mHealth for the Monitoring of Brace Compliance and Wellbeing in Adolescents with Idiopathic Scoliosis: Study Protocol for a Feasibility Study

Abstract

Attempts to optimize monitoring of brace adherence prescribed to adolescents with idiopathic scoliosis (IS) have generally relied on sensors. Sensors, however, are intrusive and do not allow the assessment of psychological and physical consequences of brace use that might underlie poor adherence. Mobile applications have emerged as alternatives to monitor brace compliance. However, the feasibility and utility of these app-based systems to assess key psychological and physical domains associated with non-adherence remain unexplored. This feasibility study aims to test the usability, acceptability, and clinical utility of an app-based system that monitors brace use and related psychological and physical factors. Forty adolescents with IS daily respond to the app for 90 days. The patient responses may generate clinical alarms (e.g., brace non-adherence, discomfort, or distress) that will be sent daily to the medical team. Primary outcomes will be app usability, acceptability, and response rates. Secondary outcomes will include brace adherence, the number of side effects reported, number and type of clinical alarms, stress, quality of life, perceived health status, and mood. If accepted by patients and clinicians, apps may allow rapid detection and response to undesired events in adolescents undergoing brace treatment.

1. Introduction

Scoliosis is defined as a torsional deformity in the shape and position of the spine, the thorax, and the trunk, which is generally diagnosed when the Cobb angle, a measure of the spinal deformity, is equal to or higher than 10° [1]. In particular, idiopathic scoliosis (IS) refers to scoliosis that occurs in apparently healthy patients without a clear agent causing the deformity [1]. IS affects 2–3% of adolescents, although it can also occur in newborns. According to the age at which the diagnosis is made, IS can be classified into infantile (0–2 years old), juvenile (3–9 years old), adolescent (Adolescent Idiopathic Scoliosis, AIS; 10–17 years old), or adult (from the age of 18) [1]. The most notable progression of IS occurs at the beginning of puberty (11–14 years), which has been associated with the faster development of the spinal curvature that takes place in this period [1]. In addition to age, IS can also be classified according to the severity of the deformity, measured with the Cobb’s degrees (Low = up to 20°; Moderate = 21°–35°; Moderate-severe = 36°–40°; Severe = 41°–50°; Severe-very severe = 51°–55°; Very severe = over 56°) [1].

IS is often unrelated to medical complications (e.g., pain or other health-related problems) [2,3]. However, even in less severe curves, the deformity can negatively impact the psychological wellbeing of individuals (e.g., depression symptoms and self-esteem) and can be associated with an increase in psychological problems, such as substance abuse and suicidal ideation [4,5], which justifies the need for adequate treatment. Wearing a brace is a conservative treatment for IS that often helps avoid surgery, improves aesthetics, and increases quality of life [1]. Brace treatment consists of the application of an external mechanical force, the objective of which is to correct the spinal deformity. The brace exerts compression forces on the convex side, distraction forces on the concave side, transverse forces on both sides, and lateral bending on the convex side [6]. The brace is especially recommended when the curvature is between 30° and 40° or between 20° and 29° with a progression of more than 5° in the last year [7]. In fact, when scoliosis angles are greater than 30°, the deformity becomes evident and disability, pain, and functional limitations increase significantly [1,8]. Next, depending on the severity of the case, the brace can be prescribed only at night (8–12 h a day), part-time (12–20 h a day), or full time (20–24 h a day) [1].

Review studies have revealed promising results regarding the effectiveness of braces in treating AIS. However, there is insufficient scientific evidence to recommend their use [9], probably due to the low adherence rates associated with brace use, which tend to be exaggerated when retrospectively evaluated [1]. Adherence to the use of the brace is in fact one of the most important factors negatively influencing the effectiveness of this orthopedic treatment [10]. Two factors that have been argued to explain non-compliance with these orthopedic treatments are (a) the appearance of unwanted effects associated with the use of braces (e.g., pain, scuffing, or discomfort sleeping) and (b) the psychological distress and general beliefs related to the deformity (i.e., “I don’t care about my back”) and its treatment (i.e., “I think people can see the brace under my clothes”) [11,12]. Different efforts have been conducted to improve the adherence to the brace. For example, brace monitoring has been proposed to improve brace compliance [13]. For this reason, it has been argued that there is a need to actively involve patients during the whole treatment process [14], including monitoring of outcomes and brace compliance [1].

