Thurmon Lockhart

Thurmon Lockhart
Arizona State University | ASU · School of Biological and Health Systems Engineering

Ph.D.

About

193
Publications
25,723
Reads
How we measure 'reads'
A 'read' is counted each time someone views a publication summary (such as the title, abstract, and list of authors), clicks on a figure, or views or downloads the full-text. Learn more
3,315
Citations

Publications

Publications (193)
Article
Full-text available
Lifestyle at the habitation immensely affects the progression of various illnesses, such as Osteoporosis and Parkinson’s disease (PD). These disorders lead patients to a sedentary lifestyle and result in significantly less movement compared to the average healthy individual. The combination of these backgrounds escalates the percentage of fall inci...
Article
Full-text available
Falls are among the most common cause of decreased mobility and independence in older adults and rank as one of the most severe public health problems with frequent fatal consequences. In the present study, gait characteristics from 171 community-dwelling older adults were evaluated to determine their predictive ability for future falls using a wea...
Article
Full-text available
The relationship between the robustness of HRV derived by linear and nonlinear methods to the required minimum data lengths has yet to be well understood. The normal electrocardiography (ECG) data of 14 healthy volunteers were applied to 34 HRV measures using various data lengths, and compared with the most prolonged (2000 R peaks or 750 s) by usin...
Article
Full-text available
Various factors are responsible for injuries that occur in the U.S. Army soldiers. In particular, rucksack load carriage equipment influences the stability of the lower extremities and possibly affects gait balance. The objective of this investigation was to assess the gait and local dynamic stability of the lower extremity of five subjects as they...
Article
Full-text available
This special issue was conceived during the 11th Annual Conference of Prognostic and Health Management Society’s Panel session on the September 25th at Scottsdale, AZ, USA. We would like to thank the panel members and their colleagues in their participation in this special issue focusing on engineered technologies for older adults. This work was pa...
Article
Full-text available
Acute injury to aged individuals represents a significant challenge to the global healthcare community as these injuries are frequently treated in a reactive method due to the infeasibility of frequent visits to the hospital for biometric monitoring. However, there is potential to prevent a large number of these cases through passive, at-home monit...
Article
Full-text available
Falls are the leading cause of disability in older adults with a third of adults over the age of 65 falling every year. Quantitative fall risk assessments using inertial measurement units and local dynamics stability (LDS) have shown that it is possible to identify at-risk persons. However, there are inconsistencies in the literature on how to calc...
Article
Full-text available
Falls represent a major burden on elderly individuals and society as a whole. Technologies that are able to detect individuals at risk of fall before occurrence could help reduce this burden by targeting those individuals for rehabilitation to reduce risk of falls. Wearable technologies especially, which can continuously monitor aspects of gait, ba...
Article
Full-text available
Injuries to ligaments of the knee are extremely common among athletes who participate in high-risk sports or any sport that requires frequent cutting motions, jumping, or contact. In order to determine the best way to heal these injuries, it is important to understand not just the pathology of the injury but also the biomechanical factors that are...
Article
Parkinson’s Disease (PD) is a neurodegenerative disorder affecting the substantia nigra, which leads to more than half of PD patients are considered to be at high risk of falling. Recently, Inertial Measurement Unit (IMU) sensors have shown great promise in the classification of activities of daily living (ADL) such as walking, standing, sitting, a...
Article
Full-text available
Parkinson’s Disease (PD) is a neurodegenerative disorder affecting the substantia nigra, which leads to more than half of PD patients are considered to be at high risk of falling. Recently, Inertial Measurement Unit (IMU) sensors have shown great promise in the classification of activities of daily living (ADL) such as walking, standing, sitting, a...
Article
Full-text available
Gait speed assessment increases the predictive value of mortality and morbidity following older adults’ cardiac surgery. The purpose of this study was to improve clinical assessment and prediction of mortality and morbidity among older patients undergoing cardiac surgery through the identification of the relationships between preoperative gait and...
Preprint
Full-text available
Falls are among the most common cause of decreased mobility and independence in older adults and rank as one of the most severe public health problems with frequent fatal consequences. In the present study, gait characteristics from 171 community-dwelling older adults were evaluated to determine their predictive ability for future falls using a wea...
Article
Full-text available
Although Support Vector Machines (SVM) are widely used for classifying human motion patterns, their application in the automatic recognition of dynamic and static activities of daily life in the healthy older adults is limited. Using a body mounted wireless inertial measurement unit (IMU), this paper explores the use of SVM approach for classifying...
