by a piezosensor bonded to the inner side of the pacemaker can. A new generation of accelerometer-based pacemakers has been introduced into clinical practice. The vibrational type detects vibration, pressure, and shock waves traveling through the body with physical stress and using the pacemaker can as a resonator. In contrast, the accelerometer is insulated from the pacemaker housing and is incorporated into electronic hybrid circuitry. The forces detected by an accelerometer are motion and acceleration of the body in an anterior-posterior direction. Clinical studies conducted to date have shown that the accelerometer to be superior to the conventional vibration activity pacemakers, as far as the discrimination of different workloads and rejection of unwanted environmental noise are concerned.

Acceleration↗
PubMed1992

[Lipid peroxidation and thrombocyte aggregation in vibration disease].

A three-fold increased level of malonic dialdehyde was found in platelets of patients suffering from the first stage of vibration disease, exposed to local vibration. The changes of the fermentative and nonfermentative lipid peroxidation (LPO) were: increased accumulation of malonic dialdehyde (by 2.5 times in ascorbate-dependent LPO and by 2.6 times in NADRH-dependent LPO). Patients with peripheral vasomotor dystonia of the upper limbs combined with vasomotor spasms of the fingers showed NADPH-dependent and ascorbate-dependent LPO respectively 41% and 29% more activated than in patients having no vasomotor spasms. In patient with vibration disease antioxidant activity was reduced by 39% on average, platelet aggregation, both spontaneous and induced by epinephrine, aggristine or adenosinediphosphoric acid, was increased. Platelet hyperaggregation in vibration disease may be caused by stimulated LPO in platelets, amassed end toxic product of LPO, decreased antioxidant activity.

Adult↗
PubMed1992

[The criterial approach to the diagnosis of changes in the osteoarticular apparatus of persons in vibration-hazardous jobs].

A criterial approach to the diagnosis of the skeletal system changes in individuals exposed to industrial vibration, involving the use of the X-ray diagnostic criteria (gerontologic, manual, vertebral) and the criterion based on the absorbed dose of vibration energy (exposure criterion) together with the data on the vibration disease manifestations (clinical criterion), makes it possible to estimate the risk of vibration disease.

Adult↗
PubMed2003

[Nystagmus and vibration test research of mechanisms, theoretical methods: on 52 cases of unilateral vestibular lesions].

OBJECTIVE: The aim of the present study was to examine the characteristics of the Vibratory Nystagmus (VN) optimise the topography and the frequency of the stimulus, determine the origin of the VN and analyse its clinical implications. MATERIAL AND METHOD: 52 severe unilateral vestibular lesions (SUVL) (post-surgical vestibular areflexy) were studied. The vibratory nystagmus was measured by 2D and 3D videonystagmography (Synapsis, France). The stimulus was applied with a 3S vibrator at the vertex, both mastoïds, and posterior cervical muscles at frequencies ranging from 20 to 150 Hz. For topographic optimisation, stimulation was given with S vibrator (Synapsis, France) at 100 Hz. The interferences between the vibratory test (VT) and the caloric test (CT) were studied on the normal ear (in 11 subjects). The same study was carried with the optokinetic test. RESULTS: The VT revealed a defective nystagmus at all frequencies of stimulation. Optimal response was obtained in a band frequency of 80-120 Hz. Stimulations at 100 Hz showed optimal responses for mastoïd topography (responses in 96% of the cases). Stimulation at the posterior cervical muscles and at the vertex indicated respectively a response in 90% and 60% of the cases. The efficiency of the mastoïd stimulation is not correlated with the side of stimulation (p = 0.9). The interference between the VT and caloric test (CT) at cold water (30 degrees et 20 degrees C) exhibited the inversion of the caloric nystagmus during the vibrator stimulation. The resulting nystagmus is respectively an algebric subtraction or addition between the pre-existing caloric nystagmus and the value of the vibratory nystagmus obtained before caloric test. Adaptation of the VN is moderate. The interference between the VT and the optokinetic test resulted in a subtraction or addition effect, according to the side of the lesion and the direction of the optokinetic stimulus. CONCLUSION: The VT is an efficient stimulation in mastoïd topography. The vestibular contribution is bilateral by bony conduction of the vibration, it explores frequencies ranging from 30 to 120 Hz, with a maximum of response at 100 Hz. The VT interacts with the caloric test and the optokinetic test. The stimulation is very strong, and is able to inverse the caloric nystagmus at cold water stimulation (20 degrees C). In labyrinthine-defective subjects, the VN is always defective at all frequencies, whatever is the topographic location of the stimulus, and the position of the head.

