The authors acknowledge the financial support of the Social Sciences and Humanities Research Council of Canada (SSHERC).

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The authors have nothing to disclose.

A critical choice when using the protocol would be ensuring the quality of the neurophysiological data. There is an inherent complication to using a tool like EEG during movement, because excessive movement can create a lot of noise in the data. It is therefore important to consider, prior to the data collection, how the data will be prepared to remove as many artefacts as possible without modifying the actual signal. Nonetheless, it is still quite likely that there will be higher rates of data exclusion because particip...

An erratum was issued for:&#160;<a href="https://www.jove.com/t/60555/measuring-the-switch-cost-of-smartphone-use-while-walking">Measuring the Switch Cost of Smartphone Use While Walking</a>. An&#160;author&#39;s name&#160;was&#160;updated.
The name was corrected from:
Gabrielle-Na&#239;m&#233; Mourra
to:
Gabrielle Na&#239;m&#233; Mourra

An erratum was issued for:&#160;<a href="https://www.jove.com/t/60555/measuring-the-switch-cost-of-smartphone-use-while-walking">Measuring the Switch Cost of Smartphone Use While Walking</a>. An&#160;author&#39;s name&#160;was&#160;updated.

Erratum: Measuring the Switch Cost of Smartphone Use While Walking

Because both smartphone penetration and the tendency to multitask are increasing, it is important to understand the impact smartphone use while walking has on attention. The literature has demonstrated repeatedly that task switching comes with a cost1, including smartphone use while walking. Studies have found that using a smartphone while walking can be distracting and dangerous2,3,4. These dangers have been linked to the attentional impairments of doing such a task3,4,5,6,7. Due to the complex nature of the pedestrian environment, studying it in an experimental context that is ecologically valid can be problematic. Nonetheless, conducting such studies in actual pedestrian environments can come with complications of their own because many extraneous variables can come into play, and there is a risk of harm to the participant due to distractions. It is important to be able to study such a phenomenon in a relatively safe environment that remains as realistic as possible. In this article, we describe a research methodology that studies the task-switching cost of texting while walking, while both increasing the validity of the task and mitigating the potential risks involved.
When using a smartphone while walking, individuals are forced to switch from the smartphone tasks to walking and environment-related tasks. Hence, in order to study such a phenomenon, we found it pertinent to frame this method within the literature on multitasking, specifically focused on the task switching paradigm. In order to do this, the task switching paradigm was used1, having participants switch between a pre-stimulus task and a post-stimulus task. One of the two pre-stimulus tasks involved multitasking, while the other one did not. In the post-stimulus task, participants had to respond to a stimulus whose perception is influenced by divided attention8. Moreover, experimental laboratory studies that try to be as ecologically valid as possible have often used virtual pedestrian environments to understand the attentional impact of smartphone use while walking4,9. Nonetheless, in order to capture the underlying neurophysiological mechanisms, we chose to focus on the specific task-switching reaction to one stimulus to minimize the number of stimuli participants had to react to. In this way, we can pinpoint more precisely the task-switching cost coming purely from switching attention away from the smartphone and towards the stimulus. With our study design, we use behavioral measures (i.e., task-switching cost) and neurophysiological data to better understand the attentional impairments found during pedestrian smartphone use.
