Absolute thresholds for the perception of fore-and-aft, lateral, and vertical vibration at the hand, the seat, and the foot
Introduction
In transport, at workplaces, and during leisure and domestic activities, vibration is felt via the hands, the seat, the back, and the feet. Discomfort, annoyance, or interference with activities may occur if the vibration exceeds the threshold for the perception of the vibration. When there is more than one vibration input to the body (e.g. at the hands, the seat, and the feet), the sensation is most easily detected at the location with greatest sensitivity. Knowledge of differences in the thresholds of perception for vibration between the hand, the seat, and the feet should assist the identification of sources of disturbance caused by vibration.
Thresholds for the perception of vibration have been determined in studies of hand-transmitted vibration [1], [2], [3], [4], [5] and in studies of whole-body vibration with seated [6], [7], [8], [9] and standing subjects [6], [7]. However, there has been little investigation of perception thresholds for the foot resting on a vibrating surface. The thresholds of hand-transmitted vibration and whole-body vibration reported in previous studies are not easily compared, partly due to the use of different experimental techniques (e.g. different ranges of frequency, different psychophysical methods, different sitting postures, etc.).
The detection of hand-transmitted vibration mainly involves the somatosensory mechanoreceptive (tactile) channels, often classified as Pacinian (P) and non-Pacinian (NP) channels. The P channel is associated with Pacinian corpuscles (FA II) that provide sensations at high frequencies of vibration (e.g. >40–50 Hz) and summate over the stimulus duration and over the excitation area, known as ‘temporal summation’ and ‘spatial summation’, respectively [10], [11]. The NP channels include the Meissner corpuscles, Merkel disks, and Ruffini endings (i.e. FA I, SA I, and SA II, respectively), and show enhanced sensitivity with increasing stimulus gradients at frequencies less than about 40 Hz [12], [13]. With vibrotactile stimuli (vibration perceived at the fingertip or thenar eminence of the hand), a four-channel model of vibrotactile perception has been proposed [14], [15]. For vibration applied over the entire hand, the identification of the channels responsible for the detection of hand-transmitted vibration has been attempted by Morioka and Griffin [16] who concluded that at least three channels (Pacinian, NP I, and NP II channels) may be involved in detecting hand-transmitted vibration. For the detection of whole-body vibration, several sensory systems are expected to be involved, including the visual, vestibular, auditory, and somatosensory senses [17].
This study was designed to determine differences in the perception of vibration at the hand, the seat, and the feet while these body parts are in contact with vibrating surfaces in a manner similar to that in transport, work, leisure, and domestic activities. Absolute thresholds for perception of vibration were determined to examine the effects of vibration frequency (8–315 Hz for the hand and foot; 2–315 Hz for the seat), vibration direction (fore-and-aft, lateral, and vertical), and input location (the hand, the seat, and the foot) on absolute thresholds for the perception of vibration. There was no backrest and so thresholds were not influenced by the vibration of a surface in contact with the back. The perception thresholds have been presented previously for hand-transmitted vibration [18] and whole-body vibration [19], in experimental studies determining equivalent comfort contours. In this paper, the frequency dependence of vibration perception thresholds at the seat and foot is compared with those at the hand, so as to assist understanding of the mechanisms involved in the detection of vibration at different body locations.
Section snippets
Subjects
The experiment was carried out with a total of 9 conditions (3 axes×3 body locations). Each experimental condition was completed within a session lasting about 1 h. Eight groups of 12 males (total of 96) aged between 20 and 29 years participated in the experiment. Subjects in each group attended a single experimental session determining perception thresholds for fore-and-aft, lateral, or vertical vibration either at the hand, seat, or foot (except subjects in Group B attended sessions with both
Effect of frequency
The median absolute thresholds and the inter-quartile range (25–75th percentiles) of the 12 subjects determined for the hand, the seat, and the foot in each of the three axes of vibration (fore-and-aft, lateral, and vertical) are presented as a function of vibration frequency in Fig. 2. Threshold contours determined from other studies are overlaid for comparison.
With vibration at the hand, the acceleration perception thresholds in all three axes were highly dependent on vibration frequency
Factors influencing the measured perception thresholds
In the present studies, forces between the body and the sources of vibration were not controlled at specific values but the subjects were instructed to maintain specific body postures (sitting upright with their feet supported while grasping handles with forces that they felt most comfortable). Variations in force or pressure at the point of contact with vibration may alter perception thresholds. For the Pacinian channel, the threshold of perception for vibration of a small circular probe
Discussion
The ways in which the perception thresholds in the present results depend on the frequency of vibration are broadly similar to those determined in other studies with vibration of the hand [1], [2], [3], [4], [5] and the seat [6], [7], [8], [9], as seen in Fig. 2. The higher thresholds for hand-transmitted vibration from Reynolds et al. [2] may be partly due to the use of different psychophysical methods. The present study employed a staircase method in conjunction with a ‘yes–no’ procedure in
Conclusions
Perception thresholds for vibration of the hand, the seat, and the foot are highly frequency dependent. Sensitivity to vibration also differs between the three locations. Thresholds for the hand suggest that at frequencies greater than about 20 Hz, perception is mediated by the Pacinian channel. A similar frequency dependence for thresholds at the hand, the seat, and the foot suggests the Pacinian channel may mediate thresholds in all three axes at frequencies greater than about 80 Hz. The
References (32)
- et al.
Whole-body vibration perception thresholds
Journal of Sound and Vibration
(1988) - et al.
Magnitude dependence of equivalent comfort contours for fore-and-aft, lateral and vertical hand-transmitted vibration
Journal of Sound and Vibration
(2006) - et al.
Magnitude dependence of equivalent comfort contours for fore-and-aft, lateral, and vertical whole-body vibration
Journal of Sound and Vibration
(2006) - et al.
Effect of phase, frequency, magnitude and posture on discomfort associated with differential vertical vibration at the seat and feet
Journal of Sound and Vibration
(2000) - et al.
The apparent mass of the seated human body in the: vertical vibration
Journal of Biomechanics
(1989) - et al.
The apparent mass of the seated human body in the fore-and-aft and lateral directions
Journal of Sound and Vibration
(1990) - et al.
The effects of vibration frequency and direction on the location of areas of discomfort caused by whole-body vibration
Applied Ergonomics
(1978) Evaluation methods for vibration effects, part 3: measurements of threshold and equal sensation contours on hand for vertical and horizontal sinusoidal vibrations
Industrial Health
(1967)- et al.
Hand–arm vibration, part III: subjective response characteristics of individuals to hand-induced vibration
Journal of Sound and Vibration
(1977) - et al.
Detection of vibration transmitted through an object grasped in the hand
Journal of Neurophysiology
(1999)
Threshold for the perception of vibration: dependence on contact area and contact location
Somatosensory and Motor Research
Evaluation methods for vibration effect, part 1: measurements of threshold and equal sensation contours of whole body for vertical and horizontal vibrations
Industrial Health
Effect of contactor area on the vibrotactile threshold
Journal of the Acoustical Society of America
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