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PubMed1988

Three-dimensional laser Doppler interferometric display of human tympanic membrane vibrations at two different frequencies and sound pressure levels.

The vibrational movements of the tympanic membrane of human in vitro specimens were studied by computerized laser Doppler interferometry. The entire surface of the vibrating tympanic membrane was scanned with the laser beam and all information was stored digitally making it possible to recreate the movements as in slow motion on the oscilloscope. Single phases of interest from the vibrational cycle were plotted as shown. The resonance patterns at 0.58 kHz and 3.11 kHz are compared and the effect of different sound pressure levels on the vibrational movement of the tympanic membrane demonstrated.

Doppler Effect↗

PubMed1987

Computerized laser Doppler interferometric scanning of the vibrating tympanic membrane.

The vibrational movements of the tympanic membrane (TM) of in vitro human specimens were studied by computerized laser Doppler interferometry. The versatility of the method for measuring the velocity of the vibrating TM was demonstrated by point measurements, horizontal sweeps, and three-dimensional scans of the entire TM. Single phases of the TM vibration were examined and plotted three-dimensionally. All information was stored digitally, making it possible to recreate the movements as in slow motion on the oscilloscope. The effect of coating the TM with a thin layer of magnesium oxide was studied. The repeatability of the method was demonstrated. TM vibrational patterns at different sound pressure levels and frequencies are displayed and discussed as also are the results of scanning the specimen in different positions.

Computers↗

PubMed1988

Transiently increased insulin-like growth factor I immunoreactivity in tendons after vibration trauma. An immunohistochemical study on rats.

The hind limbs of anaesthetized rats were exposed to vibration trauma (81 Hz; amplitude peak to peak 0.50 mm) for 4 hours during 2 consecutive days. The animals were examined in groups of 4 immediately after the last exposure, and after 1, 2, 3, 5, 7, 10, 14 and 28 days. The Achilles tendons and the tendons of the anterior tibialis muscles were sampled and processed to demonstrate IGF-I immunoreactivity. In the normal Achilles tendon and in the tendon of the anterior tibial muscle, slight IGF-I immunoreactivity was seen in many of the long slender fibroblasts between the collagen bundles. A strong increase in the IGF-I immunoreactivity appeared in the anterior tibialis muscle tendon 3 days after the last vibration exposure. In addition, the tendon fibroblasts became hypertrophic. A similar but less striking increase in IGF-I immunoreactivity appeared in the Achilles tendon. The peak intensity and frequency of stained cells were achieved after 7 days for both tendons. The intensity then levelled off, and was normalized after 28 days. It is concluded that acute exposure to vibrations induces reactive changes in fibroblasts in tendons, which may reflect a change to a more active synthesising state, as a response to the vibration trauma. The transiently altered expression of IGF-I immunoreactivity forms a link in a chain of events regulating the functional activity level of fibroblasts in response to a trauma.

Achilles Tendon↗

PubMed1990

[A physiological study of the effect of vibration on reflexive control of cats' larynx: the changes in respiratory phase and the role of internal branch of superior laryngeal nerve].

It is generally considered that the vocal cord is finely and reflexively controlled during phonation. In order to investigate the effect of vibratory stimulation of the subglottis on laryngeal reflex, experiments have been performed using cats' larynx under urethane-chloralose general anesthesia. The effect of vibration was estimated by the latency and the area of integrated EMG of the reflex. The glottic closure reflex was induced by electrical stimulation of the internal branch of the superior laryngeal nerve (ISLN) and electromyogram was recorded from contralateral Thyroarytenoid muscle (TA). When ISLN was stimulated, short latency response (early response) and long latency response (late response) in TA was observed. Maximum responses were obtained during the transitional phase, namely, from inspiration to expiration, especially before the denervation of ISLN from the larynx. This phase was tentatively designated as "phase I", being followed by "phase II", the phase prior to "phase I", as "phase III". Vibratory stimulation (100 or 200Hz, 40 microns), applied to the contralateral subglottic portion as a conditioning stimulation, had no effect on early response but enhanced late response, particularly in phase I. After denervation of ISLN, the vibratory effect on late response became phase independent. Furthermore, when the vibratory frequency was elevated from 100Hz to 350Hz at 50Hz interval in phase I, vibration effect was observed in all frequencies investigated. Maximum effect was obtained at 300Hz. However, after denervation of ISLN, this effect was minimized, and no peak observed. The vibratory effects disappeared soon after local anesthesia of the subglottic mucosa. These results suggest that the activity of the mechanoreceptors to vibration in the subglottic mucosa enhances reflexive contraction of the contralateral TA primarily via the recurrent laryngeal nerve and partially via ISLN, both of which are indispensable for reflexive laryngeal control. It is conceivable that early response is one of the primitive reflexes for the protection of the lower airway, and late response is a sort of more evolved reflexes involved in vibration and respiration during phonation.

