Mobile Phone-Based Measures of Activity, Step Count, and Gait Speed: Results From a Study of Older Ambulatory Adults in a Naturalistic Setting

Background Cellular mobile telephone technology shows much promise for delivering and evaluating healthcare interventions in cost-effective manners with minimal barriers to access. There is little data demonstrating that these devices can accurately measure clinically important aspects of individual functional status in naturalistic environments outside of the laboratory. Objective The objective of this study was to demonstrate that data derived from ubiquitous mobile phone technology, using algorithms developed and previously validated by our lab in a controlled setting, can be employed to continuously and noninvasively measure aspects of participant (subject) health status including step counts, gait speed, and activity level, in a naturalistic community setting. A second objective was to compare our mobile phone-based data against current standard survey-based gait instruments and clinical physical performance measures in order to determine whether they measured similar or independent constructs. Methods A total of 43 ambulatory, independently dwelling older adults were recruited from Nebraska Medicine, including 25 (58%, 25/43) healthy control individuals from our Engage Wellness Center and 18 (42%, 18/43) functionally impaired, cognitively intact individuals (who met at least 3 of 5 criteria for frailty) from our ambulatory Geriatrics Clinic. The following previously-validated surveys were obtained on study day 1: (1) Late Life Function and Disability Instrument (LLFDI); (2) Survey of Activities and Fear of Falling in the Elderly (SAFFE); (3) Patient Reported Outcomes Measurement Information System (PROMIS), short form version 1.0 Physical Function 10a (PROMIS-PF); and (4) PROMIS Global Health, short form version 1.1 (PROMIS-GH). In addition, clinical physical performance measurements of frailty (10 foot Get up and Go, 4 Meter walk, and Figure-of-8 Walk [F8W]) were also obtained. These metrics were compared to our mobile phone-based metrics collected from the participants in the community over a 24-hour period occurring within 1 week of the initial assessment. Results We identified statistically significant differences between functionally intact and frail participants in mobile phone-derived measures of percent activity (P=.002, t test), active versus inactive status (P=.02, t test), average step counts (P<.001, repeated measures analysis of variance [ANOVA]) and gait speed (P<.001, t test). In functionally intact individuals, the above mobile phone metrics assessed aspects of functional status independent (Bland-Altman and correlation analysis) of both survey- and/or performance battery-based functional measures. In contrast, in frail individuals, the above mobile phone metrics correlated with submeasures of both SAFFE and PROMIS-GH. Conclusions Continuous mobile phone-based measures of participant community activity and mobility strongly differentiate between persons with intact functional status and persons with a frailty phenotype. These measures assess dimensions of functional status independent of those measured using current validated questionnaires and physical performance assessments to identify functional compromise. Mobile phone-based gait measures may provide a more readily accessible and less-time consuming measure of gait, while further providing clinicians with longitudinal gait measures that are currently difficult to obtain.

Clarify the level of human involvement in the abstract, e.g., use phrases like "fully automated" vs. "therapist/nurse/care provider/physician-assisted" (mention number and expertise of providers involved, if any).(Note: Only report in the abstract what the main paper is reporting.If this information is missing from the main body of text, consider adding it) 1 2 3 4 5 subitem not at all important essential Does your paper address subitem 1b-ii?
Copy and paste relevant sections from the manuscript abstract (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brieoy explain why the item is not applicable/relevant for your study "A total of 40 ambulatory, independently dwelling older adults were recruited from Nebraska Medicine, including 22 healthy control individuals from our Engage Wellness Center and 18 frail individuals from our ambulatory Geriatrics Clinic." Abstract describes subjects receiving both validated questionnaires, a physical performance battery, and smartphone-based ambulatory monitoring to determine functional status.Copy and paste relevant sections from the manuscript abstract (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brieoy explain why the item is not applicable/relevant for your study 11/10/16, 3:45 PM See above.Questionnaires and physical performance batteries constitute the face-to-face assessments; smartphone-based ambulatory monitoring is an automated assessment not requiring immediate investigator management.

1b-iv) RESULTS section in abstract must contain use data
Report number of participants enrolled/assessed in each group, the use/uptake of the intervention (e.g., attrition/adherence metrics, use over time, number of logins etc.), in addition to primary/secondary outcomes.(Note: Only report in the abstract what the main paper is reporting.If this information is missing from the main body of text, consider adding it) 1 2 3 4 5 subitem not at all important essential Does your paper address subitem 1b-iv?
Copy and paste relevant sections from the manuscript abstract (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brieoy explain why the item is not applicable/relevant for your study "We identified statistically significant differences between control and frail subjects in percent activity (p<0.0018,t-test), active vs. inactive status (p<0.0195,t-test), average step counts (p<0.001,t-test) and gait speed (p<0.001,one-way ANOVA).Overall, both internal correlations (within individual questionnaires and the performance battery) and correlations between questionnaire/physical performance battery were greater in functionally intact compared to frail older adults."

