(889 days)
The purpose of the Symphony Device is to improve the quality of sleep in patients with primary Restless Legs Syndrome (RLS) through the use of vibratory counter-stimulation.
The Symphony Device is a non-sterile, reusable, cloth-covered foam pad that contains six embedded electric motors that swing eccentric weights to produce vibration throughout the pad. The device is designed to be placed under the user's legs while sleeping. When the device is activated, an electronic controller runs a 35 minute preset vibration cycle. The controller allows the patient to control the intensity level of the vibration for the first 30 minutes of the cycle. In the last five minutes, the controller slowly ramps down the vibration intensity of the device and then automatically shuts the device off at the end of the timed cycle. One repeat cycle can be initiated by the patient. The controller contains the on/off function and has variable mechanical counter-stimulation intensity settings (1 to 9). The motor amplitude and frequency (vibration) can be set to different levels of intensity by means of a knob. The polyurethane foam pad is covered by an inner lycra cover and an outer cover. The outer cover on the Symphony™ Device is made of cotton. The device will be offered in three sizes: Small, Medium, and Large.
Here's a summary of the acceptance criteria and the study details for the Symphony Device, organized as requested:
1. Table of Acceptance Criteria and Reported Device Performance
The provided text does not explicitly state "acceptance criteria" in a quantitative, pass/fail manner for the clinical effectiveness of the device. Instead, it describes clinical study results and a benefit/risk determination. The non-clinical acceptance criteria are implied by compliance with standards and successful completion of tests.
| Acceptance Criteria (Implied) | Reported Device Performance |
|---|---|
| Clinical Effectiveness: Improvement in RLS symptoms (general) | SMI-001: No statistically significant differences in IRLS score between active and sham groups. |
| SMI-002: No statistically significant differences in IRLS score between active and sham groups. | |
| Clinical Effectiveness: Improvement in sleep quality | SMI-001: Statistically significant improvements in mean MOS-I scores (-16.76 for Symphony vs -5.09 for sham, p=0.0117) and MOS-II scores (-15.83 for Symphony vs -5.34 for sham, p=0.0230). |
| SMI-002: Mean improvements in MOS-I scores (-10.13 for Symphony vs -5.48 for sham, p=0.2358) and MOS-II scores (-11.41 for Symphony vs -7.36 for sham, p=0.3040) did not reach statistical significance. | |
| Safety: Low incidence of device-related adverse events | SMI-001: 7 AEs (17.9%) at least possibly device-related in Symphony group vs. 1 (2.6%) in sham. All resolved. Most common: worsening RLS. |
| SMI-002: 5 AEs (9.6%) at least possibly device-related in Symphony group vs. 2 (6.9%) in sham. All resolved. Most common: worsening RLS. | |
| Biocompatibility: Patient-contacting materials safe | Justification provided: identical cotton material has a demonstrated long history of safe use. |
| Electromagnetic Compatibility (EMC) & Electrical Safety: Compliant | Found to be in compliance with IEC 60601-1, EN 55011, EN 61000-4-2, EN 61000-4-3, EN 61000-4-4, EN 61000-4-5, EN 61000-4-6. |
| Software: Adequacy of firmware | Adequacy confirmed; consistent with 'MINOR' level of concern as per FDA guidance. |
| Device Output: Performance within specifications (acceleration, velocity, displacement, frequency) | Mean, minimum, and maximum values of acceleration, velocity, displacement, and frequency were within specifications for each intensity setting. |
| Durability & Safety: Withstand various use scenarios | Life cycle testing, decibel level, pad surface temperature, motor housing deformation, drop test, bend test, strain relief & electrical cable tensile strength, and shaft tensile strength were conducted. (Results stated as "conducted to characterize" without explicit pass/fail details on outcomes, but implies satisfactory performance). |
| Shelf Life/Sterility: Appropriate for device type | Non-sterile, reusable; no stated shelf life acceptable given components and cleaning instructions. |
2. Sample Size Used for the Test Set and Data Provenance
- SMI-001 (Test Set 1):
- Sample Size: 77 subjects (39 Symphony, 38 sham).
- Data Provenance: Prospective, multicenter trial (5 sites). The country of origin is not specified but is implied to be the US given the FDA regulatory context.
- SMI-002 (Test Set 2):
- Sample Size: 81 subjects (52 Symphony, 29 sham).
