Instruments for Measuring Psychological Dimensions in Human-Robot Interaction: Systematic Review of Psychometric Properties.

BACKGROUND: Numerous user-related psychological dimensions can significantly influence the dynamics between humans and robots. For developers and researchers, it is crucial to have a comprehensive understanding of the psychometric properties of the available instruments used to assess these dimensions as they indicate the reliability and validity of the assessment. OBJECTIVE: This study aims to provide a systematic review of the instruments available for assessing the psychological aspects of the relationship between people and social and domestic robots, offering a summary of their psychometric properties and the quality of the evidence. METHODS: A systematic review was conducted following the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines across different databases: Scopus, PubMed, and IEEE Xplore. The search strategy encompassed studies meeting the following inclusion criteria: (1) the instrument could assess psychological dimensions related to social and domestic robots, including attitudes, beliefs, opinions, feelings, and perceptions; (2) the study focused on validating the instrument; (3) the study evaluated the psychometric properties of the instrument; (4) the study underwent peer review; and (5) the study was in English. Studies focusing on industrial robots, rescue robots, or robotic arms or those primarily concerned with technology validation or measuring anthropomorphism were excluded. Independent reviewers extracted instrument properties and the methodological quality of their evidence following the Consensus-Based Standards for the Selection of Health Measurement Instruments guidelines. RESULTS: From 3828 identified records, the search strategy yielded 34 (0.89%) articles that validated and examined the psychometric properties of 27 instruments designed to assess individuals' psychological dimensions in relation to social and domestic robots. These instruments encompass a broad spectrum of psychological dimensions. While most studies predominantly focused on structural validity (24/27, 89%) and internal consistency (26/27, 96%), consideration of other psychometric properties was frequently inconsistent or absent. No instrument evaluated measurement error and responsiveness despite their significance in the clinical context. Most of the instruments (17/27, 63%) were targeted at both adults and older adults (aged ≥18 years). There was a limited number of instruments specifically designed for children, older adults, and health care contexts. CONCLUSIONS: Given the strong interest in assessing psychological dimensions in the human-robot relationship, there is a need to develop new instruments using more rigorous methodologies and consider a broader range of psychometric properties. This is essential to ensure the creation of reliable and valid measures for assessing people's psychological dimensions regarding social and domestic robots. Among its limitations, this review included instruments applicable to both social and domestic robots while excluding those for other specific types of robots (eg, industrial robots).

Impact of minimally invasive surgery on surgeon health (ISSUE) study: protocol of a single-arm observational study conducted in the live surgery setting.

INTRODUCTION: The rapid evolution of minimally invasive surgery has had a positive impact on patient outcomes; however, it is reported to be associated with work-related musculoskeletal symptoms (WMS) in surgeons. Currently there is no objective measure to monitor the physical and psychological impact of performing a live surgical procedure on the surgeon. METHODS AND ANALYSIS: A single-arm observational study with the aim of developing a validated assessment tool to quantify the impact of surgery (open/laparoscopic/robotic-assisted) on the surgeon. Development and validation cohorts of major surgical cases of varying levels of complexity performed by consultant gynaecological and colorectal surgeons will be recruited. Recruited surgeons wear three Xsens DOT monitors (muscle activity) and an Actiheart monitor (heart rate). Salivary cortisol levels will be taken and questionnaires (WMS and State-Trait Anxiety Inventory) completed by the participants preoperatively and postoperatively. All the measures will be incorporated to produce a single score that will be called the 'S-IMPACT' score. ETHICS AND DISSEMINATION: Ethical approval for this study has been granted by the East Midlands Leicester Central Research Ethics Committee REC ref 21/EM/0174. Results will be disseminated to the academic community through conference presentations and peer-reviewed journal publications. The S-IMPACT score developed within this study will be taken forward for use in definitive multicentre prospective randomised control trials.

Effect of Equipment on the Accuracy of Accelerometer-Based Human Activity Recognition in Extreme Environments.

