Nihon Kohden’s Polysmith Version 5 with Polysuite Advanced Database

Review by Shane Szutenbach, RPSGT
Manager/Chief Technologist
Sleep Disorders Center, University of Chicago Medical Center
Chicago, I1


We have a relationship with Nihon Kohden that has lasted over 20 years, so the biggest factor in deciding to trial their sleep diagnostic systems was that we already owned Nihon Kohden EEG and sleep acquisition systems. We really felt like we knew the software and hardware enough to trust that what we were getting would be reliable and easy to use. Our experience has been that the service is dependable so changing to another company did not make sense to us. We work closely with the Nihon Kohden team. We communicate what we want in a system to them and the attention we receive is very positive; especially if we do not like something. They are quick to respond to our suggestions and concerns. An additional factor was that since all of our research affiliates are using Nihon Kohden’s Polysmith, staying on the same platform was very important to us.


When we went from Polysmith version 4 to version 5, we purchased all new hardware which included their 912 dedicated PSG head boxes with built-in pulse oximetry. We also purchased a couple of the 921 head boxes with built-in pulse oximetry and end tidal CO2 modules.

We were so pleased that we purchased 2 additional 921 head boxes with the end tidal units and while both Polysmith version 4 and version 5 had the same intuitive functions, there were key changes that made everyone’s life a lot better.

First, the multi-trend plot which can be viewed by the techs acquiring the study at night can be edited so that artifacts are not put into the reports, such as a false pulse oximetry reading when a patient is unhooked for a break.

Next, another key change is how the actual data is acquired and stored because it has the ability to create smaller file sizes when archiving. And since the acquisition is more streamlined, the techs are also able to go into “look-back” to stage and score while the study is running with very little compromise in processing speed.

Another key feature that is very important to us is the Polysmith advanced database. The advanced database really ties everything together for us when we need to generate custom patient reports that perform very specific queries for our research.

Finally, what is great and useful is that Nihon Kohden sent a clinical specialist out for the week so that we were all trained on the new equipment.


In the past, we were using external devices which became somewhat difficult to calibrate. With the upcoming development of Nihon Kohden’s Cap One Main Stream device for end tidal CO2 sampling, when a tech begins to start a study and we perform our mechanical calibrations, all of the built-in DC devices such as the Etco2 and the pulse oximeters will automatically be calibrated. Furthermore, the great thing about the end tidal unit is that it is in real time, so there is no 6-10 second delay like other systems. The end tidal interface that goes onto the patient will be available in the future with a nasal pressure cannula so that you can monitor both the Etco2 signal and the nasal pressure transducer airflow signal as two separate channels. We have been working on the development of the Cap One sampling canula with Nihon Kohden so we are really excited to see it come out.

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