David Ross, MD
Around 2005, it was well-known that chronic severe traumatic brain injury (TBI) was characterized by brain atrophy, and most researchers and clinicians thought that brain structure in chronic mild TBI was normal. This idea was overturned by the introduction of NeuroQuant®, FDA-cleared software for measuring MRI brain volume, and NeuroGage®, software that extends the utility of NeuroQuant® in several important ways. We now know that, in contrast to severe TBI, chronic mild TBI is characterized mostly by abnormal brain enlargement, although cerebral white matter and a few other regions show atrophy. Chronic mild TBI also is characterized by abnormal asymmetry and longitudinal brain volume changes. To date, over 100 peer-reviewed studies have supported the reliability and validity of NeuroQuant® and NeuroGage®. Given their validity, reliability, practicality, and community acceptance, there are now 10 cases in which NeuroQuant® or NeuroGage® have been admitted as evidence in federal or state courts, with no failures to be admitted. One of these cases included a judge’s written ruling that NeuroQuant® passed the Daubert standard. Accordingly, these software programs are important tools for objectively assessing the effects of brain injury or disease on patients in clinical or medicolegal settings.