1b-v) CONCLUSIONS/DISCUSSION in abstract for negative trials
Conclusions/Discussions in abstract for negative trials: Discuss the primary outcome -if the trial is negative (primary outcome not changed), and the intervention was not used, discuss whether negative results are attributable to lack of uptake and discuss reasons.(Note: Only report in the abstract what the main paper is reporting.If this information is missing from the main body of text, consider adding it) 1 2 3 4 5 subitem not at all important essential

Does your paper address subitem 1b-v?
Copy and paste relevant sections from the manuscript abstract (include quotes in quotation marks CONSORT-EHEALTH (V 1.6.1)-Submission/Publication Form https://docs.google.com/forms/d/e/1FAIpQLSfZBSUp1bwOc_...

INTRODUCTION 2a)
In INTRODUCTION: ScientiUc background and explanation of rationale Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brieoy explain why the item is not applicable/relevant for your study See above.We also provide a rationale for this approach in the previous paragraph: "In the past, gait speed studies have typically relied on measurements taken in clinic.The standard method for determining gait involves timing an individual while walking a short, predetermined distance (e.g.4-6 m).This approach is less than ideal because physical activity, including gait, is influenced by performance biases (e.g., subjects who know they are being observed try to improve their usual performance), as well as ultradian, circadian and seasonal changes which cannot be 2b) In INTRODUCTION: SpeciUc objectives or hypotheses

Does your paper address CONSORT subitem 2b? *
Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brieoy explain why the item is not applicable/relevant for your study The focus of this study does not rely on a specific hypothesis, but rather a demonstration of the approach validity in the most naturalistic environment that is clinically relevant: individuals who are ambulatory and community dwelling.We provide our justification and a brief statement of our results in the following paragraph: "Here, we show for the first time that smartphones can provide both continuous and aggregate measures of clinically relevant gait and mobility parameters, including gait speed, step count and overall METHODS 3a) Description of trial design (such as parallel, factorial) including allocation ratio 3b) Important changes to methods after trial commencement (such as eligibility criteria), with reasons Does your paper address CONSORT subitem 3b? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brieoy explain why the item is not applicable/relevant for your study Due to the nature of our protocol, there was no need to change methods during this study.

3b-i) Bug /xes, Downtimes, Content Changes
Bug Uxes, Downtimes, Content Changes: ehealth systems are often dynamic systems.A description of changes to methods therefore also includes important changes made on the intervention or comparator during the trial (e.g., major bug Uxes or changes in the functionality or content) (5-iii) and other "unexpected events" that may have inouenced study design such as staff changes, system failures/downtimes, etc. [2].

Does your paper address subitem 3b-i?
Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brieoy explain why the item is not applicable/relevant for your study We do not address these issues; they were not significant factors for our study.

4a-i) Computer / Internet literacy
Computer / Internet literacy is often an implicit "de facto" eligibility criterion -this should be explicitly clariUed.
1 2 3 4 5 subitem not at all important essential Does your paper address subitem 4a-i?
Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brieoy explain why the item is not applicable/relevant for your study In our study, we purposely designed the system to function with no user input or effort other than charging the cellphone.Thus, internet/computer literacy, per say, is not a significant factor regarding the interpretation of our results.
4a-ii) Open vs. closed, web-based vs. face-to-face assessments: Open vs. closed, web-based vs. face-to-face assessments: Mention how participants were recruited (online vs. ofoine), e.g., from an open access website or from a clinic, and clarify if this was a purely web-based trial, or there were face-to-face components (as part of the intervention or for assessment), i.e., to what degree got the study team to know the participant.In online-only trials, clarify if participants were quasi-anonymous and whether having multiple identities was possible or whether technical or logistical measures (e.g., cookies, email conUrmation, phone calls) were used to detect/prevent these.
1 2 3 4 5 subitem not at all important essential Does your paper address subitem 4a-ii?* Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brieoy explain why the item is not applicable/relevant for your study We explicitly describe the protocols for both our face-to-face assessments (questionnaire, physical performance battery), and our remote functional monitoring assessment: "Self-reported functional status.We used previously validated survey instruments to determine subject self-perceived functional status.These instruments included the (1) functional component of the Late Life Function and Disability Instrument (LLFDI, a comprehensive assessment of function and disability for use in community-dwelling

4a-iii) Information giving during recruitment
Information given during recruitment.Specify how participants were briefed for recruitment and in the informed consent procedures (e.g., publish the informed consent documentation as appendix, see also item X26), as this information may have an effect on user self-selection, user expectation and may also bias results.

Does your paper address subitem 4a-iii?
Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brieoy explain why the item is not applicable/relevant for your study 11/10/16, 3:45 PM We provided no information to subjects during recruitment or afterwards.
4b) Settings and locations where the data were collected Does your paper address CONSORT subitem 4b? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brieoy explain why the item is not applicable/relevant for your study Our settings for data acquisition were the Omaha Nebraska community.This setting is fully clarified throughout the abstract and manuscript.

