Vibration thresholds using conventional audiometry are clinically useful indicators of postural instability in older adults

Background. Falls are a major health concern with potentially dramatic consequences for people over 65 years of age. One crucial determinant in the risk of falls in older adults is postural control, a complex process that requires the contribution of different sensory modalities, namely visual, vestibular, auditory, and somatosensory. While there are well established methods to screen for age-related vision, hearing, tactile and vestibular impairments, there are very few widely available methods to screen for somatosensory function, but studies indicate that ankle audiometry (vibration thresholds) using a common B-71 bone vibrator can serve that purpose. To date, unfortunately, this technique has received little attention as a tool to measure postural instability in older adults. Purpose. The objective of the present study was to examine postural control in older adults with and without degradation of the somatosensory functions, as determined with ankle audiometry. Research design. Standard group comparison. Study sample. 36 healthy elderly aged between 65-80 years old divided in two groups (low vibration threshold (n=18) and high vibration threshold (n=18). Data collection and analysis. Standard audiometry, video head impulse test, vibration thresholds (big toe, ankle and tibia) and static postural control task using a force platform was performed. Results. Greater postural instability in participants with higher (worse) vibration thresholds as compared to participants with lower (better) vibration thresholds was observed even though both groups were comparable on hearing threshold and vestibular function. Conclusion. The results indicate that performing a simple vibration threshold evaluation, using a clinically available B-71 with a cut-off value of 42 dB HL could be an effective, fast and easy to use procedure for detecting people at risk of falls.