Full length article Early identification of declining balance in higher functioning older adults, an inertial sensor based method K.J. Sheehan a, *, B.R. Greene b , C. Cunningham a , L. Crosby a,d , R.A. Kenny a,c,d a Technology Research for Independent Living (TRIL), Trinity College Dublin, Dublin, Ireland b Technology Research for Independent Living (TRIL), University College Dublin, Dublin, Ireland c Trinity College Dublin, Department of Medical Gerontology, Dublin, Ireland d St James’s Hospital, Mercer’s Institute for Successful Ageing, Dublin, Ireland Introduction With declining fertility and increasing life expectancy for most regions of the world, the mean global age has increased [1]. This trend is expected to continue with projected figures for 2050 of 2 billion adults over the age of 60 [2]. In order to minimise the economic and health costs of these changing population demo- graphic early identification of decline coupled with timely medical intervention is required. Higher functioning older adults represent those who are community dwelling, independently mobile and have few morbidities [3]. Despite evidence that it is an essential component of the functional assessment of older adults, balance is often not assessed in these older adults [4]. Declining balance is associated with limited mobility and an increased risk of falls [5]. Early detection of decline in balance could facilitate earlier intervention and potentially reduce the risk of falls. Current clinical measures of balance are restricted by ceiling scores which higher functioning older adults are likely to obtain [6]. Inertial sensor based balance assessments may represent an appropriate substitute to current assessments for higher functioning groups. The timed up and go (TUG) is used to assess functional mobility and requires both static and dynamic balance [7,8]. The TUG is quick, easy to administer and has been shown to have some predictive power for falls and mobility impairment [9,10]. Additionally, the application of wireless inertial sensors to the lower limbs during the TUG allows measurements such as cadence, stance phase duration and angular velocity to be recorded [11,12]. These objective measures have been combined statistically to improve the accuracy of falls risk assessment as compared to TUG time [11,12]. As altered balance is associated with falls risk these inertial sensor based measures may have utility in identifying early changes in balance for higher functioning groups [4]. This study had two objectives: (1) To determine if baseline quantitative TUG parameters are associated with a decline in balance at follow-up for higher functioning older adults. Gait & Posture xxx (2014) xxx–xxx A R T I C L E I N F O Article history: Received 16 April 2013 Received in revised form 14 December 2013 Accepted 3 January 2014 Keywords: Inertial sensors Berg balance scale Timed up and go Balance decline Community dwelling older adults A B S T R A C T Higher functioning older adults rarely have their balance assessed clinically and as such early decline in balance is not captured. Early identification of declining balance would facilitate earlier intervention and improved management of the ageing process. This study sought to determine if (a) a once off inertial sensor measurement and (b) changes in inertial sensor measurements one year apart can identify declining balance for higher functioning older adults. One hundred and nineteen community dwelling older adults (58 males; 72.5  5.8 years) completed a timed up and go (TUG) instrumented with inertial sensors and the Berg balance scale (BBS) at two time points, one year apart. Temporal and spatio-temporal gait parameters as well as angular velocity and turn parameters were derived from the inertial sensor data. A change in balance from baseline to follow-up was determined by sub-components of the BBS. Changes in inertial sensor parameters from baseline to follow-up demonstrated strong association with balance decline in higher functioning older adults (e.g. mean medial-lateral angular velocity odds ratio = 0.2; 95% CI: 0.1– 0.5). The area under the Receiver operating characteristic curve (AUC) ranged from 0.8 to 0.9, a marked improvement over change in TUG time alone (AUC 0.6–0.7). Baseline inertial sensor parameters had a similar association with declining balance as age and TUG time. For higher functioning older adults, the change in inertial sensor parameters over time may reflect declining balance. These measures may be useful clinically, to monitor the balance status of older adults and facilitate earlier identification of balance deficits. ß 2014 Elsevier B.V. All rights reserved. * Corresponding author. Tel.: +353 7788555256. E-mail address: sheehakj@tcd.ie (K.J. Sheehan). G Model GAIPOS-4120; No. of Pages 6 Please cite this article in press as: Sheehan KJ, et al. Early identification of declining balance in higher functioning older adults, an inertial sensor based method. Gait Posture (2014), http://dx.doi.org/10.1016/j.gaitpost.2014.01.003 Contents lists available at ScienceDirect Gait & Posture jo u rn al h om ep age: ww w.els evier.c o m/lo c ate/g aitp os t 0966-6362/$ – see front matter ß 2014 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.gaitpost.2014.01.003