Intelligent Device For Energy Expenditure And Activity Research Articles

Gait analysis in the elderly patients with lumbar spinal stenosis.

This study aims to analyze the gait characteristics of the elderly patients with lumbar spinal stenosis by an intelligent device for energy expenditure and activity (IDEEA) to assist clinical work. A total of 98 subjects were included in this study from January 2017 to December 2018. A total of 49 elderly outpatients with symptomatic lumbar spinal stenosis in unilateral lower extremity were included as the experimental group, and another 49 healthy subjects matched with gender, age, and body mass index (BMI) were analyzed as the control group. The gait data of the subjects (including single support, double support, SLS/DLS, swing duration, step duration, cycle duration, pulling accel, swing power, ground impact, foot fall, foot off, push off, speed, cadence, step length, and stride length) were collected to compare between the experience group and control group, the affected leg and the healthy leg in experimental group. The results of this study presented that small intermittent claudication occurred in all patients. The time of single support was significantly increased (p < 0.05). Double support, step duration, and pulling accel were increased (p < 0.05), and the Push off, speed, step length, and Stride length were decreased (p < 0.05) in the experimental group compared with the control group. Small intermittent claudication was the basic gait composition of the elderly patients with lumbar spinal stenosis that can reflect the abnormal gait characteristics by IDEEA.

Altered Brain Function in Cerebral Small Vessel Disease Patients With Gait Disorders: A Resting-State Functional MRI Study

Gait disturbances are important clinical features of cerebral small vessel disease (CSVD) that increase the risk of falls and disability. Brain structural alterations and gait disturbances in CSVD patients have been well demonstrated. However, intrinsic resting cerebral function patterns in CSVD patients with gait disorders remain largely unknown. Fifty-eight CSVD patients were enrolled in our studies and categorized into the gait disorder group (CSVD-GD, n = 29) and no-gait disorder group (CSVD-NGD, n = 29) based on a gait examination. Gait was quantitatively assessed with the Timed Up and Go test and the intelligent device for energy expenditure and activity (IDEEA). Functional MRI and fractional amplitude of low-frequency fluctuation (fALFF) analyses were employed to explore local intrinsic neural oscillation alterations. Functional connectivity based on fALFF results was calculated to detect the potential changes in remote connectivity. Compared with the CSVD-NGD group, the CSVD-GD group showed decreased fALFF in regions mainly located in the sensorimotor network and frontoparietal network, such as the left supplementary motor area (SMA.L) and the left superior parietal gyrus, and increased fALFF in the right inferior frontal gyrus (orbital part), the left caudate, and the left precuneus. Moreover, the CSVD-GD patients exhibited lower connectivity between the SMA.L and temporal lobe, which was related to gait speed. The fALFF value of the SMA.L was associated with cadence. This study highlights the regional and network interaction abnormalities of the SMA in CSVD patients with gait disturbances. These findings could provide further insight into the neural mechanisms of gait disturbances in CSVD.

Associations of Frailty and Physical Function with a Daily Activities Measured by a Pattern-Recognition Activity Monitor: An Isotemporal Substitution Analysis in the IMPACT65+ Study.

The aims of this study were (i) to examine the independent associations of the time spent in daily activities measured by multi-sensor pattern-recognition with frailty and physical functioning (PF); and (ii) to analyze how relocating time between these daily activities is associated with frailty and PF in a sample of older adults. Cross-sectional study. The study sample consists of 436 (287 women) high-functioning community-dwelling older adults, aged 65 to 92 years, who participated in the IMPACT65+ Study. Frailty was calculated as a continuous measure; based on the five widely recognized Fried's criteria. PF was assessed using the SF-12 questionnaire. The time in daily activities was assessed by the Intelligent Device for Energy expenditure and Activity (IDEEA). Independent associations of daily activities with frailty and PF were examined using linear regression models adjusting for potential confounders. The isotemporal substitution models for estimate the effect of replacing time in one activity with the same amount of time in another activity while holding wake time constant. Time spent lying was directly associated, while time in walk at average and brisk pace was inversely associated with frailty. The independent associations for PF were similar to lying, walk at average pace and walk at brisk pace. Isotemporal substitution analyses revealed a clear beneficial effect of hypothetically replacing 30 min/day of sedentary behaviors or light physical activity by the same amount of moderate-to-vigorous physical activity for frailty and PF. This is the first study examining the activity-specific and isotemporal association of daily activities with frailty and PF in older adults. Isotemporal substitution analyses showed that replacing sedentary behaviors (lie, recline, passive sit) by light-intensity activities (active sit, stand and walk at slow pace), as well as light-intensity activities by activities at MVPA such as walk at brisk pace, may produce theoretical improvements in frailty and PF. These findings are important for the development of effective interventions focused on reducing age-related frailty and declines in PF.

