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At least 1,189 records · Page 66Linked to original sources
PubMed2004

Vocal fold vibration and voice source aperiodicity in 'dist' tones: a study of a timbral ornament in rock singing.

The acoustic characteristics of so-called 'dist' tones, commonly used in singing rock music, are analyzed in a case study. In an initial experiment a professional rock singer produced examples of 'dist' tones. The tones were found to contain aperiodicity, SPL at 0.3 m varied between 90 and 96 dB, and subglottal pressure varied in the range of 20-43 cm H2O, a doubling yielding, on average, an SPL increase of 2.3 dB. In a second experiment, the associated vocal fold vibration patterns were recorded by digital high-speed imaging of the same singer. Inverse filtering of the simultaneously recorded audio signal showed that the aperiodicity was caused by a low frequency modulation of the flow glottogram pulse amplitude. This modulation was produced by an aperiodic or periodic vibration of the supraglottic mucosa. This vibration reduced the pulse amplitude by obstructing the airway for some of the pulses produced by the apparently periodically vibrating vocal folds. The supraglottic mucosa vibration can be assumed to be driven by the high airflow produced by the elevated subglottal pressure.

Air Pressure↗
PubMed1981

A study of various function tests on the upper extremities for vibration syndrome.

For early diagnosis of vibration syndrome, it is necessary to detect the insidious functional disorders which appear without organic changes in it's early stage. In Japan, peripheral circulation and sensory tests, including tests after cold water immersion, and functional capacity motor tests are performed widely on the upper extremities. We have examined workers exposed to three kinds of vibration, and control workers, using these function tests, and analyzed the data with the use of principal component analysis. As a result, these function tests were considered to be of diagnostic significance as a screening test for vibration syndrome. It is also suspected that peripheral circulation disturbance, sensory disturbance and motor disturbance found in vibration syndrome advance independently of each other. Disparities in the findings of vibration syndrome were recognized and were attributed to differences of work conditions.

Adult↗
PubMed1998

Whole-body vibration of tractor drivers during harrowing.

The seat vibration of nine tractors was investigated while drivers harrowed fields in eastern Finland. The vibration acceleration of the tractor driver's seat was measured simultaneously along three mutually perpendicular axes. The triaxial seat-accelerometer was used for the measurements. The vibration signals were amplified with charge amplifiers and recorded with an FM tape recorder. The samples were analyzed with a real-time analyzer. In all cases, the average vibration of the seat exceeded the 8-hour "fatigue-decreased proficiency boundary" specified in the international standard ISO 2631/1. The instantaneous accelerations of the most harmful one-third octave band of vibration were sometimes two- to threefold compared with the average.

Agricultural Workers' Diseases↗
PubMed2006

Whole-body vibration training compared with resistance training: effect on spasticity, muscle strength and motor performance in adults with cerebral palsy.

OBJECTIVE: The aim of this study was to evaluate the effect on spasticity, muscle strength and motor performance after 8 weeks of whole-body vibration training compared with resistance training in adults with cerebral palsy. METHODS: Fourteen persons with spastic diplegia (21-41 years) were randomized to intervention with either whole-body vibration training (n=7) or resistance training (n=7). Pre- and post-training measures of spasticity using the modified Ashworth scale, muscle strength using isokinetic dynamometry, walking ability using Six-Minute Walk Test, balance using Timed Up and Go test and gross motor performance using Gross Motor Function Measure were performed. RESULTS: Spasticity decreased in knee extensors in the whole-body vibration group. Muscle strength increased in the resistance training group at the velocity 30 degrees /s and in both groups at 90 degrees /s. Six-Minute Walk Test and Timed Up and Go test did not change significantly. Gross Motor Function Measure increased in the whole-body vibration group. CONCLUSION: These data suggest that an 8-week intervention of whole-body vibration training or resistance training can increase muscle strength, without negative effect on spasticity, in adults with cerebral palsy.

Adult↗
PubMedDate not supplied

Consequences of polymorphism of 5'-GMP.Na2 in the vibrational spectra of metal complexes and isotopic derivatives.

