Publications of Mohamed Boutaayamou
Bookmark and Share    
Full Text
See detailAlgorithm for extracting initial and terminal contact timings during treadmill running using inertial sensors
Prijot, Laura ULiege; Schwartz, Cédric ULiege; Watrin, Julien et al

Conference (2020)

Inertial measurement units (IMUs) are now considered as an economical solution for long term assessment in real conditions. However, their use in running gait analysis is relatively new and limited ... [more ▼]

Inertial measurement units (IMUs) are now considered as an economical solution for long term assessment in real conditions. However, their use in running gait analysis is relatively new and limited. Detecting the timing at which the foot strikes the ground (initial contact, IC) and the timing at which the foot leaves the ground (terminal contact, TC) gives access to many relevant temporal parameters such as stance, swing or stride durations. In this paper, we present an original algorithm to extract IC and TC timings and associated parameters from running data. These data have been measured using a newly developed IMU-based hardware system in ten asymptotic participants who ran at three speeds (slow, normal, and fast) with different running patterns (natural, rearfoot strike, mid-foot strike, and forefoot strike). This algorithm has been validated against a 200 Hz video camera based on 7056 IC and TC timings and 6861 temporal parameters. This algorithm extracted ICs and TCs with an accuracy and precision of (median [1st quartile; 3rd quartile]) 5 ms [-5 ms, 15 ms] and 0 ms [-5 ms, 5 ms], respectively. The relative errors in the extraction of stride and stance durations are -1.56 ± 3.00% and 0.00 ± 1.32%, respectively. [less ▲]

Detailed reference viewed: 94 (20 ULiège)
See detailTerahertz Pulsed Imaging of Paraffin-Embedded Human Breast Cancer Tissue
Cerica, Delphine ULiege; Nguyen, Dinh; Hernandez, Yves et al

Scientific conference (2019, September)

Terahertz (THz) Pulsed Imaging (TPI) uses THz radiation for imaging biological tissue. In particular, this technique has shown potential for identifying human breast cancer during breast-conserving ... [more ▼]

Terahertz (THz) Pulsed Imaging (TPI) uses THz radiation for imaging biological tissue. In particular, this technique has shown potential for identifying human breast cancer during breast-conserving surgery (BCS) [1,2]. A key issue of BCS is the more than 20% rate of reoperation after postoperative histopathological analysis of the cancer resection margins [3], which results from the current lack of accurate intraoperative cancer margins assessment tools. As part of the Tera4All project consortium that aims to promote THz technology applications across the Walloon Region of Belgium, our goal is to investigate the use and validation of TPI in breast cancer margins assessment, in the context of reducing the re-operation rate of BCS. In this preliminary work, we study the TPI of PE excised human breast cancer tissue sections. [less ▲]

Detailed reference viewed: 95 (17 ULiège)
See detailAdaptive method for detecting zero-velocity regions to quantify stride-to-stride spatial gait parameters using inertial sensors
Boutaayamou, Mohamed ULiege; Schwartz, Cédric ULiege; Joris, Laura ULiege et al

in Proceedings of the 12th International Joint Conference on Biomedical Engineering Systems and Technologies (BIOSTEC 2019) (2019, February 25)

We present a new adaptive method that robustly detects zero-velocity regions to accurately and precisely quantify (1) individual stride lengths (SLs), (2) individual stride velocities (SVs), (3) the ... [more ▼]