Traditionally, brace adherence has been explored retrospectively [15]. This is problematic because it does not guarantee the security of the treatment, it does not provide reliable data, and it is an inefficient methodology. First, retrospective assessments do not allow the detection of undesired events in the real context and when they occur, but later when patients have a face-to-face medical appointment. As a consequence, the patient must decide what to do when they experience unwanted side effects [16], which compromises the safety of the intervention. For example, an adolescent may decide to immediately stop wearing the brace when they experience pain or itching and therefore would not receive treatment until the next appointment at the clinic (which can occur weeks or months later, depending on waiting lists). Conversely, another patient may decide to tolerate the discomfort and continue wearing the brace despite unwanted side effects until the next appointment with their doctor, which can lead to undue suffering. Therefore, leaving the decision on when and in the presence of which symptom adolescents should respond to and how they should respond can be problematic. Regarding the second point, which refers to the reliability of the data, research has shown that retrospective assessments are not free from recall bias. In particular, more severe symptoms tend to be reported when health conditions are retrospectively assessed [17]. In the specific case of brace monitoring, it is unlikely that patients will be able to remember the exact number of hours and days that they have been wearing the brace for a given period of time. It is also unlikely that adolescents will be able to remember all the side effects they experienced in the different contexts in which they occurred. The latter point refers to treatment efficiency. Retrospective evaluations are not efficient as they do not allow early detection of noncompliance with brace treatment and psychological distress related to brace use (i.e., irrational beliefs, intense unpleasant emotions, or lack of social support). Therefore, early interventions cannot be delivered in response to these, which means that the patients’ quality of life may be affected. This, in turn, could result in more lasting and severe symptoms (i.e., brace-related side effects, anxiety, and depressive symptoms), ultimately resulting in higher personal and financial costs (i.e., recurrent visits and contacts with health services).

The electronic monitoring of brace compliance has emerged as a possible solution to overcome the aforementioned shortcomings found in IS monitoring. The most commonly used devices to assess brace compliance are temperature and force sensors [13]. Some promising findings have already been reported with these devices. For example, patients are more likely to wear the brace when they know that they are being monitored to avoid professional criticism [18] and sensors have been described as non-invasive [19]. While acknowledging this, it has also been argued that adolescents may perceive that they are being controlled and judged by using these passive assessment devices, and some authors have expressed concern about how sensors may negatively affect the doctor–patient relationship [20]. Furthermore, the sensors are designed to assess isolated brace compliance, but the assessment of other important psychosocial variables related to the brace (e.g., irrational beliefs, intense unpleasant emotions, or lack of social support) cannot be evaluated with the sensors.

During the last decades, the use of the Internet and mobile devices in our daily activities has increased dramatically, especially in adolescents [21,22]. The widespread use of these technologies has reached the healthcare context to improve both physical and psychological functioning [23,24]. In the specific context of AIS, web and mobile devices have been postulated as a useful alternative to sensors in the diagnosis and monitoring of AIS. For example, mobile applications have been used as screening tools for AIS to measure the Cobb’s degrees of curvature, even more accurately than traditional hand-held scoliometers [25]. Another alternative to sensors has been a web-based system for assessing brace compliance, which was well accepted by the participants [26]. Some limitations of the literature on alternatives to sensors for IS assessment should be considered. First, the daily measurement of how braces can affect physical activities and psychological wellbeing has not yet been included in these monitoring systems. Second, to date, patients or parents have been requested to log into a web system and upload the brace usage data at least once a day. This system has some limitations compared to apps, as the former requires Internet access and cannot use specific triggers such as a push system to start the survey.

It might be reasonable to think that the inclusion of an app-based monitoring system in clinical settings can help overcome the barriers of traditional, retrospective face-to-face assessments, and electronic devices (i.e., sensors and web pages). In the present study, we aim to test the feasibility and clinical utility of a new app-based management method. With this app, we intend to improve the monitoring of brace adherence, as well as the psychological and physical status of patients with AIS. Regarding feasibility, this study aims to explore the extent to which patients (adolescents with IS) and physicians accept the use of an app for daily monitoring. In relation to clinical utility, the objective of this work is to test whether the app detects adherence problems with the brace and related side effects and the clinicians respond quickly to them. We anticipate that the implementation of the app will be feasible for AIS monitoring (high acceptability and adherence to the app). In addition, we expect to find some indicators of the potential usefulness of the app (e.g., rapid detection of brace adherence problems and psychological and physical complications that allow a quick response by the medical team).