The commercial mononucleotides are frequently used to obtain metal complexes and isotopic derivatives. Normally, the spectra of these new compounds are compared with the spectra of the commercial mononucleotides. Nevertheless, important variations in the vibrational spectra of the disodium 5'-guanosine monophosphate, 5'-GMP, have been observed in this work produced by submitting the commercial salt to the same general laboratory process that the obtained compounds, i.e., solving the commercial salt in water and subsequent recrystallization. These changes have been analyzed and interpreted. The variations are not significant in disodium 5'-cytosine monophosphate, 5'-CMP. It is important to take this information into account before carrying out vibrational studies with this type of molecules, since some bands attributed to isotopic substitutions or to the metal attack may be a result of manipulation of the nucleotide (solving and recrystallization) instead of the studied effect. Thus, before any work in which the nucleotide salt is manipulated (deuteration, synthesis of other isotopic derivatives or metal-nucleotide complexes), it should be noted that the process to which the sample is submitted on its own is enough to modify the vibrational spectrum. Then, attention should be paid to the changes observed in the vibrational spectra of recrystallized mononucleotides, since recrystallization may lead to a considerable phase change, and this can notably alter the vibrational spectra.

Crystallization↗
PubMed1984

Mapping electric currents around skeletal muscle with a vibrating probe.

A vibrating microelectrode, or vibrating probe (Jaffe and Nuccitelli, 1974), was used to map the pattern of artificially created electric currents flowing around single muscle fibers at the edge of frog cutaneous pectoris muscles. When a muscle fiber was impaled with a micropipette, a "point sink" of current was often created at the site of impalement because of injury to the cell membrane. Current, being drawn from the flanking membrane, flowed into the cell only at this point. This defined current allowed us to map the spatial resolving power of the vibrating probe by moving to different positions near the impalement site. The results suggest that under our experimental conditions the limit of resolution is a few tens of micrometers. The results were fit reasonably well by a computer model. Current was also passed through a micropipette and mapped at various positions with the vibrating probe. In this case, the current flowed to a remote reference electrode. With the current electrode in the extracellular fluid, the probe signal decayed as the inverse square of the distance, as expected. With the current electrode placed intracellularly, current was funneled along the muscle fiber axis, reflecting its cable-like properties. The signal recorded by the vibrating probe was altered accordingly, and the results could be well fit by a simple model.

Animals↗
PubMed2002

A descriptive study of women injured by hand-arm vibration.

The aim of this study was to describe the symptoms and the prognosis of vibration injuries in women. The investigation was based on a study of 374 women who had reported an injury due to hand-arm vibration to the Social Insurance Office or had received financial compensation from the Swedish Labor Market Insurance scheme during 1988-1997. Information on, for example, self-rated health symptoms and vibration exposure was collected by means of a questionnaire. On average, the first symptoms started after 7 yr of exposure and the first visit to a doctor took place after 11 yr. Neurological symptoms developed after a shorter period of exposure compared to vascular symptoms, 6.8 and 9.2 yr, respectively. The prevalence of numbness at the time of reporting the injury was 91% and the prevalence of white fingers was reported by 54%. The occupational group with the highest prevalence of vibration injuries was dental technicians. Two thirds of the women had stopped using vibrating machines in their work. Among the women who suffered from white fingers when they reported the injury, 50% declared impairment or no improvement of the symptoms. One woman in five was retired and the same number of women had retrained due to the occupational injury.

Adult↗
PubMed2001

Hand-arm vibration syndrome from exposure to high-pressure hoses.

Hand-arm vibration syndrome has been reported in the literature to occur following exposure to vibration from the use of many tools, but to date there have been no case reports of its occurrence in workers who have used high-pressure hoses, alone or with other tools. To remedy this, the case histories of nine subjects (two without mixed exposure) examined in the UK and Canada are presented, together with their severity classified according to the Stockholm scales. Attention is drawn to the need to use multiple diagnostic tests to establish the diagnosis and the need to implement vibration isolation and damping methodologies, as and when feasible, with respect to hose nozzles in order to minimize the hazard. The ultimate goal for tool manufacturers, hygienists and engineers should be to reduce workplace vibration levels to meet national and international guidelines and legislation, including UK Health & Safety Executive guidelines and European Economic Community directives. The respective risk levels are presented, together with vibration measurements on hoses used by some of the cases.

Canada↗
PubMed2006

Hand-arm vibration syndrome with concomitant arterial thrombosis in the hands.

