Network Function and Cognition
The TBI group uses functional Magnetic Resonance Imaging (fMRI), Diffusion Tensor Imaging (DTI), Positron Emission Tomography (PET), Electroencephalography (EEG) and transcranial Alternating Current Stimulation (tACS), as well as behavioural measures to investigate the effects of TBI and to better understand treatment and recovery.
Are cognitive impairments following blast injury the consequence of impaired brain connectivity? Blast-related TBI is the signature injury of recent conflicts in Iraq and Afghanistan. This frequently leads to cognitive and neuropsychiatric impairment, but why this happens is often unclear. In collaboration with the Defence Medical Services, we are using advanced MRI/PET imaging to investigate the pathophysiology of blast injury.
Pituitary Dysfunction and Brain Repair
Does growth hormone deficiency impair brain repair following TBI? Large number of patients have a degree of pituitary dysfunction following TBI. The clinical importance of this is uncertain, although growth hormone improves recovery in animal models of TBI. We are investigating whether growth hormone deficiency following TBI limits natural brain repair. Further details can be found on the Imperial Centre for Endocrinology website.
Chronic Inflammation and Amyloid Metabolism
Does inflammation persist within the brain following TBI and does TBI increase amyloid deposition? TBI is a significant risk factor for Alzheimer’s disease. The mechanism for this is unclear. We are investigating whether TBI results in chronic inflammation and altered amyloid deposition using PET tracers for activated microglia (11C-PK11195) and amyloid (11C-PIB). Our results consistently show marked thalamic inflammation that can persist for many years post TBI. This suggests progressive pathology that may explain the late development of complications following TBI (Ramlackasingh et al. Ann Neurol 2011).
Physiological Assessment of TBI
Can TMS be used to assess the severity of diffuse axonal injury following TBI? In collaboration with Professor John Rothwell and Dr Richard Greenwood at UCL we are investigating the effects of traumatic brain injury on white matter tracts using transcutaneous magnetic stimulation (TMS). We are investigating whether structural damage to white matter tracts, as demonstrated using diffusion tensor imaging, is associated with physiological evidence of white matter damage. The aim is to develop a physiological assessment of diffuse axonal injury.