Associations of daily activities measured by a pattern-recognition activity monitor with overall and abdominal obesity in older people: the IMPACT65+ study.

The aims of the present study were: (i) to analyze the associations of the time spent in daily activities (i.e., lie, recline, passive sit, active sit, stand, walk at slow pace, walk at average pace, walk at brisk pace, and other activities) with body mass index (BMI) and waist circumference (WC); and (ii) to examine how theoretically reallocating time between these daily activities is associated with BMI and WC. The sample included 437 older adults (288 women), aged 65 to 92 years, participating in the IMPACT65+ study. The time in daily activities was assessed by the Intelligent Device for Energy Expenditure and Activity (IDEEA). BMI and WC were measured following standardized procedures. Associations of daily activities with BMI and WC were examined using linear regression models adjusting for potential confounders. Isotemporal substitution models were performed to estimate the theoretical effect of replacing one activity with another activity while holding total time constant. The time spent lying and reclining was associated with increased BMI and WC, while the time spent standing, walking at average pace, and walking at brisk pace was associated with decreased BMI and WC. Isotemporal substitution analyses revealed significant hypothetical reductions in BMI and WC when reallocating 15 min from lying or reclining to standing or walking at average pace. Moreover, replacing 15 min from any sedentary activity or light physical activity (except for walking at average pace) with an equal amount of time in walking at brisk pace was associated with lower BMI and WC. This is the first study examining the activity specific and isotemporal associations of daily behaviors (considering body postures and movements) with overall and abdominal obesity in older people. The results could be used in the development of specific recommendations encouraging an active lifestyle in older people.

Interday Reliability of the IDEEA Activity Monitor for Measuring Movement and Nonmovement Behaviors in Older Adults.

The interday reliability of the Intelligent Device for Energy Expenditure and Activity (IDEEA) has not been studied to date. The study purpose was to examine the interday variability and reliability on two consecutive days collected with the IDEEA, as well as to predict the number of days needed to provide a reliable estimate of several movement (walking and climbing stairs) and nonmovement (lying, reclining, and sitting) behaviors and standing in older adults. The sample included 126 older adults (74 women) who wore the IDEEA for 48hr. Results showed low variability between the 2 days, and the reliability was from moderate (intraclass coefficient correlation = .34) to high (.80) in most of movement and nonmovement behaviors analyzed. The Bland-Altman plots showed high-moderate agreement between days, and the Spearman-Brown formula estimated that 1.2 and 9.1 days of monitoring with the IDEEA are needed to achieve intraclass coefficient correlations ≥ .70 in older adults for sitting and climbing stairs, respectively.

