Ranjana K Mehta

• PhD
• Professor (Assistant) at Texas A&M University

Background:Many office employees are spending up to 90% of their workday seated, and employers are considering stand-capable desks as a way to increase physical activity throughout the day. When deciding on adoption of stand-capable workstations, a major concern for employers is that the benefits, over time, may not offset the initial cost of imple...

Standing desks have proven to be effective and viable solutions to combat sedentary behavior among children during the school day in studies around the world. However, little is known regarding the potential of such interventions on cognitive outcomes in children over time. The purpose of this pilot study was to determine the neurocognitive benefit...

Objective: Obesity is an established risk factor for impaired cognition, which is primarily regulated by the prefrontal cortex (PFC). However, very little is known about the neural pathways that underlie obesity-related declines in neuromuscular control, particularly under stress. The purpose of this study was to determine the role of the PFC on n...

Objective: The present study used a neuroergonomic approach to examine the interaction of mental and physical fatigue by assessing prefrontal cortex activation during submaximal fatiguing handgrip exercises. Background: Mental fatigue is known to influence muscle function and motor performance, but its contribution to the development of voluntar...

Most occupational tasks involve some level of mental/cognitive processing in addition to physical work; however, the etiology of work-related musculoskeletal disorders (WMSDs) due to these demands remains unclear. The aim of this study was to quantify the interactive effects of physical and mental workload on muscle endurance, fatigue, and recovery...

Passive exoskeletons have been introduced to alleviate loading on the lumbar spine while increasing the wearer’s productivity. However, few studies have examined the neurocognitive effects of short-term human-exoskeleton adaptation. The objective of the study was to develop a novel neural efficiency metric to assess short-term human exoskeleton ada...

Introduction First responders play a pivotal role in ensuring the wellbeing of individuals during critical situations. The demanding nature of their work exposes them to prolonged shifts and unpredictable situations, leading to elevated fatigue levels. Modern countermeasures to fatigue do not provide the best results. This study evaluates the accep...

Objective: Our objectives were to assess the efficacy of active inference models for capturing driver takeovers from automated vehicles and to evaluate the links between model parameters and self-reported cognitive fatigue, trust, and situation awareness. Background: Control transitions between human drivers and automation pose a substantial safety...

Automation misuse and acceptance, influenced by trust, environmental conditions, and confidence, have hindered drivers from fully benefiting from partially automated vehicles. This study investigates how driver trust changes with AV reliance, differences in mental and physiological states, and continuous measures’ effectiveness. The takeover driver...

Fatigue is a significant contributor to accidents in the high-risk oil and gas industry. This study developed and evaluated models for forecasting fatigue manifestation in offshore workers using the Psychomotor Vigilance Task (PVT). Seventy offshore workers participated in a four-week study, providing data on sleep, physiological, subjective, and p...

Emergency Medical Technicians (EMTs) are at high risk of work-related low back injuries due to the physical demands of patient rescue and transfer operations. Despite training in proper lifting techniques and ergonomic interventions, there remains a gap in technology that can assist EMTs without hindering their movement or attention. Soft-passivelo...

Emergency responders often lack adequate training for mass casualty incidents due to cost and accessibility challenges, leading to poor coordination and fatalities. Extended Reality (XR) technologies offer accessible, cost-effective, and customizable training scenarios. However, their adoption is slow due to the lack of personalized, high-quality t...

Decrements in sensorimotor performance due to vestibular challenges associated with spaceflight are well characterized, and these impairments pose a significant risk to astronaut safety and mission success. However, the impact of fatigue on this impairment is unknown. We hypothesized that the interaction of fatigue and vestibular impairment would l...

Driver reliance on automated vehicles (AV) is a critical component of safety particularly during high-risk traffic scenarios. Factors that influence reliance, including trust, situation awareness, fatigue, and demographics, have been independently explored; however, few analyses have investigated predicting AV reliance and compared factors comprehe...