4b-i) Report if outcomes were (self-)assessed through online questionnaires
Clearly report if outcomes were (self-)assessed through online questionnaires (as common in web-based trials) or otherwise.
1 2 3 4 5 subitem not at all important essential Does your paper address subitem 4b-i?* Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brieoy explain why the item is not applicable/relevant for your study Yes.This facet of the study is fully described in the methods.
"We used previously validated survey instruments to determine subject self-perceived functional status.These instruments included the (1) functional component of the Late Life Function and Disability Instrument (LLFDI, a comprehensive assessment of function and disability for use in community-dwelling older adults that evaluates self-reported difficulty performing 32 physical activities (such as use of a stepstool, or running to catch a bus), with higher scores 4b-ii) Report how institutional af/liations are displayed Report how institutional afUliations are displayed to potential participants [on ehealth media], as afUliations with prestigious hospitals or universities may affect volunteer rates, use, and reactions with regards to an intervention.(Nota required item -describe only if this may bias results) 1 2 3 4 5 subitem not at all important essential Does your paper address subitem 4b-ii?
Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brieoy explain why the item is not applicable/relevant for your study We did not display institutional affiliations.Subjects did have to come to the University of Nebraska Medical Center's Home Instead Center for Successful Aging for their questionnaire and physical performance battery testing, and were thus exposed to institutional logos, etc., during that time.However, these subjects also received their health care from the University of Nebraska Medical Center, so we do not suspect any significant bias in one direction or another in performance of questionnaire, performance battery, or ambulatory remote monitoring.
5) The interventions for each group with sufUcient details to allow replication, including how and when they were actually administered

5-i) Mention names, credential, af/liations of the developers, sponsors, and owners
Mention names, credential, afUliations of the developers, sponsors, and owners [6] (if authors/evaluators are owners or developer of the software, this needs to be declared in a "Conoict of interest" section or mentioned elsewhere in the manuscript).

Does your paper address subitem 5-i?
Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brieoy explain why the item is not applicable/relevant for your study We describe our cell phone vendor, and our coding platform: "Nokia N79 SmartPhones (White Plains, NY) with an intrinsic threedimensional accelerometer were used to measure mobility and locomotion for extended periods of time in community dwelling individuals of both cohorts.Acceleration values were sampled and written to memory using custom Python software (Python for S60 v1.9.7, [30]) running on a Symbian S60 V3FP2 OS (San Francisco, CA).The cell phone was placed in either the participant's right or left

5-ii) Describe the history/development process
Describe the history/development process of the application and previous formative evaluations (e.g., focus groups, usability testing), as these will have an impact on adoption/use rates and help with interpreting results.

Does your paper address subitem 5-ii?
Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brieoy explain why the item is not applicable/relevant for your study We do not describe previous work but rather provide references to the preceding manuscripts that led to this work:

5-iii) Revisions and updating
Revisions and updating.Clearly mention the date and/or version number of the application/intervention (and comparator, if applicable) evaluated, or describe whether the intervention underwent major changes during the evaluation process, or whether the development and/or content was "frozen" during the trial.Describe dynamic components such as news feeds or changing content which may have an impact on the replicability of the intervention (for unexpected events see item 3b).

Does your paper address subitem 5-iii?
Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional 11/10/16, 3:45 PM information not in the ms, or brieoy explain why the item is not applicable/relevant for your study We performed no revisions or updating of questionnaires, performance battery, or smartphone software/protocol throughout this trial.

5-iv) Quality assurance methods
Provide information on quality assurance methods to ensure accuracy and quality of information provided [1], if applicable.
1 2 3 4 5 subitem not at all important essential Does your paper address subitem 5-iv?
Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brieoy explain why the item is not applicable/relevant for your study We describe our data quality control measures in the Methods: "Survey data was scored per instrument instructions.For PROMIS measures, t-scores were determined from raw scores by appropriate conversion tables (available at accessmentcenter.net).Raw acceleration data was low-pass filtered, and baseline acceleration normalized to 1 g over the entire duration of data collection [13].Our classification algorithm first identified epochs of "forgotten phone" vs epochs of subject carrying the phone.For epochs of subject carrying Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brieoy explain why the item is not applicable/relevant for your study 11/10/16, 3:45 PM We do not directly provide source code, screenshots, screencapture, or algorithm flowcharts.Of note, our algorithms are described in a secondary manuscript (Kwon et al., as mentioned above).We are willing to provide PyS60 code for persons interested in replicating this study; however, given the marked progress in this field, we suspect that providing this code would be a bit anachronistic; our group has since moved away from the Symbian OS and is now focusing our efforts on Smartphones and the Android OS.

