Postural Stability Analysis with Inertial Measurement Units in Alzheimer's Disease

Abstract

Background: The cause of frequent falls in patients with Alzheimer's disease (AD) is still not well understood. Nevertheless, balance control and sensory organization are known to be critical for moving safely and adapting to the environment. Methods: We evaluated postural stability in 20 AD patients (11 fallers and 9 nonfallers) and 16 healthy controls with an inertial measurement unit (triaxial accelerometers and gyroscopes) attached to the center of mass (COM) in different balance conditions (Romberg on flat surface and frontward/backward-inclined surface, with or without visual suppression) in a motor lab. Results: In AD patients, the group of fallers showed a different kinetic pattern of postural stability characterized by higher vulnerability to visual suppression, higher total/maximal displacement and a mediolateral/anteroposterior range of sway, and a consequent need for more corrections of COM pitch and roll angles. Conclusion: Further studies are needed to consolidate the normative values of the discriminatory kinetic variables with the potential of inclusion in a multifactorial analysis of the risk of falls. Nevertheless, these results highlight signs of impairment of central postural control in AD, which may require early therapeutic intervention.

Quantitative Mobility Assessment for Fall Risk Prediction in Dementia: A Systematic Review

“…Table 1 summarizes participant characteristics and settings for the studies included in this review. As shown in Table 1, sample size varied widely among articles, from 20 to 358 participants, with 2 studies [31,32] including data from agematched control participants.…”

“…Study design varied across articles (see Table 2): 3 studies were cross-sectional with one baseline assessment [31,32,38], 9 studies involved a gait/balance assessment at baseline (also cross-sectional) with a follow-up for up to 2, 3, 4, 5, 12, or 24 months to record occurrence of fall incidents [2,12,13,24,26,32,[34][35][36][37], and 2 studies included repeated gait and balance data collection throughout the follow-up period [23,39]. One study [29] collected gait and balance measures at baseline and captured a measure of tortuosity continuously over a 1-year period.…”

“…Seven studies were conducted in long-term care facilities [12,13,23,26,29,33,34], and 6 studies were community-based [2,24,31,32,35,36]. Two studies [37,38] included mixed settings with a majority of participants residing in the community and the remainder living in long-term care.…”

“…The type of quantitative gait and balance measures used to assess fall risk fell into two categories: (1) 7 studies included instrumented quantitative measures of gait and balance (e.g., accelerometers) [2,23,24,26,31,36,38] and (2) 5 studies included non-instrumented, performance measures (e.g., 6-min walk) [13,32,34,35,37]. A combination of instrumented and performance measures of gait and balance was used in 3 studies [12,29,39] (Table 2).…”

Assessment of Postural Sway in Individuals with Multiple Sclerosis Using a Novel Wearable Inertial Sensor

“…Given that the goal of postural control is to maintain the center of mass (COM) within the limits of stability, direct measurement of COM may provide better insights into the mechanisms of balance control [11]. Numerous studies have reported using acceleration-based and gyroscope-based sway metrics for assessing balance deficits in older adults at risk of falling [12], in patients with Parkinson disease [13], MS [14, 15], and Alzheimer disease [16]. However, conventional inertial sensor(s) often still need to be synced with a host computer through additional hardware, and the sensor needs to be secured using straps or other means.…”