Wearable technology for high-frequency cognitive and mood assessment in major depressive disorder: longitudinal observational study

May combine two claims.

Participants reported that completing assessments was easier when study sessions fit into their daily routines, and that periods of high and low mood affected their motivation to complete assessments.

“Participants reported that completing assessments was easier when study sessions fit into their daily routines, and that periods of high and low mood affected their motivation to complete assessments.”

May combine two claims.

Adherence was affected by technical problems for some participants and by forgetting to wear the Apple Watch due to low mood or bereavement.

“Adherence was also affected by technical problems for some participants, and by forgetting to wear the Apple Watch because of low mood or bereavement.”

Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

Because of a technical issue on the final study day, the evening session was not administered, resulting in lower adherence on day 42.

“Because of a technical issue on the final study day, the evening session was not administered, resulting in lower adherence on day 42.”

May combine two claims.

Correlations were highest for the PHQ-9, which also showed the highest item overlap with high-frequency assessments.

“Correlations were highest for the PHQ-9, a scale designed as both a diagnostic instrument and a severity measure [34], which also showed the highest item overlap with high-frequency assessments.”

• cites [34] sourceNot checked yet

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May combine two claims.

Correlations between n-back performance and daily reported cognitive symptoms, and all correlations with dprime slope, were nonsignificant (P=.12-.79).

“Correlations between n-back performance and daily reported cognitive symptoms and all correlations with dprime slope were nonsignificant (P=.12-.79).”

May combine two claims.

Heart rate measurement using the Apple Watch had measurement issues, including a minimum registered heart rate of 22 bpm, which was not biologically plausible.

“Measurement issues were noted for heart rate using the Apple Watch, with individual heart rates registered including a minimum of 22 beats per minute, which was not biologically plausible.”

May combine two claims.

Participants with better performance on CANTAB showed higher intercept and better mean performance on the n-back.

“Participants with better performance on CANTAB showed higher intercept and better mean performance on the n-back.”

May combine two claims.

Multilevel analysis of dprime score by study day confirmed a better fit for a cubic term rather than quadratic or linear models, indicating an initial rapid improvement in performance followed by a plateau.

“Multilevel analysis of dprime score by study day confirmed a better fit for a cubic term rather than quadratic or linear models (Bayesian information criterion=1298.05; likelihood ratio=10.36; P=.001), indicating an initial rapid improvement in performance followed by a plateau.”

Probably not a substantial claim: may not pass S3 (load-bearing).

Periods of low adherence tended to cluster temporally.

“Periods of low adherence tended to cluster temporally (Multimedia Appendix 2).”

May combine two claims.

Overall, mood symptoms showed a modest concurrent improvement, with great heterogeneity in the trajectories observed over the assessment period.

“Overall, mood symptoms showed a modest concurrent improvement, albeit with great heterogeneity in the trajectories observed over the assessment period.”

May combine two claims.

No significant correlations were seen with PDQ-D or UCLA-LS, or dprime slope.

“No significant correlations were seen with PDQ-D or UCLA-LS, or dprime slope.”

May combine two claims.

SWM between errors and strategy showed moderate correlations with daily reported mood, whereas RVP outcome measures were nonsignificant.

“Examining the relationship between daily mood assessment and CANTAB measures, SWM between errors and strategy showed moderate correlations with daily reported mood, whereas correlations with RVP outcome measures were nonsignificant.”

May combine two claims.

Participants were stabilized on monotherapy at the time of assessment, and many had started their current treatment many months before study participation (9.9 months on average).

“Participants were stabilized on monotherapy at the time of assessment, and many had started their current treatment many months before study participation (9.9 months on average).”

May combine two claims.

Step counts registered on the two devices had a moderate correlation (rho=0.61; 95% CI 0.57-0.65; P<.001), with instances of marked discrepancy.

“A moderate correlation was seen between step counts registered on the 2 devices (rho=0.61; 95% CI 0.57-0.65; P<.001), but there were also instances of marked discrepancy (Figure 3).”

May combine two claims.