During a task-switching experiment, participants usually performed at least two simple tasks pertaining to a set of stimuli, with each task requiring a different set of cognitive resources referred to as a &#8220;task-set&#8221;1. When individuals are forced to switch between tasks, their mental resources need to adapt (i.e., inhibition of previous task-set and activation of the current task-set). This &#8220;task-set reconfiguration&#8221; process is believed to be the cause of the task-switching cost1. The task-switching cost is usually determined by observing the differences in either the response time and/or the error rate between trials where participants switch between tasks and those where they do not10. In our experiment, we had three task-sets: 1) responding to a point-light walker stimulus; 2) texting on a smartphone while walking; and 3) simply walking. We compared the switch cost between two different conditions: 1) simply walking prior to responding to the stimulus, and 2) walking while texting prior to responding. In this way, we captured the cost of multitasking on a smartphone prior to switching the task and were able to directly compare it to the non-multitasking switch cost of simply walking before the appearance of the visual stimulus. Because the smartphone used in this study was of a specific brand, all participants were screened prior to the experiment to be sure they knew how to properly use the device.
In order to simulate a realistic experience representative of the pedestrian context, we decided to use a point-light walker figure as a visual stimulus, representing a human form walking with a 3.5&#176; deviation angle towards the left or the right of the participant. This figure is made up of 15 black dots on a white background, with the dots representing the head, shoulders, hips, elbows, wrists, knees, and ankles of a human (Figure 1). This stimulus is based on biological motion, which means that it follows the pattern of movement that is typical of humans and animals11. Furthermore, this stimulus is more than ecologically valid; it requires complex visual processing and attention in order to be analyzed successfully12,13. Interestingly, Thornton et al.8 found that proper identification of the point-like walker&#8217;s direction is greatly impacted by divided attention, making it suitable as a performance measure when studying task-switching costs when multitasking. Participants were asked to verbally state the direction the figure was walking. The appearance of the walker was always preceded by an auditory cue that signaled its appearance on the screen.
Performance on the point-light walker task and neurophysiological data allowed us to determine the attentional impact of both conditions and help determine what caused them. Performance was measured by looking at the error rates and response times when determining the direction of the point-light walker figure. In order to understand the underlying cognitive and attentional mechanisms involved in the attentional impairments we found with the performance measure, we assessed the participants&#39; neurophysiological data using the EEG actiCAP with 32 electrodes. EEG is an appropriate tool in terms of temporary precision, which is important when trying to see what causes poor performance at specific moments in time (e.g., the appearance of the point-light walker figure), although artefacts may be present in the data due to movements. When analyzing the EEG data, two indexes are particularly relevant: 1) alpha oscillations; and 2) cognitive engagement. Research has found that alpha oscillations may represent working memory control as well as active inhibition of task-irrelevant brain circuits14,15,16,17. By comparing the alpha oscillations at baseline levels with those occurring with the stimulus presentation18,19, we obtained the alpha ratio. With this ratio, we determined the event-related changes that could be underlying the attentional impairment observed when texting while walking. With regards to cognitive engagement, Pope et al.20 developed an index where beta activity represents increased arousal and attention, and alpha and theta activity reflect decreases in arousal and attention21,22. This analysis was done to determine whether increased engagement prior to the appearance of the stimulus would complicate the task set reconfiguration required in order to respond to the walker figure.
With the methodology described in this paper, we seek to grasp the underlying mechanisms that impact task-switching performance in participants engaged in multitasking episodes. The walking condition represents a non-multitasking task-switch performance that is compared to a multitasking task-switch performance (i.e., texting while walking). By measuring the roles of task-set inhibition and task-set activation, we sought to better understand the switch costs that occur when texting while walking. It is relevant to note that the original study was done in an immersive virtual environment23 but was later replicated in an experimental room (see Figure 2) with a projector displaying the walker figure on a screen in front of the participant. Because this virtual environment is no longer available, the protocol was adapted to the current experimental room design.

