Robustness of In-Laboratory and Daily-Life Gait Speed Measures over One Year in High Functioning 61- to 70-Year-Old Adults

In-Clinic and Natural Gait Observations master protocol (I-CAN-GO) to validate gait using a lumbar accelerometer

Traditional measurements of gait are typically performed in clinical or laboratory settings where functional assessments are used to collect episodic data, which may not reflect naturalistic gait and activity patterns. The emergence of digital health technologies has enabled reliable and continuous representation of gait and activity in free-living environments. To provide further evidence for naturalistic gait characterization, we designed a master protocol to validate and evaluate the performance of a method for measuring gait derived from a single lumbar-worn accelerometer with respect to reference methods. This evaluation included distinguishing between participants' self-perceived different gait speed levels, and effects of different floor surfaces such as carpet and tile on walking performance, and performance under different bouts, speed, and duration of walking during a wide range of simulated daily activities. Using data from 20 healthy adult participants, we found different self-paced walking speeds and floor surface effects can be accurately characterized. Furthermore, we showed accurate representation of gait and activity during simulated daily living activities and longer bouts of outside walking. Participants in general found that the devices were comfortable. These results extend our previous validation of the method to more naturalistic setting and increases confidence of implementation at-home.

Daily-Life Walking Speed, Quality and Quantity Derived from a Wrist Motion Sensor: Large-Scale Normative Data for Middle-Aged and Older Adults

Walking is crucial for independence and quality of life. This study leverages wrist-worn sensor data from UK Biobank participants to establish normative daily-life walking data, stratified by age and sex, to provide benchmarks for research and clinical practice. The Watch Walk digital biomarkers were developed, validated, and applied to 92,022 participants aged 45-79 who wore a wrist sensor for at least three days. Normative data were collected for daily-life walking speed, step-time variability, step count, and 17 other gait and sleep biomarkers. Test-retest reliability was calculated, and associations with sex, age, self-reported walking pace, and mobility problems were examined. Population mean maximal and usual walking speeds were 1.49 and 1.15 m/s, respectively. The daily step count was 7749 steps, and step regularity was 65%. Women walked more regularly but slower than men. Walking speed, step count, longest walk duration, and step regularity decreased with age. Walking speed is associated with sex, age, self-reported pace, and mobility problems. Test-retest reliability was good to excellent (ICC ≥ 0.80). This study provides large-scale normative data and benchmarks for wrist-sensor-derived digital gait and sleep biomarkers from real-world data for future research and clinical applications.

Measurement properties of the usual and fast gait speed tests in community-dwelling older adults: a COSMIN-based systematic review

OBJECTIVE

The gait speed test is one of the most widely used mobility assessments for older adults. We conducted a systematic review to evaluate and compare the measurement properties of the usual and fast gait speed tests in community-dwelling older adults.

METHODS

Three databases were searched: MEDLINE, EMBASE and CINAHL. Peer-reviewed articles evaluating the gait speed test's measurement properties or interpretability in community-dwelling older adults were included. The Consensus-based Standards for the selection of health Measurement Instruments guidelines were followed for data synthesis and quality assessment.

RESULTS

Ninety-five articles met our inclusion criteria, with 79 evaluating a measurement property and 16 reporting on interpretability. There was sufficient reliability for both tests, with intraclass correlation coefficients (ICC) generally ranging from 0.72 to 0.98, but overall quality of evidence was low. For convergent/discriminant validity, an overall sufficient rating with moderate quality of evidence was found for both tests. Concurrent validity of the usual gait speed test was sufficient (ICCs = 0.79-0.93 with longer distances) with moderate quality of evidence; however, there were insufficient results for the fast gait speed test (e.g. low agreement with longer distances) supported by high-quality studies. Responsiveness was only evaluated in three articles, with low quality of evidence.

CONCLUSION

Findings from this review demonstrated evidence in support of the reliability and validity of the usual and fast gait speed tests in community-dwelling older adults. However, future validation studies should employ rigorous methodology and evaluate the tests' responsiveness.