PO-040 IDEEA Estimation of Daily Behavior Energy Consumption: Verified by Metabolic Chamber

Objective To investigate the accuracy of Intelligent Device for Energy Expenditure and Activity (IDEEA) in the measurement of energy consumption in the evening of adults in Nanjing.&#x0D; Methods 120 subjects were selected, and worn IDEEA into the metabolic chamber for 11 hours of energy consumption test.Body composition by Dual-Energy X-ray Absorptiometry. Sleep metabolic rate（SMR）,Rest metabolic rate （RMR）and Basal metabolic rate（BMR）by metabolic chamber.&#x0D; Results The energy consumption results were paired with sample T test. The results showed significant difference between MC and IDEEA, but the effect size was between 0.004 and 0.042. The correlation between MC and IDEEA was 0.85 to 0 .96. The absolute error rate of energy consumption measurement was from 6.16 % to 7.92 %, of which the measurement error of sleep energy consumption was 6.16 %±4.16 %, and that of Internet energy consumption was 7.92 %±5.99 %.&#x0D; Conclusions Energy measurement of IDEEA absolute error rate is within acceptable range, and it provides a high-precision alternative method for estimating energy consumption. The immediate and cumulative energy consumption data can be used to estimate the energy consumption for human physical activities over a period of time.

Concurrent Criterion Validity of a Test of Usual Gait Speed in Older Adults.

Usual gait speed has been shown to have very good reliability and convincing predictive validity for evaluating older adults' gait skills, but its criterion validity is unknown. We examined the criterion validity of the 8-feet (i.e., 2.44 meters) test in a laboratory environment to assess usual gait speed by comparing its results with the Intelligent Device for Energy Expenditure and Activity (IDEEA) monitor. Participants were 200 well-functioning community-dwelling adults aged 65 and older (113 women; 87 men; mean [M] age = 71.8, standard deviation [ SD] = 5.6 years). Participants wore the IDEEA monitor for 48 consecutive hours, and we used the participants' average usual gait speed for the analysis. The Spearman correlation of usual gait speed using both the 8-feet test and IDEEA monitor was moderate and statistically significant (ρ = .364, p < .001). The mean difference between both methods was 0.20 ( SD = 0.27) meters/second, and the corresponding limits of agreement were 0.73 and -0.33 meters/second. There was a small systematic bias when the difference between the two methods was correlated with usual gait speed as measured by the IDEEA (ρ = -.20, p = .011). The perfect agreement (weighted kappa) of both instruments for classifying usual gait speed into tertiles, quartiles, and quintiles was 48.3% ( k = 0.17), 30.9% ( k = 0.23), and 25.4% ( k = 0.29), respectively. Our results indicate that the 8-feet test showed moderate criterion-related validity for evaluating and assessing usual gait speed test in older adults.

Automated algorithms for detecting sleep period time using a multi-sensor pattern-recognition activity monitor from 24 h free-living data in older adults

Objectives: The aims of the present study were (i) to develop automated algorithms to identify the sleep period time in 24 h data from the Intelligent Device for Energy Expenditure and Activity (IDEEA) in older adults, and (ii) to analyze the agreement between these algorithms to identify the sleep period time as compared to self-reported data and expert visual analysis of accelerometer raw data. Approach: This study comprised 50 participants, aged 65–85 years. Fourteen automated algorithms were developed. Participants reported their bedtime and waking time on the days on which they wore the device. A well-trained expert reviewed each IDEEA file in order to visually identify bedtime and waking time on each day. To explore the agreement between methods, Pearson correlations, mean differences, mean percentage errors, accuracy, sensitivity and specificity, and the Bland–Altman method were calculated. Main results: With 87 d of valid data, algorithms 6, 7, 11 and 12 achieved higher levels of agreement in determining sleep period time when compared to self-reported data (mean difference = −0.34 to 0.01 h d−1; mean absolute error = 10.66%–11.44%; r = 0.515–0.686; accuracy = 95.0%–95.6%; sensitivity = 93.0%–95.8%; specificity = 95.7%–96.4%) and expert visual analysis (mean difference = −0.04 to 0.31 h d−1; mean absolute error = 5.0%–6.97%; r = 0.620–0.766; accuracy = 97.2%–98.0%; sensitivity = 94.5%–97.6%; specificity = 98.4%–98.8%). Bland–Altman plots showed no systematic biases in these comparisons (all p > 0.05). Differences between methods did not vary significantly by gender, age, obesity, self-rated health, or the presence of chronic conditions. Significance: These four algorithms can be used to identify easily and with adequate accuracy the sleep period time using the IDEEA activity monitor from 24 h free-living data in older adults.

