Test and Evaluation of Non-Invasive Neuro-Assessment Devices (NINAD: Neurokinetics, Inc, iPAS

Traumatic brain injury is not only a significant medical and operational issue for the military but is a significant public health issue in the United States. The CDC reports that 1.4 million Americans sustain traumatic brain injuries each year. Of these 50,000 die, 235,000 are hospitalized and 1.1 million are treated and released from the emergency department. Among children fourteen years old and younger, there are an estimated 2685 TBI deaths per year, 37,000 hospitalizations and 435,000 emergency room visits.

Additionally, the Centers for Disease Control (CDC) also notes that TBI is significantly under-reported.

Traumatic brain injury is under detected. Neuropsychological evaluations are often nondisclosing The DoD has invested considerable funds in the development of devices for use in acute and chronic assessment of TBI. Unfortunately none of these devices have been tested systematically to establish reliability of the equipment, reliability of the signals obtained, or reliability of the measures derived from the signals obtained.

The NeuroKinetics i-PAS system is a mobile assessment device with an integrated display for eye tracking with the following properties: a head mounted display, a sampling rate of 100 frames per second, eye tracking in the horizontal, vertical and torsional axes, and pupil area measurement with a spatial resolution less than 0.1 o. The testing protocol includes: optokinetic tracking, smooth pursuit horizontal, smooth pursuit vertical, saccade random horizontal, saccade random vertical, saccade predictive horizontal, antisaccade (horizontal), self-paced saccade, saccade and reaction times, visual reaction time, auditory reaction time, gaze horizontal, light reflex, subjective visual (vertical) and subjective vertical horizontal. Several quantitative measures are computed from the data acquired in each test, and these measures are then employed in a multivariate diagnostic assessment.

It is important to distinguish between a device, a signal and a measure. As used here, the term device refers to a hardware technology used to obtain a signal. In the case of neurodiagnostic devices, the signal is usually a measurement of voltage as a function of time. Examples of signals pertinent to the present discussion include the electrocardiogram (providing an assessment of autonomic nervous system status), the electroencephalogram, evoked potentials, event related potentials, balance records and eye movement trajectories. A clear distinction must be drawn between a signal, typically a voltage record, and a measure which is a number that is computed from the voltage signal. Reliability and validity must be investigated separately for each measure For example, a dozen measures may be calculated from the same EEG voltage signal. The reliability and validity of each measure must be evaluated.