Transformative paradigms to proactively mitigate fatigue through noninvasive neurostimulation, such as transcranial direct current stimulation (tDCS), have been shown to be more effective than existing interventions. The study aimed to evaluate the effectiveness of HD-tDCS (High-Definition) as a fatigue countermeasure on vigilance and perceived fat...

Many HRI applications (such as in search and rescue; SAR) require multiple humans to interact with robot agents, making it essential to understand and evaluate both the trust in robots and trust in teams when robots are embedded into such team structures. In the present study, we utilized a virtual urban search and rescue task to compare individual...

Small unmanned aerial systems (sUAS) are used more regularly and widely in disaster response. Like other personnel involved in disaster response, the sUAS pilots work for long periods, experience extreme stress and fatigue. They often arrive at the disaster fatigued (due to long drives to get there). However, unlike other personnel in this domain,...

Recent challenges such as COVID-19 call for innovative methods of delivering training. In this study, we compare the effectiveness of augmented reality (AR) based psychomotor learning compared to videobased training. Participants completed either AR or video training to learn four basic AR interactions, before completing an AR evaluation. The AR gr...

p>In this paper, we consider strategies to label mental fatigue states during a prolonged visuospatial working memory exercise. Specifically, we look to address the need to accurately forecast these states with unobtrusive measures derived from cardiac electrical activity. We formulate this challenge as a multi-step-ahead, multivariate time-series...

p>Passive exoskeletons have been introduced to alleviate loading on the lumbar spine while increasing the wearer’s productivity. However, few studies have examined the neurocognitive effects of short-term human-exoskeleton adaptation. The objective of the study was to develop a novel neural efficiency metric to assess short-term human exoskeleton a...

p>Passive exoskeletons have been introduced to alleviate loading on the lumbar spine while increasing the wearer’s productivity. However, few studies have examined the neurocognitive effects of short-term human-exoskeleton adaptation. The objective of the study was to develop a novel neural efficiency metric to assess short-term human exoskeleton a...

Emergency medical technicians (EMTs) have a high prevalence of low back injuries and low-back pain. Low back exoskeletons, that have proven to be effective tools in injury prevention in industry, can be seen as a potential solution to reducing the risk of injury for EMTs. The aim of this study was to evaluate user perception and perceived workload...

Fatigue is a feeling of tiredness or weakness that can be physical, mental or both. Interpretable machine learning methods can be used for inference while having the dimension of time series prediction for developing intelligent health systems to manage fatigue. The study explored forecasting perception and performance scores associated with fatigu...

Acute cognitive stress affects neuromuscular fatigue, but the underlying mechanisms are not well understood. The aim of this study was to identify the influence of stress on central fatigue and associated functional changes in the brain. Thirty participants, balanced by sex, performed intermittent elbow flexion contractions at 30% of their maximum...

Twenty-five years ago, Raja Parasuraman – the pioneer of neuroergonomics – wrote the first book on neuroergonomics. Since then, neuroergonomics, the science of the brain and behavior at work, has contributed significantly to our understanding of human behavior in use-inspired domains. Aided by considerable advancements in sensor technologies, neuro...

This study used a multiplayer virtual environment simulating search and rescue to examine teaming behaviors and trust networks in two teaming conditions using the Wizard of Oz approach: (1) an all-human team (three humans) and (2) a human-robot team (two humans, one simulated quadruped robot). Neural, physiological, and subjective responses of trus...

Transitions of control are an important safety concern for human-automation teams and automated vehicle safety. While trust and situation awareness have been observed to influence transitions of control in automated vehicles, there are few objective measurements, making these concepts difficult to operationalize in increasingly automated decision s...

This study captured neurophysiological, muscular, and perceptual adaptations to shoulder exoskeleton use during overhead work with competing physical-cognitive demands. Twenty-four males and females, randomly divided into control and exoskeleton groups, performed an overhead reaching and pointing task over three days without (single task) and with...

Background Historical biases in ergonomics-related studies have been attributed to lack of participant diversity and sensitivity of measurements to capture variability between diverse groups. We posit that a neuroergonomics approach, that is, study of brain-behavior relationships during fatiguing work, allows for unique insights on sex differences...