BACKGROUND: Hand-arm vibration syndrome (HAVS) refers to the vascular, neurological and musculoskeletal effects that may occur in workers with prolonged exposure to vibrating tools. Hypothenar hammer syndrome (HHS) is a lesion of the ulnar artery at the level of the hamate bone secondary to single or repeated episodes of trauma to the hypothenar eminence. The literature suggests that digital arterial thrombosis and HHS may be associated with the use of vibrating tools. AIM: This study will familiarize investigators with the range of vascular abnormalities seen in workers using vibrating tools, and highlight the importance of screening for arterial thrombosis in the hand when assessing hand-arm vibration-exposed patients. METHODS: In the patients referred to our clinic for HAVS assessment, three were identified during the period 2001 to 2004 who had vascular occlusions in the hands in addition to HAVS. In addition to standardized HAVS vascular investigations, all three patients had arteriograms based on a significantly positive Allen's test. RESULTS: All three cases had documented HAVS based on vascular testing. Arteriograms revealed a spectrum of severity of arterial thromboses from severe HHS, to occlusion limited to the digital arteries. CONCLUSION: Our study reports three cases of HAVS with concomitant HHS and/or digital artery thrombosis. These findings support previous reports of an association between HAVS and vascular thrombosis in the hands. Screening for arterial occlusive problems in the hands should be included in the HAVS work up.

Adult↗
PubMed2006

Hand-arm vibration syndrome in South African gold miners.

BACKGROUND: Hand-arm vibration syndrome (HAVS) is associated with the use of hand-held vibrating tools. Affected workers may experience symptoms of tingling, numbness, loss of grip strength and pain. Loss of dexterity may impair everyday activities, and potentially increase the risk of occupational accidents. Although high vibration levels (up to 31 m/s(2)) have been measured in association with rock drills, HAVS has not been scientifically evaluated in the South African mining industry. AIMS: The aim of this study was to determine the prevalence and severity of HAVS in South African gold miners, and to identify the tools responsible. METHODS: A cross-sectional study was conducted in a single South African gold-mine. Participants were randomly selected from mineworkers returning from annual leave, comprising 156 subjects with occupational exposure to vibration, and 140 workers with no exposure. Miners who consented to participate underwent a clinical HAVS assessment following the UK Health and Safety Laboratory protocol. RESULTS: The prevalence of HAVS in vibration-exposed gold miners was 15%, with a mean latent period of 5.6 years. Among the non-exposed comparison group, 5% had signs and symptoms indistinguishable from HAVS. This difference was statistically significant (P < 0.05). All the cases of HAVS gave a history of exposure to rock drills. CONCLUSIONS: The study has diagnosed the first cases of HAVS in the South African mining industry. The prevalence of HAVS was lower than expected, and possible explanations for this may include a survivor population, and lack of vascular symptom reporting due to warm-ambient temperatures.

Adult↗
PubMed1981

Effects of the asymmetric tonic neck reflex and high-frequency muscle vibration on isometric wrist extension strength in normal adults.

The effects of the asymmetric tonic neck reflex and high-frequency muscle vibration on isometric wrist extension strength were studied in 150 normal, right-handed adults between the ages of 18 and 40. Subjects were randomly assigned to one of five groups. From data collected from two control groups, we determined any confounding effects of fatigue, experimental learning, or weight of the vibrator in contact with the skin surface overlying the wrist extensor muscle bellies. From measurements taken from three experimental groups, we determined the individual and combined effects of the asymmetric tonic neck reflex and vibration. The reflex was elicited with active head rotation. Strength significantly increased with active head rotation toward the extending wrist; active head rotation away from the wrist significantly decreased strength. Vibration of the extensor surface of the forearm with the head in neutral significantly increased strength. The combination of active head rotation toward the extending wrist and vibration of the extensor surface resulted in a greater increase in strength than did either technique individually.

Adolescent↗
PubMed1983

Effect of vibration on tactile sensitivity.

