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Experimental studies on the effects of vibration and noise on sympathetic nerve activity in skin
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A. Okada, M. Naito, M. Ariizumi and R. Inaba 1991 European Journal of Applied Physiology 62,324-33 1. Experimental studies on the effects of vibration and noise on sympathetic nerve activity in skin. (8 pages, 9 figures, 1 table, 24 references) (in English) Authors’ Abstract. Multi-unit sympathetic activity was recorded at elbow level from median nerve fascicles supplying glabrous skin of the left hand in five healthy subjects. The resultant vasomotor responses accompanying the neural activity were monitored by simultaneous recordings of skin blood flow by using the laser Doppler method and skin temperature in the innervation zones. No significant change in sympathetic activity was observed during handgrip exercise of the right hand under a constant gripping force of 2 kg. Subjects maintained the same gripping force of the right hand during exposure in random order to local vibration and/or noise, each type of exposure lasting 5 min with intervals of 20 min. A two-peaked significant increase in outflow from sympathetic nerves was observed during local exposure of the right hand to vibration witha frequency of 60 Hz and an acceleration of 50 m s-‘, followed by a post-exposure period which revealed a relative suppression of sympathetic nerve activity and a significant increase in blood flow. Noise at 100 dB(A) showed only an initial effect on skin sympathetic nerve activity (%A), whereas when combined with local vibration at 60 Hz, a pronounced increase in neural activity was noticed, indicating a combined effect of vibration and noise. These results from direct recordings of SSA suggest a sympathetic vasomotor reflex mechanism triggered by local vibration stimuli to the hand. Topics : Physiological Eflects (cardiovascular, muscle and nerve). D. M. Sherer, J. S. Abramowicz, M. L. D’Amico, C. B. Caverly and J. R. Woods 1991 American Journal of Obstetrics and Gynaecology 164 (4), 1104-l 106. Fetal vibratory acoustic stimulation in twin gestations with simultaneous fetal heart rate monitoring. (3 pages, 2 figures, 0 tables, 2 references) (in English) Authors’ Abstract. Sixteen vibratory acoustic stimulations were performed in seven normal twin gestations with continuous simultaneous recordings of each fetal heart rate response. All stimulations led to immediate synchronous fetal heart rate accelerations in both fetuses. This is in contrast to coinciding, yet non-synchronous, spontaneous fetal heart rate accelerations that occur naturally. This observation suggests that different mechanisms are responsible for spontaneous and evoked fetal movements in twin gestations. Topics : Physiological Efsects (cardiovascular) ; Diagnostic Applications. R. R. Klima, A. H. Weigand and J. A. DeLisa 1991 American Journal of Physical and Medical Rehabilitation 70(2), M-90. Nerve conduction studies and vibration perception thresholds in diabetic and uremic neuropathy. (5 pages, 3 figures, 3 tables, 25 references) (in English) Authors’ Abstract. Two parameters of nerve conduction studies (nerve conduction velocities and amplitudes of the evoked sensory and motor responses) were compared with quantitative vibration perception thresholds (VPT) in patients with peripheral neuropathy (diabetes mellitus and/or end-stage renal disease). VPT measurements were made by using a “two-alternative, forced-choice” method in which the patient is required to identify which of the two rods is vibrating at progressively decreasing vibration intensities. VPTs correlated significantly with nerve conduction velocities in all upper and lower extremity sensory and motor nerves tested, and with the amplitudes of the evoked motor responses in three motor nerves: median and ulna (motor components) and tibial. For the median and ulnar nerves (motor components) the amplitudes of evoked motor responses were more sensitive than nerve conduction velocities in correlation with VPTs. Comparison of VPT values based upon whether or not evoked sensory and motor responses were obtained
HUMAN
RESPONSE TO VIBRATION
A. Okada, M. Naito, M. Ariizumi and R. Inaba 1991 European Journal of Applied Physiology 62,324-33 1. Experimental studies on the effects of vibration and noise on sympathetic nerve activity in skin. (8 pages, 9 figures, 1 table, 24 references) (in English) Authors’ Abstract. Multi-unit sympathetic activity was recorded at elbow level from median nerve fascicles supplying glabrous skin of the left hand in five healthy subjects. The resultant vasomotor responses accompanying the neural activity were monitored by simultaneous recordings of skin blood flow by using the laser Doppler method and skin temperature in the innervation zones. No significant change in sympathetic activity was observed during handgrip exercise of the right hand under a constant gripping force of 2 kg. Subjects maintained the same gripping force of the right hand during exposure in random order to local vibration and/or noise, each type of exposure lasting 5 min with intervals of 20 min. A two-peaked significant increase in outflow from sympathetic nerves was observed during local exposure of the right hand to vibration witha frequency of 60 Hz and an acceleration of 50 m s-‘, followed by a post-exposure period which revealed a relative suppression of sympathetic nerve activity and a significant increase in blood flow. Noise at 100 dB(A) showed only an initial effect on skin sympathetic nerve activity (%A), whereas when combined with local vibration at 60 Hz, a pronounced increase in neural activity was noticed, indicating a combined effect of vibration and noise. These results from direct recordings of SSA suggest a sympathetic vasomotor reflex mechanism triggered by local vibration stimuli to the hand. Topics : Physiological Eflects (cardiovascular, muscle and nerve). D. M. Sherer, J. S. Abramowicz, M. L. D’Amico, C. B. Caverly and J. R. Woods 1991 American Journal of Obstetrics and Gynaecology 164 (4), 1104-l 106. Fetal vibratory acoustic stimulation in twin gestations with simultaneous fetal heart rate monitoring. (3 pages, 2 figures, 0 tables, 2 references) (in English) Authors’ Abstract. Sixteen vibratory acoustic stimulations were performed in seven normal twin gestations with continuous simultaneous recordings of each fetal heart rate response. All stimulations led to immediate synchronous fetal heart rate accelerations in both fetuses. This is in contrast to coinciding, yet non-synchronous, spontaneous fetal heart rate accelerations that occur naturally. This observation suggests that different mechanisms are responsible for spontaneous and evoked fetal movements in twin gestations. Topics : Physiological Efsects (cardiovascular) ; Diagnostic Applications. R. R. Klima, A. H. Weigand and J. A. DeLisa 1991 American Journal of Physical and Medical Rehabilitation 70(2), M-90. Nerve conduction studies and vibration perception thresholds in diabetic and uremic neuropathy. (5 pages, 3 figures, 3 tables, 25 references) (in English) Authors’ Abstract. Two parameters of nerve conduction studies (nerve conduction velocities and amplitudes of the evoked sensory and motor responses) were compared with quantitative vibration perception thresholds (VPT) in patients with peripheral neuropathy (diabetes mellitus and/or end-stage renal disease). VPT measurements were made by using a “two-alternative, forced-choice” method in which the patient is required to identify which of the two rods is vibrating at progressively decreasing vibration intensities. VPTs correlated significantly with nerve conduction velocities in all upper and lower extremity sensory and motor nerves tested, and with the amplitudes of the evoked motor responses in three motor nerves: median and ulna (motor components) and tibial. For the median and ulnar nerves (motor components) the amplitudes of evoked motor responses were more sensitive than nerve conduction velocities in correlation with VPTs. Comparison of VPT values based upon whether or not evoked sensory and motor responses were obtained