Measuring trust is an important element of effective human-robot collaborations (HRCs). It has largely relied on subjective responses and thus cannot be readily used for adapting robots in shared operations, particularly in shared-space manufacturing applications. Additionally, whether trust in such HRCs differ under altered operator cognitive stat...

Anomalous robot motions caused by cyber attacks and inherent defects can lead to task failures as well as harmful accidents in collaborative human-robot workplaces. External Internet-of-Things (IoT) sensors are essential for reliably monitoring robot tool paths and detecting deviations as early as possible, especially in anomalous situations where...

In recent years, US Emergency Medical Services (EMS) have faced a massive shortage of EMS workers. The sudden outbreak of the pandemic has further exacerbated this issue by limiting in-person training. Additionally, current training modalities for first responders are costly and time-consuming, further limiting training opportunities. To overcome t...

The use of small unmanned aerial systems, or drones, has grown rapidly in recent years, but the FAA has no formal requirement for hands-on training. Physical drone training has major limitations, and virtual reality (VR) offers a promising alternative. This study sought to identify early performance markers of learning in VR-based drone training us...

In recent years, robots have become vital to achieving manufacturing competitiveness. Especially in industrial environments, a strong level of interaction is reached when humans and robots form a dynamic system that works together towards achieving a common goal or accomplishing a task. However, the human-robot collaboration can be cognitively dema...

BACKGROUND Student mental health is an increasing concern among college student populations. OBJECTIVE To determine if college students could better self-manage their anxiety, stress, and depression symptomology by using automated mHealth to support health coaching for managing mental health. METHODS Students were provided with a mobile health se...

Diabetes is a chronic disease where blood glucose (BG) concentrations are consistently high. A dangerous diabetes-associated condition is hypoglycemia, where BG level drops below the normal threshold. Hypoglycemia is often accommodated by tremors, sweating, fatigue, anxiety, lightheadedness, disorientation, irritability, and tachycardia. Very few s...

BACKGROUND With 425 million individuals globally suffering from diabetes, it is critical to support self-management of this life-threatening condition. However, adherence and engagement with existing technologies is inadequate and needs further research. OBJECTIVE The objective of our study was to develop an integrated belief model that helps iden...

Background: With 425 million individuals globally living with diabetes, it is critical to support the self-management of this life-threatening condition. However, adherence and engagement with existing technologies are inadequate and need further research. Objective: The objective of our study was to develop an integrated belief model that helps...

BACKGROUND Diabetes affects millions of people worldwide and is steadily increasing. A serious condition associated with diabetes is low glucose levels (hypoglycemia). Monitoring blood glucose is usually performed by invasive methods or devices that are intrusive, and these devices are currently not available to all patients with diabetes. Hand tre...

Background: Diabetes affects millions of people worldwide and is steadily increasing. A serious condition associated with diabetes is low glucose levels (hypoglycemia). Monitoring blood glucose is usually performed by invasive methods or intrusive devices, and these devices are currently not available to all patients with diabetes. Hand tremor is...

Background Industry 4.0 is currently underway allowing for improved manufacturing processes that leverage the collective advantages of human and robot agents. Consideration of trust can improve the quality and safety in such shared-space human-robot collaboration environments. Objective The use of physiological response to monitor and understand t...

Firefighters often need to digest complex spatial information within a short period of time for search and rescue. Previous wayfinding literature has documented evidence about how the general population in normal situations leverages different forms of spatial information to develop spatial knowledge and guide wayfinding. However, little is known a...

Objective: We examine the spatiotemporal dynamics of neural activity and its correlates in heart rate and its variability (HR/HRV) during a fatiguing visuospatial working memory task. Background: The neural and physiological drivers of fatigue are complex, coupled, and poorly understood. Investigations that combine the fidelity of neural indices...