A little explored area of human activity recognition (HAR) is in people operating in relation to extreme environments, e.g., mountaineers. In these contexts, the ability to accurately identify activities, alongside other data streams, has the potential to prevent death and serious negative health events to the operators. This study aimed to address this user group and investigate factors associated with the placement, number, and combination of accelerometer sensors. Eight participants (age = 25.0 ± 7 years) wore 17 accelerometers simultaneously during lab-based simulated mountaineering activities, under a range of equipment and loading conditions. Initially, a selection of machine learning techniques was tested. Secondly, a comprehensive analysis of all possible combinations of the 17 accelerometers was performed to identify the optimum number of sensors, and their respective body locations. Finally, the impact of activity-specific equipment on the classifier accuracy was explored. The results demonstrated that the support vector machine (SVM) provided the most accurate classifications of the five machine learning algorithms tested. It was found that two sensors provided the optimum balance between complexity, performance, and user compliance. Sensors located on the hip and right tibia produced the most accurate classification of the simulated activities (96.29%). A significant effect associated with the use of mountaineering boots and a 12 kg rucksack was established.

Perceptions of In-home Monitoring Technology for Activities of Daily Living: Semistructured Interview Study With Community-Dwelling Older Adults.

BACKGROUND: Many older adults prefer to remain in their own homes for as long as possible. However, there are still questions surrounding how best to ensure that an individual can cope with autonomous living. Technological monitoring systems are an attractive solution; however, there is disagreement regarding activities of daily living (ADL) and the optimal technologies that should be used to monitor them. OBJECTIVE: This study aimed to understand older adults' perceptions of important ADL and the types of technologies they would be willing to use within their own homes. METHODS: Semistructured interviews were conducted on the web with 32 UK adults, divided equally into a younger group (aged 55-69 years) and an older group (≥70 years). RESULTS: Both groups agreed that ADL related to personal hygiene and feeding were the most important and highlighted the value of socializing. The older group considered several activities to be more important than their younger counterparts, including stair use and foot care. The older group had less existing knowledge of monitoring technology but was more willing to accept wearable sensors than the younger group. The younger group preferred sensors placed within the home but highlighted that they would not have them until they felt that daily life was becoming a struggle. CONCLUSIONS: Overall, technological monitoring systems were perceived as an acceptable method for monitoring ADL. However, developers and carers must be aware that individuals may express differences in their willingness to engage with certain types of technology depending on their age and circumstances.

Objective assessment of surgeon kinematics during simulated laparoscopic surgery: a preliminary evaluation of the effect of high body mass index models.

PURPOSE: Laparoscopy is used in many surgical specialties. Subjective reports have suggested that performing laparoscopic surgery in patients with a high body mass index (BMI) is leading to increased prevalence of musculoskeletal symptoms in surgeons. The aim of this study was to objectively quantify the impact on surgeon upper body kinematics and dynamic workload when performing simulated laparoscopy at different BMI levels. METHODS: Upper body kinematics and dynamic workload of novice, intermediate and expert surgeons were calculated based on measurements from inertial measurement units positioned on upper body segments. Varying thicknesses of foam were used to simulate patient BMIs of 20, 30, 40 and 50 kg/m2 during laparoscopic training. RESULTS: Significant increases in the jerkiness, angular speed and cumulative displacement of the head, torso and upper arms were found within all experience groups when subject to the 40 and 50 kg/m2 models. Novice surgeons were found to have less controlled kinematics and larger dynamic workloads compared to the more experienced surgeons. CONCLUSIONS: Our findings indicate that performing laparoscopic surgery on a high BMI model worsens upper body motion efficiency and efficacy, and increases dynamic workload, producing conditions that are more physically demanding when compared to operating on a 20 kg/m2 model. These findings also suggest that the head, torso, and upper arm segments are especially affected by high BMI models and therefore exposure to patients with high BMIs may increase the risk of musculoskeletal injury when performing laparoscopic surgery.

Effects of 1 Year of Lifestyle Intervention on Institutionalized Older Adults.