Caloric Tests↗
PubMed2003

[Hand-arm vibration syndrome in foundry workers].

INTRODUCTION: The hand-arm vibration syndrome of the foundry workers using chipping hammers and grinders were analysed in Hungary last in 1950th-s years. Therefore it seemed necessary to consider the present situation of the disease. AIM: To study of the signs of the hand-arm vibration syndrome of the foundry workers using chipping hammers and grinders. METHOD: Retrospective analysis of the clinical findings of 154 foundry workers using chipping hammers and grinders. The examination included the vascular, neurological and musculoskeletal systems of the upper extremities in 95 patients. RESULTS: The first symptoms referring to hand-arm vibration syndrome appeared on the average after seven years exposure. The signs of the 95 patients were as follows: vascular disorders: 75 cases (78.9%), peripheral neurologic lesion: 62 cases (65.3%), osteoarticular damage: 35 patients (36.8%). The Raynaud's phenomenon developed more commonly on the left than the right hand. The rate of the improvement of the Raynaud's phenomenon on the average 6.5 years after the cessation of the exposure on the basis of the result of the cold provocation test was 32.8%. Lesion of the peripheral nerves of the upper limbs, mostly of distal type was experienced in 41, whereas tunnel syndromes of the upper extremities in 21 cases. The most common amongst the latter (18 cases) was the thoracic outlet syndrome. Osteoporosis of the carpal bones was detected in 36 patients (37.9%), but osteoarthrosis of the joints of the upper limbs in 12 cases (12.6%). There was no aseptic necrosis of the bones. Fatigue fracture of the spinous process of the cervical VII vertebra occurred in one single case. CONCLUSIONS: Using chipping hammers and grinders in foundry is one of the most dangerous hand-arm vibration exposure in Hungary. The most frequent signs are the vascular and neurological lesions. Due to relatively rare occurrence of osteoarticular damages X-ray examinations are not necessary during periodical medical follow up. The most effective possibility of the prevention is the diminishing of the daily exposure time.

Adult↗
PubMedDate not supplied

[Neck vibration: usefulness in neurotology].

INTRODUCTION: Recently, mechanical vibration on the neck has begun to be used to improve diagnostic sensitivity in patients who have vestibular disorders. METHOD: We review results of studies of this stimulus in normal subjects and patients with vestibular lesions: the ocular responses, changes in the subjective straight ahead, and postural changes generated by the neck vibration. CONCLUSION: Although the underlying mechanism for the responses to neck vibration remains uncertain, it is an excellent addition to the neurotologic exam since it allows us demonstrate vestibular deficit with greater sensitivity than other maneuvers. As vibration is easy to apply it can be useful for screening in patients who complain of dizziness.

Eye Movements↗
PubMed1992

Vibration of the spine and low back pain.

There are now many studies suggesting a positive relationship between both low back pain and spinal degeneration and exposure to whole body vibration. Such relationships appear to be particularly marked in drivers of tractors, earth-moving equipment, and trucks. There is a tendency toward a greater incidence of complaints as exposure increases. Vibration affects the spine by exciting a 4-6-Hz resonance that is related to the biologic "soft spring" between S-1 and the seat. The muscle nerves fire sequentially under vibration and fatigue. In animals, vibration exposure leads to pronounced creep, increased disk pressure, and changes in the levels of neuropeptides in the dorsal root ganglia.

Animals↗