Stress impairs motor performance, which is exacerbated with age. Stress also impairs brain activity in the prefrontal cortex, which communicates with the motor areas of the brain to regulate exercise and motor performance. To develop ergogenic strategies for the aging workforce, mind (brain)-body mechanisms behind the effect of stress on neuromuscu...

Emergency response (ER) workers perform extremely demanding physical and cognitive tasks that can result in serious injuries and loss of life. Human augmentation technologies have the potential to enhance physical and cognitive work-capacities, thereby dramatically transforming the landscape of ER work, reducing injury risk, improving ER, as well a...

Emergency response (ER) workers perform extremely demanding physical and cognitive tasks that can result in serious injuries and loss of life. Human augmentation technologies have the potential to enhance physical and cognitive work‐capacities, thereby dramatically transforming the landscape of ER work, reducing injury risk, improving ER, as well a...

Trust is a central factor for long-term success of human-robot collaborations (HRC). Extending our understanding of trust dynamics and transitivity in HRC requires systematic efforts towards developing novel and continuous metrics to capture trust and trusting behaviors, which are currently limited to self-reports. Survey responses provide minimal...

The effects of cognitive stress are complex and multi-dimensional with nuanced neural and physiological representations across our lifespan. Chronic and instantaneous stressors are known to alter both executive function and motor performance — a particularly challenging prospect for older adults. Age, sex, and motor activity are critical yet under-...

Neuromuscular fatigue is exacerbated under stress and is characterized by shorter endurance time, greater perceived effort, lower force steadiness, and higher electromyographic activity. However, the underlying mechanisms of fatigue under stress are not well-understood. This review investigated existing methods of identifying central mechanisms of...

Environment, Health and Safety (EHS) trainings are used by global industries to mitigate risks and are often provided in a lingua franca (often English). This research investigated a strategy for overcoming language barriers associated with performance, comprehension, and training effectiveness. Non-linguistic (e.g., EU's Napo animated trainings) a...

Background College students are leading an evolution of device use both in the type of device and the frequency of use. They have transitioned from desktop stations to laptops, tablets, and especially smartphones and use them throughout the day and into the night. Methods Using a 35-min online survey, we sought to understand how technology daily u...

Industrial passive low-back exoskeletons have gained recent attention as ergonomic interventions to manual handling tasks. This research utilized a two-armed experimental approach (single vs dual-task paradigms) to quantify neural and biomechanical tradeoffs associated with short-term human-exoskeleton interaction (HEI) during asymmetrical lifting...

Transcranial direct current stimulation (tDCS) of the left dorsolateral prefrontal cortex (DLPFC) has been shown to promote working memory (WM), however, its efficacy against time-on-task-related performance decline and associated cognitive fatigue remains uncertain. This study examined the impact of anodal tDCS of the left DLPFC on performance dur...

The adoption and appropriate utilization of automated subsystems is dependent on the acceptance, trust, and reliance in the automated subsystem and the systems as a whole. The differences in trust attitudes between vehicle, robot, medical devices, and cyber aids, as affected by dispositional and learned factors has not been studied. As such this pa...

Oil and gas extraction (OGE) and petrochemical workers are prone to fatigue due to shiftwork, circadian rhythm disruption, and workload. Currently, there is not a standard set of worker fatigue assessment methods developed to address the constraints in this industry. A systematic review was conducted to 1) identify and categorize fatigue assessment...

Background: Sex differences in neuromuscular fatigue is well-documented, however the underlying mechanisms remain understudied, particularly for the aging population. Objective: This study investigated sex differences in fatigability of the upper and lower extremity of older adults using a neuroergonomics approach. Methods: Thirty community-dwellin...

The nature of firefighters’ duties requires them to work for long periods under unfavorable conditions. To perform their jobs effectively, they are required to endure long hours of extensive, stressful training. Creating such training environments is very expensive and it is difficult to guarantee trainees’ safety. In this study, firefighters are t...

Firefighters often need to digest complex spatial information within a short period of time for search and rescue. Previous wayfinding literature has documented evidence about how the general population in normal situations leverage different forms of spatial information, including landmarks, routes and survey (maps), to develop spatial knowledge a...

