Table 3.
Devices studied and results
| Device | Manufacturer | Device form factor | Reported findings | |||
| population | setting | endpoints | validity/reliability/accuracy | |||
| Triaxial accelerometers | ||||||
| actibelt | Trium | Waistband | MS (37) | Laboratory | Walking speed | Overestimates walking speed significantly in those with moderate (by–0.12±0.17 m/s) and severe (by–0.26±0.12 m/s) disability |
| Actical | Philips Respironics | Clip-on or custom waistband or wristband 1.14× 1.45× 0.43 in | MS (34) | Laboratory | Activity count | Test-retest reliability poor for sedentary and free-living activities, but better for more vigorous or rhythmic activities; validity not established, high variability for all activities |
| (16 g without band) | Stroke (45) | Home | Activity count | Excellent reliability for activity count and EE with Actical worn EE on both the paretic and the non-paretic hip | ||
| ActiGraph GT3X/+ | ActiGraph Corp. | Wristband or waistband 4.6×3.3× 1.5 cm (19 g) | MS (35) | Home | Activity count Step count | Both measures highly reliable across 6 months |
| MS (39) | Laboratory | Step count | ActiGraph worn on the waist is highly accurate (95.6–97.4%) in measuring steps taken under comfortable and fast walking speed; less accurate in measuring steps under slow walking conditions (95.5%), particularly in those with severe disability (87.3%) | |||
| MS (40) | Laboratory and home | Activity count | Activity counts from the ActiGraph 7164 and the GT3X are significantly different under free-living conditions; difference in output due to slow walking speeds | |||
| Manual wheelchair users (50) | Community | EE Activity count | ActiGraph worn on the wrist and upper arm and compared with the GENEActiv device worn on the wrist and upper arm; both ActiGraphs overestimate EE, with the wrist-worn device (percent estimation error: 14%) providing more valid results than that worn on the upper arm (15%) | |||
| DynaPort Activity Monitor | McRoberts | Waistband 6.2×6.2×1.3 cm (55 g) | PD (27) | Laboratory | Step count Gait duration | The DynaPort overestimated gait duration (11.1%) and underestimated the number of steps (6.9%); step count accuracy decreased significantly as the walking distance decreased (10 m, 5.7%; 5 m, 9.6%; 3 m, 18.4%); the DynaPort was less speed dependent and proved to be more appropriate for the PD patients than pedometer methods for walking trajectories of 5 m or more |
| PD (48) | Community | Walking distance Step length | The precision in estimating short walking distances was good (percent error: 16%); however, the precision in estimating long walking distances (percent error: <40%) was less appropriate; the overall moderate precision limits the use of this activity monitor for clinical purposes | |||
| Device | Manufacturer | Device form factor | Reported findings | |||
| population | setting | endpoints | validity/reliability/accuracy | |||
| FitbitUltra | FitbitInc. | Clip 5.5×1.9×1.4 cm (11.34 g) | Stroke and TBI (42) | Laboratory | Step count | The Fitbit Ultra underestimated steps (percent error: 5%); however, it had an acceptable accuracy; it was generally accurate in participants who took more steps, and it may be a less costly alternative to research-based activity monitors for identifying steps taken |
| FitbitOne | FitbitInc. | Clip/wristband 1.9×1×4.8 mm (80 g) | Stroke (43) | Laboratory | Step count | It is more accurate as the walking speed increases and is more accurate when placed at the ankle (percent error range: 4.9–15.8%) versus the waist (7.7–84.6%) |
| GENEActiv | Activinsights | Wristband 4.3×4×1.3 cm (16 g) | Manual wheelchair users (50) | Community | EE Activity coun | The GENEActiv device worn on either the upper arm t (percent error: 3%) or the wrist (4%) provided the most valid prediction of EE |
| Nike FuelBand % | Nike | Wristband | Stroke and TBI (42) | Laboratory | Step count | The Nike FuelBand is not accurate in estimating steps, grossly underestimating steps (33.9%) in this study |
| Device | Manufacturer | Device form factor | Reportedfirn | dings | ||
| population | setting | endpoints | validity/reliability/accuracy | |||
| RT3 accelerometer | Stayhealthy Inc. | Waistband 7.1×5.6×2.8 cm (65.2 g) | MS, PD, stroke (33) | Home | Activity count | Good test-retest reliability in measuring free-living activity; the daily data collected in the first 3 days were significantly different from those collected over 7 days; a 7-day monitoring period provides the most reliable measurement of physical activity |
| SCI (49) | Laboratory | EE | Overestimated EE (percent estimation error range: 22–52.8%); however, EE estimations with the RT3 were closer to the criterion EE than those with the SWA | |||
| CP (52) | Clinic | EE | The LOA revealed that the RT3 provided the best agreement with the indirect calorimeter in estimating EE compared to the SWA and IDEEA; however, the RT3 could significantly overestimate or underestimate individual estimates of EE (LOA–67.2 to 86.3% of the mean EE), with smaller errors for over-ground walking compared to treadmill walking | |||
| Biaxial accelerometers | ||||||
| StepWatch Activity Monitor | Modus Health | Ankle band 7×5×2 cm (38 g) | MS (39) | Laboratory | Step count | Accurately measures step counts at slow (99%), comfortable (99.8%), and fast (99.6%) walking speeds |
