Agreement analysis of sleep patterns between self-reported questionnaires and actigraphy in adults.

PURPOSE: To investigate the agreement in sleep pattern recording by self-reported sleep questionnaires and actigraphy in adults. METHODS: This is a cross-sectional study. Men and women who met inclusion criteria were recruited for this study. The inclusion criteria were apparently healthy Omani nationals ages 19 to 50 years. Sleep questionnaires were randomly distributed in Muscat either directly or via electronic and paper announcements. Data were collected from the participants using the self-reported questionnaires with four piloted questions for sleep pattern identification and through the actigraphy wristband given to subjects to wear for a week. Cohen's kappa test was performed for agreement analysis. RESULTS: A total of 964 Omani subjects between ages 18 and 59 years of both genders were recruited and completed the questionnaires successfully. Out of these, only 321 subjects wore the actigraphy wristband for 1 week (response rate = 33%). Agreement analysis reported a mild level of agreement for the monophasic (41%), moderate level for biphasic (59%), and good level for polyphasic (70%) sleep patterns. The overall agreement level of sleep patterns between the two methods was 57%. There is a low specificity of self-reported assessment in reporting sleep pattern. CONCLUSION: The average agreement level of subjective versus objective assessments of sleep patterns was moderate at 57% and self-reported sleep pattern is not specific. The study recommends the use of actigraphy along with sleep questionnaires for accurate assessment of sleep patterns in cohort studies.

Does Spinal Cord Stimulation Really Influence Sleep?

BACKGROUND: To date, clinical pain research has typically used subjective questionnaires to assess effectiveness of treatment. However, in the near future, new technologies may provide us objective outcome measures as an alternative to self-report. The goal of this study is to compare subjective and objective sleep assessments in a population of failed back surgery syndrome (FBSS) patients, treated with spinal cord stimulation (SCS). METHODS: Twenty-two patients diagnosed with FBSS received SCS. Sleep data was collected at three time point: prior to SCS implantation (B), one month after SCS (T1), and two months after SCS (T2). Sleep data measured by actigraphy provided objective sleep data and were compared to Pittsburgh sleep quality index (PSQI) scores. Agreement between sleep parameters, total sleep time (TST), sleep efficiency (SE), and sleep onset latency (SOL), was examined. RESULTS: Nineteen out of 22 patients completed the study. We identified significant differences between objective and subjective measurements for TST and SE at baseline and after two months of SCS, with patients underestimating both parameters on the PSQI in comparison to objective measurements. For SOL no significant differences were found, although patients subjectively overestimated SOL at B. CONCLUSION: The results about sleep measurements shown in this population of chronic pain patients, suggest that the subjective ratings scored worse than the objective measurements. Second, short-term SCS mainly seems to affect subjectively measured sleep parameters, especially SOL. This study shows the discrepancies between objective and subjective assessments in chronic pain research. Objective tools are indispensable for a correct assessment and treatment of sleep parameters. They are also playing a role as a biofeedback tool and are supporting the rehabilitation process.

Feasibility of objectively measured physical activity and sedentary behavior in patients with malignant pleural effusion.

PURPOSE: Malignant pleural effusion (MPE) affects 1 million people worldwide annually and can significantly impair physical activity. Accelerometry is a validated method of objectively assessing physical activity. The purpose of this study was to determine the compliance in patients with MPE to accelerometry and describe their activity. METHODS: Patients with MPE wore an Actigraph GT3X accelerometer over a 7-day continuous wear protocol. Compliance was measured as the percent of patients who had ≥4 valid days (i.e., 8-h/day of waking wear-time). Eastern Cooperative Oncology Group performance status was documented the day of actigraphy initialization. RESULTS: Forty-six patients with MPE received accelerometers; 44 (95.7%) returned their device. No complications were reported on their use. Forty subjects (90.9%) had ≥4 valid days of wear-time. Patients spent most of their waking hours sedentary [mean 11.0 h (SD 1.95)], with limited participation in moderate and vigorous physical activity [mean 9.5 min (SD 14.16)]. Compared to patients with better performance status (n = 32), patients with poorer performance status (n = 11) spent significantly more hours/day sedentary [mean difference 2.1 (CI 0.86-3.32); p = 0.001], as did those who survived <3 months (n = 5) compared to >12 months (n = 27) [mean difference 2.6 (CI 0.49-4.77); p = 0.013). CONCLUSION: Accelerometry was applied successfully in patients with MPE with high compliance and no adverse events. This is the first reported objectively measured physical activity in patients with MPE and revealed high sedentary behavior and low physical activity. The data reflected patient performance status and discriminated between survival groups. Accelerometry can provide a useful measure for future interventional studies in patients with MPE.

An Evaluation of Commercial Pedometers for Monitoring Slow Walking Speed Populations.

BACKGROUND: Pedometers are considered desirable devices for monitoring physical activity. Two population groups of interest include patients having undergone surgery in the lower extremities or who are otherwise weakened through disease, medical treatment, or surgery procedures, as well as the slow walking senior population. For these population groups, pedometers must be able to perform reliably and accurately at slow walking speeds. The objectives of this study were to evaluate the step count accuracy of three commercially available pedometers, the Yamax (Tokyo, Japan) Digi-Walker(®) SW-200 (YM), the Omron (Kyoto, Japan) HJ-720 (OM), and the Fitbit (San Francisco, CA) Zip (FB), at slow walking speeds, specifically at 1, 2, and 3 km/h, and to raise awareness of the necessity of focusing research on step-counting devices and algorithms for slow walking populations. MATERIALS AND METHODS: Fourteen participants 29.93 ±4.93 years of age were requested to walk on a treadmill at the three specified speeds, in four trials of 100 steps each. The devices were worn by the participants on the waist belt. The pedometer counts were recorded, and the error percentage was calculated. RESULTS: The error rate of all three evaluated pedometers decreased with the increase of speed: at 1 km/h the error rates varied from 87.11% (YM) to 95.98% (FB), at 2 km/h the error rates varied from 17.27% (FB) to 46.46% (YM), and at 3 km/h the error rates varied from 22.46% (YM) to a slight overcount of 0.70% (FB). CONCLUSIONS: It was observed that all the evaluated devices have high error rates at 1 km/h and mixed error rates at 2 km/h, and at 3 km/h the error rates are the smallest of the three assessed speeds, with the OM and the FB having a slight overcount. These results show that research on pedometers' software and hardware should focus more on accurate step detection at slow walking speeds.

