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 1,675 records · Page 93Linked to original sources
PubMedDate not supplied

An automatic method to quantify the vibration properties of human vocal folds via videokymography.

The study offers an automatical quantitative method to obtain vibration properties of human vocal folds via videokymography. The presented method is based on image processing, which combines an active contour model with a genetic algorithm to improve detecting precision and processing speed, can accurately extract the vibration wave in videokymograms and quantify the vibration properties in terms of eight typical parameters automatically. To verify the precision of the proposed algorithm, an indirect simulation setup of vocal folds has been performed. The verification result shows that the relative error of the entire simulation system is less than 5%. Applying the method to analyzing hundreds of videokymograms from 12 subjects, the result indicates that the vibration characteristics of vocal folds can be recognized more exactly, and diseases of the vocal folds can be diagnosed quantitatively.

Algorithms↗
PubMed1991

Vibration-evoked startle behavior in larval lampreys.

Larval lampreys (ammocoetes) exhibit a rapid vibration-evoked startle response involving a bilateral activation of musculature along the length of the body. The resulting movement is variable, contingent on the animal's prestimulus posture: lateral curves along the trunk and tail contract more on the inner side of the curve than on the outer side. Thus, the startle response increases preexisting body curvature. Because ammocoetes are burrowing filter feeders, this startle behavior results in rapid withdrawal of the head into the burrow. A vibratory pulse to the otic capsules in a semi-intact preparation evokes simultaneous action potentials in both primary Mauthner neurons. Vibration also excites several Müller cells. Intracellular stimulation of one primary Mauthner axon (eliciting one action potential) produces bilateral trunk electromyographic potentials that are smaller than those evoked by vibration; simultaneous stimulation of both Mauthner axons (one action potential each) reproduces the vibration-evoked electromyographic amplitudes. The Mauthner cell's sensitivity to vestibular input is centrally modulated during changes in behavioral state. Mauthner action potentials are most easily elicited by vibratory or electrical stimulation of vestibular afferents while an intact animal is at rest; the same stimuli become subthreshold for Mauthner activity while the animal is swimming. A similar depression of Mauthner excitability is observed in semi-intact preparations during arousal. 'Arousal' was defined by the occurrence of tonic, descending spinal cord discharge. Mauthner cells are tonically depolarized during arousal and exhibit an increased membrane conductance; excitatory postsynaptic potentials evoked by vibratory or electrical stimulation of vestibular afferents are greatly attenuated. Modulated sensory transmission to the Mauthner cell may help to prevent inappropriate activation of the startle circuit.

Animals↗
PubMed1987

Vibrational analysis of bioprosthetic heart valve leaflets using numerical models: effects of leaflet stiffening, calcification, and perforation.

The fundamental natural frequency of the closed cusps of porcine bioprosthetic valves, fabricated from the normal leaflets of pig aortic valves, was estimated using a finite element model. Both normal and stiffened leaflets were considered in the vibrational analysis. The effects of conditions that simulated degeneration, such as stiffening, central perforation, a tear, calcium deposits in the commissural attachments, and combinations of these were determined. The primary frequency of vibration of the normal leaflets was within the range of the dominant frequency of the heart sounds determined clinically by spectral analysis of the recorded phonocardiogram. If only one leaflet was stiffened or calcified, there was only a marginal change of frequency. With stiffening and calcification of the commissures of all 3 leaflets, the frequency of vibration increased. Introduction of a tear in a single leaflet of a stiffened and calcified valve markedly reduced the fundamental frequency. In view of the relation between the frequency content of heart sounds and the frequency of valve vibration, this mathematical simulation establishes a possible basis for the observation of a varying dominant frequency of heart sounds in patients with bioprosthetic valves that are in the process of degenerating.

Biomechanical Phenomena↗
PubMed2006

Long-term effects of 6-week whole-body vibration on balance recovery and activities of daily living in the postacute phase of stroke: a randomized, controlled trial.

