NeXus technology was first introduced by Mind Media in 2004. We decided it was time to introduce a new series of products with radically better technology than what was then available on the market. We based the best-in-class NeXus-10 specifications on 12 years of customer feedback and engineering experience. The challenge was to create the best, most reliable and flexible platform ever, for physiological data acquisition, biofeedback and neurofeedback.
NeXus-10 became a huge success. As a result, there are now thousands of NeXus systems in the market and NeXus sets new quality standards in the field. It is truly ‘the Swiss army knife of physiology’. The NeXus-32 which was introduced in 2007, is a full blown 32 channel system, which added wireless full-cap EEG functionality.
So what user feedback did we get and what are the unique features of the NeXus instruments?
More flexibility and ease of use
Users told us that they wanted an extended range of physiological sensors integrated with powerful software that would allow them to use the system out of the box as well as having lots of options to configure sensors, frequency settings, digital processing, data display, export, report functions and so on.
In response, we created a new sensor line covering signals like DC-EEG, EEG, SCP, EOG, EMG, ECG, BVP/PPG, Respiration, Skin conductance/GSR, High res skin temperature, blood flow, SpO2/Oximetry, Force, Movement/Accellerometry and HEG. And last but not least we created the new BioTrace+ software with our acclaimed easy to use point-and-click protocol suites to get you up and running quickly. All our NeXus systems ship with our BioTrace+ software.
ACTIVE noise cancelation: better signals, less artifacts
Signal quality is key, researchers and clinicians told us. Therefore NeXus was created with unique active noise cancelation technology and carbon coated electrode cables. The environmental noise is electronically subtracted from the EXG signal, resulting in very clean signals with very few artifacts. Movement artifact is virtually absent, 50/60Hz noise is very low ( we do not use notch filters). NeXus is one of the few systems that have implemented active noise cancelation for physiological signals. You may be familiar with this concept from smart headphones that people wear in airplanes.
Better Sensors: the NeXus EXG wideband amplifier
Our users asked us whether sensor technology and pricing could be improved. We told them: Yes! Instead of relying on expensive active sensors, where you need a special external amplifier for each electrophysiological channel, NeXus has a built-in universal DC-wideband amplifier which covers bio-potentials in the range of DC (0) to about 800 Hz. A single dual-channel EXG cable, which costs about the same as a single active sensor, can be used to measure 2 channels of DC-EEG, EMG, ECG or EOG. The EXG concept does not only provides excellent signal quality, but it is very cost-effective as well.
NeXus digital front end – filterless design
Users asked us whether the classical amplifier design could be improved. This is a rather technical matter, but important. As a result, the NeXus EXG wideband amplifiers do not use any fixed analog high-pass, notch or low-pass filters. All of the typical analog filters are removed (except anti-aliasing), resulting in pure ‘undistorted’ signals which the user can filter digitally on the PC in real-time. Since the original and unprocessed digital signal is stored, the user can always return to the source. In other words, the NeXus is a pure digital system without any analog filtering that limits the user. Using BioTrace+ software, the user can implement their own IIR/FIR/FFT filters with various programmable characteristics.
Better Sensors: durability
Because physiological sensors suffer from wear and tear, durable cables and sturdy connectors are important. A low cost plastic connector that breaks, where pins may get bent or where galvanical contact is poor, can significantly degrade signal quality. Therefore we implemented very high quality brushed metal connectors (some say ‘medical grade’).
More options: digital sensor line
Besides recording physiological signals, users told us they wanted to record events, markers and connect sensors that input lots of channels. So we created two types of digital inputs. NeXus has an event input which, in combination with the NTI (Nexus Trigger Interface), can record external audio, visual and digital (RS232) events. Typical applications are for research, ERP (event related potentials, P300) and VEP. Besides that, we are creating an entirely new digital sensor line. Take for example our 6 axis accelerometer. This device is connected to NeXus with a single connecter, but outputs X,Y,Z data for 2 sensors, so 6 data streams in all. The digital sensor input can extend your NeXus-10 Mark II with up to 16 input channels.
More freedom: wireless design
Our users told that having a cable between the client/user and the computer can be really limiting. In applications like sports, physiotherapy, movement science and rehabilitation you want the client/user to be able to move freely. Therefore, all NeXus systems have a built-in wireless function (and some have an additional fiber or USB link as well).
More precision: 24-bit resolution
There are still systems around that use multiplexed 12, 13 or 14-bit ADC technology to quantify physiological signals. This is completely outdated technology! It is like being told by a salesman that a 1 megapixels digital camera wil do just fine, when low-cost 10 megapixels cameras, where the picture will remain sharp and detailed even if you magnify it or zoom into detail, are available today for a reasonable prices. NeXus delivers ultra-high resolution 24-bit resolution for such very high precision and detail. The NeXus-10 and 32 have individual 24-bit ADC’s for each channel, so there is no time lag between input channels.
Better signals: electrode preparation and signal checking
Our users did not really like having to abrade the skin (EEG) and doing exhaustive impedance checking (EEG) which typically interrupts your recording, before they would get a decent EEG signal.
NeXus uses ultra-high input impedance amplifiers (1,000,000 Megaohms) which work great whether your electrode contact is 5, 10, 50, 100 KOhm or even more. Electrode impedance is no longer so critical. Besides that, our DC-EXG amplifiers constantly monitor electrode (skin) contact without any need for stopping or interrupting a session. The result is that skin-preparation is generally unnecessary and you quickly get reliable (EEG) signals without much effort.
Ambulatory function: SD flash recording
Our research users told us they wanted to be able to record signals without any need for a computer, on flash memory, just like a digital camera. So we implemented this using the secure digital (SD) flash technology. Basically it means that you can record up to 24 hours of physiological data (sometimes even more) on a flash card for later review on your PC. After the recording has been done, you import the data from the SD card to the PC and review and analyze it, just like any other session. The new NeXus-10 Mark II can automatically start and stop flash recording at pre-programmed times.
More power: lithium polymer technology
You told us, you did not like it when batteries ran empty after a few hours, so we implemented the latest rechargeable battery technology (LiPo) in the new NeXus-10 Mark II. This is actually a rechargeable battery pack with some 9000 mAh capacity, enabling 24+ hour recordings. Because the Mark II has a super capacitor built-in, you can switch battery packs without any interruption of the data recording (10 second window). This means that even in demanding situations where you want to switch batteries or where a battery contact can be interrupted briefly (high G-forces) the system will keep running.
More information: OLED display
Just having an LED that shows whether power is ON or OFF was a little minimal you told us. So we implemented a large graphical OLED display on the NeXus-10 Mark II which informs you about the battery and internal status. Seeing is believing.
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