2. Materials and Methods

The current study uses a single group open trial design. In this feasibility study, we will monitor the use of brace and several outcomes related to brace use (e.g., psychological and physical status in relation to the brace) in a sample of adolescents with IS who are cared for in the Physical Medicine and Rehabilitation Service of a public tertiary hospital in Spain (Vall d’Hebron University Hospital). All adolescents who meet the inclusion criteria will be offered a mobile application for scoliosis monitoring. This app-based monitoring involves a daily evaluation for 90 days (3 months). Additionally, the assessment protocol includes two measurement points: before the brace use (baseline) and after three months of brace use (end of the study). These assessments (e.g., baseline and end of study) will be conducted using the Qualtrics online platform. The Ethics Committee of the Vall d’Hebron University Hospital approved the study and all its procedures. The Ethics Committee mentioned above aims to protect the safety of clinical trial participants and to ensure that there are no deviations from the expected plan. This study was previously registered in Clinicaltrials.gov (NCT04881591) on 10 May 2021. A standard Protocol Items Recommendations for Interventional Trial (SPIRIT) was followed to inform the protocol of the present study (Appendix A).

2.1. Participants

The participants included in this feasibility study will be 40 adolescents with IS. Sample size has been calculated according to previous recommendations suggesting a minimum of 30 participants in feasibility and pilot studies [27] and a minimum of 15 participants in usability studies with devices used in healthcare settings [28]. Sample size calculation includes a conservative correction of 20% for attrition.

Inclusion criteria:

• Age between 10 and 18 years when the brace is prescribed, Risser 0–2 and, if female, either before menarche or less than 1 year after menarche
• Primary curve angles 25°–40°.
• No prior brace treatment.
• The patient has a mobile phone with an Android or iOS operating system.
• The patient has the physical ability to use the mobile application.
• The patient does not present a serious psychological and/or cognitive problem or language alterations.
• Signed informed consent.
• Exclusion criteria:
• Not having a mobile phone or having a mobile phone with incompatible characteristics (i.e., unable to download the app).
• The patient has cognitive impairment or language problems to understand the use of the app and/or answer its questions.
• The patient has a serious mental health or substance abuse problem.

2.2. Recruitment and Procedures

Participants will be adolescents attending the Physical Medicine and Rehabilitation Service at Vall d’Hebron University Hospital who have been prescribed a brace for their IS. Participants who meet inclusion criteria (including their parents if participants are under 18 years of age) will receive the study information sheet (see Appendix B). If they give their voluntary consent to participate, they will be asked to sign the written informed consent (see Appendix B). Once the diagnosis is made by a physician from the Physical Medicine and Rehabilitation Service, patients with IS are prescribed a brace. Patients are asked to obtain the brace from an orthopedic center within the following week and are asked to test the brace for a few hours daily, mostly overnight, for a couple of weeks. This test period is used to verify if adjustments to the brace are required before a final version of the brace is provided and prescribed full time. An on-site consultation at the Physical Medicine and Rehabilitation Service is set to make these adjustments. This is the time when the app is also downloaded because it is at this stage that the final version of the brace is prescribed full time and on-site appointments become less frequent.

This recruitment session is used to conduct the baseline assessment and download the app. A trainee hired for the present study will assign a unique anonymous alphanumeric code to patients (see Appendix C) that is linked to their identifying information (medical record number) in a separate document. This alphanumeric code is used to identify patients in both online and app assessments. The participants are asked to respond to a baseline assessment with Qualtrics. Their responses do not contain any identifying information. This evaluation includes sociodemographic data (i.e., age, sex, nationality), as well as scoliosis-related variables (i.e., stress, quality of life, perceived health, anxiety, and depressive symptoms). The trainee then helps the participants to download the app and explain to them how to use it daily for the next 90 days. After this period, a follow-up appointment is arranged to administer the end-of-study evaluation, again with Qualtrics. Figure 1 shows the study schedule.