Towards a core-set of mobility measures in ageing research: The need to define mobility and its constructs

BACKGROUND

Mobility is a key determinant and outcome of healthy ageing but its definition, conceptual framework and underlying constructs within the physical domain may need clarification for data comparison and sharing in ageing research. This study aimed to (1) review definitions and conceptual frameworks of mobility, (2) explore agreement on the definition of mobility, conceptual frameworks, constructs and measures of mobility, and (3) define, classify and identify constructs.

METHODS

A three-step approach was adopted: a literature review and two rounds of expert questionnaires (n = 64, n = 31, respectively). Agreement on statements was assessed using a five-point Likert scale; the answer options 'strongly agree' or 'agree' were combined. The percentage of respondents was subsequently used to classify agreements for each statement as: strong (≥ 80%), moderate (≥ 70% and < 80%) and low (< 70%).

RESULTS

A variety of definitions of mobility, conceptual frameworks and constructs were found in the literature and among respondents. Strong agreement was found on defining mobility as the ability to move, including the use of assistive devices. Multiple constructs and measures were identified, but low agreements and variability were found on definitions, classifications and identification of constructs. Strong agreements were found on defining physical capacity (what a person is maximally capable of, 'can do') and performance (what a person actually does in their daily life, 'do') as key constructs of mobility.

CONCLUSION

Agreements on definitions of mobility, physical capacity and performance were found, but constructs of mobility need to be further identified, defined and classified appropriately. Clear terminology and definitions are essential to facilitate communication and interpretation in operationalising the physical domain of mobility as a prerequisite for standardisation of mobility measures.

Validity and reliability of the Apple Health app on iPhone for measuring gait parameters in children, adults, and seniors

This study assessed the concurrent validity and test-retest-reliability of the Apple Health app on iPhone for measuring gait parameters in different age groups. Twenty-seven children, 28 adults and 28 seniors equipped with an iPhone completed a 6-min walk test (6MWT). Gait speed (GS), step length (SL), and double support time (DST) were extracted from the gait recordings of the Health app. Gait parameters were simultaneously collected with an inertial sensors system (APDM Mobility Lab) to assess concurrent validity. Test-retest reliability was assessed via a second iPhone-instrumented 6MWT 1 week later. Agreement of the Health App with the APDM Mobility Lab was good for GS in all age groups and for SL in adults/seniors, but poor to moderate for DST in all age groups and for SL in children. Consistency between repeated measurements was good to excellent for all gait parameters in adults/seniors, and moderate to good for GS and DST but poor for SL in children. The Health app on iPhone is reliable and valid for measuring GS and SL in adults and seniors. Careful interpretation is required when using the Health app in children and when measuring DST in general, as both have shown limited validity and/or reliability.

Association between daily life walking speed and frailty measured by a smartphone application: a cross-sectional study

OBJECTIVES

To assess whether frailty can be assessed using a smartphone and whether daily walking speed (DWS) is associated with frailty.

DESIGN

Cross-sectional study.

SETTING

Three prefectures (Kanagawa, Saitama and Tokyo) in Japan.

PARTICIPANTS

The study enrolled 163 participants (65 in the robust group, 69 in the prefrailty group and 29 in the frailty group) by sending letters to house owners aged≥55 years.

PRIMARY AND SECONDARY OUTCOME MEASURES

The participants downloaded the DWS measurement application on their smartphones, which measured the daily walking (DW) parameters (DWS, step length and cadence) and the Kihon checklist for frailty assessment. The differences in the DW parameters between the robust, prefrailty and frailty groups were examined using one-way analysis of variance. We conducted logistic regression analysis for the Crude model (each DW parameter), model 1 (adjusted for the number of steps) and model 2 (model 1+age, sex and the number of chronic diseases).