Animals↗

PubMed1990

[Influence of liquid volume in the middle ear on tympanic membrane vibration (experimental study by holographic interferometry)].

The influence of middle ear liquid on the tympanic membrane (TM) vibration was studied using the holographic interferometry. The physiological saline solution was injected into the middle ear cavity of the canine temporal bone. The liquid volume in the middle ear cavity was changed into 3 grades in order to observe the difference of the vibration pattern between them. The vibratory patterns of a normal canine TM remained unchanged in their first mode up to a frequency of approximately 2 kHz. In this mode, there were peak displacement regions in the posterior and anterior quadrants. The TM vibrations showed sectional patterns, above 3 kHz in the posterior and above 4 kHz in the anterior. After liquid retention, the following were observed. 1. The frequency at which sectional patterns occurred shifted to a lower frequency in the immerged portion, but showed no definite tendency in the unimmerged portion. 2. Maximum amplitudes of the anterior and posterior quadrants of the TM and the mallar tip shifted to somewhat higher frequencies for the liquid volume below the level of the tip portion, but contrary, shifted to lower frequencies for the liquid volume there above. 3. The ossicular chain tended not to make normal function for the TM vibration with an increase of liquid volume.

Animals↗

PubMed1991

[Simultaneous recording of vocal cord vibrations by ultrasound laryngography and photoelectroglottography].

A newly developed ultrasonic laryngeal imaging system, ultrasound laryngography (ULG), can record vocal cord vibrations by the simultaneous use of high-speed M-mode, ultrasonic pulse transmissions, and the other methods. The purpose of this study was to compare normal male vocal cord vibrations simultaneously recorded by ULG at several pitches and loudness with those obtained by photoelectroglottography (PGG). The open quotient (OQ), speed quotient (SQ), and speed index (SI) were measured by these two methods. While only relative glottal area can be obtained by PGG, exact glottal width can be obtained by ULG. So the mean opening/closing velocity as well as the mean opening/closing steepness of the vocal cord vibration plot were measured by ULG. The results are summarized as follows: 1) The OQ, SQ, and SI values measured by these two methods were very similar. There was a trend for greater mean values in these parameters as measured by ULG compared with those determined by PGG. 2) This difference was presumed to be due to (1) vocal cord phase differences in horizontal and vertical components, (2) the location of the light source and that of photosensor from the glottis, and (3) ULG beam width in relation to vertical movements of the vocal cords. 3) Glottal width curve obtained by ULG was asymmetrical triangular wave because closing phase was shorter. By ULG observation, as voice loudness increased, opening/closing steepness became greater and closed phase longer, while closing phase shorter. The waveform obtained by ULG was presumed to be relatively similar to glottal flow waveform because there was a trend of more asymmetrical triangular waveform obtained by ULG than those obtained by PGG. In conclusion, ULG is the only method to be able to obtain exact glottal width compared with the other glottography, and this method is considered to be useful for the investigation of the vocal cord vibrations.

Electrodiagnosis↗

PubMed1997

[Effects of frame of reference on the judgments of whole-body vibration intensity].

Although the concept of the term 'riding comfort' is ambiguous, in the present paper it means a perceptual experience derived from the vibrational factors of a running railway vehicle. When we regard riding comfort evaluation as a perceptual judgment process, we must consider that what is perceived is dependent not only on the physical properties of the stimuli, but also on the frame of reference. The purpose of the present study is to examine the effect of the frame on the judgments of vibration intensity in the anchoring effect paradigm. Using the four-axis vibration apparatus, we conducted experiments for eighty subjects, in which frequencies and lateral accelerations of vibrations were changed. As the result, we found a clear anchoring effect. This suggests that we must take into consideration effects of frame of reference in terms of riding comfort criterion of railway vehicles.

Adult↗

PubMed1990

Psychological aspects of occupational vibration.

A short review is given of the subjective responses to vibration (primarily whole-body vibration) and of its performance and psychophysiological effects. The subjective importance of the basic physical vibration parameters and the effects of whole-body vibration on performance of tasks requiring manual control and visual acuity have been well covered by research, whereas knowledge of the effects on cognitive performance is rather meager.

Biomechanical Phenomena↗

PubMed1987

A new principle for assessing vibrotactile sense in vibration-induced neuropathy.