BACKGROUND AND PURPOSE: The long-term effects of 6-weeks whole-body vibration, as a novel method of somatosensory stimulation, on postural control and activities of daily living were compared with those of 6 weeks of exercise therapy on music of the same intensity in the postacute phase of stroke. METHODS: Fifty-three patients with moderate to severe functional disabilities were randomized within 6 weeks poststroke and within 3 days after admission to a rehabilitation center to either whole-body vibration or exercise therapy on music in addition to a regular inpatient rehabilitation program. The whole-body vibration group received 4x45-second stimulation on the Galileo 900 (30-Hz frontal plane oscillations of 3-mm amplitude) for 5 days per week during 6 weeks. The exercise therapy on music group received the same amount of exercise therapy on music. Outcome variables included the Berg Balance Scale, Trunk Control Test, Rivermead Mobility Index, Barthel Index, Functional Ambulation Categories, Motricity Index, and somatosensory threshold at 0, 6, and 12 weeks follow up. RESULTS: At baseline, both groups were comparable in terms of prognostic factors and outcome measures. Both at 6 and 12 weeks follow up, no clinically relevant or statistical differences in outcome were observed between the groups. No side effects were reported. CONCLUSIONS: Daily sessions of whole-body vibration during 6 weeks are not more effective in terms of recovery of balance and activities of daily living than the same amount of exercise therapy on music in the postacute phase of stroke.

Activities of Daily Living↗
PubMed1976

A preliminary study of the effect of a vibrating pad on bronchial clearance.

The effect of vibration (41.0 +/- 5.4 Hz; 2 mm amplitude) on the clearance of lung secretions was ascertained in 10 patients with chronic bronchitis who complained of difficulty in raising sputum. Vibration was applied to the back for one hour by an electrically driven pad while the patients reclined on a couch with the trunk at 45 degrees to the vertical. Each patient had randomized control and experimental runs of 5 hours' duration that were identical in all respects except for vibration. The rate of clearance of secretions from the lung was assessed by serial whole lung counts after inhaling monodispersed tracer particles tagged with a gamma-emitting radioisotope (technetium-99m) and by sputum production. The mean rates of clearance and of sputum production were slightly higher during the vibration runs than the control runs but the differences were not significant.

Aged↗
PubMed1981

The effect of mechanical vibration physiotherapy on arterial oxygenation in acutely ill patients with atelectasis or pneumonia.

The effect of mechanical chest vibration on arterial blood gases was studied in 10 patients requiring oxygen therapy who had acute lung disease and an abnormal chest roentgenogram. Eight patients were using mechanical ventilators. For the duration of the study, patients were seated or in a high semi-Fowlers position. No other pharmacologic or physical therapy was given during the study period, nor was there any change in the fraction of inspired oxygen or the respirator settings. The patients ranged from 23 to 89 yr of age. After control blood gas measurements were taken, each patient received 30 min of mechanical vibration to the thorax followed immediately by tracheal suction. Blood gases were re-examined 30 min and 1 h after completion of the physiotherapy. Results showed a significant increase in PO2 at 30 min and 1 h after completion of mechanical chest vibration with no change in PCO2 or pH. This study demonstrated that external mechanical vibration of the chest is a useful therapeutic modality in the management of hypoxemia in patients with atelectasis or pneumonia. This was reflected by the increase in PO2 with no change in alveolar ventilation. We presume the better matching of ventilation to perfusion accounted for our results.

Adult↗
PubMed1985

Effects of diltiazem on occupational Raynaud's syndrome (vibration disease).

An open trial on the therapeutic effect of diltiazem, a calcium antagonist, was conducted on occupational Raynaud's syndrome (vibration disease). Seventeen men with vibration disease were studied. The mean age was 54 years. No patient had cardiovascular disease. Primary and secondary cases of Raynaud's phenomenon were excluded. Diltiazem, 30mg orally 3 times daily, was given to the patients for 6 weeks. Before and after this treatment period, we evaluated the subjective symptoms (11 items including Raynaud's phenomenon, numbness of hands and arms, stiffness of shoulder and neck, and others) and peripheral function (by cold water immersion test, vibration and pain sensations for fingers, tapping test, and momentary grasp strength test), and did laboratory blood tests (12 variables). The "effective" rates of subjective symptoms evaluating by the method of 5 steps and the peripheral function was 69.6% and 52.9%, respectively. The overall effectiveness of diltiazem therapy was assessed by collectively evaluating the changes in subjective symptoms, peripheral functions, and the occurrence of side effects. No side effects occurred during the treatment period. Thus, the collective effectiveness of diltiazem was 64.7%. In conclusion, diltiazem, a calcium antagonist, can be effective in long-term treatment of patients with vibration disease.