RESULTS

DWS was marginally significantly slower in the frailty group than in the prefrailty and robust group (robust 1.26 m/s vs prefrailty 1.25 m/s vs frailty 1.19 m/s, p=0.060). Step length was significantly smaller in the frailty group than in the robust group (robust 66.1 cm vs prefrailty 65.9 vs frailty 62.3 cm, p<0.01). Logistic regression analysis for the three models revealed that DWS was significantly associated with frailty.

CONCLUSIONS

DWS measured using the smartphone application was associated with frailty. This was probably due to the shorter step length and body height seen in frail individuals.

Reliability, responsiveness, and validity of slow walking speed in community dwelling older adults

BACKGROUND

Independent ambulation requires adaptability. Self-selected and maximum walking speeds are often both assessed to demonstrate the ability to adapt speed to different tasks and environments. However, purposefully walking at a slow speed (slowWS) could also be an appropriate adaptation in certain situations but has rarely been investigated.

RESEARCH QUESTION

The purpose of this study was to assess the reliability, responsiveness, and concurrent validity of slowWS in community-dwelling older adults.

METHODS

This was an observational, cross-sectional study of 110 community-dwelling older adults. Test-retest and inter-rater reliabilities of slowWS were assessed with intra-class correlation coefficients. Standard error of measurement (SEM) and minimal detectable change (MDC₉₅) were calculated to determine responsiveness. Concurrent validity was assessed with Spearman rank-order correlations between slowWS and a battery of tests previously shown to be related to walking speed.

RESULTS

Walking speed measurement for slowWS was shown to have excellent test-retest and interrater reliability (ICCs values of 0.971-0.997). Standard error of measurement value was small (0.015 m/sec) and MDC₉₅ was 0.04 m/sec. SlowWS was not found to significantly correlate to any other study variable.

SIGNIFICANCE

Walking speed, whether self-selected, maximum, or slow, can be measured reliably with a stopwatch and specific verbal commands. While slowWS could be beneficial for certain tasks or environments, walking slowly was not associated with age, sex, comorbidity, or measures of cognition, depression, strength, balance, disability, or life-space in this sample.

Responsiveness of Daily Life Gait Quality Characteristics over One Year in Older Adults Who Experienced a Fall or Engaged in Balance Exercise

Gait quality characteristics obtained from daily-life accelerometry are clinically relevant for fall risk in older adults but it is unknown whether these characteristics are responsive to changes in gait quality. We aimed to test whether accelerometry-based daily-life gait quality characteristics are reliable and responsive to changes over one year in older adults who experienced a fall or an exercise intervention. One-week trunk acceleration data were collected from 522 participants (65-97 years), at baseline and after one year. We calculated median values of walking speed, regularity (sample entropy), stability (logarithmic rate of divergence per stride), and a gait quality composite score, across all 10-s gait epochs derived from one-week gait episodes. Intraclass correlation coefficients (ICC) and limits of agreement (LOA) were determined for 198 participants who did not fall nor participated in an exercise intervention during follow-up. For responsiveness to change, we determined the number of participants who fell (n = 209) or participated in an exercise intervention (n = 115) that showed a change beyond the LOA. ICCs for agreement between baseline and follow-up exceeded 0.70 for all gait quality characteristics except for vertical gait stability (ICC = 0.69, 95% CI [0.62, 0.75]) and walking speed (ICC = 0.68, 95% CI [0.62, 0.74]). Only walking speed, vertical and mediolateral gait stability changed significantly in the exercisers over one year but effect sizes were below 0.2. The characteristic associated with most fallers beyond the LOA was mediolateral sample entropy (4.8% of fallers). For the exercisers, this was gait stability in three directions and the gait quality composite score (2.6% of exercisers). The gait quality characteristics obtained by median values over one week of trunk accelerometry were not responsive to presumed changes in gait quality after a fall or an exercise intervention in older people. This is likely due to large (within subjects) differences in gait behaviour that participants show in daily life.