<table border="0" cellpadding="0" cellspacing="0" style="width:1068px;" width="1068">
	<colgroup>
		<col />
		<col />
		<col />
		<col />
	</colgroup>
	<tbody>
		<tr height="63">
			<td height="63" style="height:63px;width:216px;">The Observer XT</td>
			<td style="width:292px;">Noldus</td>
			<td style="width:83px;"></td>
			<td style="width:477px;">Integration and synchronization software: The Noldus Observer XT (Noldus Information Technology) is used to synchronize all behavioral, emotional and cognitive engagement data.</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">MediaRecorder</td>
			<td style="width:292px;">Noldus</td>
			<td style="width:83px;"></td>
			<td>Audio and video recording software</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">FaceReader</td>
			<td style="width:292px;">Noldus</td>
			<td style="width:83px;"></td>
			<td>Software for automatic analysis of the 6 basic facial expressions</td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;width:216px;">E-Prime</td>
			<td style="width:292px;">Psychology Software Tools, Inc.</td>
			<td style="width:83px;"></td>
			<td>Software for computerized experiment design, data collection, and analysis</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">BrainVision Recorder</td>
			<td style="width:292px;">Brain Vision</td>
			<td style="width:83px;"></td>
			<td>Software used for recording neuro-/electrophysiological signals (EEG in this case)</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Analyzer</td>
			<td style="width:292px;"></td>
			<td style="width:83px;"></td>
			<td>EEG signal processing software</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Qualtrics</td>
			<td style="width:292px;">Qualtrics</td>
			<td style="width:83px;"></td>
			<td>Online survey environment</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Tapis Roulant</td>
			<td style="width:292px;">ThermoTread GT Office Treadmill</td>
			<td style="width:83px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Syncbox</td>
			<td style="width:292px;">Noldus</td>
			<td style="width:83px;"></td>
			<td>Syncbox start the co-registration of EEG and gaze data by sending a Transistor-Transistor Logic (TTL) signal to the EGI amplifier and a keystroke signal to the Tobii Studio v 3.2.</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Move2actiCAP</td>
			<td style="width:292px;">Brain Vision</td>
			<td style="width:83px;"></td>
			<td>Add-on for a digital wireless system for EEG</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">iPhone 6s</td>
			<td style="width:292px;">Apple</td>
			<td style="width:83px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">iMessage</td>
			<td style="width:292px;">Apple</td>
			<td style="width:83px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">iPad</td>
			<td style="width:292px;">Apple</td>
			<td style="width:83px;"></td>
			<td></td>
		</tr>
	</tbody>
</table>

measuring the switch cost of smartphone use while walking

This paper presents a study protocol to measure the task-switching cost of using a smartphone while walking. This method involves having participants walk on a treadmill under two experimental conditions: a control condition (i.e., simply walking) and a multitasking condition (i.e., texting while walking). During these conditions, the participants must switch between the tasks related to the experimental condition and a direction determining task. This direction task is done with a point-light walker figure, seemingly walking towards the left or the right of the participant. Performance on the direction task represents the participant&#8217;s task-switching costs. There were two performance measures: 1) correct identification of the direction and 2) response time. EEG data are recorded in order to measure the alpha oscillations and cognitive engagement occurring during the task switch. This method is limited in its ecological validity: pedestrian environments have many stimuli occurring simultaneously and competing for attention. Nonetheless, this method is appropriate for pinpointing task-switching costs. The EEG data allow the study of the underlying mechanisms in the brain that are related to differing task-switching costs. This design allows the comparison between task switching when doing one task at a time, as compared to task switching when multitasking, prior to the stimulus presentation. This allows understanding and pinpointing both the behavioral and neurophysiological impact of these two different task-switching conditions. Furthermore, by correlating the task-switching costs with the brain activity, we can learn more about what causes these behavioral effects. This protocol is an appropriate base for studying the switching cost of different smartphone uses. Different tasks, questionnaires, and other measures can be added to it in order to understand the different factors involved in the task-switching cost of smartphone use while walking.

This study protocol was originally conducted with 54 participants, each responding to 88 direction trials. Half of those trials occurred when participants were simply walking prior to the stimulus presentation; the other half occurred when the participants were texting while walking prior to the stimulus presentation.
Behavioral results 
Performance on the point-light walker&#8217;s direction represents task-switching costs, with lower performance representing higher task...

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Measuring the Switch Cost of Smartphone Use While Walking

This study design measures the task-switching cost of using a smartphone while walking. Participants undergo two experimental conditions: a control condition (walking) and a multitasking condition (texting while walking). Participants switch between these tasks and a direction determining task. EEG data as well as behavioral measures are recorded.

This paper presents a study protocol to measure the task-switching cost of using a smartphone while walking. This method involves having participants walk ...

measuring-the-switch-cost-of-smartphone-use-while-walking

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1.8K Views.  HEC Montréal. This study design measures the task-switching cost of using a smartphone while walking. Participants undergo two experimental conditions: a control condition (walking) and a multitasking condition (texting while walking). Participants switch between these tasks and a direction determining task. EEG data as well as behavioral measures are recorded.