Benzazepines↗
PubMed1984

Development of an implantable hearing aid using a piezoelectric vibrator of bimorph design: state of the art.

A new, implantable hearing aid has been developed. An ultraminiature electric microphone placed under the skin of the external ear canal transduces sound waves into electrical impulses that are amplified with battery power. The amplified electrical impulses are fed into a piezoelectric vibrator directly in contact with the stapes. The vibrator transduces the electrical impulses into mechanical vibration with minimal consumption of electrical energy. Direct coupling of the vibrator to the stapes allows a high degree of fidelity in the perception of sound. The developmental process and the structure and function of each component are described together with clinical problems. Preliminary and tentative implantation of this new device during middle ear surgery indicated that it would be beneficial to patients who have suffered hearing loss from middle ear disease and whose condition does not lend itself to surgical correction.

Electric Power Supplies↗
PubMed1996

A search for possible cytogenetic effects of low frequency vibrations in cultured human lymphocytes.

1. Acute cytogenetic effects expressed as sister-chromatid exchanges (SCE) in peripheral blood lymphocytes were investigated after in vitro exposure to low vibration regimes (5-30 Hz. at 0.1 cm amplitude) for 20 min intervals and compared to non-vibrated control cultures. 2. There was no significant (P < 0.05) increase in the range of SCE incidence at any vibration frequency compared to the mean value of control; 6.88 +/- 0.11 to 7.97 +/- 0.22 versus 6.83 +/- 0.86, respectively. 3. When cultures were incubated for 1 h in the presence of 0.5 microgram ml-1 mitomycin C (MMC; the positive control) significant elevations in the SCE frequency were observed (19.81 +/- 0.67), indicating the sensitivity of the system to in vitro SCE induction. 4. Other cell parameters, such as mitotic index and cell proliferation index were statistically similar in the experimental cultures and the negative control. 5. The observed differences in the investigated end-points are considered within those typically found in vitro. This suggests no relation between low frequency vibrations and cytogenetic effects.

Adult↗
PubMed2001

Vibrational angioplasty in the treatment of chronic femoropopliteal arterial occlusions: preliminary experience.

PURPOSE: To evaluate the safety and efficacy of vibrational angioplasty in chronic femoropopliteal arterial occlusions. METHODS: Six patients (5 men; ages 52 to 84 years) with peripheral arterial occlusive disease were treated percutaneously using vibrational angioplasty to recanalize the lesion. Three occlusions ranging from 10 to 15 cm long were in the superficial femoral artery (SFA), while 3 other diffusely diseased popliteal arteries were occluded distally (length from 3.5 to 4.5 cm). Vibrational angioplasty using coronary equipment was applied to assist passage of a coronary guidewire, which was followed by conventional angioplasty. Follow-up surveillance featured periodic physical examination, ankle brachial index measurements, and duplex scanning. RESULTS: In all 6 cases, recanalization of the occlusions was successful and without complications. The time to cross the occlusions with the wire ranged from 20 to 25 minutes for the SFA lesions and from 4 to 10 minutes for the popliteal occlusions. Two SFA occlusions were treated with stent implantation. Over a follow-up of 3 to 9 months, all treated vessels were patent. In 3 patients with skin ulcers, healing of the ulcers was observed. CONCLUSIONS: Vibrational angioplasty using coronary guidewires seems to be a promising ancillary technique in the management of chronic femoropopliteal arterial occlusions.

Aged↗
PubMed2004

Airway clearance in bronchiectasis: a randomized crossover trial of active cycle of breathing techniques (incorporating postural drainage and vibration) versus test of incremental respiratory endurance.

OBJECTIVES: The purpose of this study was to compare the efficacy of the test of incremental respiratory endurance (TIRE) with active cycle of breathing techniques (ACBT) [incorporating postural drainage (PD) and vibration] as methods of airway clearance in adults with bronchiectasis. DESIGN: A randomized crossover study in which a single session of ACBT (incorporating PD and vibration) was compared to a single session of TIRE was carried out in 20 patients (14 female) with stable, productive bronchiectasis. MEASUREMENTS: Weight of sputum (treatment plus 30 min) was the primary outcome measure recorded. Pre- and post-treatment measures of lung function and SpO2 were also recorded. RESULTS: All 20 patients were stable during the study period. Sputum weight expectorated during and 30 min post-ACBT (incorporating PD and vibration) treatment was significantly greater than the sputum weight expectorated during and 30 min post-TIRE treatment [mean difference 2.44 g (95% CI 0.43-4.45)]. CONCLUSION: ACBT (incorporating PD and vibration) is a more effective method of airway clearance in bronchiectasis than TIRE during single treatment sessions.