Mobility improvement in the first 6 postoperative weeks in orthogeriatric fracture patients

Background

Physical activity is a relevant outcome parameter in orthopedic surgery, that can be objectively assessed. Until now, there is little information regarding objective gait parameters in the orthogeriatric population. This study focuses on the first 6 weeks of postoperative rehabilitation, and delivers objective data about gait speed and step length in typical orthogeriatric fracture patterns.

Methods

Thirty-one orthogeriatric fracture patients [pertrochanteric femur fractures (PFF), femoral neck (FN), and proximal humerus fractures (PHF)] were consecutively enrolled in a maximum care hospital in a prospective study design. All patients wore an accelerometer placed at the waist during the postoperative stay (24 h/d) and at 6-week follow-up, to measure real gait speed and step length. In addition, self-assessment of mobility (Parker mobility score) and activities of daily living (Barthel index) were collected at baseline, during the inpatient stay, and at 6-week follow-up.

Results

During postoperative hospitalization, significantly higher gait speed (m/s) was observed in the PHF group (0.52 ± 0.27) compared with the FN group (0.36 ± 0.28) and PFF group (0.19 ± 0.28) (p < 0.05). Six weeks postoperatively, gait speed improved significantly in all groups (PHF 0.90 ± 0.41; FN 0.72 ± 0.13; PFF 0.60 ± 0.23). Similarly, step length (m) differed between groups postoperatively [FN 0.16 ± 0.13; PFF 0.12 ± 0.15; PHF 0.31 ± 0.05 (p < 0.005)] and improved over time significantly (FN 0.47 ± 0.01; 0.39 ± 0.19; 0.50 ± 0.18). Self-assessment scores indicate that the majority of the patients had minor restrictions in mobility before the fracture. These values decreased immediately postoperatively and improved in the first 6 weeks, but did not reach the initial level.

Conclusions

Gait speed, step length, and self-assessment in terms of mobility and activities of daily living improve significantly in the first 6 postoperative weeks in orthogeriatric fracture patients. As very low postoperative mobility during hospitalization was observed, this collective shows great potential in postoperative rehabilitation regardless of their fracture pattern. For this reason, specific aftercare concepts similar to the “fast track” concepts in primary arthroplasty are crucial for orthogeriatric patients in clinical practice.

Level of evidence

Prospective cohort study, 2.

Real-world gait speed estimation, frailty and handgrip strength: a cohort-based study

Gait speed is a reliable outcome measure across multiple diagnoses, recognized as the 6th vital sign. The focus of the present study was on assessment of gait speed in long-term real-life settings with the aim to: (1) demonstrate feasibility in large cohort studies, using data recorded with a wrist-worn accelerometer device; (2) investigate whether the walking speed assessed in the real-world is consistent with expected trends, and associated with clinical scores such as frailty/handgrip strength. This cross-sectional study included n = 2809 participants (1508 women, 1301 men, [45-75] years old), monitored with a wrist-worn device for 13 consecutive days. Validated algorithms were used to detect the gait bouts and estimate speed. A set of metrics were derived from the statistical distribution of speed of gait bouts categorized by duration (short, medium, long). The estimated usual gait speed (1-1.6 m/s) appears consistent with normative values and expected trends with age, gender, BMI and physical activity levels. Speed metrics significantly improved detection of frailty: AUC increase from 0.763 (no speed metrics) to 0.798, 0.800 and 0.793 for the 95th percentile of individual's gait speed for bout durations < 30, 30-120 and > 120 s, respectively (all p < 0.001). Similarly, speed metrics also improved the prediction of handgrip strength: AUC increase from 0.669 (no speed metrics) to 0.696, 0.696 and 0.691 for the 95th percentile of individual's gait speed for bout durations < 30, 30-120 and > 120 s, respectively (all p < 0.001). Forward stepwise regression showed that the 95th percentile speed of gait bouts with medium duration (30-120 s) to be the best predictor for both conditions. The study provides evidence that real-world gait speed can be estimated using a wrist-worn wearable system, and can be used as reliable indicator of age-related functional decline.