Criterion-related validity of self-reported stair climbing in older adults.

Stair climbing is an activity of daily living that might contribute to increase levels of physical activity (PA). To date, there is no study examining the validity of climbing stairs assessed by self-report. The aim of this study was, therefore, to examine the validity of estimated stair climbing from one question included in a common questionnaire compared to a pattern-recognition activity monitor in older adults. A total of 138 older adults (94 women), aged 65-86years (70.9 ± 4.7years), from the IMPACT65 + study participated in this validity study. Estimates of stair climbing were obtained from the European Prospective Investigation into Cancer and Nutrition (EPIC) PA questionnaire. An objective assessment of stair climbing was obtained with the Intelligent Device for Energy Expenditure and Activity (IDEEA) monitor. The correlation between both methods to assess stair climbing was fair (ρ = 0.22, p = 0.008 for PA energy expenditure and ρ = 0.26, p = 0.002 for duration). Mean differences between self-report and the IDEEA were 7.96 ± 10.52 vs. 9.88 ± 3.32 METs-min/day for PA energy expenditure, and 0.99 ± 1.32 vs. 1.79 ± 2.02min/day for duration (both Wilcoxon test p < 0.001). Results from the Bland-Altman analysis indicate that bias between both instruments were -1.91 ± 10.30 METs-min/day and -0.80 ± 1.99min/day, and corresponding limits of agreement for the two instruments were from 18.27 to -22.10 METs-min/day and from 3.09 to -4.70min/day, respectively. Our results indicate that self-reported stair climbing has modest validity to accurately rank old age participants, and underestimates both PAEE and its duration, as compared with an objectively measured method.

Validation of two novel monitoring devices to measure physical activity in healthy women.

Measurement of physical activity is increasingly important in health research. We sought to determine the accuracy and sensitivity to non-exercise activity of three activity monitors worn simultaneously by healthy adult women participating in a structured activity protocol. Ten normal-weight women wore the Intelligent Device for Energy Expenditure and Activity (IDEEA), the SmartShoe, and the SenseWear Armband, during activities that included standing, sitting still, sitting and fidgeting, lying down, and walking at varying speeds. Percentage of time postures correctly identified was determined for the IDEEA and the SmartShoe, and activity counts collected from all three devices were compared. Posture was detected with high accuracy by both the IDEEA and the SmartShoe (97.4% and 94.2% accuracy, respectively). The SmartShoe showed superior sensitivity to movement while seated ("fidgeting") compared with the IDEEA (p=0.004 and 0.049 difference between postures, respectively); all three devices distinguished between fast and slow walking. Data support the ability of the IDEEA and the SmartShoe to recognize basic postures in healthy normal-weight women, as well as to detect fidgeting within the seated position.

An evaluation of the IDEEA™ activity monitor for estimating energy expenditure

Objective estimates of activity patterns and energy expenditure (EE) are important for the measurement of energy balance. The Intelligent Device for Energy Expenditure and Activity (IDEEA) can estimate EE from the thirty-five postures and activities it can identify and record. The present study evaluated the IDEEA system's estimation of EE using whole-body indirect calorimetry over 24 h, and in free-living subjects using doubly-labelled water (DLW) over 14 d. EE was calculated from the IDEEA data using calibration values for RMR and EE while sitting and standing, both as estimated by the IDEEA system (IDEEA(est)) and measured by indirect calorimetry (IDEEA(meas)). Subjects were seven females and seven males, mean age 38·1 and 39·7 years, mean BMI 25·2 and 26·2 kg/m2, respectively. The IDEEA(est) method produced a similar estimate of EE to the calorimeter (10·8 and 10·8 MJ, NS), while the IDEEA(meas) method underestimated EE (9·9 MJ, P < 0·001). After removing data from static cycling, which the IDEEA was unable to identify as an activity, both the IDEEA(est) and IDEEA(meas) methods overestimated EE compared to the calorimeter (9·9 MJ, P < 0·001; 9·1 MJ, P < 0·05 and 8·6 MJ, respectively). Similarly, the IDEEA system overestimated EE compared to DLW over 14 d; 12·7 MJ/d (P < 0·01), 11·5 MJ/d (P < 0·01) and 9·5 MJ/d for the IDEEA(est), IDEEA(meas) and DLW, respectively. The IDEEA system overestimated EE both in the controlled laboratory and free-living environments. Using measured EE values for RMR, sitting and standing reduced, but did not eliminate, the error in estimated EE.

