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Methods
A multi-centre, open-label, feasibility and usability study comprising 22 participants was conducted. Eleven PD patients were invited to use the SENSE-PARK System for 12 weeks and perform clinical assessments every other week. The other 11 patients only completed the clinical assessments.
The primary outcome was the frequency of drop-outs and the first secondary outcome was assessed through the IBM Post-Study Usability Questionnaire (PSSUQ - rating score from 1, best, to 7, worst).
Technology Overview
The SENSE-PARK System consists of a set of wearable sensors (3 to be used during the day and one at night), a Wii Balance Board, software and a smartphone app (Fig. 1).
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Figure 1.
From left to right: Inertial sensor unit with housing and wristlet band; Wii balance board; interface software; SENSE-PARK App
The sensors monitor movements of PD patients during daily activities, collecting motor-related raw data. Accelerometers and angular rate sensors measure the motion of the user, and map certain activities. When awake, the user wears a small sensor at the wrist and the leg of the more affected side, as well as at the lower back according to Fig. 1. When asleep, the user wears one sensor at the lower back only. This set of sensors, together with algorithms developed during the SENSE-PARK project phase, allows monitoring parameters associated with gait, hypokinesia, dyskinesia, tremor and sleep. Through the Wii Balance Board, data such as body weight and sway are also collected. The user also performs cognitive tests through specific software. These tests use virtual environments on a screen to evaluate specific cognitive domains, including alertness, divided attention, response control, visual exploration and working and topological memory.
Staff Training
A two day investigator meeting was conducted to train staff, including installation of equipment, and procedures for training participants in the use of the System. Investigators received training in test administration and scoring.
Participants
A sample of 22 PD patients was divided into two groups: SENSE-PARK System users and non-users. Inclusion criteria were (1) PD patients between 40 and 85 years of age, (2) stage 1 to 2.5 (ON) of the Modified Hoehn and Yahr (H&Y) scale and (3) having experience or interest in technical equipment (computer, regular mouse and keyboard).
Exclusion criteria included (1) illiteracy, (2) ≤24 in the Mini Mental State Examination (MMSE), (3) postural instability item MDS-UPDRS > 2, (4) inability to handle the device for some other reason.
There were no restrictions on prior and concomitant therapy. An approval was obtained from the local ethics committee at the three sites (University of Lisbon, Portugal; University of Tübingen, Germany; and University of Tromsö, Norway), and in compliance with national legislation and Declaration of Helsinki.
Study Design and Assessments
After signing the informed consent, participants were screened for eligibility. For the group of users, a home visit was scheduled to ensure users had the required home facilities for the use of the SENSE-PARK System and to install the full system (the mouse setting was defined according to the hand the user normally writes with). The users were also invited to perform a demo session, in order to get acquainted with the SENSE-PARK System. Only balance and cognitive testing had to be performed "actively". On cognitive test occasions, patients were instructed to be seated in a chair in front of the computer and place the computer and mouse on a table. Balance tests had to be performed with a Wii Balance Board which was connected to the local computer and the SENSE-PARK System. The other domains' data were collected with the sensors which were worn 24 hours per day: three to be used during the day and one at night.
After the installation, participants used the SENSE-PARK System at home for one week and then they were observed by the investigator who registered whether the participants made mistakes during the tasks and whether they needed assistance. When necessary, another week of training was allowed. The time needed for confident SENSE-PARK System operation, test taking, data storage and data transfer was recorded. As soon as the user was able to use the SENSE-PARK System adequately and it was working properly, the assessment phase of the study started.
During the assessment period, patients who used the SENSE-PARK System were asked to perform sway assessment and cognitive tests every other day at a similar time of day during ON stage. Patients selected, in advance, the days of the week they would perform their testing, which was then programmed into the SENSE-PARK System with a reminder coming up on the interface of the software. An ongoing check of data arrival allowed users who were near to missing their two day window to be contacted by the study staff. If any problems or questions developed, users had access to the study staff for backup support.
Every other week during the study, participants from both groups returned to a health professional expert in movement disorders or were visited to perform the control of concomitant medications, check data download, record the occurrence of any Adverse Event, confirm patient compliance and to perform the following rating scales: MDS-UPDRS, H&Y, Montreal Cognitive Assessment (MoCA), Mini–Mental State Examination (MMSE), Parkinson's Disease Questionnaire-39 (PDQ-39), EQ-5D, Epworth Sleepiness Scale (ESS), Panic Disorder Severity Scale (PDSS), Non-Motor Symptoms Scale (NMSS), Unified Dyskinesia Rating Scale (UdysRS), Clinical Global Impression - Severity Scale and Improvement Scale (CGI-S and CGI-I).
Between investigator visits, semi-structured interviews were conducted by phone to gain insight into the experiences of the participants using the SENSE-PARK System. Topics discussed were: willingness to continue in the study, satisfaction with the SENSE-PARK System, changes in health status or medical condition, adverse events, feedback messages and doubts about the system. Those participants who were not using the SENSE-PARK System were asked about willingness to continue in the study, health status, medical condition and adverse events (usability evaluation).
After 4 weeks of active data collection with the SENSE-PARK System, the participants received a modified version of the software. This new version provided feedback to users (Fig. 2).
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Figure 2.
Study design. V: Visit; PC: Phone Contact; VH: Home visits
At the end of the study period (V8), participants were asked to fill in the IBM Post-Study Usability Questionnaire (PSSUQ) which assesses user satisfaction with, and usability of, technical devices. It is a 19-item closed-ended ordinal questionnaire, based on 7-point graphic Likert scales. The items address five important components of user satisfaction with general computer systems usability: ease of use, ease of learning, simplicity, effectiveness, information, and the user interface.
Statistical Analysis
Statistical analyses were performed in R, version 3.0.3. Subject demographic and clinical data were examined by descriptive summary. Usability was assessed for system users and was tested with the PSSUQ values obtained at the end of the study (see above). Feasibility was assessed for users and non-users. For non-users, feasibility was assessed through willingness to continue in the study and through completeness of the study, i.e. withdrawals from the study. For users, feasibility was assessed through the following indices: willingness to continue in the study and through completeness of the study, duration of time to train participants to use the SENSE-PARK System confidently, compliance in terms of the number of completed test sessions and their timeliness with every other day assessments, compliance/adherence to system measures, success of data transfer and decryption, ease of use and program satisfaction.
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