The vibrotactile perception threshold has been evaluated in 20 manual workers not exposed to occupational vibration and in 27 workers using hand-held vibrating tools. Threshold values were evaluated with a Békesy type of vibrometer at frequencies ranging from 8 to 500 Hz. The earliest sign of vibration lesion was a reduction of sensation at frequencies of 125 to 250 Hz, indicating dysfunction in receptors of the fast adapting type II (stage 1 curve), followed in more severe cases by a prominent loss of sensation at all frequencies higher than 65 Hz (stage 2 curve). The stage 3 curve indicated the most severe loss of sensation in which the function of slowly adapting type I receptors, as well as fast adapting type I receptors, was deteriorated; consequently the vibrotactile thresholds at low-, median-, and high-frequency ranges were impaired. The vibrotactile changes corresponded well to numbness and the presence of vibration-induced white finger.

Adolescent↗

PubMed1986

Measures of vibrotactile sensitivity in persons exposed to hand-arm vibration.

A group of 57 persons occupationally exposed to hand-arm vibration was studied in an investigation of factors affecting their vibrotactile thresholds. The group contained 42 persons with symptoms of vibration-induced white finger (VWF). Measures of finger thresholds and temperatures were obtained from both hands. It was found that vibrotactile thresholds were higher in subjects reporting VWF. A laboratory investigation indicated that finger temperature had a great effect on the thresholds but that this effect only occurred outside the range of temperatures found in the study of occupationally exposed persons. Laboratory research showed that vibrotactile thresholds should be expected to depend upon vibration exposure immediately prior to the test. The vibration frequency and general configuration of the vibrotactile apparatus also influenced threshold. An awareness of these factors allows guidelines for their control to be suggested.

Adult↗

PubMed1986

Elaboration of a standard procedure for the measurement of vibration emitted by percussive tools--application to breakers.

The Association Française de Normalisation (AFNOR) is preparing a standard on the exposure assessment of vibration from percussive tools. Therefore, a test code was developed for the measurement of vibration from percussive tools under laboratory conditions. The handle vibration from six different breakers, among which three tools were of "antivibration design," was measured with the following energy absorption methods: hydraulic base, steel shot, actual breaking of concrete, AFNOR concrete block, pointed chisel embedded in concrete. The last four methods were applied with breakers held by three successive operators. In addition, the first two were used with tools mounted in a rig which held them vertically and loaded them with a vertical downforce. The results indicated that the steel shot method was preferable although it gave 20% lower vibration results than those recorded for the actual breaking of concrete. It has the advantages of yielding consistent results with low scatter and being simple and cheap. Since difficulties have been experienced during the use of a pneumatic rig with breakers of antivibration design conception, the shot method should be applied with human operators.

Humans↗

PubMed1998

Effects of long-term organophosphate exposures on neurological symptoms, vibration sense and tremor among South African farm workers.

OBJECTIVES: This study assessed the relationship between long-term exposure to organophosphate insecticides and neurological symptoms, vibration sense, and motor tremor after control for the effect of past poisoning and acute exposure. METHODS: This cross-sectional study included 164 pesticide applicators and 83 nonspraying reference workers on deciduous fruit farms. The workers were tested on the Vibratron II, on tests of dynamic and static tremor, and for a set of neurological and "dummy" symptoms. Exposure was derived with the use of a job-exposure matrix for pesticides in agriculture. RESULTS: Compared with nonapplicators, current applicators reported significantly more dizziness, sleepiness, and headache and had a higher overall neurological symptom score. This association remained statistically significant after multiple logistic regression analyses controlling for a range of confounders and effect modifiers [odds ratio (OR) 2.25, for current applicators having high neurological score, 95% confidence interval (95% CI) 1.15-4.39]. The average lifetime intensity of organophosphate exposure was nonsignificantly associated with both neurological (OR 1.98, 95% CI 0.49-7.94) and "dummy" symptoms (OR 2.37, 95% CI 0.54-10.35). Previous pesticide poisoning was significantly associated with the neurological scores (OR 4.08, 95% CI 1.48-11.22) but not with the "dummy" symptoms. Vibration sense outcomes were associated with age and height, but not with the organophosphate exposure measures. In the multiple linear regression modeling for tremor intensity in the dominant hand, recent organophosphate exposure in the past 10 days was a significant predictor (partial correlation coefficient = 0.04), but none of the long-term organophosphate exposure measures were significant. CONCLUSIONS: Strong evidence was found for an association between symptom outcomes and past organophosphate poisoning and between symptom outcomes and current spray activity. In contrast to symptoms, there was no association between either past poisoning or current spray activity and vibration sense or tremor outcome. Long-term organophosphate exposure did not appear to predict symptoms, vibration sense, or tremor outcome.

Adult↗

PubMed1997

Color Doppler ultrasonographic detection of a vibrating needle system.

