The need for new technologies of prognostication is evident daily in the lives of rehabilitation clinicians. For example, the lead story of the April 2006 issue of the Physiatrist1 reported that the American Academy of Physical Medicine and Rehabilitation had organized a task force to develop a consensus position regarding elements needing to be addressed when evaluating patients for admission to acute inpatient rehabilitation. The task force believed that defining standards would stimulate the research necessary to assess clinical decisions objectively while helping to conserve healthcare resources. Predicting who requires inpatient rehabilitation is really at the heart of the 75% rule, yet the science behind such predictions needs greater development.

The Journal of Head Trauma Rehabilitation 21(4), ably organized and edited by Dr Sunil Kothari, is entitled Technologies of Prognostication. The issue dives into a very young field and gives the reader an opportunity to explore the possibilities for making future clinical decisions on the basis of technology-driven prognostic information. For example, Dr Diaz-Arrastia describes very recent advances in genetic technology that offer the promise of helping to predict outcomes after traumatic brain injury. In an inviting and enthusiastic comment, he concludes his article on the Human Genome Project by stating: "There will be many opportunities for creative clinical investigations interested in TBI to exploit the most exciting development in medical science."

The Human Genome Project has indeed excited the medical world with its storehouse of genetic data that promises to inform medical science in many areas, including diagnosis, treatment, and prognosis. It may be worth reviewing for our readers that DNA, the core genetic material of life, is composed of repetitions of 4 amino acid building blocks, known by the letters A (adenine), G (guanine), C (cytosine), and T (thymine). The full human genome consists of a combination of 3 billion letters, and the code is nearly identical for any two people. However, about 0.1% of the letters commonly vary. These variations are believed to be behind many of the differences among people-what they look like, how vulnerable they are to particular diseases, or how they might respond to injury.

These gene variants are called "snips," shorthand for single-nucleotide polymorphisms, or SNPs. Just 10 years ago, cataloging these SNPs was costly and slow. However, in the past year, miniature chips have been developed that can detect more than 300,000 genetic markers, or SNPs, at once.2 While the technology is still expensive, the price of chips is falling rapidly and, by means of a simple blood test, the technology could soon be used to easily and inexpensively screen patients for disease susceptibility and other biological characteristics including neural response to injury, a phenomenon of vital concern to our readership. Dr Diaz-Arrastia discusses this topic elegantly in his article on the Human Genome Project, and from his article and the other articles in this issue, our readers will get a glimpse of how future technologies are expected to contribute to patient care in the key area of medical prognosis. A new era of technologies of prognostication is dawning and the Journal of Head Trauma Rehabilitation, early in it third decade of publication, is pleased to alert its readership to this new dawn's early light.

Nathaniel H. Mayer, MD, Editor

REFERENCES