5-vi) Digital preservation
Digital preservation: Provide the URL of the application, but as the intervention is likely to change or disappear over the course of the years; also make sure the intervention is archived (Internet Archive, webcitation.org,and/or publishing the source code or screenshots/videos alongside the article).As pages behind login screens cannot be archived, consider creating demo pages which are accessible without login.

Does your paper address subitem 5-vi?
Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brieoy explain why the item is not applicable/relevant for your study We do not address this subitem.We think that the power of this study is not its ability to be exactly replicated with the technology we used, but rather the implication that this technological approach (implemented with available smartphones) has significant clinical relevance.

5-vii) Access
Access: Describe how participants accessed the application, in what setting/context, if they had to pay (or were paid) or not, whether they had to be a member of speciUc group.If known, describe how participants obtained "access to the platform and Internet" [1].To ensure access for editors/reviewers/readers, consider to provide a "backdoor" login account or demo mode for reviewers/readers to explore the application (also important for archiving purposes, see vi). to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brieoy explain why the item is not applicable/relevant for your study This item is not really applicable to our study.Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brieoy explain why the item is not applicable/relevant for your study

5-viii) Mode of delivery, features/functionalities/components of the intervention and comparator, and the theoretical framework
We describe our deployment in the Methods: "Participants were fitted with a pedometer and smartphone.The proper use and correct placement of these devices were demonstrated.Subjects were instructed to wear these devices for the next 24 hours, except when bathing, swimming or sleeping.
Subjects were then briefly videotaped walking on a treadmill (SCIFIT, Tulsa, OK, scifit.com)for 5 minutes (normally 2 mi/hr but flexible to

5-ix) Describe use parameters
Describe use parameters (e.g., intended "doses" and optimal timing for use).Clarify what instructions or recommendations were given to the user, e.g., regarding timing, frequency, heaviness of use, if any, or was the intervention used ad libitum.
1 2 3 4 5 subitem not at all important essential Does your paper address subitem 5-ix?
Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brieoy explain why the item is not applicable/relevant for your study This item is not really relevant to our study.

5-x) Clarify the level of human involvement
Clarify the level of human involvement (care providers or health professionals, also technical assistance) in the e-intervention or as co-intervention (detail number and expertise of professionals involved, if any, as well as "type of assistance offered, the timing and frequency of the support, how it is initiated, and the medium by which the assistance is delivered".It may be necessary to distinguish between the level of human involvement required for the trial, and the level of human involvement required for a routine application outside of a RCT setting (discuss under item 21generalizability).
1 2 3 4 5 subitem not at all important essential Does your paper address subitem 5-x?
Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brieoy explain why the item is not applicable/relevant for your study We discuss in detail that this system requires a minimum of subject user input; specifically, the ability to charge the smartphone and wear it while they perform their day-to-day activities.
Interpretation of the data requires input from the research team; the data quality control, classification, and analysis steps are provided in great detail in the manuscript Methods.

5-xi) Report any prompts/reminders used
Report any prompts/reminders used: Clarify if there were prompts (letters, emails, phone calls, SMS) to use the application, what triggered them, frequency etc.It may be necessary to distinguish between the level of prompts/reminders required for the trial, and the level of prompts/reminders for a routine application outside of a RCT setting (discuss under item 21 -generalizability).
1 2 3 4 5 subitem not at all important essential Does your paper address subitem 5-xi?* Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brieoy explain why the item is not applicable/relevant for your study We did not employ any reminders or prompts.Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brieoy explain why the item is not applicable/relevant for your study

5-xii
We did not require co-interventions or support teams.
6a) Completely deUned pre-speciUed primary and secondary outcome measures, including how and when they were assessed

Does your paper address subitem 6a-i?
Copy and paste relevant sections from manuscript text We did not apply CHERRIES to our survey results.The instruments themselves were standardized and validated in that particular form, and we did not change any of the items in any manner whatsoever.We did not use validation in an online context as a specific factor; we rather focused on instruments well-validated to measure functional status.Our rationale was that the instruments were administered once, in a quasi-clinical setting that does not really resemble the average individual's on-line experience.

6a-ii) Describe whether and how "use" (including intensity of use/dosage) was de/ned/measured/monitored
Describe whether and how "use" (including intensity of use/dosage) was deUned/measured /monitored (logins, logUle analysis, etc.).Use/adoption metrics are important process outcomes that should be reported in any ehealth trial.
7a) How sample size was determined NPT: When applicable, details of whether and how the clustering by care provides or centers was addressed

7a-i) Describe whether and how expected attrition was taken into account when calculating the sample size
Describe whether and how expected attrition was taken into account when calculating the sample size.