Video: Measuring the Switch Cost of Smartphone Use While Walking

The Use of the Puzzle Box as a Means of Assessing the Efficacy of Environmental Enrichment

Environmental enrichment can dramatically influence the development and function of neural circuits. Further, enrichment has been shown to successfully delay the onset of symptoms in models of Huntington&#8217;s disease 1-4, suggesting environmental factors can evoke a neuroprotective effect against the progressive, cellular level damage observed in neurodegenerative disorders. The ways in which an animal can be environmentally enriched, however, can vary considerably. Further, there is no straightforward manner in which the effects of environmental enrichment can be assessed: most methods require either fairly complicated behavioral paradigms and/or postmortem anatomical/physiological analyses. This protocol describes the use of a simple and inexpensive behavioral assay, the Puzzle Box 5-7 as a robust means of determining the efficacy of increased social, sensory and motor stimulation on mice compared to cohorts raised in standard laboratory conditions. This simple problem solving task takes advantage of a rodent&#8217;s innate desire to avoid open enclosures by seeking shelter. Cognitive ability is assessed by adding increasingly complex impediments to the shelter&#8217;s entrance. The time a given subject takes to successfully remove the obstructions and enter the shelter serves as the primary metric for task performance. This method could provide a reliable means of rapidly assessing the efficacy of different enrichment protocols on cognitive function, thus paving the way for systematically determining the role specific environmental factors play in delaying the onset of neurodevelopmental and neurodegenerative disease.

Environmental enrichment provides a potential protective effect against neurodegenerative disorders. Currently, however, there is no easy way of determining the efficacy of enrichment procedures. This protocol describes a simple &#8220;Puzzle Box&#8221; method for assessing an animal&#8217;s cognitive function, in order to reveal the effectiveness of environmental enrichment.

Environmental enrichment can dramatically influence the development and function of neural circuits.  Further, enrichment has been shown to successfully ...

Evaluation of a Smartphone-based Human Activity Recognition System in a Daily Living Environment

An evaluation method that includes continuous activities in a daily-living environment was developed for Wearable Mobility Monitoring Systems (WMMS) that attempt to recognize user activities. Participants performed a pre-determined set of daily living actions within a continuous test circuit that included mobility activities (walking, standing, sitting, lying, ascending/descending stairs), daily living tasks (combing hair, brushing teeth, preparing food, eating, washing dishes), and subtle environment changes (opening doors, using an elevator, walking on inclines, traversing staircase landings, walking outdoors). 
To evaluate WMMS performance on this circuit, fifteen able-bodied participants completed the tasks while wearing a smartphone at their right front pelvis. The WMMS application used smartphone accelerometer and gyroscope signals to classify activity states. A gold standard comparison data set was created by video-recording each trial and manually logging activity onset times. Gold standard and WMMS data were analyzed offline. Three classification sets were calculated for each circuit: (i) mobility or immobility, ii) sit, stand, lie, or walking, and (iii) sit, stand, lie, walking, climbing stairs, or small standing movement. Sensitivities, specificities, and F-Scores for activity categorization and changes-of-state were calculated.
The mobile versus immobile classification set had a sensitivity of 86.30% &#177; 7.2% and specificity of 98.96% &#177; 0.6%, while the second prediction set had a sensitivity of 88.35% &#177; 7.80% and specificity of 98.51% &#177; 0.62%. For the third classification set, sensitivity was 84.92% &#177; 6.38% and specificity was 98.17 &#177; 0.62. F1 scores for the first, second and third classification sets were 86.17 &#177; 6.3, 80.19 &#177; 6.36, and 78.42 &#177; 5.96, respectively. This demonstrates that WMMS performance depends on the evaluation protocol in addition to the algorithms. The demonstrated protocol can be used and tailored for evaluating human activity recognition systems in rehabilitation medicine where mobility monitoring may be beneficial in clinical decision-making.

A standardized evaluation method was developed for Wearable Mobility Monitoring Systems (WMMS) that includes continuous activities in a realistic daily living environment. Testing with a series of daily living activities can decrease activity recognition sensitivity; therefore, realistic testing circuits are encouraged for valid evaluation of WMMS performance.

An evaluation method that includes continuous activities in a daily-living environment was developed for Wearable Mobility Monitoring Systems (WMMS) that ...

