More than a year has passed since I first tried OCZ's Neural Impulse Actuator, and I've had the finished product in my possession for a good three weeks now, yet I'm still not sure how to tackle this review. Writing about something as peculiar and downright unique as the NIA is no easy task. To set the stage, I should probably discuss control systems in general.

For thousands of years now, man has used simple, relatively intuitive controls to make machines and animals do his bidding—be it squeezing his thighs to make a horse gallop faster, cranking a wheel and axle to draw water from a well, or flooring a car's gaspedal to run a red light. Applying mechanical force to get something done is second nature to most folks, and video games are no different. We use joysticks, gamepads, mice, keyboards, and other controllers to translate finger or limb movements into actions on the screen. Want to move your character left? Push the analog stick to the side. Want to fire? Squeeze the trigger. Easy.

What OCZ has done with the NIA is throw most of that out the window. By incorporating an electro-myogram, electro-encephalogram, and electro-oculogram into a small headband and a little black box with a USB connector, the company has developed a control system that can translate eye movements, facial muscle movements, and brain waves into game input. As a result, the NIA is a strange contraption that requires some very unusual participation from the user.
When was the last time you used your jaw to control a machine? Unless you're Stephen Hawking or extremely lazy, you probably can't remember. How about using your eyes or your alpha brain waves? Didn't think so.

The NIA makes those things possible thanks to a headband with three diamond-shaped sensors positioned at the front. According to OCZ Technology Development Director Michael Schuette's article on the subject, the sensors are made of a plastic injected with highly conductive nanofibers, which the NIA hardware uses to read electrical potentials from the user's forehead. OCZ built the remainder of the headband out of soft rubber, with a lanyard at the back to allow for adjustment. A cable runs down the left side of the headband and plugs into the black NIA box, which includes two completely separate circuits: one hooked up to the headband and the other hooked up to the host PC's USB port. The two circuits only talk to each other through an optical transceiver, ensuring that users won't get electrical shocks if things go awry.

On the user's PC, the NIA control software converts electrical potentials from the headband into usable input. Schuette explains that the software separates the different frequencies in these potentials using proprietary algorithms not unlike fast Fourier transforms. Running these algorithms on a continuously streaming flow of data can apparently hog some "serious CPU cycles," although we didn't see the control application eat up much more than 10-15% of our test rig's Core 2 Duo E6400.

At this point, you might be wondering just how the NIA actually interfaces with games. OCZ's solution to that problem is quite clever: when it enters the game mode, the NIA app simply translates inputs into keystrokes. You can hit CTRL-F12 to enable and disable the input system in order to avoid any accidental key presses in setup screens, but in theory, the NIA should work with almost any game. That's quite convenient for such a novel device, even if Schuette says it could be done better:

Even though this still works – with a certain amount of sluggishness, the concept is somewhat atrocious, since it takes an analog physical reaction that is then emulated into a manual keyboard input that is then translated into a command on the game level. A more elegant solution would encompass taking the biological response and streaming it directly into the game using the DirectX platform as vehicle.

The NIA software lists eight different inputs in total. The bulk of those inputs are made up by a "muscle" input that tracks facial muscle tension (largely from jaw and eyebrow muscles) and a "glance" control that tracks lateral eye movement. Six brain-wave inputs—three for alpha waves and three for beta waves—fill out the neural control aspect of the NIA. This post by Dr. Schuette suggests alpha waves correspond to aggression and that beta waves can correspond to pain management. For instance, one can trigger the Alpha 2 meter by thinking of an expletive. Schuette told us he successfully used this method to get his character to jump in a game, but I could never get this to work myself.