PDQ-D scores correlated with daily mood assessments but not with cognitive performance.

“PDQ-D scores were correlated with daily mood assessments but not with cognitive performance, indicating that self-reported cognitive function cannot substitute for objective assessments.”

May combine two claims.

Mood trajectories were highly heterogeneous and showed no clear relationship with change in cognitive performance.

“The trajectory of moods reported by patients during the course of the study was highly heterogeneous, showing no clear relationship with change in cognitive performance (Figure 2).”

May combine two claims.

Research has highlighted discrepancies between objectively measured cognitive function and patients' self-report from questionnaires, with the latter being affected by depressed mood.

“Research has highlighted discrepancies between objectively measured cognitive function and patients’ self-report from questionnaires, with the latter being affected by depressed mood [15,24,25].”

• cites [15] sourceNot checked yet

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• cites [24] sourceNot checked yet

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• cites [25] sourceNot checked yet

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Classified as probably not a substantial claim.

Cognitive symptoms, including difficulty concentrating or making decisions, are features of major depressive disorder.

“Cognitive symptoms, including difficulty concentrating or making decisions, are features of MDD [3] that may offer a target for intervention [4].”

• cites [3] 2013, DSM-5 Diagnostic And Statistical Manual Of Mental Disorders. Fifth EditionNot checked yet

  Not checked in the free run.

May combine two claims.

Cognitive symptoms have been associated with poor occupational functioning and unemployment, work-related disability, and adverse psychosocial outcomes.

“Cognitive symptoms have also been associated with poor occupational functioning [18] and unemployment [19], work-related disability, and adverse psychosocial outcomes [20-22].”

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• cites [21] sourceNot checked yet

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• cites [22] sourceNot checked yet

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Classified as probably not a substantial claim.

Cognitive symptoms of major depressive disorder include deficits in several domains, including processing speed, attention, executive function, learning, and memory.

“Cognitive symptoms of MDD include deficits in several domains, including processing speed, attention, executive function, learning, and memory [5-7].”

• cites [5] sourceNot checked yet

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• cites [6] sourceNot checked yet

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May combine two claims.

Mobile digital technologies allow for sampling outside of the clinic and in the patient's home or work environment, providing a shared platform for clinicians and patients to monitor symptoms.

“Mobile digital technologies allow for sampling outside of the clinic and in the patient’s home or work environment, providing a shared platform for clinicians and patients to monitor symptoms [26].”

• cites [26] sourceNot checked yet

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Probably not a substantial claim: may not pass S3 (load-bearing).

The PHQ-2 is a validated brief form of the PHQ-9.

“Mood was assessed with 2 questions adapted from the PHQ-2, a validated brief form of the PHQ-9, which assesses only low mood and loss of interest or pleasure and is sensitive to depression and suitable for brief assessments [36].”

• cites [36] sourceNot checked yet

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Probably not a substantial claim: may not pass S3 (load-bearing).

The brevity of the current protocol in conjunction with the proximity to wearable assessments may have helped to support the high levels of compliance seen here.

“The brevity of the current protocol in conjunction with the proximity to wearable assessments may have helped to support the high levels of compliance seen here.”

Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

Previous studies in patients with mood disorders have shown good overall feasibility and acceptability of high-frequency assessments, although there is likely to be an interaction between protocol burden and burden of illness.

“Previous studies in patients with mood disorders have shown good overall feasibility and acceptability of high-frequency assessments, although there is likely to be an interaction between protocol burden and burden of illness [46].”

• cites [46] sourceNot checked yet

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May combine two claims.

The three daily mood items showed overall good reliability indices, supporting their combined use.

“The 3 mood items showed overall good reliability indices, supporting the combined use of the 3 question items.”

Classified as probably not a substantial claim.

To reduce multiple comparisons, overall scores from self-report questionnaires and CANTAB cognitive testing were calculated by taking the mean of outcome measures obtained at weeks 1, 3, and 6.

“To reduce multiple comparisons, overall scores from self-report questionnaires and CANTAB cognitive testing were calculated by taking the mean of outcome measures obtained at weeks 1, 3, and 6.”