Does your paper address subitem 7a-i?
Copy and paste relevant sections from manuscript title (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brieoy explain why the item is not applicable/relevant for your study Given the short duration of the study, we did not anticipate attrition to be a significant problem.Our greater problem (as detailed in the methods and results) was identifying persons with functional impairments and relatively intact cognitive status.
7b) When applicable, explanation of any interim analyses and stopping guidelines Does your paper address subitem 11a-i?* Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brieoy explain why the item is not applicable/relevant for your study We were unable to blind either ourselves of our subjects to their group, since both investigators and participants fully understood who was functionally intact and who was not.We did not provide any sham interventions.
11a-ii) Discuss e.g., whether participants knew which intervention was the "intervention of interest" and which one was the "comparator" Informed consent procedures (4a-ii) can create biases and certain expectations -discuss e.g., whether participants knew which intervention was the "intervention of interest" and which one was the "comparator".

Does your paper address subitem 11a-ii?
Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brieoy explain why the item is not applicable/relevant for your study We did not use a comparator design.

11b) If relevant, description of the similarity of interventions
(this item is usually not relevant for ehealth trials as it refers to similarity of a placebo or sham intervention to a active medication/intervention)

Does your paper address CONSORT subitem 11b? *
Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brieoy explain why the item is not applicable/relevant for your study We not provide a sham intervention.
12a) Statistical methods used to compare groups for primary and secondary outcomes NPT: When applicable, details of whether and how the clustering by care providers or centers was addressed

Does your paper address CONSORT subitem 12a? *
Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brieoy explain why the item is not applicable/relevant for your study We describe our statistical methods in detail in the manuscript Methods: "We analyzed our smartphone based measures by two-way analysis of variance (ANOVA).
Step count, gait speed, and activity count were primary outcomes with cohort (functionally intact vs impaired) and time as factors.Our first models included all interaction terms, and interactions not found to be significant were dropped from later models.We managed multiple comparisons testing by Bonferroni

12a-i) Imputation techniques to deal with attrition / missing values
Imputation techniques to deal with attrition / missing values: Not all participants will use the intervention/comparator as intended and attrition is typically high in ehealth trials.Specify how participants who did not use the application or dropped out from the trial were treated in the statistical analysis (a complete case analysis is strongly discouraged, and simple imputation techniques such as LOCF may also be problematic [4]).
1 2 3 4 5 subitem not at all important essential Does your paper address subitem 12a-i?* Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brieoy explain why the item is not applicable/relevant for your study Subjects missing a specific data (either survey, performance battery, or functional monitoring data) were dropped from the analysis of that particular metric.
12b) Methods for additional analyses, such as subgroup analyses and adjusted analyses Does your paper address CONSORT subitem 12b? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brieoy explain why the item is not applicable/relevant for your study We required no subgroup analysis.We did not perform any analysis adjustments.
X26) REB/IRB Approval and Ethical Considerations [recommended as subheading under "Methods"] (not a CONSORT item)

X26-i) Comment on ethics committee approval
1 2 3 4 5 subitem not at all important essential

Does your paper address subitem X26-i?
Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brieoy explain why the item is not applicable/relevant for your study 11/10/16, 3:45 PM We describe this in our Methods: "The UNMC Institutional Review Board approved this study.Written informed consent was obtained from all participants"

x26-ii) Outline informed consent procedures
Outline informed consent procedures e.g., if consent was obtained ofoine or online (how?Checkbox, etc.?), and what information was provided (see 4a-ii).See [6] for some items to be included in informed consent documents.

Does your paper address subitem X26-ii?
Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brieoy explain why the item is not applicable/relevant for your study We describe this in our Methods: "The UNMC Institutional Review Board approved this study.Written informed consent was obtained from all participants"

X26-iii) Safety and security procedures
Safety and security procedures, incl.privacy considerations, and any steps taken to reduce the likelihood or detection of harm (e.g., education and training, availability of a hotline) 1 2 3 4 5 subitem not at all important essential

Does your paper address subitem X26-iii?
Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brieoy explain why the item is not applicable/relevant for your study 11/10/16, 3:45 PM This study was deemed minimal risk by our IRB.Our software kept no personally identifying information on smartphones during data collection.

RESULTS
13a) For each group, the numbers of participants who were randomly assigned, received intended treatment, and were analysed for the primary outcome NPT: The number of care providers or centers performing the intervention in each group and the number of patients treated by each care provider in each center

Does your paper address CONSORT subitem 13a? *
Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brieoy explain why the item is not applicable/relevant for your study We provide in the manuscript how many members of each cohort successfully completed data collection for questionnaires, physical performance batteries, and smartphone data collection.
13b) For each group, losses and exclusions after randomisation, together with reasons

Does your paper address CONSORT subitem 13b? (NOTE: Preferably, this is shown in a CONSORT ]ow diagram) *
Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brieoy explain why the item is not applicable/relevant for your study 11/10/16, 3:45 PM We provide this information in Figure 1.