| PD and MS (43) | Clinic | Number of strides | Accurately counts the number of strides in both MS (Pearson CC 0.99) and PD (Pearson CC 1.0) patients | |||
| Stroke and TBI (42) | Laboratory | Step count | Accurately counts steps, with only marginal overestimation (percent error: 2.4%) in this population | |||
| Stroke (44) | Home | Step count | The total step count has excellent test-retest reliability when used for 3 days in individuals with stroke; monitoring for less than a 3-day period is not recommended due to high variability | |||
| Rett syndrome (27) | Home | Step count | Accurately counts steps (mean difference: 0 steps/min); agreement did not differ with the level of general or complex gross motor skills | |||
| Device | Manufacturer | Device form factor | Reported findings | |||
| population | setting | endpoints | validity/reliability/accuracy | |||
| Uniaxial accelerometers | ||||||
| ActiGraph 7164 | ActiGraph Corp. | Clip-on or waist/wristband 5.1×4.1×1.5 cm (45.5 g) | MS (36) | Home | Activity coun Minutes of MVPA | t Highly reliable over a 6-month period in an MS population |
| MS (38) | Home | Step count | Accurately measures steps during moderate (percent error: 0.2%) and fast (0.3%) walking in persons with MS; however, there is a small degree of underestimation of step counts during slower walking (4.1%) | |||
| MS (40) | Laboratory and home | Activity coun | t Activity counts from the ActiGraph 7164 and the GT3X are significantly different under free-living conditions; difference in output due to slow walking speeds | |||
| ActivPAL | PAL Technologies Ltd. | Adheres directly to skin using PALStickies (hydrogel/waterproof attachment pad) 3.5×5.3×7 cm (15 g) | CP (51) | Clinic | Time spent standing Time spent sitting Time spent lying Step counts | Validity was high (r2≥0.96); the limits of group agreement were relatively narrow, but the LOA for individuals were narrow only for the number of steps (>5.5%); the relative reliability was high for the number of steps and moderate for the time spent sitting and lying and the time spent standing; the ActivPAL is sufficiently accurate and reliable to be used for research purposes, but less so for measuring physical activity and sedentary behaviour in an individual |
| Multisensors | ||||||
| SWA | BodyMedia, Inc. | Biaxial accelerometer, heat flux sensor, skin temperature sensor, near-body ambient temperature sensor, and galvanic skin response sensor; armband around the right upper arm 8.5×5.3×2 cm (79 g including armband) | Stroke (46) | Clinic | Step count EE | There was a poor validity of the SWA in measuring steps and EE during a range of activities and walking tasks; there was good-to-excellent test-retest reliability in measuring steps and EE |
| SCI (49) | Laboratory | EE | Significantly overestimated EE (percent error estimation range: 24.4–125.8%) in this population | |||
| CP (52) | Clinicl | EE | Overestimated EE in adults with CP, with smaller errors for over-ground walking compared to treadmill walking | |||
| IDEEA | MiniSun, LLC | Intelligent Device for Energy Expenditure and Activity (IDEEA) 5 biaxial accelerometers collect data and transmit it through thin, flexible wires to a recorder; the accelerometer is placed on the chest, thighs, and soles of the feet Recorder: 7×5.4×1.7 cm (59 g) Sensor: 1.8×1.5×0.3 cm (2 g) | CP (52) | Clinic | EE | The mean absolute percentage error was smallest for the IDEEA (range: 8.4–24.5%) when compared to the RT3 and the SWA |
| Device | Manufacturer | Device form factor | Reported findings | |||
| population | setting | endpoints | validity/reliability/accuracy | |||
| VitaportActivityMonitor | TEMEC Instruments Inc. | Five accelerometers attached to the body connected to a portable battery-powered activity monitor (Vitaport) by cables which run under the clothes; the Vitaport is attached to a belt worn around the waist, with 1 accelerometer on each and 3 placed on the lower third of the sternum 9×4.5×1.5 cm (1,360 g) | PD (47) | Laboratory | Gait speed Step length Step frequency | Excellent validity (ICC(2, 2) = 0.92–0.99,p<0.0001) for the use of the Vitaport Activity Monitor to measurespatiotemporalgait characteristics during a functional walking test for PD |
| Spring-mounted lever arm pedometer | ||||||
| Digi-Walker SW-701/SW-200 | Yamax Corporation | Clip to waistband or belt 5×3.8×1.4 cm (21 g) | Stroke and TBI (42) | Laboratory | Step count | Moderate accuracy, tending to underestimate steps in this study (percent error: 14.7%) |
| Stroke, MS, SCI, ABI, muscular dystrophy (32) | Clinic | Step count | Undercounts steps (percent error: 24–35%) in a neurological population; however, this is not strongly related to walking speed | |||
| Stroke (46) | Clinic | Step count | Reliably counts steps; wearing it on the knee is a valid option for measuring steps, except during high-intensity walking; the device is more valid as walking speed increases | |||
| PD (34) | Laboratory | Step count | Underestimates step counts (percent error: left, 11.1%; right, 16.3%) and is less accurate for short trajectories and as the walking pace decreases |
ABI, acquired brain injury; CC, correlation coefficient; CP, cerebral palsy; EE, energy expenditure; ICC, intra-class correlation coefficient; LOA, limits of agreement; MS, multiple sclerosis; MVPA, moderate-to-vigorous-intensity physical activity; PD, Parkinson disease; SCI, spinal cord injury; TBI, traumatic brain injury.