Diffuse axonal injury (DAI) is one of the most important types of brain damage that can occur as a result of acceleration-deceleration head injury. This type of injury can be classified as 3 types according to the lesion site and severity of damage by MRI findings. This study was undertaken to estimate the neurobehavioral impairment and disability according to DAI degree.

Total 50 patients from 1998 to 2003 with DAI cases were analyzed according to MRI finding, psychometry results and locomotor dysfunction retrospectively. Main analyses of psychometry were about intelligence quotient (IQ) (K-WAIS test) and memory (Rey-Kim test). Disability was estimated by single doctor (author) according to neurocognitive dysfunction in psychometry and the severity of locomotor ataxia comparing the degree of DAI.

1) There was no significant difference in intelligence and memory according to DAI grade. But memory quotient (MQ) was decreased in grade III vs grade I+II with significance. 2) There was high incidence of locomotor ataxia and increasing McBride disability due to locomotor ataxia (category III) as increasing DAI grade with significance. 3) There was significant difference of verbal IQ and decreasing tendency of memory quotient (MQ) in case of positive temporal lobe lesion, excluding the effect of corpus callosum and brain stem injury.

In diffuse axonal injury, estimations of main disability were cognitive dysfunction, especially intelligence and memory and locomotor ataxia. As increasing the grade of DAI, there were decreasing memory quotient, increasing locomotor ataxia, and McBride disability. The Significant difference of verbal IQ and decreasing tendency of MQ were presented in positive temporal lesion.