13b-i) Attrition diagram
Strongly recommended: An attrition diagram (e.g., proportion of participants still logging in or using the intervention/comparator in each group plotted over time, similar to a survival curve) or other Ugures or tables demonstrating usage/dose/engagement.

Does your paper address subitem 13b-i?
Copy and paste relevant sections from the manuscript or cite the Ugure number if applicable (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brieoy explain why the item is not applicable/relevant for your study We experienced no attrition in this study due to the short (2-day from start to finish) time requirement for participation 14a) Dates deUning the periods of recruitment and follow-up

Does your paper address CONSORT subitem 14a? *
Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brieoy explain why the item is not applicable/relevant for your study 11/10/16, 3:45 PM We performed no follow up.We do not specifically mention how long recruitment was open; we spent more than 30 months recruiting individuals for this study.
14a-i) Indicate if critical "secular events" fell into the study period Indicate if critical "secular events" fell into the study period, e.g., signiUcant changes in Internet resources available or "changes in computer hardware or Internet delivery resources" 1 2 3 4 5 subitem not at all important essential Does your paper address subitem 14a-i?
Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brieoy explain why the item is not applicable/relevant for your study There were no "secular events" during the study period.
14b) Why the trial ended or was stopped (early) We provide this information in Table 2.

15-i) Report demographics associated with digital divide issues
In ehealth trials it is particularly important to report demographics associated with digital divide issues, such as age, education, gender, social-economic status, computer/Internet/ehealth literacy of the participants, if known.
1 2 3 4 5 subitem not at all important essential Does your paper address subitem 15-i?* Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brieoy explain why the item is not applicable/relevant for your study Most of the subjects we recruited were white, suburban, relatively affluent, with relatively higher degrees of health literacy, social support, and access to high quality healthcare.This feature by itself does not change the fact that our smartphone-based approach can accurately measure important aspects of their at-home functional status; however, it does suggest that future studies may see different degrees of usability decline in subjects with less affluent, less healthliterate, less social support status.
16) For each group, number of participants (denominator) included in each analysis and whether the analysis was by original assigned groups 16-i) Report multiple "denominators" and provide de/nitions Report multiple "denominators" and provide deUnitions: Report N's (and effect sizes) "across a range of study participation [and use] thresholds" [1], e.g., N exposed, N consented, N used more than x times, N used more than y weeks, N participants "used" the intervention/comparator at speciUc pre-deUned time points of interest (in absolute and relative numbers per group).Always clearly deUne "use" of the intervention.
1 2 3 4 5 subitem not at all important essential Does your paper address subitem 16-i?* Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brieoy explain why the item is not applicable/relevant for your study We address this in Figure 1.All subjects were only studies once.

16-ii) Primary analysis should be intent-to-treat
Primary analysis should be intent-to-treat, secondary analyses could include comparing only "users", with the appropriate caveats that this is no longer a randomized sample (see 18-i).
1 2 3 4 5 subitem not at all important essential Does your paper address subitem 16-ii?
Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brieoy explain why the item is not applicable/relevant for your study This is not a major point, since our study was not randomized to receive this intervention.
17a) For each primary and secondary outcome, results for each group, and the estimated effect size and its precision (such as 95% conUdence interval) Does your paper address CONSORT subitem 17a? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brieoy explain why the item is not applicable/relevant for your study We provide the following results regarding our primary and secondary outcomes: "Gait assessment survey instruments and clinical performance measures differentiate between functionally-intact and frail subjects.We chose our questionnaires and performance assessments based on prior validation, current clinical/research use, and face validity.31 of 32 subjects had sufficient survey data for analysis.As expected, our analysis demonstrated that LLFDI, SAFFE, PROMIS-PH and

17a-i) Presentation of process outcomes such as metrics of use and intensity of use
In addition to primary/secondary (clinical) outcomes, the presentation of process outcomes such as metrics of use and intensity of use (dose, exposure) and their operational deUnitions is critical.This does not only refer to metrics of attrition (13-b) (often a binary variable), but also to more continuous exposure metrics such as "average session length".These must be accompanied by a technical description how a metric like a "session" is deUned (e.g., timeout after idle time) [1] (report under item 6a).

Does your paper address subitem 17a-i?
Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brieoy explain why the item is not applicable/relevant for your study We provide usability metrics in the results as well: "During our 24-hour study period, all 22 functionally-intact subjects recorded at least 14 hours of data (mean=17.3hours; range 14-20 hours) for a total of 380 hours suitable for analysis.All 11 frail subjects recorded at least 9 hours of data (mean=19.9hours; range 9-24 hours) for a total of 210 hours of which 209 were suitable for analysis (one hour prematurely truncated).There was no significant difference in the number of hours recorded for the functionally-intact 17b) For binary outcomes, presentation of both 11/10/16, 3:45 PM

19-i) Include privacy breaches, technical problems
Include privacy breaches, technical problems.This does not only include physical "harm" to participants, but also incidents such as perceived or real privacy breaches [1], technical problems, and other unexpected/unintended incidents."Unintended effects" also includes unintended positive effects [2].