Accuracy of Multisensor Activity Monitors in Normal Versus High BMI African American Children

Overweight children show different movement patterns during walking than normal-weight children, suggesting the accuracy of multisensory activity monitors may differ in these groups. Eleven normal and 15 high BMI African American children walked at 2, 4, 5, and 6 km/h on a treadmill wearing the Intelligent Device for Energy Expenditure and Activity (IDEEA) and SenseWear (SW). Accuracy was determined using indirect calorimetry and manually counted steps as references. For IDEEA, no significant differences in accuracy were observed between BMI groups for energy expenditure (EE), but differences were significant by speed (+15% at 2 km/h to -10% at 6 km/h). For SW, EE accuracy was significantly different for high (+21%) versus normal BMI girls (-13%) at 2 km/h. For high BMI girls, EE was overestimated at low speed and underestimated at higher speeds. Underestimations in steps did not differ by BMI group at 4 to 6 km/h, but were significantly larger at 2 km/h than at the other speeds for all groups with IDEEA, and for normal BMI children with SW. Similar accuracies during walking may be expected in normal and overweight children using IDEEA and SW. Both monitors showed small errors for steps provided speed exceeded 2 km/h.

Duration of physical activity is normal but frequency is reduced after stroke: an observational study

What is the free-living physical activity of community-dwelling people with stroke compared with that of age-matched healthy controls? A cross-sectional observational study. 42 people with stroke and 21 age-matched healthy controls aged 52 to 87 years living in Sydney, Australia. Free-living physical activity was measured using the Intelligent Device for Energy Expenditure and Activity (IDEEA) and reported as duration (time on feet in min) and frequency (activity counts). People with stroke spent 79 (95% CI 20 to 138) fewer min on their feet and performed 5308 (95% CI 3171 to 7445) fewer activity counts than healthy controls. The observation period of the free-living physical activity of stroke survivors was significantly less than that of the healthy controls. Data adjusted to a fixed observation period (12 hr) showed no relative difference in time on feet between the groups (mean difference 36 min, 95% CI -27 to 99) but that people after stroke still had relatively fewer activity counts than healthy controls (mean difference 4062 counts, 95% CI 1787 to 6337). The reduction in physical activity after stroke is not primarily because of a decrease in the time spent being active but rather a decrease in frequency of activity during that time. Future research into physical activity after stroke needs to consider energy expenditure because stroke survivors exhibit a reduced frequency of physical activity due to the nature of their impairments.

Physical Activity Patterns in Morbidly Obese and Normal-Weight Women

To compare physical activity patterns between morbidly obese and normal-weight women. Daily physical activity of 18 morbidly obese and 7 normal-weight women aged 30-58 years was measured for 2 days using the Intelligent Device for Energy Expenditure and Activity (IDEEA) device. The obese group spent about 2 hr/day less standing and 30 min/day less walking than did the normal-weight group. Time spent standing (standing time) was positively associated with time spent walking (walking time). Age- and walking time-adjusted standing time did not differ according to weight status. Promoting standing may be a strategy to increase walking.

