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

Model Number	DC-200B
Medical Device Problem Codes	Failure to Deliver Shock/Stimulation (1133); Defibrillation/Stimulation Problem (1573)
Health Effect - Clinical Code	No Clinical Signs, Symptoms or Conditions (4582)
Date of Event	03/18/2020
Type of Reportable Event	Malfunction
Event or Problem Description
The customer reported that the main unit device failed stemming during procedure.The customer reported receiving an error message stating "error a3 and a4 stimulators were not connected" during a procedure.The customer reported that everything was connected and the program was restarted, but the issue persisted.The customer swapped the stim cable and boxes but the issue still persisted.The customer removed and replaced the main unit for a working unit and continued the procedure.There was patient involvement but no injury occurred.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
The customer reported that the main unit device failed stemming during procedure.The customer reported receiving an error message stating "error a3 and a4 stimulators were not connected" during a procedure.The customer reported that everything was connected and the program was restarted, but the issue persisted.The customer swapped the stim cable and boxes but the issue still persisted.The customer removed and replaced the main unit for a working unit and continued the procedure.There was patient involvement but no injury occurred.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.The following field(s) contain no information (ni), as attempts to obtain information were made, but not provided: d10: attempt # 1: on (b)(6) 2025 emailed the customer via microsoft outlook for all information in the ni list above: the customer replied that he had no information to provide.
Event or Problem Description
The customer reported that the stimulator for the mee-2000 system failed to stimulate and gave "a3" and "a4" error codes, indicating that the stimulators were not connected.The connections were confirmed, and the program was restarted, but the issue persisted.They then swapped the stim cable and boxes, but this also did not resolve the issue.No patient harm was reported.
Additional Manufacturer Narrative
Details of complaint: the customer reported that the stimulator for the mee-2000 system failed to stimulate and gave "a3" and "a4" error codes, indicating that the stimulators were not connected.The connections were confirmed, and the program was restarted, but the issue persisted.They then swapped the stim cable and boxes, but this also did not resolve the issue.The issue was resolved after the main unit was swapped out with a working one.No patient harm was reported.The complaint unit was returned and was evaluated.The reported issue could not be duplicated.There were no issues found on the device during the extended testing period.The available information suggests that the issue is unlikely to be caused by the device.Possible causes of the issue are hospital environment, inadequate setup, incorrect cable connections, and user error.Nk will continue to trend and monitor.Additional information: b4 date of this report.D9 device available for evaluation? d10 concomitant medical device.G3 date received by manufacturer.G6 type of report.H2 if follow-up, what type? h3 device evaluated by manufacturer? h6 event problem and evaluation codes.H11 additional manufacturer narrative.

• 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: 21810680
• Report Number: 8030229-2025-04844
• Device Sequence Number: 18394597
• 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: Other Health Care Professional
• Type of Report: Initial,Followup
• Report Date (Section B): 07/16/2025

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?: Device Returned to Manufacturer
• Is the Reporter a Health Professional?: Yes
• Type of Report(Section G): Thirty-Day
• Initial Date Received by Manufacturer: 03/18/2025
• Supplement Date Received by Manufacturer: 07/15/2025
• Initial Report FDA Received Date: 04/09/2025
• Supplement Report FDA Received Date: 07/16/2025
• Was Device Evaluated by Manufacturer? (Y/N): Yes
• Date Device Manufactured: 05/09/2024
• 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
• Patient Sex: Unknown