Does your paper address subitem 19-i?
Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brieoy explain why the item is not applicable/relevant for your study Our major technical problem was from inexperience; the investigator responsible for collecting the functional monitoring data did not ensure that there were no critical data on the phones from a previous experiment before assigning them to new subjects.
"Unfortunately, we lost smartphone data from 10 subjects (3 in the functionally intact arm, 7 from the frail arm) due to technologist error.By far, the greatest challenge we encountered during subject recruitment was to identify frail individuals with preserved cognition."

19-ii) Include qualitative feedback from participants or observations from staff/researchers
Include qualitative feedback from participants or observations from staff/researchers, if available, on strengths and shortcomings of the application, especially if they point to unintended/unexpected effects or uses.This includes (if available) reasons for why people did or did not use the application as intended by the developers.

Does your paper address subitem 19-ii?
Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brieoy explain why the item is not applicable/relevant for your study We did not solicit feedback from our study participants.
DISCUSSION 22) Interpretation consistent with results, balancing beneUts and harms, and considering other relevant evidence NPT: In addition, take into account the choice of the comparator, lack of or partial blinding, and unequal expertise of care providers or centers in each group

22-i)
Restate study questions and summarize the answers suggested by the data, starting with primary outcomes and process outcomes (use) Restate study questions and summarize the answers suggested by the data, starting with primary outcomes and process outcomes (use).
1 2 3 4 5 subitem not at all important essential Does your paper address subitem 22-i?* Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brieoy explain why the item is not applicable/relevant for your study We discuss this in the second paragraph: "Our study advances the goal of an easy-to-use, robust, accurate, second nature system that measures clinically relevant activity metrics (onsets, durations, step counts, and gait speeds) in different ambulatory populations.This goal is attainable with appropriate hardware and software.For example, over fifty years ago Stunkard [32] showed the feasibility of using pedometers to estimate individual walking distance over long observations.Technical refinements

22-ii) Highlight unanswered new questions, suggest future research
Highlight unanswered new questions, suggest future research.
1 2 3 4 5 subitem not at all important essential Does your paper address subitem 22-ii?
Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brieoy explain why the item is not applicable/relevant for your study We discuss this in the final paragraph: "Given the worldwide ubiquity of smartphone technology, and decreasing costs associated with smartphone ownership, this study suggests that future health care systems should consider leveraging patient smartphones to collect data associated with individual function status (respecting individual privacy and autonomy), develop patient functional 'exemplars', and refine algorithms that not only calculate activity and gait functional metrics as above, but 20) Trial limitations, addressing sources of potential bias, imprecision, and, if relevant, multiplicity of analyses

20-i) Typical limitations in ehealth trials
Typical limitations in ehealth trials: Participants in ehealth trials are rarely blinded.Ehealth trials often look at a multiplicity of outcomes, increasing risk for a Type I error.Discuss biases due to non-use of the intervention/usability issues, biases through informed consent procedures, unexpected events.
1 2 3 4 5 subitem not at all important essential Does your paper address subitem 20-i?* Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brieoy explain why the item is not applicable/relevant for your study We have an entire section in the discussion focused on study limitations.
21) Generalisability (external validity, applicability) of the trial Undings NPT: External validity of the trial Undings according to the intervention, comparators, patients, and care providers or centers involved in the trial