The socio-economic and health consequences of our ageing population are well documented, with older adults living in long-term care facilities amongst the frailest possessing specific and significant healthcare and social care needs. These needs may be exacerbated through the sedentary behaviour which is prevalent within care home settings. Reducing sedentary time can reduce the risk of many diseases and improve functional health, implying that improvements in health may be gained by simply helping older adults substitute time spent sitting with time spent standing or in light-intensity ambulation. This study identified the impact of 1 year of lifestyle intervention in a group of older adults living in a long-term care setting in Italy. One hundred and eleven older adults (mean age, 82.37 years; SD = 10.55 years) participated in the study. Sixty-nine older adults were in the intervention group (35 without severe cognitive decline and 34 with dementia) and 42 older adults were in the control group. Data on physical functioning, basic activities of daily living (BADL) and mood were collected 4 times, before, during (every four months) and after the 1 year of intervention. The lifestyle intervention focused on improving the amount of time spent every week in active behaviour and physical activity (minimum 150 min of weekly activities). All participants completed the training program and no adverse events, related to the program, occurred. The intervention group showed steady and significant improvements in physical functioning and a stable situation in BADL and mood following the intervention in older adults with and without dementia, whilst the control group exhibited a significant decline over time. These results suggest that engagement in a physical activity intervention may benefit care home residents with and without dementia both physically and mentally, leading to improved social care and a reduced burden on healthcare services.

The ergonomic impact of patient body mass index on surgeon posture during simulated laparoscopy.

Laparoscopy is a cornerstone of modern surgical care, with clear advantages for the patients. However, it has also been associated with inducing upper body musculoskeletal disorders amongst surgeons due to their propensity to assume non-neutral postures. Further, there is a perception that patients with high body mass indexes (BMI) exacerbate these factors. Therefore, surgeon upper body postures were objectively quantified using inertial measurement units and the LUBA ergonomic framework was used to assess posture during laparoscopic training on patient models that simulated BMIs of 20, 30, 40 and 50 kg/m2. In all surgeons the posture of the upper body significantly worsened during simulated laparoscopic surgery on the BMI 50 kg/m2 model as compared to the baseline BMI model of 20 kg/m2. These findings suggest that performing laparoscopic surgery on patients with high BMIs increases the prevalence of non-neutral posture and may further increase the risk of musculoskeletal disorders in surgeons.

Analysis of the validity of the mathematical assumptions of electrical impedance tomography for human head tissues.

Objective:To determine the validity of the key mathematical assumptions used in electrical impedance tomography for human head tissues.Approach:Conductivity and permittivity data collected from available literature for each tissue within the human head have been evaluated and critiqued. The most relevant dielectric tissue data for each tissue was then used to assess the validity of the mathematical assumptions of electrical impedance tomography in terms of their suitability for human head imaging in order to estimate related errors.Main Results:For induced currents with frequencies greater than 200 Hz the internal current source density is negligible. The assumption that magnetic effects are negligible is valid to an error of 1.7% for human head tissues for frequencies below 1 MHz. The capacitive effects are negligible for CSF, dura mater, blood, bone (cortical), and deep tissue skin for frequencies less than 3.2 MHz, 320 kHz, 25 kHz, 3.2 kHz, and 130 Hz respectively. However, the capacitive effects are not negligible for brain tissues, as the minimum error for brain tissues across the frequency range of 10 Hz to 100 GHz is 6.2% at 800 Hz, and the maximum error is 410% at 20 GHz.Significance:It is often assumed that the mathematical reduction of the base equations is valid for human head tissues over a broad frequency range; this study shows that these assumptions are not true for all tissues at all frequencies. False assumptions will result in greater errors and local distortions within tomographic images of the human head using electrical impedance tomography. This study provides the relationships between injected current frequency and the validity of the mathematical assumptions for each individual tissue, providing greater awareness of the magnitude of possible distortions.

Technology Used to Recognize Activities of Daily Living in Community-Dwelling Older Adults.