Tactile hypersensitivity is a common sequela of traumatic hand injury. Vibration is used clinically to reduce this hypersensitivity. The purpose of this study was to determine if vibration has an effect on tactile threshold and if so to determine the duration of that effect. Mean tactile thresholds were determined for 24 healthy adults by means of a pressure aesthesiometer. The experimental group (6 men, 6 women) received 10 minutes of vibration. Mean tactile thresholds were redetermined at the end of the 10-minute treatment period in the experimental group and after a 10-minute rest period in the control group (6 men, 6 women). Thresholds were also redetermined at 5-minute intervals for the next 20 minutes in all subjects. The experimental group showed a significant change in mean tactile threshold after 10 minutes of vibration (p less than .001). This difference remained at 5 (p less than .001) and 10 (p less than .05) minutes postvibration but not at 15 and 20 minutes. No significant change in mean tactile threshold was found in the control group. The results indicate that vibration does increase tactile threshold in "normal" hands and the effect lasts for at least 10 minutes. The application of this information to the clinical setting is discussed.

Adult↗
PubMed2000

Neck muscle vibration alters visually-perceived roll after unilateral vestibular loss.

Unilateral sternocleidomastoid muscle vibration was applied to 21 normal and six unilateral vestibular deafferented (uVD) human subjects at head erect and during 30 degrees left and right whole body roll-tilt. In normal subjects, neck vibration had no effect upon the settings of a visual bar to subjective visual horizontal (SVH) in any roll-tilt condition. In uVD subjects settings to SVH were significantly altered by neck vibration, with ipsilesional neck vibration increasing the SVH bias at head erect. Further, during contralesional roll-tilt, ipsilesional neck vibration in uVD subjects significantly increased the E-effect. These results suggest that compensation after vestibular loss allows cervical signals to influence visual perception of roll-tilt.

Adult↗
PubMed2001

Effect of ultrasonic vibration and various sealer and cement combinations on titanium post removal.

The purpose of this study was to determine the effect of ultrasonic vibration on the force required to remove prefabricated posts. Ninety-six extracted human canines were divided into eight groups, which were prepared and obturated with gutta-percha and either a eugenol-containing (Roth's 801 Elite) or eugenol-free (AH26) sealer. Titanium #6 Parapost XH posts were cemented with either zinc phosphate or Panavia 21 resin cement. One half of the sample was subjected to ultrasonic vibration for 16 min at the post-dentin interface, whereas the other half received no vibration (controls). Each combination of sealer, cement, and vibration status was subjected to tensile load to failure using an Instron testing machine. Posts cemented in teeth obturated with gutta-percha and AH26 sealer demonstrated significantly greater resistance to dislodgement, compared with teeth obturated with gutta-percha and Roth's 801 Elite sealer. There was no statistical difference in retention of posts cemented with either zinc phosphate or Panavia 21, regardless of the sealer used. Additionally ultrasonic vibration increased post retention for both cements.

Analysis of Variance↗
PubMed1999

Videostrobokymography: a new method for the quantitative analysis of vocal fold vibration.

OBJECTIVES: To develop a new analysis method for the quantitative assessment of vibration of the vocal folds, using conventional videostroboscopic image data. METHODS: We used prerecorded videostroboscopic images to evaluate quantitatively the vibration of the vocal folds. Successive images were converted as digital images by means of an image-grabbing board, processed for analysis, and reconstructed as kymograms by rearranging the same lines of all processed images along the time axis. RESULTS: We developed a new technique for evaluating the vibration of the vocal folds. The vibrations of multiple vocal fold regions were easily and objectively evaluated by this technique. The objective parameters, such as open quotient and asymmetry index, could be obtained easily using this technique. CONCLUSIONS: Videostrobokymography demonstrated objectively the vibrations of several vocal fold regions at the same time. This technique has the potential to be a new tool to analyze and monitor the pathological changes and treatment results of vocal fold movement in a more refined quantitative fashion, using videostroboscopic images.

Electrophysiology↗
PubMed2000

Two-dimensional analysis of vocal fold vibration in unilaterally atrophied larynges.

