Leveraging biomarker platforms and systems biology for rehabilomics and biologics effectiveness research.

Although traumatic brain injury (TBI) remains a major health problem, with approximately 2 million incidents occurring annually in the United States, no therapeutic agents to treat TBI have been approved by the Food and Drug Administration despite several clinical trials. It is estimated that 3.5 million Americans now have a lifelong condition that might be termed "chronic traumatic brain injury disease.'' Some health care providers categorize TBI as an "event" for which patients require brief periods of rehabilitation with no further treatment. On the contrary, TBI should be seen as a chronic disease process that fits the World Health Organization definition as being a non-reversible pathologic condition requiring special rehabilitation training. Among the major obstacles that contribute to this type of misconception is the absence of brain injury-specific diagnostic biomarker(s) that can indicate and monitor the long-term health status of patients with TBI after use of conventional therapeutics and a rehabilitation process. It is of interest that recent advances in genomics, proteomics, and systems biology have enabled us to use these high throughput-based approaches in developing biomarkers and therapeutic targets in the area of TBI. One aim of this article is to provide an overview that evaluates the current status of TBI biomarker discovery using neuroproteomics/systems biology techniques, along with their clinical utilization. In addition, we discuss the need for strengthening the role of biomarker-based neuroproteomics/systems biology and its potential utility in the field of rehabilitation, which would lead to the establishment of rehabilomics studies, where biomarkers would indicate and predict the long-term efficacy and health status of patients with chronic TBI conditions.

Effects of stimulus variation on the reinforcing capability of nonpreferred stimuli.

We examined the effects of stimulus (reinforcer) variation in several different contexts. In Study 1, we identified high-quality (HQ) and low-quality (LQ) stimuli based on results of a paired-stimulus assessment and examined their effects when available under concurrent-reinforcement schedules for 8 participants. No participants showed preference for the LQ stimuli when compared singly or in a varied arrangement to the HQ stimulus. In Study 2, we identified nonpreferred (NP) stimuli based on results of a single-stimulus assessment and examined their effects when available under single-reinforcement schedules for 3 participants. Results of Study 2 were mixed. One participant's data indicated that the varied presentation of NP stimuli produced a modest improvement in performance over that observed when the stimuli were presented singly. By contrast, a second participant's data showed no facilitative effect for the varied delivery of NP stimuli and that the inclusion of an HQ stimulus in the varied arrangement obscured the reinforcing effects of the HQ stimulus. The 3rd participant's data showed no effect for the varied delivery of NP stimuli but an apparent facilitative effect when an HQ stimulus was included in the varied arrangement, which was attributable solely to the presence of the HQ stimulus.