The use of technology has been suggested as a means of allowing continued autonomous living for older adults, while reducing the burden on caregivers and aiding decision-making relating to healthcare. However, more clarity is needed relating to the Activities of Daily Living (ADL) recognised, and the types of technology included within current monitoring approaches. This review aims to identify these differences and highlight the current gaps in these systems. A scoping review was conducted in accordance with PRISMA-ScR, drawing on PubMed, Scopus, and Google Scholar. Articles and commercially available systems were selected if they focused on ADL recognition of older adults within their home environment. Thirty-nine ADL recognition systems were identified, nine of which were commercially available. One system incorporated environmental and wearable technology, two used only wearable technology, and 34 used only environmental technologies. Overall, 14 ADL were identified but there was variation in the specific ADL recognised by each system. Although the use of technology to monitor ADL of older adults is becoming more prevalent, there is a large variation in the ADL recognised, how ADL are defined, and the types of technology used within monitoring systems. Key stakeholders, such as older adults and healthcare workers, should be consulted in future work to ensure that future developments are functional and useable.

Psychometric proprieties of the Test of Gross Motor Development-Third Edition in a large sample of Italian children.

OBJECTIVES: The Test of Gross Motor Development-3 (TGMD-3) evaluates fundamental gross motor skills across two domains: locomotor and ball skills. This study aimed to perform a full psychometric assessment of this test in a large sample of Italian pre- and primary school children. DESIGN: Cross-sectional and test-retest study design. METHOD: Children N = 5210; mean age years = 8.38, SD = 1.97; % females = 48 completed three trials, including one practice. Only the scores of the two latter 'formal' trials were recorded for the evaluation. Factorial validity and measurement invariance of TGMD-3 across age and gender groups and test-retest reliability for the overtime measure consistency were tested. Item response theory analysis further tested single items' performances. RESULTS: Explorative and confirmatory factor analyses confirmed the two-factor structure of the TGMD-3. Multi-group confirmatory factor analyses indicated that there were no significant reductions in model adjustments between the configural, metric and structural invariance solutions for gender and age groups. Test-retest results ranged between 0.967 and 0.990 for both skill sets across age groups. Item response theory analysis using a graded response model showed low standard error and high-test information levels covering a wide spectrum range of both locomotor and ball skills. CONCLUSIONS: These results highlight the strong construct validity and reliability of the TGMD-3 to measure gross motor skills in children across gender and age groups. Item response theory analysis evidenced how the performance criteria included in this test cover a wide range of gross the motor skills spectrum. The use of TGMD-3 may inform motor development programs and support curricular decisions in schools.

Impact of Obesity on Surgeon Ergonomics in Robotic and Straight-Stick Laparoscopic Surgery.

STUDY OBJECTIVE: Work-related musculoskeletal symptoms (WMSs) are reported to be increasing in surgeons performing minimally invasive procedures. Therefore, we investigated the use of inertial measurement units (IMUs) and electromyography (EMG) sensor recorders to record real-time information on the muscle movement/activity required to perform training exercises in simulated in normal and high body mass index (BMI) models. DESIGN: Prospective study. SETTING: University hospital. PARTICIPANTS: Four consultant gynecologic oncology surgeons experienced in complex straight-stick (SS) laparoscopic and robotically assisted (RA) surgery. INTERVENTIONS: Three exercises (hoops onto pegs and wire chase) using SS and RA surgery on 2 abdominal models: normal BMI and high BMI. MEASUREMENTS AND MAIN RESULTS: We measured time to complete exercise and surgeon muscle movement/activity. The time to complete all exercises was significantly lower for RA surgery as compared with SS laparoscopy (p <.05 or better). The movement of the surgeons' core was significantly greater in high BMI SS laparoscopy compared with normal BMI SS laparoscopy for exercises 1 and 2 (p <.001). Muscle usage, as determined by EMG peak, was significantly higher in normal BMI SS laparoscopy and even higher in high BMI SS laparoscopy but was generally flat for all normal and high BMI RA surgery exercises (p <.05 or better). CONCLUSION: Detailed real-time information can be collected through IMUs/EMG sensors. Our results indicate that RA surgery requires less surgeon movements and muscle activity to complete tasks compared with SS laparoscopy, particularly in a high BMI model. The implications of these results are that RA surgery in high BMI patients may therefore have less physical impact on the surgeon compared with SS laparoscopy and may result in lower WMS rates.