Validation of a Novel Physical Activity Assessment Device in Morbidly Obese Females

Assessment of physical activity in morbidly obese subjects is important especially in bariatric surgery. We examined the validity of Intelligent Device for Energy Expenditure and Activity (IDEEA) for measuring physical activity and sedentary behavior in morbidly obese women. Activity types, gait counts, and speed detected by the IDEEA monitor were compared to those reported by an observer. The IDEEA monitor detected activity types and gait counts with relatively high accuracy, although slightly lower in extremely obese women than in normal weight controls. The IDEEA monitor accurately estimated gait speeds in both groups. Since gait speed predicts energy expenditure more accurately than gait counts, it is of greater clinical relevance. Reliability of the IDEEA monitor was excellent. The IDEEA monitor is a valid instrument for measuring physical activity and sedentary behavior in extremely obese women, and therefore has potential applications in bariatric surgery both in preoperative evaluation and long-term follow-up.

Influence of Activity Monitor Location and Bout Duration on Free-Living Physical Activity

The purpose of this study was to evaluate the influence of the location (ankle, hip, wrist) where an activity monitor (AM) is worn and of the minimum bout duration (BD) on physical activity (PA) variables during free-living monitoring. Study 1 participants wore AMs at three locations for 1 day while wearing the Intelligent Device for Energy Expenditure and Activity (IDEEA) system. Study 2 participants wore AMs at the same locations for 3 days. Variables included time (TMV, min/day) and AEE (AEEMV, kcal/day) for each monitor location and BD above a moderate-vigorous (MV) intensity. TMV and AEEMV in Study 1 were similar across AMs to IDEEA values at BD = 10 min, as was TMV in Study 2. This suggests that ankle-, wrist- and hip-worn AMs can provide similar PA outcome values during free-living monitoring at 10-min BDs.

The Sensitivity and Specificity of an Activity Monitor in Detecting Functional Activities in Young People With Cerebral Palsy

Mackey AH, Hewart P, Walt SE, Stott NS. The sensitivity and specificity of an activity monitor in detecting functional activities in young people with cerebral palsy. Objective To evaluate the sensitivity and specificity of the Intelligent Device for Energy Expenditure and Activity (IDEEA) monitor in detecting functional activities in young people with cerebral palsy (CP). Design Validation study. Setting Two identical data collections completed 1 week apart at a gait laboratory. Participants Twenty-five young people with CP and 30 able-bodied (AB) peers (age 8–25y; mean age CP 14.1y, Gross Motor Function Classification System Level I–III; mean age AB, 14.2y). Interventions Not applicable. Main Outcome Measures Each participant completed 5 functional activities (sitting, lying, standing, walking, and stairs), with the monitor attached. The sensitivity and specificity of the monitor in detecting each activity was calculated by comparison to a written timed report. Results Sitting, lying, and standing were detected with median 100% sensitivity in both participant groups and across both testing sessions. Accuracy of walking detection was reduced compared with static activities ( P<.05) across the 2 sessions and groups. The CP group had a significantly higher number of participants where the activity was not detected with 100% sensitivity (lie: 18% CP, 5% AB, P<.04; stand: 12% CP, 0% AB, P<.02; walk: 96% CP, 81% AB, P<.03). Stair climbing was detected in only half of the 12 participants with CP who could achieve the task. The IDEEA demonstrated high specificity (range, 97%–100%) for both participant groups. Conclusions The IDEEA activity monitor had high levels of sensitivity and specificity in determining everyday static activities in participants with CP, with greater difficulties in detecting dynamic activities of walking and stair climbing.

Reliability and validity of an activity monitor (IDEEA) in the determination of temporal–spatial gait parameters in individuals with cerebral palsy