We present a new adaptive method that robustly detects zero-velocity regions to accurately and precisely quantify (1) individual stride lengths (SLs), (2) individual stride velocities (SVs), (3) the average of SL, (4) the average of SV, and (5) the cadence during slow, normal, and fast overground walking conditions in young and healthy people. The measurements involved in the estimation of these spatial gait parameters are obtained using only one inertial measurement unit attached on a regular shoe at the level of the heel. This adaptive method reduced the integration drifts across consecutive strides and improved the accuracy and precision in the spatial gait parameter estimation. The validation of the proposed algorithm has been carried out using reference spatial gait parameters obtained from a kinematic reference system. The accuracy ± precision results were for SLs: 0.0 ± 4.7 cm, −0.7 ± 4.4 cm, and −5.8 ± 5.8 cm, during slow, normal, and fast walking conditions, respectively, corresponding to −0.1 ± 4.2 %, −0.5 ± 3.2 %, and −3.3 ± 3.0 % of the respective mean SL. The accuracy ± precision results were for SVs: 0.0 ± 2.9 cm/s, −0.7 ± 3.8 cm/s, and −6.7 ± 6.7 cm/s, during slow, normal, and fast walking conditions, respectively, corresponding to −0.6 ± 3.3 %, −0.1 ± 4.5 %, and −3.5 ± 3.1 % of the respective mean SV. These validation results show a good agreement between the proposed method and the reference, and demonstrate a fairly accurate and precise estimation of these spatial gait parameters. The proposed method paves the way for an objective quantification of spatial gait parameters in routine clinical practice. [less ▲]

Detailed reference viewed: 155 (44 ULiège)
See detailTerahertz imaging of breast cancer tissue: preliminary results
Cerica, Delphine ULiege; Nguyen, Dinh; Hernandez, Yves et al

Poster (2019, February)

This work is part of the Tera4All project that aims to develop and disseminate the terahertz (THz) technology in various research fields and associated applications across the Wallonia, Belgium. Our ... [more ▼]

This work is part of the Tera4All project that aims to develop and disseminate the terahertz (THz) technology in various research fields and associated applications across the Wallonia, Belgium. Our research goal, for the ULiège-EECS contribution to this project, is to study the application of THz pulsed spectroscopy to the mapping of human breast cancer margins, in the context of breast conserving surgery (BCS). [less ▲]

Detailed reference viewed: 78 (10 ULiège)
Full Text
See detailUsing supervised learning machine algorithm to identify future fallers based on gait patterns: A two-year longitudinal study
Gillain, Sophie ULiege; Boutaayamou, Mohamed ULiege; Schwartz, Cédric ULiege et al

in Experimental Gerontology (2019), 127(first online),

Introduction: Given their major health consequences in the elderly, identifying people at risk of fall is a major challenge faced by clinicians. A lot of studies have confirmed the relationships between ... [more ▼]

Introduction: Given their major health consequences in the elderly, identifying people at risk of fall is a major challenge faced by clinicians. A lot of studies have confirmed the relationships between gait parameters and falls incidence. However, accurate tools to predict individual risk among independent older adults without a history of falls are lacking. Objective: This study aimed to apply a supervised learning algorithm to a data set recorded in a two-year longitudinal study, in order to build a classification tree that could discern subsequent fallers based on their gait patterns. Methods: A total of 105 adults aged >65 years, living independently at home and without a recent fall history were included in a two-year longitudinal study. All underwent physical and functional assessment. Gait speed, stride length, frequency, symmetry and regularity, and minimum toe clearance were recorded in comfortable, fast and dual task walking conditions in a standardized laboratory environment. Fall events were recorded using personal falls diaries. A supervised machine learning algorithm (J48) has been applied to the data recorded at inclusion in order to obtain a classification tree able to identify future fallers. Results: Based on fall information from 96 volunteers, a classification tree correctly identifying 80% of future fallers based on gait patterns, gender, and stiffness, was obtained, with accuracy of 84%, sensitivity of 80%, specificity of 87%, a positive predictive value of 78%, and a negative predictive value of 88%. Discussion: While the performances of the classification tree warrant further confirmation, it is the first predictive tool based on gait parameters that are identified (not clustered) allowing its use by other research teams. Conclusion: This original longitudinal pilot study using a supervised machine learning algorithm, shows that gait parameters and clinical data can be used to identify future fallers among independent older adults. © 2019 Elsevier Inc. [less ▲]

