Brain Injury Recovery and Rehabilitation
Traumatic brain injury (TBI) involves a blow to the head followed by an alteration in consciousness. Depending on the severity of the injury, consciousness alteration can range from a few moments of confusion to coma lasting weeks or even months. The degree of handicap in terms of independent function is related to the severity of injury, but the nature of this relationship is unknown. Some patients with moderate to severe injuries make complete or nearly complete recoveries, while others are permanently disabled.
The answer to this puzzle may lie in improving the technologies for assessing both injury severity and behavior (Levine et al., 2006
). Brain injury severity is usually assessed indirectly by measures of coma depth at the time of injury. While such indices are indispensible for acute neurotrauma management, their utility diminishes with time.
The Toronto TBI Study
In the Toronto TBI study, 70 patients spanning the full range of TBI severity were assessed at one year post-injury with extensive behavioral testing and concurrent high-resolution structural MRI. Structural MRI data were analyzed with our locally developed image analysis pipeline (Kovacevic et al., 2002
; Dade et al., 2004
). We demonstrated that quantified MRI is highly sensitive to TBI severity, with distributed volume loss even in patients without large focal lesions (Levine et al., 2008
). We are now investigating the relationship of this volume loss to behavioral measures (e.g., Fujiwara et al., 2008
Functional Neuroimaging of TBI
We are also conducting activation functional neuroimaging studies to examine changes in brain networks in response to tasks of memory and attention. For an early example using positron emission tomography (PET; Levine et al., 2002
), click here
. More recently, Gary Turner has examined the effects of significant head injury on brain networks supporting complex short-term (working) memory operations (Turner & Levine, 2008
). In addition to better specifying brain impairments due to TBI, this research may illustrate processes of natural recovery, neural plasticity, and functional reorganization.
Much of our research pertains to rehabilitation through the application of metacognitive strategies to train people with disorganized behavior to compensate for their deficits. Results from a randomized-control trial of a brief version of our protocol and a longer case-study trial in a post-encephalitic patient, support the efficacy of this treatment protocol (Levine et al., 2000
). We have also applied a version of this protocol in a healthy eldery sample (Levine et al., 2007
) and in a case study of cerebellar damage (Schweizer et al., 2007
). We are currently applying an expanded version of our program in a larger scale randomized-control rehabilitation program.