Substantiating Appropriate Motion Capture Techniques for the Assessment of Nordic Walking Gait and Posture in Older Adults

Nordic walking (NW) has become a safe and simple form of exercise in recent years, and in studying this gait pattern, various data collection techniques have been employed, each with positives and negatives. The aim was to determine the effect of NW on older adult gait and posture and to determine optimal use of different data collection systems in both short and long duration analysis. Gait and posture during NW and normal walking were assessed in 17 healthy older adults (age: 69 &#177; 7.3). Participants performed two trials of 6 Minute Walk Tests (6MWT) (1 with poles (WP) and 1 without poles (NP)) and 6 trials of a 5m walk (3 WP and 3 NP). Motion was recorded using two systems, a 6-sensor accelerometry system and an 8-camera 3-dimensional motion capture system, in order to quantify spatial-temporal, kinematic, and kinetic parameters.
With both systems, participants demonstrated increased stride length and double support and decreased gait speed and cadence WP compared to NP (p &#60;0.05). Also, with motion capture, larger single support time was found WP (p &#60;0.05). With 3-D capture, smaller hip power generation and moments of force were found at heel contact and pre-swing as well as smaller knee power absorption at heel contact, pre-swing, and terminal swing WP compared to NP, when assessed over one cycle (p &#60;0.05). Also, WP yielded smaller moments of force at heel contact and terminal swing along with larger moments at mid-stance of a gait cycle (p &#60;0.05). No changes were found for posture.
NW seems appropriate for promoting a normal gait pattern in older adults. Three-dimensional motion capture should primarily be used during short duration gait analysis (i.e. single gait cycle), while accelerometry systems should be primarily employed in instances requiring longer duration analysis such as during the 6MWT.

The aim was to substantiate optimal use of data collection techniques for Nordic walking gait and posture analysis. Three-dimensional motion capture should be used during short duration analysis (i.e. single gait cycle), while accelerometry should be employed for longer duration analysis (i.e. repeated cycles) like a 6 Minute Walk Test.

Nordic walking (NW) has become a safe and simple form of exercise in recent years, and in studying this gait pattern, various data collection techniques ...

Reversible Cooling-induced Deactivations to Study Cortical Contributions to Obstacle Memory in the Walking Cat

On complex, naturalistic terrain, sensory information about an environmental obstacle can be used to rapidly adjust locomotor movements for avoidance. For example, in the cat, visual information about an impending obstacle can modulate stepping for avoidance. Locomotor adaptation can also occur independent of vision, as sudden tactile inputs to the leg by an expected obstacle can modify the stepping of all four legs for avoidance. Such complex locomotor coordination involves supraspinal structures, such as the parietal cortex. This protocol describes the use of reversible, cooling-induced cortical deactivation to assess parietal cortex contributions to memory-guided obstacle locomotion in the cat. Small cooling loops, known as cryoloops, are specially shaped to deactivate discrete regions of interest to assess their contributions to an overt behavior. Such methods have been used to elucidate the role of parietal area 5 in memory-guided obstacle avoidance in the cat.

Complex locomotion in naturalistic environments requiring careful coordination of the limbs involves regions of the parietal cortex. The following protocol describes the use of reversible cooling-induced deactivation to demonstrate the role of parietal area 5 in memory-guided obstacle avoidance in the walking cat.

On complex, naturalistic terrain, sensory information about an environmental obstacle can be used to rapidly adjust locomotor movements for avoidance. For ...

A Simple and Low-cost Assay for Measuring Ambulation in Mouse Models of Muscular Dystrophy

Measuring functional outcomes in the treatment of muscular dystrophy is an essential aspect of preclinical testing. The assessment of voluntary ambulation in mouse models is a non-invasive and reproducible activity assay that is directly analogous to measures of patient ambulation such as the 6-minute walk test and related mobility scores. Many common methods for testing mouse ambulation speed and distance are based on the open field test, where an animal&#39;s free movement within an arena is measured over time. One major downside to this approach is that commercial software and equipment for high-resolution motion tracking is expensive and may require transferring mice to specialized facilities for testing. Here, we describe a low-cost, video-based system for measuring mouse ambulation that utilizes free and open-source software. Using this protocol, we demonstrate that voluntary ambulation in the dystrophin-null mdx mouse model for Duchenne muscular dystrophy (DMD) is decreased relative to wild-type mouse activity. In mdx mice expressing the utrophin transgene, these activity deficits are not observed and the total distance traveled is indistinguishable from wild-type mice. This method is effective for measuring changes in voluntary ambulation associated with dystrophic pathology, and provides a versatile platform that can be readily adapted to diverse research settings.