Article
Full-text available
Although Support Vector Machines (SVM) are widely used for classifying human motion patterns, their application in the automatic recognition of dynamic and static activities of daily life in the healthy older adults is limited. Using a body mounted wireless inertial measurement unit (IMU), this paper explores the use of SVM approach for classifying...
Article
Full-text available
Although Support Vector Machines (SVM) are widely used for classifying human motion patterns, their application in the automatic recognition of dynamic and static activities of daily life in the healthy older adults is limited. Using a body mounted wireless inertial measurement unit (IMU), this paper explores the use of SVM approach for classifying...
Article
Full-text available
One of the most basic pieces of information gained from dynamic electromyography is accurately defining muscle action and phase timing within the gait cycle. The human gait relies on selective timing and the intensity of appropriate muscle activations for stability, loading, and progression over the supporting foot during stance, and further to adv...
Article
Full-text available
Although Support Vector Machines (SVM) are widely used for classifying human motion patterns, their application in the automatic recognition of dynamic and static activities of daily life in the healthy older adults is limited. Using a body mounted wireless inertial measurement unit (IMU), this paper explores the use of an SVM approach for classify...
Article
The Lyapunov exponent (LyE) is a trending measure for characterizing gait stability. Previous studies have shown that data length has an effect on the resultant LyE, but the origin of why it changes is unknown. This study investigates if data length affects the choice of time delay and embedding dimension when reconstructing the phase space, which...
Article
Full-text available
One of the most basic pieces of information gained from dynamic electromyography is accurately defining muscle action and phase timing within the gait cycle. The human gait relies on selective timing and the intensity of appropriate muscle activations for stability, loading, and progression over the supporting foot during stance, and further to adv...
Article
Full-text available
Although Support Vector Machines (SVM) are widely used for classifying human motion patterns, their application in the automatic recognition of dynamic and static activities of daily life in the elderly is limited. Using a body mounted wireless inertial measurement unit (IMU), this paper explores the use of an SVM approach for classifying dynamic (...
Article
Objective Evaluate dynamic balance and postural stability in patients with adult spinal deformity (ASD) compared with published age-matched normative data. Methods Eleven patients with ASD were prospectively enrolled. Postural stability was tested using static and dynamic posturography; patients stood on a movable platform with integrated force pl...
Article
Full-text available
As there is lack of understanding about the effect of transitioning between different flooring materials on the gait of older adults, this study investigated the effect of transitioning between a carpeted floor and a vinyl floor on the gait characteristics of older adults. Fourteen older (65 years old and over) and 14 younger (18 to 35 years old) a...
Article
Full-text available
As there is lack of understanding about the effect of transitioning between different flooring materials on the gait of older adults, this study investigated the effect of transitioning between a carpeted floor and a vinyl floor on the gait characteristics of older adults. Fourteen older (65 years old and over) and 14 younger (18 to 35 years old) a...
Article
Full-text available
As there is lack of understanding about the effect of transitioning between different flooring materials on the gait of older adults, this study investigated the effect of transitioning between a carpeted floor and a vinyl floor on the gait characteristics of older adults. Fourteen older (65 years old and over) and 14 younger (18 to 35 years old) a...
Article
Full-text available
As there is lack of understanding about the effect of transitioning between different flooring materials on the gait of older adults, this study investigated the effect of transitioning between a carpeted floor and a vinyl floor on the gait characteristics of older adults. Fourteen older (65 years old and over) and 14 younger (18 to 35 years old) a...
Article
Full-text available
Injuries to the ligaments of the knee are extremely common among athletes who participate in high-risk sports, or any sport that requires frequent cutting motions, jumping, or contact. In order to determine the best way to heal these injuries, it is important to understand not just the pathology of the injury, but also the biomechanical factors tha...
Article
Epidemiological studies link increased fall risk to obesity in older adults, but the mechanism through which obesity increases falls and fall risks is unknown. This study investigates if obesity (Body Mass Index: BMI>30 kg/m2) influenced gait and standing postural characteristics of community dwelling older adults leading to increased risk of falls...
Article
Full-text available
Our retrospective study of falls and resultant trauma in consecutive Parkinson disease (PD) patients seen in one year at the Muhammad Ali Parkinson Clinic found that multiple-fallers could be divided into patients who fell mainly when walking or those who fell mainly when standing. Patients who fell when walking were more likely to visit an emergen...
Article
Full-text available
Objective: Determine if NC001, an oral formulation of nicotine that reduces levodopa-induced dyskinesias (LIDs) in MPTP-Parkinson monkeys, could reduce falls, freezing of gait (FOG), and LIDs in Parkinson disease (PD) patients. Methods: Previously collected data from a study analyzing the effects of NC001 on LIDs in PD patients were reanalyzed. Bec...
