Dataset for: The Effect of Fear of Falling on Vestibular Feedback Control of Balance
datasetposted on 06.10.2017, 07:43 by Jonathan L. A. de Melker Worms, John F Stins, Peter J Beek, Ian D. Loram
Vestibular sensation contributes to cervical-head stabilisation and fall prevention. To what extent fear of falling influences the associated vestibular feedback processes is currently undetermined. We used galvanic vestibular stimulation (GVS) to induce vestibular reflexes while participants stood at ground level and on a narrow walkway at 3.85 m height to induce fear of falling. Fear was confirmed by questionnaires and elevated skin conductance. Full-body kinematics was measured to differentiate the whole-body centre of mass response (CoM) into component parts (cervical, axial trunk, appendicular short-latency and medium-latency). We studied the effect of fear of falling on each component to discern their underlying mechanisms. Statistical parametric mapping analysis provided sensitive discrimination of early GVS and height effects. Kinematic analysis revealed responses at 1 mA stimulation previously believed marginal through EMG and force plate analysis. The GVS response comprised a rapid, anode-directed cervical-head acceleration, a short-latency cathode-directed acceleration (cathodal-buckling) of lower extremities and pelvis, an anode-directed upper thorax acceleration and subsequently a medium-latency anode-directed acceleration of all body parts. At height, head and upper thorax early acceleration were unaltered, however short-latency lower extremity acceleration was increased. The effect of height on balance was a decreased duration and increased rate of change of the CoM acceleration pattern. These results demonstrate that fear modifies vestibular control of balance, whereas cervical-head stabilisation is governed by different mechanisms unaffected by fear of falling. The mechanical pattern of cathodal-buckling, and its modulation by fear of falling both support the hypothesis that short-latency responses contribute to regulate balance.