OBJECTIVE: Considerable inconsistencies regarding the vibratory pattern of the vocal fold among patients with unilateral vocal fold paralysis (UVFP) have been reported. These differences are derived from differences in the position, stiffness, and atrophy of the paralyzed vocal fold and other factors among patients. The purpose of this study was to assess the effects of unilateral atrophy of the vocal fold on vocal fold vibration. METHODS: Seven excised canine larynges were studied. The unilateral recurrent laryngeal nerve was severed to cause vocal fold atrophy in four of the seven. The lateral and vertical displacements were monitored simultaneously with photoglottography and a laser Doppler vibrometer, respectively. Videostroboscopy of each larynx was also performed before and after the experiment to translate photoglottographic output into absolute lengths. Atrophy of the unilateral vocal fold was confirmed histologically. RESULTS: The lateral amplitude was significantly greater than the vertical amplitude in all larynges. The Lissajous trajectories in the normal larynges were shaped like a reverse crescent. Vibration in the unilaterally atrophied larynges was periodical and symmetrical in phase when the thyroid ala on the atrophied side was pressed medially. The lateral and vertical amplitudes on the atrophied side were significantly greater than those on the normal side. The Lissajous trajectories differed from those of the normal larynges. CONCLUSIONS: In the absence of a prephonatory glottal gap, periodical vibration occurs in unilaterally atrophied larynges and the amplitude of vibrations of the atrophied vocal fold is greater in the lateral and vertical directions than that of the normal fold. This implies that phonosurgical procedures aiming at closure of the prephonatory glottal gap may have a beneficial effect on hoarseness in UVFP patients, although displacements of the vocal folds during vibration are not symmetrical.

Animals↗
PubMed1992

Effects of continuous quantitative vibration on rheologic and biological behaviors of the intervertebral disc.

The authors attempted to investigate the effect of vibration on the physiologic behavior of the intervertebral disc from rheologic and biological responses. Using fresh disc-cartilaginous end plate complexes of porcine coccygeal vertebrae, the frequency characteristics of dynamic compressive elastic modulus and dissipated energy were monitored by means of a biomechanical spectrometer. The effect of vibration on proteoglycan synthetic rates and solute transport in the intervertebral disc were analyzed using a radioisotope. When the disc-cartilaginous plate complexes were subjected to sinusoidal vibration with a static load of 5 N and a vibratory load of 3 N, the elastic modulus decreased at 11 Hz compared with 3.5 Hz. After this, it increased again at 35 Hz. The dissipated energy increased rapidly with an increase in frequency. Proteoglycan synthetic rates did not change appreciably down to the inner and outer layers of the anulus fibrosus, but the rate in the nucleus pulposus alone decreased remarkably at 10 Hz and 35 Hz. Solute transport increased as a response to vibration, particularly in the nucleus pulposus. When the intervertebral disc is exposed to vibration for a long period of time, therefore, the proteoglycan content in the nucleus pulposus may be decreased, eventually resulting in disruption of matrix integrity.

Animals↗
PubMed1996

Ultrasonic imaging of lumbar discs combined with vibration pain provocation compared with discography in the diagnosis of internal anular fissures of the lumbar spine.

STUDY DESIGN: The diagnostic information achieved by a combination of ultrasonographic imaging of discs and local bony vibration of lumbar vertebrae was compared to that obtained by discographic imaging and pain provocation. OBJECTIVES: The purpose of this study was to find a noninvasive method for spine diagnostics to replace expensive and invasive methods such as discography. SUMMARY OF BACKGROUND DATA: Internal anular fissures of the lumbar discs have been shown to be a source of back pain. Intradiscal changes associated with disc degeneration can be imaged by ultrasonography. The bony vibration test of spinal processes has shown to correlate well with discographic pain provocation tests in cases of internal anular ruptures. Discographic examination of the spine is the only widely accepted diagnostic method that combines pathoanatomic changes and patients' pain. METHODS: Patients with back pain in this study were examined by means of ultrasonography, bony vibration stimulation, and discography. The three lowest lumbar discs were examined. RESULTS: In the cases of intradiscal ultrasound findings, the vibration provocation test showed a sensitivity of 0.90 and a specificity of 0.75 compared to the discographic pain provocation test. In cases of total anular ruptures seen in ultrasound examination, the sensitivity and the specificity of the vibration pain provocation test were much lower, being 0.50 and 0.50, respectively. CONCLUSION: The combination of the two noninvasive methods provides a useful screening test for the evaluation of low back pain. The combination test can accurately depict painful disc degeneration with internal disc rupture and the use of discography can be limited to the cases suggesting total anular rupture in ultrasound examination.

Adult↗