Technological advancements pave the way for improvements in all aspects of health care delivery, and chiropractic is no exception. While conducting original research on the Impulse Adjusting Instrument®, important discoveries were made, identifying a target frequency that maximized vertebral motion during repeated impulsive thrusts. Derived from this work, the Impulse Adjusting Instrument was given an overhaul by adding an accelerometer (motion sensor) to its nosepiece and reprogramming its internal computer algorithm to give birth to Impulse IQ™, which will debut this summer worldwide.

With these technological advancements, Impulse IQ was designed to monitor the patient's biomechanical response during the adjustment and subsequently vary the frequency of adjustments in real time based on the patient's response. To assist the DC in determining when the adjustment has been accomplished, "maximized mobility" is sensed within the Impulse IQ computer algorithm. In other words, by examining the peak-to-peak acceleration responses of the spine during the adjustment, the spine's mobility can be examined and stopped when the motion has been optimized. This methodology produces optimum spinal motion and simultaneously prevents so-called "over-adjusting," a novel discovery within the chiropractic domain. Because these features make the Impulse Adjusting Instrument intelligent, IQ was added to the name. Its intelli-adjust™ sensing ability is termed auto-sense™ technology.

Figure 1. Christopher J. Colloca, DC, applies the Impulse Adjusting Instrument to the spine while intersegmental motions are measured by means of tri-axial accelerometers rigidly affixed to bone pins mounted into the spinous processes. Needle EMG responses are recorded from the paraspinal muscles.

Born Out of Research

Following the invention of the Impulse Adjusting Instrument, validation research was performed in bench-test experiments comparing Impulse to other hand-held adjusting instruments,¹ and in vivo² to measure the forces, speeds, and frequency characteristics of each of the instruments' three force settings. Original research has shown that thrusts delivered at the right frequency can produce two to three times the amount of bone movement at a given force.³ At the natural or resonant frequency, vertebral motions are maximized while controlling force and subsequently creating safer and more efficient adjustments. To test these theories, high-tech accelerometers were attached to bone pins mounted into the spinous processes in sheep, whereby vertebral motions could be recorded while simultaneous needle EMG responses were monitored in the adjacent muscles during Impulse thrusts (Figure 1).

Applying the Impulse Adjusting Instrument, the first thrust was compared to a series of consecutive thrusts delivered six times per second (6 Hz). The research revealed a general trend toward maximizing vertebral motions typically anywhere between the third and eighth thrust in most trials. EMG responses were also found to be improved with increasing adjustment speed.⁴

The study's results reported that multiple-impulse chiropractic adjustments could create up to 25% more vertebral movement than single chiropractic thrusts alone (Figure 2).⁵

Figure 2. Pictured are posterior-anterior spinal-acceleration responses recorded during multiple-impulse adjusting thrusts. Note the appreciable increase in acceleration response during the eighth consecutive thrust.

This represented the first biomechanical investigation of its kind measuring the effect of multiple-impulse thrusts on vertebral motions. Just as theorized in the study's design, examining pulse-train series of repeated thrusts showed that vertebral motions could be optimized at the right frequency. The research represents a rare multidisciplinary collaboration at the Institute for Medical and Veterinary Science in affiliation with the Adelaide Center for Spinal Research (Adelaide, South Australia), combining talents from chiropractic and bioengineering with experts in orthopedic surgery and pathology with coauthors Robert Gunzburg, MD, PhD, and Robert Moore, PhD. Our research team has combined on several studies published in scientific journals, including the European Spine Journal, Journal of Biomechanics, Journal of Manipulative and Physiological Therapeutics, and Clinical Biomechanics, among others.

Impulse Update

To see how one chiropractor uses adjusting instruments in his practice, go to the February 2007 article titled, "Instrument of Success."

To create the Impulse IQ, the Impulse Adjusting Instrument was fitted with an accelerometer inside of its nosepiece that sends spinal-motion signals during the adjustment back to a microprocessor controller computer chip inside the Impulse device. Following the initial thrust, subsequent thrusts are delivered at a speed determined to optimize the spinal motion. Comparing each consecutive thrust to its predecessors, once maximum mobility is achieved, the instrument ceases firing. In this manner, no external computer hardware is needed, which significantly reduces the cost of the Impulse IQ compared to other adjusting instruments. The Impulse IQ™ is expected to be priced less than $5,000. Its predecessor, the Impulse Adjusting Instrument, will continue to be marketed under $1,000, so chiropractors can enter the instrument-adjusting domain at either price point.

Christopher J. Colloca, DC, is the CEO and founder of Neuromechanical Innovations, a research-based products and postgraduate education company that has been serving the chiropractic profession since 2000. For information, contact .

References

1. Colloca CJ, Keller TS, Black P, Normand MC, Harrison DE, Harrison DD. Comparison of mechanical force of manually assisted chiropractic adjusting instruments. J Manipulative Physiol Ther. 2005;28:414–422.
2. Keller TS, Colloca CJ, Moore RJ, Gunzburg R, Harrison DE, Harrison DD. Three-dimensional intersegmental motion validation of mechanical force spinal manipulation. J Manip Physiol Ther. 2006; in press.
3. Keller TS, Colloca CJ, Beliveau JG. Force-deformation response of the lumbar spine: a sagittal plane model of posteroanterior manipulation and mobilization. Clin Biomech. 2002;17:185–196.
4. Colloca CJ, Keller TS, Harrison DE, Moore RJ, Gunzburg R, Harrison DD. Spinal manipulation force and duration affect vertebral movement and neuromuscular responses. Clin Biomech. 2006;21:254–262.
5. Keller TS, Colloca CJ, Moore RJ, Gunzburg R, Harrison DE. Increased multiaxial lumbar motion responses during multiple-impulse mechanical force manually assisted spinal manipulation. Chiropr Osteopat. 2006;14:6