Detailed reference viewed: 65 (17 ULiège)
Full Text
See detailGait symmetry in the dual task condition as a predictor of future falls among independent older adults: a 2-year longitudinal study
GILLAIN, Sophie ULiege; Boutaayamou, Mohamed ULiege; Schwartz, Cédric ULiege et al

in Aging Clinical and Experimental Research (2019), 31(8), 1057-1067

Detailed reference viewed: 190 (26 ULiège)
Full Text
See detailDoes negative information about aging influence older adults’ physical performance and subjective age?
Marquet, Manon ULiege; Boutaayamou, Mohamed ULiege; Schwartz, Cédric ULiege et al

in Archives of Gerontology and Geriatrics (2018), 78

his study investigated the way negative stereotypes influence older adults’ physical performance and how old they feel mentally and physically. Sixty-four older adults aged 65 years and older performed ... [more ▼]

his study investigated the way negative stereotypes influence older adults’ physical performance and how old they feel mentally and physically. Sixty-four older adults aged 65 years and older performed different physical tasks using a 3D optoelectronic system under a low or high stereotype threat condition. Self-perceptions of aging were considered as a moderator of the effects of threat. Overall, the effects of threat on physical performance were mostly not significant across tasks. However, threat condition influenced older adults' mental subjective age after they had performed the physical tests; people in the high-threat condition felt closer to their chronological age. Threat also influenced participants' physical subjective age, and this effect was moderated by self-perceptions of aging. More precisely, participants in the high-threat condition felt 7% physically older than their chronological age when they had more negative self-perceptions, while participants in the low-threat condition felt 13% younger. No differences emerged for participants who had more positive self-perceptions. The present findings suggest that performing physical tests under stereotype threat might worsen older people’s subjective experience of their own aging by making them feel older. [less ▲]

Detailed reference viewed: 124 (22 ULiège)
Full Text
See detailAssessing gait parameters with accelerometer-based methods to identify older adults at risk of falls: a systematic review
GILLAIN, Sophie ULiege; Boutaayamou, Mohamed ULiege; Beaudart, Charlotte ULiege et al

in European Geriatric Medicine (2018), 9

Purpose The purpose of this study was to perform a systematic review to assess the utility of accelerometric methods to identify older adults at risk of falls. Methods The Preferred Reporting Item for ... [more ▼]

Purpose The purpose of this study was to perform a systematic review to assess the utility of accelerometric methods to identify older adults at risk of falls. Methods The Preferred Reporting Item for Systematic review and Meta-Analysis (PRISMA) guidelines were followed during all steps of this systematic review. Cross sectional and longitudinal studies assessing gait parameters in older adults using accelerometric devices, and comparing groups based on the risk of falls or fall history were identified from studies published in the MEDLINE, SCOPUS and Cochrane Database of Systematic Reviews databases between January 1996 and January 2017. Study selection and data extraction were performed independently by two reviewers. The quality of the methodology used in the studies included was assessed using the Newcastle–Ottawa Scale. Results In total, 354 references were identified through the database search. After selection, ten studies were included in this systematic review. According to the cross sectional studies, people who fall or are at risk of fall are slower, and walk with shorter steps, lower step frequency, worse stride and step regularity in terms of time, position and acceleration profiles. One longitudinal study suggests considering harmonic ratio of upper trunk acceleration in the vertical plane. Two other longitudinal studies highlight the importance of considering more than one gait parameter, and sophisticated statistical tools to discern older adults at risk for future fall(s). Conclusion This systematic review essentially highlights the lack of available literature providing strong evidence that gait parameters obtained using acceleration-based methods could be useful to discern older people at risk of fall. Available literature is encouraging, but further high quality studies are needed to highlight the cross-sectional and longitudinal relationships between gait parameters and falls in older adults. [less ▲]

Detailed reference viewed: 114 (34 ULiège)
Full Text
See detailValidated assessment of gait sub-phase durations in older adults using an accelerometer-based ambulatory system
Boutaayamou, Mohamed ULiege; GILLAIN, Sophie ULiege; Schwartz, Cédric ULiege et al

in Proceedings of the 11th International Joint Conference on Biomedical Engineering Systems and Technologies (BIOSTEC 2018) (2018)

Validated extraction of gait sub-phase durations using an ambulatory accelerometer-based system is a current unmet need to quantify subtle changes during the walking of older adults. In this paper, we ... [more ▼]

