MAUDE Adverse Event Report: NIHON KOHDEN CORPORATION NEUROMASTER G1; NEURAL FUNCTION MEASURING SYSTEM

Model Number	DC-200B
Medical Device Problem Codes	Electrical /Electronic Property Problem (1198); Unintended Application Program Shut Down (4032)
Health Effect - Clinical Code	No Clinical Signs, Symptoms or Conditions (4582)
Date of Event	02/05/2025
Type of Reportable Event	Malfunction
Additional Manufacturer Narrative
The customer reported that the device shut down during a procedure.The customer reported there was an error message for a main unit failure and then the program would not close and it kept stimulating sseps when they were trying to close it.There was no patient harm.The mee system measures and displays electric, auditory, and visual evoked potentials (ep), electroencephalograms (eeg), and electromyographs (emg).No patient harm was reported.Nihon kohden continues to investigate the reported event.Nihon kohden will submit a supplemental report in accordance with 21 cfr section 803.56 when additional information becomes available.H4: device manufacturer data- ni.
Event or Problem Description
The customer reported that the device shut down during a procedure.The customer reported there was an error message for a main unit failure and then the program would not close and it kept stimulating sseps when they were trying to close it.There was no patient harm.The mee system measures and displays electric, auditory, and visual evoked potentials (ep), electroencephalograms (eeg), and electromyographs (emg).No patient harm was reported.
Additional Manufacturer Narrative
Details of complaint: the biomedical engineer (bme) reported that while in the middle of obtaining the baseline data, the eeg tech stated that all signals went black and she got a "main unit failure" error message, then the system shut down.When trying to close the program, it kept stimulating sseps.The tech was able to reboot the device, which temporarily resolved the issue.The customer did not supply the system's serial number.No patient harm was reported.Investigation summary: an investigation was performed under irc-499 on a similar incident and reported to fda for this and ticket (b)(4): the log files were requested for an nkc investigation, but they were not provided.The phenomenon could not be reproduced on the reported device where the phenomenon occurred.Nka requested that the investigation be suspended because the phenomenon could not be reproduced.Under normal use conditions, the issue could not be replicated during nkc testing in nkc's operating environment.However, it should be noted that when nkc intentionally dropped the power below 70v (low voltage), the main unit powered off and thus lead to a "main unit failure" error message.70v is not enough power to power the main unit.Trending for similar issues and devices will continue to be monitored by nk.Additional information: b4 date of this report.G3 date received by manufacturer.G6 type of report.H2 if follow-up, what type?.H6 event problem and evaluation codes.H11 additional manufacturer narrative.
Event or Problem Description
The customer reported that while in the middle of obtaining the baseline data, the eeg tech stated that all signals went black and she got a "main unit failure" error message, then the system shut down.When trying to close the program, it kept stimulating sseps.No patient harm was reported.The mee system measures and displays electric, auditory, and visual evoked potentials (ep), electroencephalograms (eeg), and electromyographs (emg).No patient harm was reported.

• Brand Name: NEUROMASTER G1
• Common Device Name: NEURAL FUNCTION MEASURING SYSTEM
• Manufacturer (Section D): NIHON KOHDEN CORPORATION; attn: shama mooman; 1-31-4 nishiochia; shinjuku-ku, tokyo 161-8 560; JA 161-8560
• Manufacturer (Section G): NIHON KOHDEN TOMIOKA CORPORATION; attn: shama mooman; 1-1 tajino; tomioka city, gunma 370-2 314; JA 370-2314
• Manufacturer Contact: shama mooman ; seibu bldg 2, 4th floor 1-11-2; kusunokidai tokorozawa, saitama 359-8-580 ; JA 359-8580
• MDR Report Key: 21529348
• Report Number: 8030229-2025-04759
• Device Sequence Number: 20916569
• Product Code: GWF
• UDI-Device Identifier: 04931921118054
• UDI-Public: (01)04931921118054
• Combination Product (Y/N): N
• Initial Reporter State: TN
• Initial Reporter Country: US
• PMA/510(K) Number: K142624
• Number of Events Summarized: 1
• Summary Report (Y/N): N
• Serviced by Third Party (Y/N): N
• Reporter Type: Manufacturer
• Report Source: Health Professional,User Facility
• Initial Reporter Occupation: Biomedical Engineer
• Type of Report: Initial,Followup
• Report Date (Section B): 09/12/2025

1 Device was Involved in the Event

1 Patient was Involved in the Event

• Is this an Adverse Event Report?: No
• Is this a Product Problem Report?: Yes
• Operator of Device: Health Professional
• Device Model Number: DC-200B
• Device Catalogue Number: DC-200BA
• Was Device Available for Evaluation?: No
• Is the Reporter a Health Professional?: Yes
• Type of Report(Section G): Thirty-Day
• Initial Date Received by Manufacturer: 02/05/2025
• Supplement Date Received by Manufacturer: 09/10/2025
• Initial Report FDA Received Date: 03/05/2025
• Supplement Report FDA Received Date: 09/12/2025
• Was Device Evaluated by Manufacturer? (Y/N): No
• Date Device Manufactured: 08/06/2024
• Is the Device Labeled for Single Use? (Y/N): No
• Is This a Single-Use Device that was Reprocessed and Reused on a Patient? (Y/N): No
• Usage of Device: Reuse
• Patient Sequence Number: 1
• Concomitant Medical Products and Therapy/Usage Dates: NI.; NI.
• Patient Sex: Unknown