Bronchiectasis↗
PubMed1999

Abnormal perception of vibration-induced illusion of movement in dystonia.

OBJECTIVES: To examine the illusional sensation of movement evoked by vibration of an immobilized arm. METHODS: Patients with idiopathic focal dystonia were compared with those with idiopathic PD and with patients with dystonia secondary to PD. A 100-Hz transcutaneous vibratory stimulus was applied to the biceps brachii tendon to elicit an illusional sensation of arm extension. Blindfolded patients were instructed to copy any perceived movement of the vibrated arm with the opposite (tracking) arm. By recording movement of reflective markers on the tracking arm using infrared video cameras, the change in elbow angle was quantified over 45 seconds. The effect of treatment with botulinum toxin was examined by retesting previously untreated patients after commencing therapy. These results were also compared with patients with hemifacial spasm who had ongoing treatment with botulinum toxin. RESULTS: Vibration of the biceps in dystonic patients produced a smaller sensation of arm extension than in control subjects unaffected by botulinum toxin treatment. There were no differences between the types of idiopathic focal dystonia examined, including patients with dystonia in sites other than the arm. Those with idiopathic PD and hemifacial spasm did not differ from healthy control subjects. Patients with dystonia secondary to PD showed a unilateral abnormality on the side of dystonic symptoms. CONCLUSION: Bilateral abnormal perception of the illusion of vibration-induced movement is a feature of idiopathic focal dystonia but not idiopathic PD, and is independent of treatment with botulinum toxin. Unilateral, abnormal sensorimotor integration is implicated in dystonia secondary to PD. These results may reflect abnormal sensorimotor integration of Ia afferent activity.

Adult↗
PubMed2006

Flexibility enhancement with vibration: Acute and long-term.

INTRODUCTION: The most popular method of stretching is static stretching. Vibration may provide a means of enhancing range of motion beyond that of static stretching alone. PURPOSE: This study sought to observe the effects of vibration on static stretching to determine whether vibration-aided static stretching could enhance range of motion acquisition more than static stretching alone in the forward split position. METHODS: Ten highly trained male volunteer gymnasts were randomly assigned to experimental (N = 5) and control (N = 5) groups. The test was a forward split with the rear knee flexed to prevent pelvic misalignment. Height of the anterior iliac spine of the pelvis was measured at the lowest split position. Athletes stretched forward and rearward legs to the point of discomfort for 10 s followed by 5 s of rest, repeated four times on each leg and split position (4 min total). The experimental group stretched with the device turned on; the control group stretched with the device turned off. A pretest was followed by an acute phase posttest, then a second posttest measurement was performed following 4 wk of treatment. Difference scores were analyzed. RESULTS: The acute phase showed dramatic increases in forward split flexibility for both legs (P < 0.05), whereas the long-term test showed a statistically significant increase in range of motion on the right rear leg split only (P < 0.05). Effect sizes indicated large effects in all cases. CONCLUSION: This study showed that vibration can be a promising means of increasing range of motion beyond that obtained with static stretching in highly trained male gymnasts.

Biomechanical Phenomena↗
PubMed1986

Observations on the effects of vibration and noise on plasma ACTH and zinc levels, pregnancy and respiration rate in the guineapig.

The responses of female guineapigs to vibration and noise were examined with the use of an apparatus designed to simulate transport. Peak levels of plasma ACTH and zinc concentrations were attained after 4 min of exposure to vibration and 80-90 dB of noise. The respiration rate, normally around 90/min, was increased to 103/min when the animals were moved (while still in their cages) to the experimental area; it rose to 129/min when the apparatus was switched on to expose the animals to vibration and noise. Those left adjacent to the apparatus and exposed to noise alone elevated their respiration rates to 115/min. Respiration rates returned to normal within 2.5 h. There was no apparent effect on the maintenance of pregnancy, gestation length, litter size or post-partum growth of the young born to guineapigs exposed to this vibration and noise for a period of 1 h at mid-term.