Article
Full-text available
As there is lack of understanding about the effect of transitioning between different flooring materials on the gait of older adults, this study investigated the effect of transitioning between a carpeted floor and a vinyl floor on the gait characteristics of older adults. Fourteen older (65 years old and over) and 14 younger (18 to 35 years old) a...
Article
Full-text available
Parkinson's disease (PD) is a neurological disorder traditionally associated with degeneration of the dopaminergic neurons within the substantia nigra, which results in bradykinesia, rigidity, tremor, and postural instability and gait disability (PIGD). The disorder has also been implicated in degradation of motor learning. While individuals with P...
Article
Full-text available
Monitoring human gait is essential to quantify gait issues associated with fall-prone individuals as well as other gait-related movement disorders. Being portable and cost-effective, ambulatory gait analysis using inertial sensors is considered a promising alternative to traditional laboratory-based approach. The current study aimed to provide a me...
Article
BACKGROUND CONTEXT Postural stability (PS) is closely associated with quality of life and falls in the elderly. Recent work has demonstrated impaired gait and increased falls in patients with ASD, suggesting impaired postural stability due to biomechanical constraints of the spinal deformity. However, while previous studies have investigated the ef...
Article
Full-text available
Cardiovascular disease (CVD) patients with intrinsic cardiac cause for falling have been found to be frail and submissive to morbidity and mortality as post-operative outcomes. In these older CVD patients, gait speed is conjectured by the Society of Thoracic Surgeons (STS) as an independent predictor of post-operative morbidity and mortality. Howev...
Article
Full-text available
Postural control is a key aspect in preventing falls. The aim of this study was to determine if obesity affected balance in community-dwelling older adults and serve as an indicator of fall risk. The participants were randomly assigned to receive a comprehensive geriatric assessment followed by a longitudinal assessment of their fall history. The s...
Article
Full-text available
Parkinson’s disease (PD) can be divided into two subtypes based on clinical features—namely tremor dominant (TD) and postural instability and gait difficulty (PIGD). This categorization is important at the early stage of PD, since identifying the subtypes can help to predict the clinical progression of the disease. Accordingly, correctly diagnosing...
Article
Full-text available
Falls are a recognized risk factor for unintentional injuries among older adults, accounting for a large proportion of fractures, emergency department visits, and urgent hospitalizations. Human balance and gait research traditionally uses linear or qualitative tests to assess and describe human motion; however, human motion is neither a simple nor...
Conference Paper
Introduction: To measure gait dynamics the common gold standard is the use of an infrared camera system, but an alternative would be the application of pressure sensitive insoles. Barometric sensors are less costly than the commonly used pressure sensitive insoles today, and provide comparative results to their competitors [1].
Conference Paper
Full-text available
Basic requirement for recruitment training is Rucksack march that majority of soldiers must qualify. External weight of rucksack is approximately more than 35pounds and 12miles are minimum required distance. Previous reports indicated that during rucksack march, ankle, knee and other injuries has been occurring because of slips, trips and falls. To...
Conference Paper
Introduction: Fall risk assessment is becoming increasingly relevant as the population distribution transitions into a predominantly older one. More recently, techniques that attempt to quantify complexity and stability of systems such as multi-scale entropy (MSE) [5] and recurrent quantification analysis (RQA) [2] are being explored as possible in...
Conference Paper
Introduction: Gait parameters may change in response to internal or external changes to one's walking environment. Altering these gait parameters allows for greater stability to maintain normal walking [1]. There have been many previous studies that have used dynamic perturbations to understand how subjects react to situations in which gait stabili...
Conference Paper
Introduction: By 2020 it is expected that adult population above the age of 55 in the United States will reach 97.8 million, approximately 28.7% of the entire population. Falls are the leading cause of fatal and non-fatal injuries for elderly and have developed to be one of the primary areas of research in health and safety. In order to better unde...
Conference Paper
Basic requirement for recruitment training is Rucksack march that majority of soldiers must qualify. External weight of rucksack is approximately more than 35pounds and 12miles are minimum required distance. Previous reports indicated that during rucksack march, ankle, knee and other injuries has been occurring because of slips, trips and falls. To...
Conference Paper
Dynamic Stability is accurate indicator of the determine the fall risk. This can quantify the average logarithmic rate of divergence, which is indicator from maximum Lyapunov exponent. Therefore, this parameter can determine how stable a subject is during their gait cycles. Four different subjects' data were collected for six different scenarios. T...