Probably not a substantial claim: may not pass S3 (load-bearing).

The Perceived Deficits Questionnaire-Depression (PDQ-D) is a measure that assesses subjective cognitive dysfunction in depression.

“One additional item assessing self-perceived concentration was taken from the Perceived Deficits Questionnaire—Depression (PDQ-D) [37,38], a measure that assesses subjective cognitive dysfunction in depression.”

• cites [37] sourceNot checked yet

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• cites [38] sourceNot checked yet

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Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

The study was reviewed and approved by the Proportionate Review Sub-Committee of the Wales Research Ethics Committee 6 at Swansea University (REC reference: 17/WA/0042) and performed in accordance with the current version of the Declaration of Helsinki.

“The study was reviewed and approved by the Proportionate Review Sub-Committee of the Wales Research Ethics Committee 6 at Swansea University (REC reference: 17/WA/0042) and performed in accordance with the current version of the Declaration of Helsinki.”

Probably not a substantial claim: may not pass S3 (load-bearing).

Normality of summary measures and data was assessed with visual examination and the Shapiro-Wilk test before further analysis.

“Normality of all summary measures was assessed with visual examination of the data and with the Shapiro-Wilk test before further analysis.”

• Also stated in: § Statistical Analysis · plain

  “Normality of data was assessed with visual examination of the data and with the Shapiro-Wilk test before further analysis.”

Probably not a substantial claim: may not pass S3 (load-bearing).

As this was an exploratory study, no corrections for multiple comparisons were made.

“As this was an exploratory study, no corrections for multiple comparisons were made.”

Probably not a substantial claim: may not pass S3 (load-bearing).

Assumptions of logistic regression models were investigated by examining the distribution and patterns of residuals versus fitted values.

“Assumptions of logistic regression models were investigated by examining the distribution and patterns of residuals versus fitted values.”

May combine two claims.

The capacity to improve performance is not directly affected by either depressive symptoms or cognitive impairment.

“This suggests that the capacity to improve performance is not directly affected by either depressive symptoms or cognitive impairment, consistent with research in a previous study showing that practice effects in cognitive tasks were not moderated by depressive symptomatology [50].”

• cites [50] sourceNot checked yet

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Probably not a substantial claim: may not pass S3 (load-bearing).

Studies exploring gamification show that the use of game design elements (eg, points and scoreboards) can improve motivation.

“This finding is supported by studies exploring gamification of tasks, where the use of game design elements (eg, points and scoreboards) can improve motivation [47,48].”

• cites [47] sourceNot checked yet

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• cites [48] sourceNot checked yet

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Probably not a substantial claim: may not pass S3 (load-bearing).

The n-back paradigm activates a network of frontoparietal areas.

“The n-back paradigm is commonly used alongside functional neuroimaging, where it activates a network of frontoparietal areas [51].”

• cites [51] sourceNot checked yet

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May combine two claims.

This study was significantly longer in duration than most previous high-frequency assessment studies, spanning 6 weeks rather than the typical 1- to 2-week duration, and the daily frequency of assessment was lower, with most other studies typically sampling 5 to 10 times per day.

“However, it is notable that although this study was significantly longer in duration than most previous high-frequency assessment studies, spanning 6 weeks rather than the typical 1- to 2-week duration, the daily frequency of assessment was lower, with most other studies typically sampling 5 to 10 times per day [45].”

• cites [45] sourceNot checked yet

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Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

No corrections for missing data and no other adjustments to raw data were made.

“No corrections for missing data and no other adjustments to raw data were made.”

Probably not a substantial claim: may not pass S3 (load-bearing).

Mobile apps have been used as part of randomized controlled trials to evaluate treatment efficacy.

“In depression, mobile apps have tracked changes in patient-reported mood [27-29] and have been used as part of randomized controlled trials to evaluate treatment efficacy [30].”

• cites [30] sourceNot checked yet

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Probably not a substantial claim: may not pass S3 (load-bearing).