Development of Sensorised Resistance Band for Objective Exercise Measurement: Activities Classification Trial.

Resistance bands are often used in resistance training programs for older adults. Despite their widespread use, there is a lack of objective assessment of the actual strength, speed and precision of the movements during these exercises. Therefore, this paper presents the development of a sensorised resistance-band and a preliminary trial of activities classification by using artificial intelligence. The results show that in the preliminary trial, the classification accuracy of 4 different activities reached over 96% using accelerometer data only. A future study will be based on the sensorised resistance band to quantify resistance band exercises objectively in elderly people.

Measurement invariance of TGMD-3 in children with and without mental and behavioral disorders.

This study evaluated whether the Test of Gross Motor Development 3 (TGMD-3) is a reliable tool to compare children with and without mental and behavioral disorders across gross motor skill domains. A total of 1,075 children (aged 3-11 years), 98 with mental and behavioral disorders and 977 without (typically developing), were included in the analyses. The TGMD-3 evaluates fundamental gross motor skills of children across two domains: locomotor skills and ball skills. Two independent testers simultaneously observed children's performances (agreement over 95%). Each child completed one practice and then two formal trials. Scores were recorded only during the two formal trials. Multigroup confirmatory factor analysis tested the assumption of TGMD-3 measurement invariance across disability groups. According to the magnitude of changes in root mean square error of approximation and comparative fit index between nested models, the assumption of measurement invariance across groups was valid. Loadings of the manifest indicators on locomotor and ball skills were significant (p < .001) in both groups. Item response theory analysis showed good reliability results across locomotor and the ball skills full latent traits. The present study confirmed the factorial structure of TGMD-3 and demonstrated its feasibility across normally developing children and children with mental and behavioral disorders. These findings provide new opportunities for understanding the effect of specific intervention strategies on this population. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

A Novel Algorithm for Determining the Contextual Characteristics of Movement Behaviors by Combining Accelerometer Features and Wireless Beacons: Development and Implementation.

BACKGROUND: Unfortunately, global efforts to promote "how much" physical activity people should be undertaking have been largely unsuccessful. Given the difficulty of achieving a sustained lifestyle behavior change, many scientists are reexamining their approaches. One such approach is to focus on understanding the context of the lifestyle behavior (ie, where, when, and with whom) with a view to identifying promising intervention targets. OBJECTIVE: The aim of this study was to develop and implement an innovative algorithm to determine "where" physical activity occurs using proximity sensors coupled with a widely used physical activity monitor. METHODS: A total of 19 Bluetooth beacons were placed in fixed locations within a multilevel, mixed-use building. In addition, 4 receiver-mode sensors were fitted to the wrists of a roving technician who moved throughout the building. The experiment was divided into 4 trials with different walking speeds and dwelling times. The data were analyzed using an original and innovative algorithm based on graph generation and Bayesian filters. RESULTS: Linear regression models revealed significant correlations between beacon-derived location and ground-truth tracking time, with intraclass correlations suggesting a high goodness of fit (R2=.9780). The algorithm reliably predicted indoor location, and the robustness of the algorithm improved with a longer dwelling time (>100 s; error <10%, R2=.9775). Increased error was observed for transitions between areas due to the device sampling rate, currently limited to 0.1 Hz by the manufacturer. CONCLUSIONS: This study shows that our algorithm can accurately predict the location of an individual within an indoor environment. This novel implementation of "context sensing" will facilitate a wealth of new research questions on promoting healthy behavior change, the optimization of patient care, and efficient health care planning (eg, patient-clinician flow, patient-clinician interaction).