2.3. Usual AIS Treatment + App-Based Ecological Momentary Assessment

In addition to the app, all adolescents receive the usual treatment for scoliosis that is provided in the Physical Medicine and Rehabilitation Service during the study period (90 days), that is, they are prescribed the daily use of a brace. In terms of monitoring, routine practice in the unit only includes a face-to-face assessment 3 months after the final version of the brace is prescribed, which means that problems with this final version of the brace are traditionally assessed retrospectively. Therefore, to minimize the problems associated with relying only on retrospective and episodic evaluations, the present study incorporates a daily app-based monitoring during 90 days since the start of brace treatment, which is a critical period in which the physical and psychological adaptation to full-time use of the brace might be more challenging.

The Pain Monitor app is a mobile application whose contents have been adapted to conduct ecological momentary assessments (EMA) in different health conditions. It has been previously validated in chronic pain conditions [29] and has received several awards since then (https://www.consalud.es/saludigital/145/premios-saludigital-2019-reconocen-mejores-iniciativas-tecnologia-sanitaria_60524_102.html, accessed on 11 July 2021). It is currently available for free in the Android (https://play.google.com/store/apps/details?id=monitorinvestigacion.code, accessed on 3 July 2021) and iPhone (https://apps.apple.com/es/app/monitor-de-dolor-multic%C3%A9ntrico/id1546241257, accessed on 3 July 2021) stores. The app evaluates important brace-related physical and psychological domains, namely side effects of the brace, pain intensity, mood, brace interference, brace adherence, avoidance behavior, discomfort, and social support. Following the procedure of a similar investigation [29], to create the EMA assessment protocol, a multidisciplinary team of psychologists and physicians revised the most frequent assessment tools in the AIS literature and selected the most representative constructs to create a representative, but short set of items (see a detailed description in Appendix D).

Participants respond daily to the questions in the app. They are prompted in the afternoon (at 7 pm) and have 2 h to respond (until 9 pm). If participants do not respond to the assessment by 8:30 p.m., a second reminder is sent. If participants access the application after 9 p.m., they are not allowed to complete the daily assessment, which is treated as missing data, and participants are instructed to access to the app the next day at the scheduled time. This is done to avoid backfilling and non-ecological assessment. EMA involves the assessment of the current or very recent status of patients [30]. If participants were allowed to respond to the daily assessments later than 9 p.m., this would compromise the ecological nature and comparability of the assessments. After 3 days of app non-compliance, the app sends a notification to the doctors, and they will call the patients to encourage compliance with the app.

Clinical alarms are generated in the app according to certain preset unwanted events (see

Table 1. Pre-specified clinical alarms detected by the mobile application.

Domain	Clinical Alarms	Recommendations 1
Side effects
Pressure pain	3 consecutive days	Call the patient
Friction pain	3 consecutive days	Call the patient
Excessive heat/sweating	7 consecutive days	Call the patient
Movement difficulties	3 consecutive days	Call the patient
Teased by peers/relatives	4 consecutive days	Psychoeducation
Pain
Pain intensity	≥3 during 3 consecutive days	Call the patient
Emotions
Sadness	5 consecutive days	Psychoeducation
Anxiety	5 consecutive days	Psychoeducation
Anger	5 consecutive days	Psychoeducation
Shame	5 consecutive days	Psychoeducation
Overwhelm	5 consecutive days	Psychoeducation
Frustration	5 consecutive days	Psychoeducation
Interference
Sleeping	3 consecutive days	Call the patient
Basic movements	3 consecutive days	Call the patient
Relationships (friends)	5 consecutive days	Psychoeducation
Relationships (relatives)	5 consecutive days	Psychoeducation
Leisure activities	5 consecutive days	Psychoeducation
Academic activities	5 consecutive days	Psychoeducation
Mood	5 consecutive days	Psychoeducation
Dressing	5 consecutive days	Psychoeducation
Self-image	5 consecutive days	Psychoeducation
Motivation for going out	3 consecutive days	Psychoeducation
Avoid talking about the brace	≥7 during 7 consecutive days	Psychoeducation
Avoid activities/being with others	≥5 during 5 consecutive days	Psychoeducation
Overall physical discomfort	≥5 during 5 consecutive days	Call the patient
Brace adherence
Morning only (8–14 h)	7 consecutive days	Call the patient
Afternoon only (14–19 h)	7 consecutive days	Call the patient
Sleeping only (last night)	7 consecutive days	Call the patient
Morning and afternoon only	7 consecutive days	Call the patient
Sleeping and morning	15 consecutive days	Call the patient
Sleeping and afternoon	15 consecutive days	Call the patient
No use of the brace	3 consecutive days	Call the patient
Poor social support
Friends	5 consecutive days	Psychoeducation
Family	5 consecutive days	Psychoeducation
Teachers	5 consecutive days	Psychoeducation
Other people	5 consecutive days	Psychoeducation

¹ The physician may change the recommended action according to the patient’s condition.