Validated extraction of gait sub-phase durations using an ambulatory accelerometer-based system is a current unmet need to quantify subtle changes during the walking of older adults. In this paper, we describe (1) a signal processing algorithm to automatically extract not only durations of stride, stance, swing, and double support phases, but also durations of sub-phases that refine the stance and swing phases from foot-worn accelerometer signals in comfortable walking of older adults, and (2) the validation of this extraction using reference data provided by a gold standard system. The results show that we achieve a high agreement between our method and the reference method in the extraction of (1) the temporal gait events involved in the estimation of the phase/sub-phase durations, namely heel strike (HS), toe strike (TS), toe-off (TO), maximum of heel clearance (MHC), and maximum of toe clearance (MTC), with an accuracy and precision that range from ‒3.6 ms to 4.0 ms, and 6.5 ms to 12.0 ms, respectively, and (2) the gait phase/sub-phase durations, namely stride, stance, swing, double support phases, and HS to TS, TO to MHC, MHC to MTC, and MTC to HS sub-phases, with an accuracy and precision that range from ‒4 ms to 5 ms, and 9 ms to 15 ms, respectively, in comfortable walking of a thirty-eight older adults ( (mean ± standard deviation) 71.0 ± 4.1 years old). This demonstrates that the developed accelerometer-based algorithm can extract validated temporal gait events and phase/sub-phase durations, in comfortable walking of older adults, with a promising degree of accuracy/precision compared to reference data, warranting further studies. [less ▲]

Detailed reference viewed: 156 (38 ULiège)
See detailA gait cycle partitioning method using a foot-worn accelerometer system
Boutaayamou, Mohamed ULiege; Bruls, Olivier ULiege; Denoël, Vincent ULiege et al

Conference (2017, November 30)

Detailed reference viewed: 27 (5 ULiège)
Full Text
See detailA gait cycle partitioning method using a foot-worn accelerometer system
Boutaayamou, Mohamed ULiege; Bruls, Olivier ULiege; Denoël, Vincent ULiege et al

Conference (2017, November 30)

Detailed reference viewed: 106 (12 ULiège)
See detailA Novel Accelerometer-Based Method for Stride Length Estimation
Boutaayamou, Mohamed ULiege; Schwartz, Cédric ULiege; Denoël, Vincent ULiege et al

Poster (2017, July 14)

We demonstrate the feasibility of accurately and precisely estimating the left/right average stride length from measured heel/toe accelerations in the gait of healthy, old adults. Our approach relies on ... [more ▼]

We demonstrate the feasibility of accurately and precisely estimating the left/right average stride length from measured heel/toe accelerations in the gait of healthy, old adults. Our approach relies on (1) a novel method that uses only accelerometer data without the need of additional data from, e.g., gyroscopes and/or magnetometers, and on (2) the validation of the results using reference 3D optoelectronic system data. [less ▲]

Detailed reference viewed: 119 (24 ULiège)
See detailAmbulatory System for Gait Analysis
Boutaayamou, Mohamed ULiege; Bruls, Olivier ULiege; Croisier, Jean-Louis ULiege et al

Conference (2017, April 29)

We describe the principle and use of a wireless, 3-axis accelerometer-based ambulatory system that records acceleration signals and automatically analyses them to characterize normal and pathological gait ... [more ▼]

We describe the principle and use of a wireless, 3-axis accelerometer-based ambulatory system that records acceleration signals and automatically analyses them to characterize normal and pathological gait. The associated algorithm is versatile enough to detect, on a stride-by-stride basis, refined gait parameters that quantify subtle gait disturbances in, e.g., in Parkinson’s disease in a rater-independent way. The experimental results show the potential of the developed accelerometer-based technique to be used in neurology (e.g., characterization of Parkinsonian gait: slowness, shuffling, short steps, freezing of gait, asymmetries in gait), rehabilitation, geriatrics (ex. monitoring activity parameters in the elderly), orthopedics and sport. [less ▲]

Detailed reference viewed: 70 (7 ULiège)
Full Text
See detailMotion analysis: a prevention tool
Schwartz, Cédric ULiege; CROISIER, Jean-Louis ULiege; Forthomme, Bénédicte ULiege et al

Conference (2017, April 28)

Detailed reference viewed: 51 (23 ULiège)