A Scoping Review on Minimum Foot Clearance Measurement: Sensing Modalities

Abstract

Background: Falls are a major public health issue and tripping is the most common self-reported cause of outdoor falls. Minimum foot clearance (MFC) is a key parameter for identifying the probability of tripping. Optical motion capture systems are commonly used to measure MFC values; however, there is a need to identify alternative modalities that are better suited to collecting data in real-world settings. Objective: This is the first of a two-part scoping review. The objective of this paper is to identify and evaluate alternative measurement modalities to optical motion capture systems for measuring level-ground MFC. A companion paper identifies conditions that impact MFC and the range of MFC values individuals that these conditions exhibit. Methods: We searched four electronic databases, where peer-reviewed journals and conference papers reporting level-ground MFC characteristics were identified. The papers were screened by two independent reviewers for inclusion. The reporting was done in keeping with the PRISMA-ScR reporting guidelines. Results: From an initial search of 1571 papers, 17 papers were included in this paper. The identified technologies were inertial measurement units (IMUs) (n = 10), ultrasonic sensors (n = 2), infrared sensors (IR) (n = 2), optical proximity sensors (OPS) (n = 1), laser ranging sensors (n = 1), and ultra-wideband sensors (n = 1). From the papers, we extracted the sensor type, the analysis methods, the properties of the proposed system, and its accuracy and validation methods. Conclusions: The two most commonly used alternative modalities were IMUs and OPS. There was a lack of standardization among studies utilizing the same measurement modalities, as well as discrepancies in the methods used to assess performance. We provide a list of recommendations for future work to allow for more meaningful comparison between modalities as well as future research directions.

Identification of characteristics of foot position and angle during swing phase in fallers using principal component analysis

“…Furthermore, based on Figure 3 , we can conclude that the foot height during the initial swing phase is lower in fallers than in non-fallers. Many previous studies have focused on minimum toe clearance (i.e., foot height) during the mid-swing phase in fallers and non-fallers ( Chiba et al, 2005 ; Khandoker et al, 2008b , 2008a ; Barrett et al, 2010 ; Karmakar et al, 2013 ; Cebolla et al, 2015 ; Watanabe, 2018 ; Delfi et al, 2021 ). However, based on our results, we consider it important to focus on foot height during the initial swing phase (e.g., maximum toe clearance) to assess fall risk instead of focusing on foot height during the mid-swing phase.…”

“…Several previous studies have reported that some variables related to foot position and angle during gait (e.g., sagittal foot angle at heel contact ( Chiba et al, 2005 ), minimum toe clearance ( Chiba et al, 2005 ; Delfi et al, 2021 ), stride length ( Kerrigan et al, 2000 ; Lee and Chou, 2006 ; Newstead et al, 2007 ), and variability of stride length ( Reelick et al, 2011 ; Doi et al, 2020 ; Bytyçi and Henein, 2021 ) are significantly different between non-fallers and fallers. This knowledge is beneficial for identifying the characteristics of older adults who are prone to falls.…”

“…This knowledge is beneficial for identifying the characteristics of older adults who are prone to falls. However, previous studies ( Chiba et al, 2005 ; Reelick et al, 2011 ; Doi et al, 2020 ; Bytyçi and Henein, 2021 ; Delfi et al, 2021 ) have focused on discrete variables of foot positions and angles during gait in older adults at risk of falling. However, if we focus only on discrete variables, it may not be possible to detect crucial information in large portions of unanalyzed data.…”

Using Deep Learning to Predict Minimum Foot–Ground Clearance Event from Toe-Off Kinematics

“…Delfi et al [16,17] reviewed sensor technologies for MFC detection suitable for integration into wearable assistive devices; when considering cost and ease of use, inertial measurement units (IMUs) were the preferred application. Linear acceleration and angular velocity can be recorded from IMUs, and by double integrating the acceleration data (m/s 2 ), the critical foot displacement (m) can be computed.…”

Barefoot walking is more stable in the gait of balance recovery in older adults

“…Falls during walking put older adults at risk of serious injuries, e.g., fractures, brain injuries, or even death [ 1 – 3 ]. Trips are the most prevalent known cause of outdoor falls [ 4 ] and are considered to be the most challenging of falls [ 5 , 6 ].…”