Stimulator, electrical, evoked response: medical device reports filed with FDA

3,308 reports carry this product code, 1994–2026; 10 brands with a page.

Read first · FDA's statement on these data

Adverse event reports submitted to FDA do not undergo extensive validation or verification. Therefore, a causal relationship cannot be established between product and reactions listed in a report. While a suspected relationship may exist, it is not medically validated and should not be the sole source of information for clinical decision making or other assumptions about the safety or efficacy of a product. Additionally, it is important to remember that adverse event reports represent a small percentage of total usage numbers of a product. Common products may have a higher number of adverse events due to the higher total number of people using the product. openFDA, FDA

FDA adds: "Although MDRs are a valuable source of information, this passive surveillance system has limitations, including the potential submission of incomplete, inaccurate, untimely, unverified, or biased data. In addition, the incidence or prevalence of an event cannot be determined from this reporting system alone due to potential under-reporting of events and lack of information about frequency of device use." And: "MDR data alone cannot be used to establish rates of events, evaluate a change in event rates over time or compare event rates between devices. The number of reports cannot be interpreted or used in isolation to reach conclusions about the existence, severity, or frequency of problems associated with devices."

Do not rely on openFDA to make decisions regarding medical care. While we make every effort to ensure that data is accurate, you should assume all results are unvalidated.

Not medical advice. This site counts what was reported to FDA. Questions about a medicine or device belong with a pharmacist or clinician.

3,308
reports with this product code: 0% of all MAUDE reports; 1,007
reports, 12 months to August 2026: 1,120 in the 12 months before; 96.1%
classified as malfunction: 62.3% across all reports; 0%
classified as death, as reported: 0.9% across all reports

Product code GWF is FDA's classification for "Stimulator, electrical, evoked response" (neurology panel), a class 2 device. 3,308 medical device reports carry this product code, 0% of the MAUDE database, from January 1994 to August 2026.

1,007 reports arrived in the 12 months to August 2026, down 10% from 1,120 in the 12 months before. FDA releases MAUDE data monthly; reports can arrive months after an event, so the newest months grow in later releases. The event types recorded are malfunction (96.1%), injury (3.4%) and other (0.4%). 10 brand names with a page on this site carry this code; the brands table is ordered by report count for navigation only. FDA states that "MDR data alone cannot be used to establish rates of events, evaluate a change in event rates over time or compare event rates between devices. The number of reports cannot be interpreted or used in isolation to reach conclusions about the existence, severity, or frequency of problems associated with devices." It adds that the reporting system "has limitations, including the potential submission of incomplete, inaccurate, untimely, unverified, or biased data."

Brands with this product code

Brand	Reports	Latest 12 months	Classified as death	Classified as malfunction
Nim 4 0 Console	1,422	528	0%	97.4%
Patient Interface Nim4cpb1 Nim 4 0	278	122	0%	100%
Nim-Eclipse Controller	221	33	0%	95.9%
Nim Vital Patient Interface 4 Channel	158	123	0%	100%
Nim-Eclipse Preamplifier	153	35	0%	99.3%
Nim 3 0 Interface	32	48	0%	99.4%
Nim 3 0 Mainframe International	27	69	0%	96.1%
Nim 3 0 Mainframe	23	39	0%	91.4%
Nim-Neuro 3 0 Mainframe	11	38	0%	97.2%
Bravo	1	568	0%	93.1%

Ordered by report count for navigation only. FDA states that "MDR data alone cannot be used to establish rates of events, evaluate a change in event rates over time or compare event rates between devices. The number of reports cannot be interpreted or used in isolation to reach conclusions about the existence, severity, or frequency of problems associated with devices." It adds that the reporting system "has limitations, including the potential submission of incomplete, inaccurate, untimely, unverified, or biased data."

Manufacturers named

Manufacturer (as written on reports)	Reports	Share
Medtronic Xomed	3,028	91.5%
Nihon Kohden	102	3.1%
Alphatec Spine	17	0.5%
Natus Medical	6	0.2%
Nuvasive	3	0.1%

Reports by month, five years

FDA releases MAUDE data monthly; reports can arrive months after an event, so the newest months grow in later releases.

Event type and report source

Event type

Death0%1

Injury3.4%112

Malfunction96.1%3,180

Other0.4%12

Not given0.1%3

Who filed

Manufacturer report98.1%3,244

Voluntary report1.4%46

User facility report0%0

Distributor report0.1%3

Not given0.5%15

Grey bar: all 26,136,888 MAUDE reports.

Device problems coded

Device problem (FDA code)	Reports	Share
Incorrect, inadequate or imprecise result or readings	1,637	49.5%
Inappropriate audible prompt/feedback	302	9.1%
False negative result	272	8.2%
Device operates differently than expectedthe device behaved unexpectedly	158	4.8%
Failure to power up	134	4.1%
Computer software problema software problem	113	3.4%
False positive result	101	3.1%
Connection problema connection problem	80	2.4%
Unable to obtain readings	77	2.3%
Application program freezes or fails to launch	64	1.9%
Incomplete or inadequate connection	61	1.8%
Problem with software installation	54	1.6%
Breakthe device broke	52	1.6%
Device sensing problem	48	1.5%
Signal artifact/noise	48	1.5%
Battery problema problem with the battery	43	1.3%
Electrical /electronic property probleman electrical or electronic problem	39	1.2%
Failure to sense	23	0.7%
Mechanical problema mechanical problem	20	0.6%
Output problem	20	0.6%

Questions about stimulator, electrical, evoked response reports

What is product code GWF?

FDA's classification code for "Stimulator, electrical, evoked response", class 2, reviewed by the neurology panel. Every device report carries the product code of the device involved.

How many reports carry this code?

3,308 reports through August 2026, 1,007 of them in the latest 12 months.

Which brands appear most often?

Nim 4 0 Console (1,422), Patient Interface Nim4cpb1 Nim 4 0 (278), Nim-Eclipse Controller (221), Nim Vital Patient Interface 4 Channel (158) and Nim-Eclipse Preamplifier (153). Widely used products collect more reports because more people use them.

Can the brands table be used to rank the devices?

No. FDA states that "MDR data alone cannot be used to establish rates of events, evaluate a change in event rates over time or compare event rates between devices. The number of reports cannot be interpreted or used in isolation to reach conclusions about the existence, severity, or frequency of problems associated with devices." It adds that the reporting system "has limitations, including the potential submission of incomplete, inaccurate, untimely, unverified, or biased data." Brands differ in how many are in use, how long they have been sold and how reports are collected.

Where this comes from. Counts are built from the openFDA Device Adverse Event (MAUDE) bulk export released 28 Sep 2026, which holds reports FDA received through 31 Aug 2026. Brand, generic and manufacturer names are as written on the reports; product code names come from FDA's device classification. No report narrative, lot number, patient detail or reporter identity is published. See the methodology and sources; FDA's record is authoritative, and corrections are handled within five working days.

Drug data (FAERS) through 30 Jun 2026; device data (MAUDE) through 31 Aug 2026. Not medical advice.