Adrenocorticotropic Hormone↗
PubMed1987

Vibration arthrography as a diagnostic aid in diseases of the knee. A preliminary report.

The detection and recording of vibration emission from human joints, a technique which we have termed "vibration arthrography", is a sensitive, non-invasive method for the objective study of the locomotor system. Using vibration sensors attached to bony prominences around the knee, we studied the joints of both normal and symptomatic subjects. Normal subjects produced three signal types--physiological patellofemoral crepitus, patellar clicks, and the lateral band signal. In symptomatic subjects we identified and categorised many signal types and related them to pathology. Lesions of the menisci produced distinctive signals, and it was possible not only to lateralise the tear, but in many cases to determine the type of meniscal injury present. Vibration arthrography promises to be a useful tool in the non-invasive diagnosis of knee disorders.

Auscultation↗
PubMed1984

Effect of chest wall vibrations on pulmonary function in chronic bronchitis.

Manual chest wall vibration is one physiotherapeutic technique frequently employed in the management of respiratory disease. A clinical study was undertaken to examine the effects of manual chest wall vibrations on pulmonary function and arterial oxygen saturation in patients with chronic bronchitis. Twelve patients participated in a three-day experimental design where the factors of three different days and three different treatments were randomized and balanced. On one day, deep-breathing exercises were given; on another, deep-breathing exercises with vibrations; and on the remaining day, no treatment was given. Lung volumes were measured before and after each maneuver, and arterial oxygen saturation was monitored continuously. There was a significant decrease in the expiratory reserve volume (ERV) immediately following the deep-breathing exercises alone, which remained constant after the 15-minute rest period (p = 0.032). The remaining outcome parameters do not appear to be significantly affected. Chest wall vibrations do not decrease the ERV in patients with chronic bronchitis.

Aged↗
PubMed1979

[A study on the vibration hazards due to using bush cutters (author's transl)].

Bush cutters were introduced into Japanese forestry for cutting bush in 1957 or thereabout. Thereafter, they have been used widely not only in forestry but also in agriculture, public engineering, etc. In spite of the fact that vibration acceleration levels of the bush cutters are high, vibration hazards due to using these tools have not been studied. The reason lies in few professions using bush cutters exclusively. Moreover, the tool is only used seasonally from June to September. The author examined 641 bush cutters users in the State Forestry in southern Kyushu and compared the results with a sample of chain saw users matched by age, duration of use, and district. The prevalence rate of Raynaud's phenomenon is 0.4% at 4 years after beginning the use of bush cutters, 4.0% after 10 years and 9.2% after 18 years. The prevalence of Raynaud's phenomenon in chain saw users is twice as great as that in bush cutter users. Bush cutter users are attacked by Raynaud's phenomenon after about 1,000 hours' use of the tool. The difference is regarded to depend on the difference in the density of use and the difference in the levels of vibration acceleration. The vibration hazards due to using bush cutters were characterized by relatively mild complaints in the upper extremities, together with disturbances of peripheral circulation but not always with peripheral neuropathy.

Adult↗
PubMed1983

[Vibration syndrome among forestry workers. Subjective symptoms and diagnostic norm].

Three hundred fourteen male forestry workers using vibrating tools were analyzed to evaluate the relationship among 11 items of the special examinations for the diagnosis of vibration syndrome and the relationship between the items and 13 subjective symptoms. The following results were obtained: Age of the workers had the strongest relationship to the grip strength. However, it showed less strong relationship with other items, such as the threshold of pain sense and that of vibration sense, and the degree of Raynaud's phenomenon (number of fingers affected). Working time in years with vibrating tools showed statistically significant correlations with the threshold of pain sense, that of vibratory sense, and with the degree of Raynaud's phenomenon. The threshold of pain sense, that of vibratory sense, and the degree of Raynaud's phenomenon correlated with each other but not with the skin temperature nor the recovery time of blood flow in the finger nail-beds. The rise of pain threshold exhibited the strongest association with the subjective symptoms. Vibratory sense threshold at 250 Hz also showed similar association with the latter. The skin temperature and the recovery time of blood flow had no association with any complaints except for gastric disorders. The grip strength, only when extremely lowered, was associated with the rise of ratio of complaints, i.e. percentage of the number of workers who complain among all the workers. The age was associated in general with the decreased ratio of complaints except for muscle weakness in arms and forgetfulness.

Age Factors↗