). Every working day, the physicians will receive an anonymous report that will contain only the alphanumeric code described above, together with the description of the alarm. Next, the physicians access the document where the alphanumerical code is linked with the medical record number (Appendix C) to check the clinical history of the patients and decide the type of action necessary to solve the clinical alarm. Clinical alarms are not an emergency service and patients should use the services they usually use (i.e., emergency services, primary care, call to the Physical Medicine and Rehabilitation Service, etc.) in case they are faced with any symptom that worries them.

2.4. Physical Medicine and Rehabilitation Service Support According to Clinical Alarms

As reported in Table 1, each alarm generated by the app triggers a response from the medical team. This includes calling the patient (e.g., in the presence of intense and persistent pain) or sending the patient psychoeducational content by mail (see an example in Appendix E). This document has been created by a team of four psychologists trained in Cognitive Behavioral Therapy and Acceptance and Commitment Therapy for health problems and includes components of both types of interventions. Since the unit where the brace treatment is delivered does not have a psychologist, this content has been created to provide some psychological support when receiving alarms associated with psychological distress.

2.5. Outcome Measures

Primary outcome measures:

• The usability and acceptability of the app will be assessed by both patients (end users) and clinicians (relevant stakeholders). In the patients, this is evaluated both objectively and subjectively. To obtain an objective feasibility result, we calculate the adherence with the app by dividing the number of completed assessments by the number of planned evaluations and provide the response rate. To obtain a subjective measure of usability and acceptability, at the end of the study period (3 months after the first use of the app), we administer the System Usability Scale (SUS) [31] using an online survey tool that will be sent by mail (Qualtrics).
  In the clinicians, the acceptability of the new app-based monitoring method is evaluated using an assessment protocol developed for a similar earlier study [16]. As reported in Appendix D, this includes items that are consistent with the technology acceptance model [32], including perceived utility, acceptability, and intended use. This will be evaluated at the end of the study with the Qualtrics online survey tool anonymously.

Secondary outcomes measures:

Assessed by the Pain Monitorapplication (all once daily from 7 p.m. to 9 p.m.):

• Brace adherence: Ad hoc self-reported item: “When have you been able to wear the brace since you went to bed yesterday?” Response options cover all daily periods (morning only, afternoon only, only for sleeping, or any combination of these). To avoid bias due to socially desirable responses, honesty will be encouraged both during recruitment and in the informed consent.
• Treatment safety: An ad hoc question has been created including the most frequent side effects of brace use according to the literature [10,12] and the authors’ clinical expertise. These include: pain due to pressure, pain due to friction, excessive heat/sweating, movement difficulties, and being teased by peers or close ones.
• Clinical alarms: in addition to the assessment of brace adherence and side effects, several items were adapted from validated questionnaires (Appendix D) to assess pain intensity, unpleasant emotions, interference, avoidance, discomfort, and social support daily. Clinical alarms will be automatically generated and sent to the physicians by the app depending on the patients’ responses to these items (Table 1).

Assessed at baseline and at the end of the study with the Qualtrics online platform (see Appendix D for a detailed instrument description):

• Stress is measured with the Sobberheim Stress Questionnaire-Brace (BSSQ-Brace) [33,34].
• The Patients’ health-related quality of life is measured with the Italian Spine Youth Quality Of Life (ISYQOL) [35,36].
• Perceived health status is measured with the Scoliosis Research Society -22 (SRS-22) [37,38].
• Anxiety and depressive symptoms is measured with the Hospital Anxiety and Depression Scale (HADS) [39,40].

2.6. Ethics and Protection Data

The authors state that all the procedures included in this work comply with the ethical standard of the relevant national and institutional committees on human experimentation and with the Helsinki Declaration [41]. All the procedures described in this work were approved by the ethical committee of the Vall d’Hebron University Hospital. Modifications in the protocol are communicated to the ethical committee of the aforementioned hospital.