Older adults are more likely to get severely injured or die in vehicle crashes. Advanced driver-assistance systems (ADAS) can reduce their risk of crashes; however, due to the lack of knowledge and training, usage rate of these systems among older drivers is limited. The objective of this study was to evaluate the impact of two ADAS training approa...

Fatigue is defined as “a loss of force-generating capacity” in a muscle that can intensify tremor. Tremor quantification can facilitate early detection of fatigue onset so that preventative or corrective controls can be taken to minimize work-related injuries and improve the performance of tasks that require high-levels of accuracy. We focused on d...

There has been increasing use of small unmanned aerial systems in disaster and incident response. We evaluated sUAS pilot states during the tactical response to the 2018 Kilauea Volcano Lower East Rift Zone event, using a 3-minute psychomotor vigilance test (PVT) and wrist worn heart rate sensor. The field data, collected over four days, indicated...

Type 1 diabetes (T1D) is associated with reduced muscular strength and greater muscle fatigability. Along with changes in muscular mechanisms, T1D is also linked to structural changes in the brain. How the neurophysiological mechanisms underlying muscle fatigue is altered with T1D and sex related differences of these mechanisms are still not well i...

Shutdown maintenance, i.e., turning off a facility for a short period for renewal or replacement operations is a highly stressful task. With the limited time and complex operation procedures, human stress is a leading risk. Especially shutdown maintenance workers often need to go through excessive and stressful on-site trainings to digest complex o...

Background Postflight orthostatic challenge (OC), resulting from blood pooling in lower extremities, is a major health concern among astronauts that fly long-duration missions. Additionally, astronauts undergo physical demanding tasks resulting in acute fatigue, which can affect performance. However, the effects of concurrent OC and acute physical...

Objective We aimed to identify opportunities for application of human factors knowledge base to mitigate disaster management (DM) challenges associated with the unique characteristics of the COVID-19 pandemic. Background The role of DM is to minimize and prevent further spread of the contagion over an extended period of time. This requires address...

Background: Advances in technology engender the investigation of technological solutions to opioid use disorder (OUD). However, in comparison to chronic disease management, the application of mobile health (mHealth) to OUD has been limited. Objective: The overarching aim of our research was to design OUD management technologies that utilize wearab...

Neuromuscular fatigue affects workers’ productivity and health, which is further deteriorated with chronic conditions such as type 1 diabetes (T1D). Enhanced physiological tremor, a key indicator of neuromuscular fatigue, shows great potential in detecting the onset of neuromuscular fatigue. This study aims to determine the feasibility of using a c...

Information visualization affords us the ability to reason, understand, and gain insight into data. Traditional behavioral and subjective methods of evaluating visualizations are inadequate. Neuroergonomic techniques can be used to complement traditional evaluation methods by assessing noninvasively and unobtrusively participants’ working memory as...

Major depressive disorder (MDD) has shown to negatively impact physical recovery in a variety of medical events (e.g., stroke and spinal cord injuries). Yet depression assessments, which are typically subjective in nature, are seldom considered to develop or guide rehabilitation strategies. The present study developed a predictive depression assess...

BACKGROUND Hypoglycemia or low blood sugar for people with diabetes can be a serious life-threatening condition and serious outcomes can be avoided if low levels are proactively detected. While technologies exist to detect the onset of hypoglycemia, they are invasive, costly, or suffer from high false alarms. Tremors are a commonly reported symptom...

Background Hypoglycemia, or low blood sugar levels, in people with diabetes can be a serious life-threatening condition, and serious outcomes can be avoided if low levels of blood sugar are proactively detected. Although technologies exist to detect the onset of hypoglycemia, they are invasive or costly or exhibit a high incidence of false alarms....

There are about 44 million licensed older drivers in the U.S. Older adults have higher crash rates and fatalities as compared to middle-aged and young drivers, which might be associated with degradations in sensory, cognitive, and physical capabilities. Advanced driver-assistance systems (ADAS) have the potential to substantially improve safety by...