Evaluation of human vibration thresholds at various body loci

Researchers at the University of Nebraska - Lincoln are currently designing a vibrotactile alerting mechanism for a neutron sensor. The instrument will vibrate on users' skin in the presence of high levels of neutron radiation. The head, neck, upper arm, wrist, waist, and ankle are potential body placements for the device. However, there is minimal information about the vibration frequency thresholds at those body sites. The investigators divided the aforementioned body loci into 24 stimulation sites representing orthogonal directions at each site. The objective of the study was to investigate the underlying effect of stimulation site, subcutaneous fat, and gender on low frequency vibration perception thresholds. Thirty-six subjects were categorized into a dichotomous body fat content group and gender. The results show that vibratory threshold depends significantly on the body site stimulated (p = 0.001). The site with the lowest frequency threshold was the nape of neck while the right lateral area of the waist had the highest frequency threshold. There was no statistical difference in frequency thresholds for the variables of the body fat group or gender (p = 0.302, p = 0.159, respectively). Although, the mean frequency thresholds of participants in the low body fat group was consistently lower than that of those in the high body fat group.