An investigation of white matter integrity and attention deficits following traumatic brain injury

ABSTRACT

Objective: This study aimed to investigate the association between white matter tracts and multiple aspects of attention and working memory deficits in a relatively acute traumatic brain injury (TBI) sample.

Method: Neuropsychological measures of attention and working memory were administered to 20 participants with complicated mild-to-very severe TBI and 20 control participants. Tract-based spatial statistics was used to assess fractional anisotropy (FA) and mean diffusivity (MD) of white matter tracts for 15 TBI participants and 20 controls.

Results: When compared to controls, participants with TBI were found to have lower FA (p < 0.001) and higher MD (p < 0.001) values in the majority of white matter tracts. TBI participants were also slower to complete tasks including Trail Making Test, Hayling, computerized Selective Attention Task, n-back and Symbol Digit Modalities Test (p < 0.001), when compared to controls. When controlling for age and estimated premorbid intelligence, slowed information processing speed following TBI was found to be associated with FA values in the corpus callosum, superior longitudinal fasciculus, cingulum, inferior fronto-occipital fasciculi, corona radiata and cerebral white matter.

Conclusion: The results highlight the widespread damage associated with TBI, as well as the impact of these alterations on information processing speed.

KEYWORDS:

• Traumatic brain injury
• attention
• processing speed
• diffusion tensor imaging
• tract-based spatial statistics

Acknowledgements

The authors would like to thank the participants and their families who generously gave their time. We are grateful to the staff at the Monash-Epworth Rehabilitation Research Centre for initially screening admissions for eligibility, and the Epworth HealthCare neuropsychology staff for providing additional information in the screening process. We would also like to thank the staff at the Monash Biomedical Imaging Centre for expertise and assistance with the use of their facilities. In particular, we would like to especially acknowledge Dr Qi-Zhu Wu for his assistance with developing the imaging sequence. We also acknowledge the assistance of Antonio Benci at the Monash Facility for Instrumentation & Technology Development for designing and building the computer response box and Mr Christopher Hocking for programming the n-back task.

Declaration of interest

The authors declare that there are no conflicts of interest. The authors alone are responsible for the content and preparation of the paper.