This protocol describes a flexible, low-cost system for measuring mouse ambulation in an open field activity assay. We show that a 6-minute ambulation assay based on this system detects a decrease in voluntary movement in mdx mice, and accurately distinguishes improvement in a muscle-specific rescue of these animals.

Measuring functional outcomes in the treatment of muscular dystrophy is an essential aspect of preclinical testing. The assessment of voluntary ambulation ...

Using Rapid Serial Visual Presentation to Measure Set-Specific Capture, a Consequence of Distraction While Multitasking

This method uses a rapid serial visual presentation (RSVP) paradigm to measure the cost of distraction when participants maintain multiple search goals. The protocol identifies two types of distraction within a single task - contingent attentional capture and set-specific capture - that represent different types of limitations of cognitive processing. Participants search for letters in two or more &#34;target&#34; ink colors (e.g., green and orange) within a continuous RSVP stream of heterogeneously colored letters, while ignoring two peripheral RSVPs of letters. Upon detecting a target, participants are to identify the letter. On some trials, target-colored distractors appear in the periphery just prior to the presentation of a target, causing a drop in target identification performance. Contingent attentional capture is observed by examining performance on trials in which the peripheral distractor is the same color as the target on that trial (e.g., both orange). Set-specific capture is represented by performance on trials in which the peripheral distractor is target-colored (e.g., orange), but not the same color as the target on that trial (e.g., green.) By varying the amount of time (i.e., the number of stimuli appearing) between the presentation of the distractor and the target, researchers can observe how participants recover from these distraction costs over time. As compared to static displays that are often used to measure contingent attentional capture, the dynamic display produces much larger effects, allowing the researcher to identify subtle effects of smaller manipulations. An unusual aspect of our design is that it employs a continuous display; &#34;filler&#34; stimuli connect one trial to the next seamlessly, and participants respond during this interval whenever they detect a target. The continuous display reduces chance performance to near-zero levels (rather than 50%) and provides researchers with a more sensitive measure of performance differences across trial types.

This method uses a dynamic visual display to index costs of distraction during visual search, including both &#34;contingent attentional capture&#34; and &#34;set-specific capture,&#34; which is a cost of distraction that occurs when the participants maintain multiple search goals simultaneously. This method has revealed basic mechanisms and limitations of visual attention.

This method uses a rapid serial visual presentation (RSVP) paradigm to measure the cost of distraction when participants maintain multiple search goals. ...

Using a Virtual Reality Walking Simulator to Investigate Pedestrian Behavior

To cross a road successfully, individuals must coordinate their movements with moving vehicles. This paper describes use of a walking simulator in which people walk on a treadmill to intercept gaps between two moving vehicles in an immersive virtual environment. Virtual reality allows for a safe and ecologically varied investigation of gap crossing behavior. Manipulating the initial starting distance can further the understanding of a participant&#8217;s speed regulation while approaching a gap. The speed profile may be assessed for various gap crossing variables, such as initial distance, vehicle size, and gap size. Each walking simulation results in a position/time series that can inform how velocity is adjusted differently depending on the gap characteristics. This methodology can be used by researchers investigating pedestrian behavior and behavioral dynamics while employing human participants in a safe and realistic setting.

This protocol describes use of a walking simulator that serves as a safe and ecologically valid method to study pedestrian behavior in the presence of moving traffic.

To cross a road successfully, individuals must coordinate their movements with moving vehicles. This paper describes use of a walking simulator in which ...