The purpose of this study was to compare needle detection using a commercially available vibrating needle system that is used with color Doppler sonography and conventional real-time needle guidance during ultrasonographically guided intervention. Twenty-four paired (48 total) sonographically guided needle placements were performed in 22 patients for fine needle biopsy. Two patients underwent two additional needle placements at later times and, therefore, underwent a total of four needle passes each. Twenty-four of the needles were placed utilizing conventional real-time ultrasonographic guidance, and 24 were guided using a commercially available vibrating needle system. The Color Mark System was compared with standard technique for needle visualization and graded according to ease of needle visualization (improved, no change, or more difficult visualization). This was done for both needle tip and needle shaft visualization. Visualization was graded in both superficial (less than 3 cm deep) and deep structures. Overall needle tip and shaft visualization improved in 14 of 24 cases in superficial tissues and in three of 24 cases in superficial and deep tissues with the Color Mark System. The vibrating needle system also was judged to be somewhat cumbersome when used with a 22 gauge needle, as its weight tended to bend the needle shaft. The needle vibrating system may enhance needle visualization in superficial structures, but with the present design it is of limited use in deep tissues.

Biopsy, Needle↗

PubMed1999

[Current aspects of vibration disease pathogenesis].

The authors proved impaired venous drainage and lower vascular tone to be among the first signs of vibration disease. Adaptational and trophic disorders, compromised humoral regulation appear to be characteristic for vibration disease and associated with disturbances of sympathetic autonomous system. The experiments diagnosed phases in sympathetic and adrenals response to vibration. Vibration appeared to depress functional activity of "pituitary-gonads" system.

Animals↗

PubMed1999

[The role of associated factors in the evaluating the effet of local vibration influence].

Present measurement method of local vibration dose and of corresponding factors characterizes degree of unfavorable effects caused by those components in humans rather indistinctly, because of the following reasons: 1) considering muscular efforts put on a vibrating instrument, "vibration-force" complex incompletely accounts static load on flexor muscles of fingers, if those efforts referred to individual functional abilities; 2) work hardiness used in this method sometimes inadequately reflects value of static muscular efforts in "vibration-force" complex; 3) combined effect of cooling microclimate parameters are evaluated, rather inexactly.

Adult↗

PubMed1999

[The morphology and constitution-based criteria for the assessment of individual risk for the development of vibration disease].

The authors studied morphologic and constitutional features in individuals with various durability to vibration. Patients fragile to vibration were pectoral and indefinite somatotypes with connective tissue dysplasia and small congenital abnormalities (spondylodysplasia, venous wall deficiency. "dysplastic" heart signs and others). Patients durable to vibration were muscular and abdominal somatotypes with rare connective tissue dysplasia and small congenital abnormalities (2.5-10.2% of cases). Evaluation of morphologic and constitutional characteristics is recommended in preliminary and periodic medical examinations of workers subjected to vibration, for assessment of individual risk degree and differential medical follow-up.

Adult↗

PubMed1999

[Clinical endoscopic and pathomorphologic study of the stomach in vibration disease].

The authors present results of manifold evaluation of stomach in 109 patients with vibration disease caused by various vibration characteristics. The evaluation covered clinical signs, laboratory studies, endoscopic and pathomorphologic methods with light and electronic microscopy, in vitro radioautography and morphostereologic analysis. Features of gastric disease in vibration disease are asymptomatic course, depressed gastric secretion, prevalent atrophic changes of mucosa on endoscopy. Morphologic analysis of gastric biopsies revealed marked dystrophy and atrophy of the lining, glandular atrophy, diffuse stromal sclerosis and in most cases no signs of gastritis. The findings are termed vibration gastropathy.

Adult↗

PubMed1999

Effect of vibrations on male reproductive system and function.

From data in the literature, the potential risk of mechanical vibrations on reproduction in experimental, clinical and epidemiological studies (in experimental animals, men occupied in transport and industry), as well as the influence on sexuality are summarised. Results of the authors own experimental and clinical studies on the influence of the vibration on the male reproductive system are also presented. In male rats, decreased sperm counts, spermatogenesis index and size of testes, changed character of their motion, chronic venous stagnation and dystrophic alterations in tubuli contorti, changed ScDH, ATP-ase, LDH and GL-6-PDH activity, germ cells structural damages were observed. Workers exposed to vibrations had an increased prevalence of oligozoospermia, asthenozoospermia and teratozoospermia. Sexual disorders are also observed. The authors suggest that reproductive disorders should be included in the list of non-specific effects of vibrations. The detected changes justify further investigations and development of mathematical models for early detection and prognosis of the unfavourable effect on male reproductive function.

Animals↗