(90 days)
The Medi-Dx 7000 is a diagnostic device for the quantitative detection of sensory neurological imparments. The population of subjects for whom this device may be used for diagnostic purposes would include any individual capable of communicating their perception of cutaneous sensation.
The Medi-Dx 7000 diagnostic examination may be conducted as part of a routine neurological examination or as a screening procedure for the detection of peripheral neuropathy which may be caused by various pathological conditions or exposures to toxic substances.
Approved 12/01/97, the Medi-Dx 7000 is a Current Perception Threshold (CPT) device for the examination of peripheral neuropathies. It generates sinusoidal electrical currents in the 5 Hz, 250 Hz and 2000 Hz frequencies from 0 mA to 9.99 mA.
The Medi-Dx 7000 weighs approximately 15 Ibs. and is housed within a 12" x 5" x 11" heavy duty plastic case with metal face and rear panels. The rear panel has an access door for installation and replacement of (8) standard (6) Volt Alkaline Batteries. The Face panel has an 'ON/OFF' switch, a 'Battery Test' switch (also functioning as an automatic calibration switch), and three (3) switches, one for each of the frequencies; 5 Hz, 250 Hz and 2000 Hz respectively. The intensity control is immediately below an LCD which reads mA output. Two ports are available on the from panel for connection with electrodes.
The provided text does not contain detailed acceptance criteria for the Medi-Dx 7000 device, nor does it describe a specific study that formally proves the device meets such criteria with quantitative performance metrics.
However, based on the information provided, the submission emphasizes substantial equivalence to a predicate device (Neurometer) rather than presenting a performance study against specific acceptance criteria. The manufacturer's argument for equivalence is based on shared functional and technical characteristics, and improved safety features of the Medi-Dx 7000.
Here's an attempt to structure the information based on your request, highlighting what is implicitly or explicitly stated and what is missing:
Acceptance Criteria and Reported Device Performance
| Acceptance Criteria (Implied/Stated) | Reported Device Performance (as stated in the submission) |
|---|---|
| Functional Equivalence: | Current output, waveform, minimum/maximum output (0.0 mA to 9.99 mA), and frequencies (5 Hz, 250 Hz, 2000 Hz) are the same as the predicate device. |
| Safety: | The Medi-Dx 7000 offers "improved safety" compared to the equivalent device. Specific safety features include: isolated output via transformer (unlike predicate), largely non-conducting plastic case (unlike predicate's all-metal case), output dampening to prevent electrical field build-up at electrodes under no-load conditions (not known for predicate), four independent clocks for frequency production (does not produce RFI, unlike predicate), and a safety interlock. |
| Biological Compatibility & Patient/Operator Safety: | Both devices "deliver current to the subject that is biologically compatible and posses no threat of injury to the patient or operator." |
| Accuracy/Calibration: | Both manufacturers "burn in the devices for 168 hours and testing insures accuracy/calibration." (No specific accuracy metrics are provided). |
| Environmental Risk: | Neither device poses "any environmental risk from chemical, thermal, radiation or mechanical factors." |
| Display/User Interface: | The Medi-Dx 7000 has a "digital LCD output meter" (predicate does not). Both use an LCD readout of current. |
| Battery Level Warning: | The Medi-Dx 7000 "WARNING" light flashes if power drops below that needed for max output. (Predicate has a "steady on" warning for low batteries and flashing for waveform clipping). |
| Clinical Performance for Diagnosing Neuropathies: (Implied) | The submission argues that "it is reasonable to assume that the two devices are the same in function and reliability" due to shared output characteristics. It also states that several physicians have compared the devices clinically and "have agreed to share their opinions if contacted." However, no formal study results are provided. |
Study Details
The submission describes a comparison to a predicate device for substantial equivalence, rather than an independent performance study with quantitative acceptance criteria. Therefore, many of the requested details are not explicitly provided.
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Sample size used for the test set and the data provenance:
- Test Set Sample Size: Not specified. The submission mentions that "several of these physicians have compared the devices clinically," implying some form of clinical observation or comparison, but no formal test set size is given.
- Data Provenance: Not specified. It's unclear if objective data was collected, or if it refers to anecdotal clinical experience from unnamed physicians.
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Number of experts used to establish the ground truth for the test set and the qualifications of those experts:
- Number of Experts: "Several" physicians are mentioned.
- Qualifications of Experts: They are described as "neurologists and other medical experts." No specific experience or board certifications are provided.
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Adjudication method for the test set:
- Adjudication Method: Not specified. It appears to be based on "opinions" of physicians rather than a formal adjudicated consensus process.
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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:
- MRMC Study: No, this type of study was not described. The device is not an AI-assisted diagnostic tool. The comparison is between two CPT (Current Perception Threshold) devices. The discussion around physicians' opinions is anecdotal and not a formal MRMC study.
- Effect Size: Not applicable.
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If a standalone (i.e., algorithm only without human-in-the-loop performance) was done:
- Standalone Performance: Not applicable in the context of an algorithm. This device is a measurement tool. Its "standalone" performance would relate to its physical output characteristics, which are stated to be equivalent to the predicate device. The submission makes a case for the device's inherent functional equivalence and improved safety features.
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The type of ground truth used (expert consensus, pathology, outcomes data, etc.):
- Ground Truth: Based on the text, the "ground truth" for the clinical comparison was essentially the clinical judgment and opinion of the consulted neurologists and medical experts regarding the device's ability to elicit threshold perception without "over stimulating" receptors, and its overall functional performance in line with the predicate device. There is no mention of an objective, independent ground truth like pathology or outcomes data.
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The sample size for the training set:
- Training Set Sample Size: Not applicable. This submission concerns a medical device, not a machine learning algorithm requiring a "training set."
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How the ground truth for the training set was established:
- Training Set Ground Truth: Not applicable.
§ 882.1870 Evoked response electrical stimulator.
(a)
Identification. An evoked response electrical stimulator is a device used to apply an electrical stimulus to a patient by means of skin electrodes for the purpose of measuring the evoked response.(b)
Classification. Class II (performance standards).