The responses provided by both assessment tools, namely Qualtrics and the app, are completely anonymous. Data collection and storage follow the Spanish law and data protection rules (“Ley Orgánica 3/2018, de 5 de diciembre, de Protección de Datos Personales y garantía de los derechos digitales”) [Spanish Data Protection Law], as well as Regulation (EU) 2016/679 of the European Parliament and of the Council of 27 April 2016 and Directive 95/46/EC (GDPR) on the protection of personal data and on the free movement of such data. Qualtrics^® is in accordance with the new General Data Protection Regulation (GDRP), is ISO 27,001 certified, and FedRAMP authorized. In addition, it allows correction, modification, and suppression of personal data in a permanent way (https://www.qualtrics.com/uk/platform/gdpr/ accessed on 11 May 2021).

If authorized by the patient in the informed consent form, the external researcher responsible for the study (Dr. Carlos Suso Ribera) has access to their personal information (i.e., phone number) to contact them and solve app-related technical issues (e.g., the app is not working or was deleted by mistake and needs to be reinstalled). These actions are recorded and reported as potential barriers for future implementation and acceptability of the new monitoring method. The study and its procedures are not associated with clinical complications or harmful effects. All participants may voluntarily suspend their participation in the study at any point. Their IS treatment and doctor–patient relationship will not be compromised by the discontinuation of the study.

3. Data Plan Analyses

Data are analyzed using intention-to-treat principles. Descriptive data (means, standard deviation, and frequencies) are reported for all study variables. These include usability and acceptability and response rates in the app (primary outcomes), together with brace adherence, the number of side effects, the number and type of clinical alarms generated by the app, stress, quality of life, perceived health status, and mood (secondary outcomes). Statistical differences between completers and non-completers are calculated. Completers are those who respond to at least 85% of the requested daily assessments, which is the average completion rate in EMA revealed in past meta-analytic research [42]. Adolescents who provide less than 85% responses to the app are considered non-completers.

Regarding feasibility, app adherence is calculated by dividing the number of responses registered in the app and the number of assessments programmed in the app (90 assessments, once daily during the whole study).

In relation to the clinical utility of the app, brace adherence is calculated by dividing the number of hours of use reported by the prescription they were given, as suggested in previous research [43]. Low brace adherence serves as a clinical alarm (Table 1). Changes in the remaining secondary measures (i.e., stress, perceived quality of life, perceived health status, and mood) from baseline to end of study are also explored, although it is expected to find minimal changes because these are not the main aim of the present study.

The results derived from the statistical analyses described above will be reported in the form of tables, graphs, and flowcharts. All the analyses are performed separately by the lead researcher and an independent researcher. An interim analysis is planned at the end of the study once 50% of the total sample has been evaluated. All coauthors and the Ethics Committee of the Vall d’Hebron University Hospital have access to these analyses and are allowed to participate in the decision to terminate the trial. The database is available under reasonable request for any researcher who requests it. Personal information from the participants is not included in this data set. The results from this feasibility study will be published anonymously in international journals and conferences.

4. Discussion

IS is a prevalent health condition that usually appears during adolescence due to the development of the spine that occurs at puberty [1,44]. IS can have a negative impact on psychological wellbeing, quality of life, disability, and physical health status, so early detection and treatment are essential [1,4,5,8]. The brace can be effective in the treatment of IS. However, its efficacy has also been questioned due to low adherence rates [9]. In an effort to improve brace compliance, studies have conducted retrospective assessments to investigate adherence and the factors that may negatively influence it [15]. Unfortunately, this methodology has a limited impact on the safety and effectiveness of treatment because assessment is conducted long after problems have arisen and is based on recall and memory, often leading to bias [17]. Additionally, face-to-face assessments require traveling (sometimes long distances), which increases costs and burden for patients (and their families). Electronic assessments can help overcome the limitations of retrospective face-to-face episodic assessments. Due to the widespread use of web and app-based devices in our daily activities, it seems feasible to integrate these devices into the daily monitoring of IS in adolescent populations. Some web and mobile applications have been used previously in detection of AIS and the assessment of adherence to the brace [25,26]. However, the assessment of the psychological and physical state of the patient, which could explain individual differences in adherence and provides important information for the safety and effectiveness of the treatment, has been never included in the daily monitoring of adolescents with IS.