Conference Paper
Introduction: The CDC expects by the year 2030 that over 60 million elderly adults (65yr+) will fall costing $31 billion in healthcare cost [1]. Vitamin D levels are shown to correlate with the elderly population's physical performance when an intervention occurs [2]. Vitamin D levels normal range is 20(ng/L) to 50(ng/mL), while levels below 20(ng/...
Article
Previous studies on lateral stepping gait have demonstrated decreased variability and also decreased involvement of central nervous system's active control in the direction of progression. This study sought to further explore this notion through the variability of stride interval time series (SIT) and signal magnitude difference time series (SMD) w...
Article
Performance of secondary task i.e. dual task affects certain aspects of gait, but the relationship between gait variability and dual tasking is not well understood. This study evaluated the effects of the dual-task paradigm on measures of movement variability changes in two healthy age groups. Seven young (age 22.6±2.5 years, height 170.3±9.3 cm an...
Article
Full-text available
Discriminating the two subtypes of tremor dominant (TD) and postural instability/gait difficulty (PIGD) in Parkinson's disease (PD) at early stage is highly valuable and crucial for progression treatment of disease for caregivers. However, there is no objective method or a subtype-specific biomarker yet available for identifying these two subtypes....
Article
Full-text available
Lower extremity fatigue has been associated with decline in postural stability, alteration of normal walking patterns and increased fall risk. Effects of lower extremity fatigue on amount of movement variability as assessed by linear variability such as standard deviation and root mean square is well known but there is lack of information about how...
Article
Full-text available
Dual-task tests can identify gait characteristics peculiar to fallers and nonfallers. Understanding the relationship between gait performance and dual-task related cognitive-motor interference is important for fall prevention. Dual-task adapted changes in gait instability/variability can adversely affect fall risks. Although implicated, it is uncle...
Conference Paper
Fall risk is a major threat in growing elderly population. A significant challenge is to assess fall risk owing to unstable gait. Smartphones with inbuilt inertial sensors provides an easy way to estimate gait stability in non-laboratory environments. In this study, two smartphones were attached to eight participants on their right and left ASIS us...
Article
Fall risk is a major threat in growing elderly population. A significant challenge is to assess fall risk owing to unstable gait. Smartphones with inbuilt inertial sensors provides an easy way to estimate gait stability in non-laboratory environments. In this study, two smartphones were attached to eight participants on their right and left ASIS us...
Conference Paper
Introduction: By 2020 it is expected that adult population above the age of 55 in the United States will reach 97.8 million, approximately 28.7% of the entire population. Falls are the leading cause of fatal and non-fatal injuries for elderly and have developed to be one of the primary areas of research in health and safety. In order to better unde...
Conference Paper
Fall risk is a major threat in growing elderly population. A significant challenge is to assess fall risk owing to unstable gait. Smartphones with inbuilt inertial sensors provides an easy way to estimate gait stability in non-laboratory environments. In this study, two smartphones were attached to eight participants on their right and left ASIS us...
Article
Full-text available
Injuries associated with fall incidences continue to pose a significant burden to persons with Parkinson's disease (PD) both in terms of human suffering and economic loss. Freezing of gait (FOG), which is one of the symptoms of PD, is a common cause of falls in this population. Although a significant amount of work has been performed to characteriz...
Article
Full-text available
Occupational slips, trips and falls on the same level (STFL) result in substantial injuries worldwide. This paper summarises the state of science regarding STFL, outlining relevant aspects of epidemiology, biomechanics, psychophysics, tribology, organisational influences and injury prevention. This review reaffirms that STFL remain a major cause of...
Article
Full-text available
The health and financial cost of falls has spurred research to differentiate the characteristics of fallers and non-fallers. Postural stability has received much of the attention with recent studies exploring various measures of entropy. This study compared the discriminatory ability of several entropy methods at differentiating two paradigms in th...
Conference Paper
Introduction: Injuries associated with fall incidences continue to pose a significant burden to persons with Parkinson's disease (PD) both in terms of human suffering and economic losses. Freezing of gait (FOG) which is one of the symptoms of the PD is a common cause of falls. This investigation compared time and frequency varying features of FOG u...
Article
Introduction: Injuries associated with fall incidences continue to pose a significant burden to persons with Parkinson's disease (PD) both in terms of human suffering and economic losses. Freezing of gait (FOG) which is one of the symptoms of the PD is a common cause of falls. This investigation compared time and frequency varying features of FOG u...
Article
The objective of the study was to investigate the relationship between different components of an auditory warning signal and determine elderly driver’s detection, criticality and urgency perceptions under varied auditory warning conditions. A laboratory study was conducted involving 28 younger and 28 older adults. A pure-tone audiogram was adminis...