- Data Provenance: Prospective, multicenter trial (4 sites). The country of origin is not specified but is implied to be the US given the FDA regulatory context.
3. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications of Those Experts
The study design described is a clinical trial involving patient-reported outcomes for RLS and sleep quality. The "ground truth" for RLS severity (IRLS) and sleep quality (MOS Sleep Scale) is established directly by the patients' subjective responses to the validated questionnaires. There is no mention of experts establishing a separate ground truth for these endpoints. Physicians/investigators at the study sites would have been involved in participant diagnosis and monitoring, but not in creating a "ground truth" for the device's performance in the way an imaging study would use expert radiologists.
4. Adjudication Method for the Test Set
The clinical trials used patient-reported outcome measures (IRLS, MOS Sleep Scale, RLSQOL). These measures are self-administered questionnaires, so an adjudication method in the sense of multiple expert reviews of data to establish a single ground truth is not applicable. The outcomes are the direct responses of the participants. Adverse events were collected and monitored by the clinical sites, and their device-relatedness was assessed, but a formal adjudication committee process is not detailed.
5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study Was Done, If So, What Was the Effect Size of How Much Human Readers Improve with AI vs Without AI Assistance
No, an MRMC comparative effectiveness study was not done. This device is a therapeutic device for RLS, not an imaging diagnostic device that would typically involve human readers (like radiologists) or AI assistance in interpretation.
6. If a Standalone (i.e., algorithm only without human-in-the-loop performance) Was Done
This question is not applicable to the Symphony Device. The Symphony Device is a physical, therapeutic vibratory counter-stimulation device. It does not involve an algorithm or AI that operates in a standalone diagnostic or interpretive capacity. Its software controls the vibration cycle, which is a functional control, not an analytical or diagnostic algorithm.
7. The Type of Ground Truth Used
The ground truth used in the clinical studies was patient-reported outcomes (PROs):
- International Restless Legs Scale (IRLS) score: A validated scale for RLS symptom severity.
- Medical Outcomes Study (MOS) Sleep Scale scores: Patient-reported assessment of sleep disturbance and quality.
- Johns Hopkins Restless Legs Syndrome Quality of Life questionnaire (RLSQOL): Patient-reported quality of life related to RLS.
8. The Sample Size for the Training Set
The provided text describes two prospective clinical trials (SMI-001 and SMI-002) which serve as the primary effectiveness and safety studies presented for regulatory review. There is no mention of a separate "training set" for an algorithm, as this device does not utilize a machine learning algorithm in the way a diagnostic AI would. The clinical trials themselves provide the data upon which the device's performance is assessed.
9. How the Ground Truth for the Training Set Was Established
Since there is no "training set" in the context of an algorithm for this device (see point 8), this question is not applicable. The data from the clinical trials (SMI-001 and SMI-002) were used to demonstrate the device's safety and effectiveness, with "ground truth" established via patient-reported outcomes (IRLS, MOS Sleep Scale, RLSQOL) as described in point 7.
§ 882.5895 Vibratory counter-stimulation device.
(a)
Identification. A vibratory counter-stimulation device is a prescription device that provides electrically powered mechanical vibration to improve the quality of sleep in patients with primary Restless Legs Syndrome.(b)
Classification. Class II (special controls). The device is exempt from the premarket notification procedures in subpart E of part 807 of this chapter subject to the limitations in § 882.9. The special controls for this device are:(1) Appropriate analysis/testing must demonstrate electromagnetic compatibility (EMC), electrical safety, and thermal safety.
(2) If the device contains software or firmware, appropriate verification, validation, and hazard analysis must be performed.
(3) The elements of the device that contact the patient must be assessed to be biocompatible.
(4) Non-clinical testing data (including vibration frequency, amplitude, and acceleration) must demonstrate that the device performs as intended under anticipated conditions of use.
(5) Labeling must include:
(i) Specific information pertinent to use of the device by the intended patient population and the treatment regimen;
(ii) Warning to only use the device on normal, intact, clean, healthy skin;
(iii) Warning to not use the device if the user has leg skin disorders, such as eczema, psoriasis, cellulitis, non-healing wounds;
(iv) Warning to discontinue use if Restless Leg Syndrome symptoms worsen; and
(v) Instructions for end users to contact the device manufacturer and MedWatch in case they experience any adverse events when using this device.