21-i) Generalizability to other populations
Generalizability to other populations: In particular, discuss generalizability to a general Internet population, outside of a RCT setting, and general patient population, including applicability of the study results for other organizations 1 2 3 4 5 subitem not at all important essential Does your paper address subitem 21-i?
Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brieoy explain why the item is not applicable/relevant for your study  Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brieoy explain why the item is not applicable/relevant for your study We perform this trial in what we hope was the routine setting of subject day-to-day lives, and thus hope that we provide some insight about the feasibility of performing this interaction in a routine fashion.
1b-iii) Open vs. closed, web-based (self-assessment) vs. face-to-face assessments in the METHODS section of the ABSTRACT Mention how participants were recruited (online vs. ofoine), e.g., from an open access website or from a clinic or a closed online user group (closed usergroup trial), and clarify if this was a purely web-based trial, or there were face-to-face components (as part of the intervention or for assessment).Clearly say if outcomes were self-assessed through questionnaires (as common in web-based trials).Note: In traditional ofoine trials, an open trial (open-label trial) is a type of clinical trial in which both the researchers and participants know which treatment is being administered.To avoid confusion, use "blinded" or "unblinded" to indicated the level of blinding instead of "open", as "open" in web-based trials usually refers to "open access" (i.e.participants can self-enrol).(Note: Only report in the abstract what the main paper is reporting.If this information is missing from the main body of text, consider adding it) 2a-i) Problem and the type of system/solutionDescribe the problem and the type of system/solution that is object of the study: intended as stand-alone intervention vs. incorporated in broader health care program?Intended for a particular patient population?Goals of the intervention, e.g., being more cost-effective to other interventions, replace or complement other solutions?(Note: Details about the intervention are provided in "address subitem 2a-i?* Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brieoy explain why the item is not applicable/relevant for your study "The rise of ubiquitous electronics offers great potential for remote monitoring of patient health parameters.We have shown the feasibility of using cell phone technology to measure an individual's activity and lifespace (e.g., the geographic expanse of an individual's day-to-day travels) over prolonged periods of time in a noninvasive, near-continuous, robust, inexpensive, and user friendly manner[11].In order to extrapolate health parameters (aligned with Healthy People 2010, [12]) from our subject derived smartphone data, we designed algorithms to measure clinically relevant aspects of activity, 2a-ii) Scienti/c background, rationale: What is known about the (type of) system ScientiUc background, rationale: What is known about the (type of) system that is the object of the study (be sure to discuss the use of similar systems for other conditions/diagnoses, if appropiate), motivation for the study, i.e. what are the reasons for and what is the context for this speciUc study, from which stakeholder viewpoint is the study performed, potential impact of Undings[2].Brieoy justify the choice of the comparator.
5-v) Ensure replicability by publishing the source code, and/or providing screenshots/screen-capture video, and/or providing ]owcharts of the algorithms usedEnsure replicability by publishing the source code, and/or providing screenshots/screen-capture video, and/or providing oowcharts of the algorithms used.Replicability (i.e., other researchers should in principle be able to replicate the study) is a hallmark of scientiUc reporting.
all important essentialDoes your paper address subitem 5-vii?*Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" Describe mode of delivery, features/functionalities/components of the intervention and comparator, and the theoretical framework [6] used to design them (instructional strategy [1], behaviour change techniques, persuasive features, etc., see e.g.,[7, 8]  for terminology).This includes an in-depth description of the content (including where it is coming from and who developed it) [1]," whether [and how] it is tailored to individual circumstances and allows users to track their progress and receive feedback"[6].This also includes a description of communication delivery channels and -if computer-mediated communication is a component -whether communication was synchronous or asynchronous[6].It also includes information on presentation strategies [1], including page design principles, average amount of text on pages, presence of hyperlinks to other resources, etc. [1 ) Describe any co-interventions (incl.training/support) Describe any co-interventions (incl.training/support): Clearly state any interventions that are provided in addition to the targeted eHealth intervention, as ehealth intervention may not be designed as stand-alone intervention.This includes training sessions and support [1].It may be necessary to distinguish between the level of training required for the trial, and the level of training for a routine application outside of a RCT setting (discuss under item 21 -generalizability. 6a-i) Online questionnaires: describe if they were validated for online use and apply CHERRIES items to describe how the questionnaires were designed/deployedIf outcomes were obtained through online questionnaires, describe if they were validated for online use and apply CHERRIES items to describe how the questionnaires were designed/deployed [9 21-ii) Discuss if there were elements in the RCT that would be different in a routine application setting Discuss if there were elements in the RCT that would be different in a routine application setting (e.g., prompts/reminders, more human involvement, training sessions or other co-interventions) and what impact the omission of these elements could have on use, adoption, or outcomes if the intervention is applied outside of a RCT setting.

Does your paper address CONSORT subitem 6a? *
Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brieoy explain why the item is not applicable/relevant for your study

Does your paper address CONSORT subitem 8b? * Copy
and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brieoy explain why the item is not applicable/relevant for your study *Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brieoy explain why the item is not applicable/relevant for your study 11/10/16, 3:45 PM * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brieoy explain why the item is not applicable/relevant for your study Not applicable to our study.8b) Type of randomisation; details of any restriction (such as blocking and block size) Does your paper address CONSORT subitem 10? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brieoy explain why the item is not applicable/relevant for your study NPT: Whether or not administering co-interventions were blinded to group assignment 11a-i) Specify who was blinded, and who wasn't Specify who was blinded, and who wasn't.Usually, in web-based trials it is not possible to blind the participants [1, 3] (this should be clearly acknowledged), but it may be possible to blind outcome assessors, those doing data analysis or those administering co-interventions (if any).

Does your paper address CONSORT subitem 14b? *
Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brieoy explain why the item is not applicable/relevant for your study information not in the ms, or brieoy explain why the item is not applicable/relevant for your study Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brieoy explain why the item is not applicable/relevant for your study Our subjects experienced no harms throughout the study.
CONSORT-EHEALTH (V 1.6.1)-Submission/PublicationForm https://docs.google.com/forms/d/e/1FAIpQLSfZBSUp1bwOc_...This was not a significant focus our our study, and we do not devote any text toward discussing generalizability to other clinical populations.This effort will be one of our future research directions.