Commentary and perspectives on R.M. Allen's "The test performance of the brain injured".

Significant advances have occurred in the study of the neuropsychology of head injury since R.M. Allen's (1947) paper. These include better conceptualization of brain-behavior relationships, advances in neuropsychological instruments, normative data and assessment paradigms, structural and functional brain imaging techniques, greater understanding of the mechanisms of brain injury, and the classification and quantification of brain injury. However, because of conceptual and methodological problems there has been a relative lack of progress in understanding the etiology of symptoms in mild head injury. To date, studies of mild head injury have produced widely mixed findings. Further, orthopedic injury, chronic pain, litigation, and other conditions may also produce cognitive and behavioral changes similar to those seen in mild head injury. The authors outline a study design with two control groups (other injury and noninjury) contrasted with mild closed head injury to resolve the issue of whether functional changes following an injury are due to a specific head injury effect or to more general injury factor(s). Results of extant studies using this design are discussed, along with future directions for neuropsychological assessment.