(88 days)
The NeuroMetrix NC-stat is intended to measure neuromuscular signals that are useful in diagnosing and evaluating systemic and entrapment neuropathies. The NC-stat is intended to be used as an adjunct to and not a replacement for conventional electrodiagnostic measurements.
The NC-stat consists of a hand-held, battery-operated monitor and a disposable sensor. The NC-stat measures two median nerve electrophysiological parameters, the distal motor latency (DML) and the median F-wave latency (F-LAT). The DML is the interval, in milliseconds, between the onset of the stimulus and the onset of the resultant compound muscle action potential (CMAP) in the thenar muscles. The F-LAT is the median interval, in milliseconds, between the onset of the stimulus and the onset of a CMAP in the thenar muscle resulting from antidromic activation of the motor neurons in the spinal cord. The primary and secondary functions of the NC-stat are controlled by software routines. The primary function of the NC-stat software is to carry out nerve conduction measurements. Secondary functions of the software include displaying previously acquired measurement data, communicating stored data to an external target such as a printer and operating hardware diagnostics when the device is initially powered on. The single-use disposable sensor, containing a proprietary electrode array, is placed on the patient's wrist in alignment with the distal most wrist crease and connected to the monitor non-invasively stimulates the patient's median nerve and detects the subsequent CMAP as an electrical potential on the skin, via the sensor. The sensor also contains a temperature electrode that monitors surface temperature of the patient's skin. All this data is analyzed and digitally stored in a non-volatile manner by the monitor. The resulting DML and F-LAT are displayed on the NC-stat L.C.D.
The provided 510(k) summary for the NC-stat device does not contain a specific table of acceptance criteria and reported device performance metrics in the format requested. However, it does outline the performance testing conducted and states that these tests demonstrate the device "yields the appropriate outcome with a high probability" and "conforms to the safety related system and software requirements."
Here's a breakdown of the requested information based on the document:
1. A table of acceptance criteria and the reported device performance
The document does not provide a quantitative table of acceptance criteria and specific performance metrics (e.g., accuracy, sensitivity, specificity, or specific error rates) with numerical values. Instead, it broadly states that the NC-stat was tested to ensure appropriate outcomes and conformance to safety and software requirements.
2. Sample size used for the test set and the data provenance (e.g. country of origin of the data, retrospective or prospective)
The document dedicates a section to "PERFORMANCE TESTING" but does not specify the sample size used for the test sets (e.g., number of patients or measurements). It also does not mention the country of origin of the data or whether the study was retrospective or prospective.
3. Number of experts used to establish the ground truth for the test set and the qualifications of those experts (e.g. radiologist with 10 years of experience)
The document does not provide information on the number or qualifications of experts used to establish ground truth.
4. Adjudication method (e.g. 2+1, 3+1, none) for the test set
The document does not describe any adjudication method for the test set.
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
The document describes the NC-stat as a "Nerve Conduction Monitoring System" that measures electrophysiological parameters (DML and F-LAT). It is a device that directly measures and displays data, not an AI system designed to assist human readers in interpreting images or other complex data. Therefore, an MRMC comparative effectiveness study involving human readers' improvement with AI assistance would not be applicable to this device as described.
6. If a standalone (i.e. algorithm only without human-in-the loop performance) was done
The NC-stat is described as a "hand-held, battery-operated monitor and a disposable sensor" that directly measures and displays DML and F-LAT. It operates to "carry out nerve conduction measurements" and "display previously acquired measurement data." This implies it functions as a standalone measurement device, providing direct output without requiring human interpretation as part of its primary function. The performance testing section describes "System testing" in which "several complete tests were simulated to obtain all possible test outcomes," which further supports a standalone evaluation of the device's measurement capabilities.
7. The type of ground truth used (expert consensus, pathology, outcomes data, etc)
The document mentions "evaluation of DMLs acquired by volume conduction and those signals acquired and measured using conventional methods." This suggests that conventional nerve conduction measurement methods were used as the reference or ground truth to compare the NC-stat's measurements.
8. The sample size for the training set
The document does not refer to a "training set." The NC-stat is a measurement device that directly acquires and processes electrophysiological signals, not a machine learning model that requires a training set in the conventional sense.
9. How the ground truth for the training set was established
As there is no mention of a training set, the establishment of its ground truth is not applicable.
§ 882.1550 Nerve conduction velocity measurement device.
(a)
Identification. A nerve conduction velocity measurement device is a device which measures nerve conduction time by applying a stimulus, usually to a patient's peripheral nerve. This device includes the stimulator and the electronic processing equipment for measuring and displaying the nerve conduction time.(b)
Classification. Class II (performance standards).