Validation of the ADAMO Care Watch for step counting in older adults.

BACKGROUND: Accurate measurement devices are required to objectively quantify physical activity. Wearable activity monitors, such as pedometers, may serve as affordable and feasible instruments for measuring physical activity levels in older adults during their normal activities of daily living. Currently few available accelerometer-based steps counting devices have been shown to be accurate at slow walking speeds, therefore there is still lacking appropriate devices tailored for slow speed ambulation, typical of older adults. This study aimed to assess the validity of step counting using the pedometer function of the ADAMO Care Watch, containing an embedded algorithm for measuring physical activity in older adults. METHODS: Twenty older adults aged ≥ 65 years (mean ± SD, 75±7 years; range, 68-91) and 20 young adults (25±5 years, range 20-40), wore a care watch on each wrist and performed a number of randomly ordered tasks: walking at slow, normal and fast self-paced speeds; a Timed Up and Go test (TUG); a step test and ascending/descending stairs. The criterion measure was the actual number of steps observed, counted with a manual tally counter. Absolute percentage error scores, Intraclass Correlation Coefficients (ICC), and Bland-Altman plots were used to assess validity. RESULTS: ADAMO Care Watch demonstrated high validity during slow and normal speeds (range 0.5-1.5 m/s) showing an absolute error from 1.3% to 1.9% in the older adult group and from 0.7% to 2.7% in the young adult group. The percentage error for the 30-metre walking tasks increased with faster pace in both young adult (17%) and older adult groups (6%). In the TUG test, there was less error in the steps recorded for older adults (1.3% to 2.2%) than the young adults (6.6% to 7.2%). For the total sample, the ICCs for the ADAMO Care Watch for the 30-metre walking tasks at each speed and for the TUG test were ranged between 0.931 to 0.985. CONCLUSION: These findings provide evidence that the ADAMO Care Watch demonstrated highly accurate measurements of the steps count in all activities, particularly walking at normal and slow speeds. Therefore, these data support the inclusion of the ADAMO Care Watch in clinical applications for measuring the number of steps taken by older adults at normal, slow walking speeds.

Fear of falling and activities of daily living function: mediation effect of dual-task ability.

OBJECTIVE: The aim of the study was to explore the association between fear of falling (FOF), dual-task ability during a mobility task, and the activities of daily living (ADL) in a sample of older adults. METHODS: Seventy-six older adults (mean age M = 70.87 ± 5.16 years) participated in the study. Data on FOF (using the Falls Self-Efficacy Scale-International), walking ability during both single- and dual-task performances and ADL were collected. RESULTS: Mediation analysis demonstrated the mediation effect of dual-task ability (ß = 0.238, p = 0.011) between FOF and ADL level (ß = 0.559, p < 0.001). Moreover, significantly lower performances were observed during dual-task condition [F (2, 73) = 7.386, p < 0.001], and lower ADL levels were also found in older adults with FOF [F (2, 73) = 13.734, p < 0.001]. CONCLUSION: The study underlines the relationship between FOF, dual-task ability and ADL level. These results could be used to develop specific intervention programmes for successful ageing.

Age-related decrements in dual-task performance: Comparison of different mobility and cognitive tasks. A cross sectional study.

This cross-sectional study investigated the age-related differences in dual-task performance both in mobility and cognitive tasks and the additive dual-task costs in a sample of older, middle-aged and young adults. 74 older adults (M = 72.63±5.57 years), 58 middle-aged adults (M = 46.69±4.68 years) and 63 young adults (M = 25.34±3.00 years) participated in the study. Participants performed different mobility and subtraction tasks under both single- and dual-task conditions. Linear regressions, repeated-measures and one-way analyses of covariance were used, The results showed: significant effects of the age on the dual and mobility tasks (p<0.05) and differences among the age-groups in the combined dual-task costs (p<0.05); significant decreases in mobility performance under dual-task conditions in all groups (p<0.05) and a decrease in cognitive performance in the older group (p<0.05). Dual-task activity affected mobility and cognitive performance, especially in older adults who showed a higher dual-task cost, suggesting that dual-tasks activities are affected by the age and consequently also mobility and cognitive tasks are negatively influenced.

