ABSTRACT

Functional biomarkers are measures that index functional capacity and also decline with age (Butler et al., 2004). They typically include measures of visual function (acuity, accommodation, contrast sensitivity), auditory acuity, lung function, muscle strength (grip, quadriceps, or ankle dorsi-flexion), blood pressure, and reaction time or processing speed (Anstey, Lord, & Smith, 1996). Vibration sense, touch sensitivity, and reach are also used (Anstey et al., 1996). These biomarkers generally have high test–retest reliability (Anstey, Smith, & Lord, 1997). Selected batteries of functional biomarkers strongly predict functional outcomes such as falls (Lord, Ward, Williams, & Anstey, 1994; Stalenhoef, Diederiks, Knottnerus, Kester, & Crebolder, 2002; van Schoor, Smit, Pluijm, Jonker, & Lips, 2002), mortality (Anstey, Luszcz, Giles, & Andrews, 2001), general mobility, and driving (Wood, Anstey, Kerr, Lacherez, & Lord, 2008).