In depression, mobile apps have tracked changes in patient-reported mood.

“In depression, mobile apps have tracked changes in patient-reported mood [27-29] and have been used as part of randomized controlled trials to evaluate treatment efficacy [30].”

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• cites [29] sourceNot checked yet

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Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

The PHQ-2 is sensitive to depression and suitable for brief assessments.

“Mood was assessed with 2 questions adapted from the PHQ-2, a validated brief form of the PHQ-9, which assesses only low mood and loss of interest or pleasure and is sensitive to depression and suitable for brief assessments [36].”

• cites [36] sourceNot checked yet

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Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

A sample size of 30 provides 80% power to detect correlations of r=0.5.

“This sample size also provides 80% power to detect correlations of r=0.5.”

Probably not a substantial claim: may not pass S3 (load-bearing).

All participants provided written informed consent before enrollment.

“All participants provided written informed consent before enrollment.”

Probably not a substantial claim: may not pass S3 (load-bearing).

The PHQ-2 assesses only low mood and loss of interest or pleasure.

“Mood was assessed with 2 questions adapted from the PHQ-2, a validated brief form of the PHQ-9, which assesses only low mood and loss of interest or pleasure and is sensitive to depression and suitable for brief assessments [36].”

• cites [36] sourceNot checked yet

  Not checked in the free run.

Probably not a substantial claim: may not pass S3 (load-bearing).

Striking a balance between difficulty and attainability can promote engagement.

“Attainability encouraged them to set personal goals to improve or maintain their scores, indicating that striking a balance between difficulty and attainability can promote engagement [49].”

• cites [49] sourceNot checked yet

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Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

Assessment using a small touch screen may not be feasible for patients with visual impairments or those requiring a larger typeface.

“In addition, assessment using a small touch screen may not be feasible for patients with visual impairments or those requiring a larger typeface.”

Probably not a substantial claim: may not pass S3 (load-bearing).

It is unclear whether results would generalize to patients with different severity or to those who are less motivated.

“As our study focused on patients with mild-to-moderate MDD who volunteered for participation, it is unclear whether results would generalize to patients with different severity or to those who are less motivated.”

May combine two claims.

The study supports the feasibility and validity of high-frequency assessment on wearable devices to assess cognitive function and mood in patients with MDD.

“This study supports the feasibility and validity of high-frequency assessment on wearable devices to assess cognitive function and mood in patients with MDD.”

Probably not a substantial claim: may not pass S3 (load-bearing).

Wrist-worn heart rate monitors, including the Apple Watch, have variable accuracy compared with electrocardiogram measurement.

“Variable accuracy for wrist-worn heart rate monitors, including the Apple Watch, compared with electrocardiogram measurement has also been noted previously in brief comparisons of bouts of exercise [56].”

• cites [56] sourceNot checked yet

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May combine two claims.

n-back performance can be used as a sensitive but nonspecific marker of cognitive function.

“Consistent with this suggestion, n-back mean and intercept correlated with full-length CANTAB cognitive tests of attention and working memory, supporting the use of n-back performance as a sensitive but nonspecific marker of cognitive function.”

May combine two claims.

Discrepancies between objectively and subjectively assessed cognitive function have been reported, with subjective assessments affected by depressed mood.

“Discrepancies between objectively and subjectively assessed cognitive function have been reported before, with the latter being affected by depressed mood [15,24,25].”

• cites [15] sourceNot checked yet

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Classified as probably not a substantial claim.

Caution is required when this equipment is used to examine heart rate in scientific research.

“Although the wearable nature and ease of use of the technology allow for data to be collected over longer periods of time, our findings indicate that caution is required when this equipment is used to examine heart rate in scientific research.”

May combine two claims.

Heart rate measurement issues may reflect that the equipment was not of medical grade, or occasions when the Apple Watch was not fitted sufficiently tightly for reliable measures to be obtained.

“Measurement issues with heart rate data may reflect that the equipment was not of medical grade, or occasions when the Apple Watch was not fitted sufficiently tightly for reliable measures to be obtained.”