Lower-Limb Biomechanical Characteristics Associated with Unplanned Gait Termination Under Different Walking Speeds

Gait termination caused by unexpected stimulus is a common occurrence in everyday life. This study presents a protocol to investigate the lower-limb biomechanical changes that occur during unplanned gait termination (UGT) under different walking speeds. Fifteen male participants were asked to perform UGT on a walkway at normal walking speed (NWS) and fast walking speed (FWS), respectively. A motion analysis system and plantar pressure platform were applied to collect lower-limb kinematic and plantar pressure data. Paired-sampled T-test was used to examine the differences in lower-limb kinematics and plantar pressure data between two walking speeds. The results showed larger range of motion in the hip, knee, and ankle joints in the sagittal plane as well as plantar pressure in forefoot and heel regions during UGT at FWS when compared with NWS. With the increase in walking speed, subjects exhibited different lower-limb biomechanical characteristics that show FWS associated with greater potential injury risks.

This study compared the biomechanical characteristics of the lower extremity during unplanned gait termination under different walking speeds. The lower-limb kinematic and kinetic data from fifteen subjects with normal and fast walking speeds were collected using a motion analysis system and plantar pressure platform.

Gait termination caused by unexpected stimulus is a common occurrence in everyday life. This study presents a protocol to investigate the lower-limb ...

An Improved Assay and Tools for Measuring Mechanical Nociception in Drosophila Larvae

Published assays for mechanical nociception in Drosophila have led to variable assessments of behavior. Here, we fabricated, for use with Drosophila larvae, customized metal nickel-titanium alloy (nitinol) filaments. These mechanical probes are similar to the von Frey filaments used in vertebrates to measure mechanical nociception. Here, we demonstrate how to make and calibrate these mechanical probes and how to generate a full behavioral dose-response from subthreshold (innocuous or non-noxious range) to suprathreshold (low to high noxious range) stimuli. To demonstrate the utility of the probes, we investigated tissue damage-induced hypersensitivity in Drosophila larvae. Mechanical allodynia (hypersensitivity to a normally innocuous mechanical stimulus) and hyperalgesia (exaggerated responsiveness to a noxious mechanical stimulus) have not yet been established in Drosophila larvae. Using mechanical probes that are normally innocuous or probes that typically elicit an aversive behavior, we found that Drosophila larvae develop mechanical hypersensitization (both allodynia and hyperalgesia) after tissue damage. Thus, the mechanical probes and assay that we illustrate here will likely be important tools to dissect the fundamental molecular/genetic mechanisms of mechanical hypersensitivity.

An Improved Assay and Tools for Measuring Mechanical Nociception in Drosophila Larvae

The goal of this protocol is to show how to perform an improved assay for mechanical nociception in Drosophila larvae. We use the assay here to demonstrate that mechanical hypersensitivity (allodynia and hyperalgesia) exists in Drosophila larvae.

Published assays for mechanical nociception in Drosophila have led to variable assessments of behavior. Here, we fabricated, for use with Drosophila ...

Iterative Development of an Innovative Smartphone-Based Dietary Assessment Tool: Traqq

To collect dietary intake data in a fast and reliable manner, a flexible and innovative smartphone application (app) called Traqq was developed (iOS/Android). This app can be used as a food record and&#160;24-h recall (or shorter recall periods). Different sampling schemes can be created on either prespecified or random days/times within a predetermined period for both methods, with&#160;push notifications to urge the participants to register their food intake. In case of non-response, notifications are automatically rescheduled to ensure complete data collection. For use as a food record, respondents can access the app and log their food intake throughout the day. Food records close automatically at the end of the day; recalls close after submission of the consumed items. The recall as well as the food record module provide access to an extensive food list based on the Dutch food composition database (FCDB), which can be accustomed to fit different research purposes. When selecting a food item, respondents are simultaneously prompted to insert portion size, i.e., in household measures (e.g., cups, spoons, glasses), standard portion sizes (e.g., small, medium, large), or weight in grams, and eating occasion/time of consumption. Portion size options can be adjusted, e.g., only entry in grams in case of a weighed food record or time of consumption instead of eating occasion). The app also includes a My Dishes function, which allows the respondent to create their own recipes or product combinations (e.g., a daily breakfast) and only report the total quantity consumed. Subsequently, the app accounts for yield and retention factors. The data are stored on a secure server. If desired, additional questions, i.e., in general or those related to specific food items or eating occasions can be incorporated. This paper describes the development of the system (app and backend), including expert evaluations and usability testing.

This article describes the protocol for the development of an innovative smartphone-based dietary assessment application Traqq, including expert evaluations and usability testing.