This study evaluated within- and between-session reliability and validity of temporal–spatial gait parameters derived from the intelligent device for energy expenditure and activity (IDEEA) activity monitor (Minisun, Fresno, CA) in subjects with cerebral palsy, using three-dimensional gait analysis (3-DGA) as the criterion standard. Twenty-five subjects with cerebral palsy (mean age 14.1 years, range 8–23) and 30 control subjects (mean age 14.2 years, range 7–24) completed two 3-DGA, 1 week apart with simultaneous IDEEA data collection. The IDEEA had lower within-session reliability than the 3-DGA for both groups, indicated by greater measurement errors and wider repeatability values for all temporal–spatial parameters. Between-session reliability of 3-DGA was high for both groups with intra-class correlation coefficients (ICC) >0.80. The IDEEA monitor showed high between-session reliability for control subjects (ICC 0.71–0.89), but lower reliability in subjects with cerebral palsy, particularly for walking velocity and stride length (ICC 0.53 and 0.62, respectively). Validity comparison between IDEEA and 3-DGA measures using Bland Altman 95% limits of agreement showed a measurement bias, with the IDEEA over-estimating step and stride length and underestimating cadence in both subject groups compared to 3-DGA. The 95% limits of agreement were smaller in controls (step ±0.20 m; stride ±0.27 m; walking velocity ±0.28 m/s) than in subjects with cerebral palsy (step ±0.36 m; stride ±0.37 m; velocity ±0.58 m/s). Modifications may be necessary to improve the reliability and validity of the IDEEA in children, particularly for use in neurological conditions.

Ambulatory measurement of knee motion and physical activity: preliminary evaluation of a smart activity monitor

BackgroundThere is currently a paucity of devices available for continuous, long-term monitoring of human joint motion. Non-invasive, inexpensive devices capable of recording human activity and joint motion have many applications for medical research. Such a device could be used to quantify range of motion outside the gait laboratory. The purpose of this study was to test the accuracy of the modified Intelligent Device for Energy Expenditure and Activity (IDEEA) in measuring knee flexion angles, to detect different physical activities, and to quantify how often healthy subjects use deep knee flexion in the ambulatory setting.MethodsWe compared Biomotion Laboratory (BML) "gold standard" data to simultaneous IDEEA measures of knee motion and gait, step up/down, and stair descent in 5 healthy subjects. In addition, we used a series of choreographed physical activities outside the BML to confirm the IDEEA's ability to accurately measure 7 commonly-performed physical activities. Subjects then continued data collection during ordinary activities outside the gait laboratory.ResultsPooled correlations between the BML and IDEEA knee flexion angles were .97 +/- .03 for step up/down, .98 +/- .02 for stair descent, and .98 +/- .01 for gait. In the BML protocol, the IDEEA accurately identified gait, but was less accurate in identifying step up/down and stair descent. During sampling outside the BML, the IDEEA accurately detected walking, running, stair ascent, stair descent, standing, lying, and sitting. On average, subjects flexed their knees >120° for 0.17% of their data collection periods outside the BML.ConclusionThe modified IDEEA system is a useful clinical tool for evaluating knee motion and multiple physical activities in the ambulatory setting. These five healthy subjects rarely flexed their knees >120°.

Improving energy expenditure estimation for physical activity.

The purpose of this study was to validate the Intelligent Device for Energy Expenditure and Activity (IDEEA) for estimation of energy expenditure during a variety of activities. An additional aim was to improve the accuracy of the estimation of energy expenditure of physical activity based on second-by-second information of type, onset, and duration of activity. This study included two tests: a mask calorimetry test with 27 subjects [age = 33.7 +/- 13.8 (mean +/- SD) yr; BMI = 24.8 +/- 4.8 kg x m] and a respiratory chamber calorimetry test with 10 subjects (age = 32.9 +/- 12.4 yr; BMI = 26.1 +/- 5.6 kg x m). In the mask test, the subjects performed activities (sitting, standing, lying down, level treadmill walking, and running at different speeds) for 50-min durations. For the chamber test, subjects lived in the metabolic chamber for 23 h and performed three exercise sessions to compensate for the confined environment. The results showed significant correlations (P < 0.0001) between energy expenditure estimated by IDEEA and energy expenditure measured by the calorimeters with an accuracy >95%. After corrections for the decrease in sleeping metabolic rate, the estimation accuracy for the chamber test was increased by 1-96.2%, whereas the estimation accuracy for nighttime activity was significantly improved by 4-99%. IDEEA provides a suitable method for estimating the energy expenditure of physical activity. It provides both instantaneous and cumulative estimates of energy expenditure over a given period.