Comparison of uniaxial and triaxial accelerometry in the assessment of physical activity among adolescents under free-living conditions: the HELENA study.

BACKGROUND: Different types of devices are available and the choice about which to use depends on various factors: cost, physical characteristics, performance, and the validity and intra- and interinstrument reliability. Given the large number of studies that have used uniaxial or triaxial devices, it is of interest to know whether the different devices give similar information about PA levels and patterns. The aim of this study was to compare physical activity (PA) levels and patterns obtained simultaneously by triaxial accelerometry and uniaxial accelerometry in adolescents in free-living conditions. METHODS: Sixty-two participants, aged 13-16 years, were recruited in this ancillary study, which is a part of the Healthy Lifestyle in Europe by Nutrition in Adolescence (HELENA). All participants wore a uniaxial accelerometer (ActiGraph GT1M®, Pensacola, FL) and a triaxial accelerometer (RT3®, Stayhealthy, Monrovia, CA) simultaneously for 7 days. The patterns were calculated by converting accelerometer data output as a percentage of time spent at sedentary, light, moderate, and vigorous PA per day. Analysis of output data from the two accelerometers were assessed by two different tests: Equivalence Test and Bland & Altman method. RESULTS: The concordance correlation coefficient between the data from the triaxial accelerometer and uniaxial accelerometer at each intensity level was superior to 0.95. The ANOVA test showed a significant difference for the first three lower intensities while no significant difference was found for vigorous intensity. The difference between data obtained with the triaxial accelerometer and the uniaxial monitor never exceeded 2.1% and decreased as PA level increased. The Bland & Altman method showed good agreement between data obtained between the both accelerometers (p < 0.05). CONCLUSIONS: Uniaxial and triaxial accelerometers do not differ in their measurement of PA in population studies, and either could be used in such studies.

Comparison of the IPAQ-A and actigraph in relation to VO2max among European adolescents: the HELENA study.

The purpose was to compare data obtained from a modified, long, self-administered version of the International Physical Activity Questionnaire (IPAQ-A) with objective data obtained in parallel from Actigraph accelerometers, and VO(2)max in adolescents. The study comprised a total of 2018 adolescents (46% male) from ten European cities participating in the HELENA (Healthy Lifestyle in Europe by Nutrition in Adolescence) study. Physical activity was assessed over seven consecutive days by accelerometry and expressed as min/day of moderate, vigorous, and moderate to vigorous (MVPA) physical activity (PA). PA was also assessed with the IPAQ-A. VO(2)max was estimated from a 20-m shuttle run test. Poor to fair correlations between the two methodologies were found for the whole study sample and when stratified by age and gender (r(s) = 0.08-0.26, p < 0.01). On average, the self-reported time spent in moderate PA was higher compared to the time measured with the accelerometer, while the differences between both instruments were less clear for vigorous intensity. Adolescents reporting high levels of PA (3rd tertile IPAQ-A) also showed higher levels of PA (accelerometers) in all the study variables (moderate, vigorous and MVPA), compared to adolescents reporting low PA (1st tertile IPAQ-A) (all p < 0.001). Both methods were moderately correlated with estimated VO(2)max. Within the HELENA-study, the IPAQ-A showed the modest comparability with the accelerometer data for assessing PA in each intensity level and was the highest for vigorous intensity. Both instruments are able to detect the adolescents with the highest cardio respiratory fitness, which are the most active adolescents.

Relationship between physical activity measured using accelerometers and energy expenditure measured using doubly labelled water in Indian children.

BACKGROUND/OBJECTIVES: To test the association between physical activity measured using accelerometer counts (Actigraph) and energy expenditure (EE) measured using the doubly labelled water (DLW) method in free-living children in India. The aim of this study was to explore the usefulness of Actigraphs in estimating EE. SUBJECTS/METHODS: Total EE (TEE) was measured in 58 children aged 8-9 years over a period of 2 weeks using the DLW technique. Physical activity level (PAL) was estimated from TEE, and the basal metabolic rate was predicted from weight. Physical activity was measured simultaneously using the Actigraph accelerometers (MTI AM7164 and GT1M). TEE was also calculated from the Actigraph counts using a published equation. RESULTS: TEE (mean: 6.6 vs 5.7 MJ, P=0.04) and Actigraph counts (counts/minute: 557 vs 465, P=0.02; total counts: 445 534 vs 354 748, P=0.004) were higher in boys than in girls. There were no significant correlations between either total Actigraph counts (r=0.15, P=0.3) or counts/minute (r=0.18, P=0.2), and TEE estimated using DLW. Similarly, there were no significant correlations between Actigraph counts and PAL (r=0.10, P=0.5; r=0.17, P=0.2, respectively). The Bland-Altman analysis showed poor agreement between TEE estimated using the DLW method and TEE derived from the Actigraph equation. CONCLUSIONS: Activity measured using Actigraph accelerometers was not related to TEE and PAL derived using the DLW technique in children in Mysore. Actigraphs may not be useful in predicting EE in this setting, but may be better used for judging activity patterns.