Anatomical Calibration through Post-Processing of Standard Motion Tests Data.

The inertial measurement unit is popularly used as a wearable and flexible tool for human motion tracking. Sensor-to-body alignment, or anatomical calibration (AC), is fundamental to improve accuracy and reliability. Current AC methods either require extra movements or are limited to specific joints. In this research, the authors propose a novel method to achieve AC from standard motion tests (such as walking, or sit-to-stand), and compare the results with the AC obtained from specially designed movements. The proposed method uses the limited acceleration range on medial-lateral direction, and applies principal component analysis to estimate the sagittal plane, while the vertical direction is estimated from acceleration during quiet stance. The results show a good correlation between the two sets of IMUs placed on frontal/back and lateral sides of head, trunk and lower limbs. Moreover, repeatability and convergence were verified. The AC obtained from sit-to-stand and walking achieved similar results as the movements specifically designed for upper and lower body AC, respectively, except for the feet. Therefore, the experiments without AC performed can be recovered through post-processing on the walking and sit-to-stand data. Moreover, extra movements for AC can be avoided during the experiment and instead achieved through the proposed method.

Reliability of the step phase detection using inertial measurement units: pilot study.

The use of inertial sensors for the gait event detection during a long-distance walking, for example, on different surfaces and with different walking patterns, is important to evaluate the human locomotion. Previous studies demonstrated that gyroscopes on the shank or foot are more reliable than accelerometers and magnetometers for the event detection in case of normal walking. However, these studies did not link the events with the temporal parameters used in the clinical practice; furthermore, they did not clearly verify the optimal position for the sensors depending on walking patterns and surface conditions. The event detection quality of the sensors is compared with video, used as ground truth, according to the parameters proposed by the Gait and Clinical Movement Analysis Society. Additionally, the performance of the sensor on the foot is compared with the one on the shank. The comparison is performed considering both normal walking and deviations to the walking pattern, on different ground surfaces and with or without constraints on movements. The preliminary results show that the proposed methodology allows reliable detection of gait events, even in case of abnormal footfall and in slipping surface conditions, and that the optimal location to place the sensors is the shank.

Development of subliminal persuasion system to improve the upper limb posture in laparoscopic training: a preliminary study.

PURPOSE: Current training for laparoscopy focuses only on the enhancement of manual skill and does not give advice on improving trainees' posture. However, a poor posture can result in increased static muscle loading, faster fatigue, and impaired psychomotor task performance. In this paper, the authors propose a method, named subliminal persuasion, which gives the trainee real-time advice for correcting the upper limb posture during laparoscopic training like the expert but leads to a lower increment in the workload. METHODS: A 9-axis inertial measurement unit was used to compute the upper limb posture, and a Detection Reaction Time device was developed and used to measure the workload. A monitor displayed not only images from laparoscope, but also a visual stimulus, a transparent red cross superimposed to the laparoscopic images, when the trainee had incorrect upper limb posture. One group was exposed, when their posture was not correct during training, to a short (about 33 ms) subliminal visual stimulus. The control group instead was exposed to longer (about 660 ms) supraliminal visual stimuli. RESULTS: We found that subliminal visual stimulation is a valid method to improve trainees' upper limb posture during laparoscopic training. Moreover, the additional workload required for subconscious processing of subliminal visual stimuli is less than the one required for supraliminal visual stimuli, which is processed instead at the conscious level. CONCLUSIONS: We propose subliminal persuasion as a method to give subconscious real-time stimuli to improve upper limb posture during laparoscopic training. Its effectiveness and efficiency were confirmed against supraliminal stimuli transmitted at the conscious level: Subliminal persuasion improved upper limb posture of trainees, with a smaller increase on the overall workload.