The present protocol described a feasibility study whose aim is to test the usability, acceptability, and clinical utility of an app-based system for the monitoring of adolescents with IS who use a brace. Specifically, we hope to provide new insights into the feasibility of the app (i.e., app adherence and usability), as well as into its utility in detecting non-compliance with brace (treatment adherence), brace-related side effects like pain and interference in sleep (treatment safety), and psychological distress associated with wearing the brace (i.e., intense unpleasant emotions and poor social support). Regarding feasibility, we expect to find high compliance rates with the app-based monitoring system in the end users. Non-adherence to the app will generate clinical alarms, so the professional will be able to contact the participants to encourage them to interact with the app. For this reason, we expect to find low attrition rates during the study period (90 days). Additionally, in relation to the feasibility results, we anticipate that the participants will be very satisfied with the app in terms of acceptability and usability (i.e., “I needed to learn many things before I could start using the system”). Based on previous similar research [45,46], we also anticipate that the clinicians will be satisfied with the app in terms of perceived utility, low burden, and high intention to use. Regarding the clinical utility of the app, we also hypothesized that the app would allow early detection of low brace adherence, brace-related side effects, and psychological distress associated with brace use. Ultimately, we expect that the early detection of these symptoms with the app-based monitoring system will allow clinicians to quickly detect and solve unwanted events and thus provide safer and more effective treatment. To our knowledge, this is the first study to test the feasibility and clinical utility of telemonitoring adolescents with IS through a multidimensional app.

The present study has some limitations. Regarding the inclusion criteria, only adolescents with a smartphone will participate in the study. Therefore, a small proportion of patients may not be able to participate in the study. According to recent global statistics on smartphones, between 80% and 86% of adolescents between 12 and 17 years old own a smartphone [47,48]. Therefore, sample loss from not owning a smartphone is expected to be low. This information will be recorded and will be considered in the discussion on the feasibility of including this methodology for the monitoring of adolescents with IS. An additional shortcoming lies in the study’s ability to produce reliable findings regarding treatment effectiveness. Since this is a feasibility study and there will be no control group, it will be not possible to establish differences between groups and preliminary data on the clinical utility of the app should be interpreted with caution. However, note that the current study design is the preferred to provide information on the feasibility and potential clinical utility of implementing an app-based device for AIS monitoring. This type of study is important to justify whether a larger-scale randomized controlled trial, which is more expensive and time consuming, should be conducted [49]. Feasibility studies are crucial for novel interventions in general and for medical devices and health technology solutions in particular.

5. Conclusions

While we recognize the limitations mentioned above, if the app-based telemonitoring of adolescents with IS leads us to the hypothesized results in terms of feasibility and possible clinical utility, this study will have important clinical implications. Among the novelties of the present study is the implementation of an app-based EMA system for the multidimensional monitoring of adolescents with IS. An advantage of implementing this methodology includes the minimization of problems found in retrospective face-to-face episodic assessments (i.e., recall bias, poor monitoring that could compromise the safety of the treatment, and the burden on the physician associated with the time required for evaluations). Taking recall bias, ecological assessments are known to be more accurate than retrospective ones [17]. Therefore, the information obtained with these assessments is more reliable than that obtained from face-to-face appointments where the reliability of the data depends on the recall capacity of the patients [50]. Regarding treatment safety, the app will automatically detect the clinical alarms and send them to the physicians. Therefore, it will allow for timely detection of adverse brace-related symptoms and prompt management. Consequently, the app-based EMA will allow clinicians to provide more efficient and personalized treatments. Finally, and in relation to the burden of assessment, the app monitoring system will allow doctors to receive alarms passively, without the need to actively call patients at random moments during treatment and without patients having to travel to clinics. In fact, the entire monitoring process, as explained in this text, can be performed in an automated way with very little burden for the professionals.

In short, we hope that this new passive telemonitoring method will reduce the current burden on health care services, as doctors will contact patients only when necessary rather than routinely calling patients to assess their physical and psychological functioning. Last but not least, because alarms will occur on an individual level, treatments will become more personalized as specific responses and adaptations will be possible due to the variety of brace-related physical and psychological dimensions evaluated in the app.