2.2 Diffuse Axonal Injury

Describe Diffuse Axonal Injuries (DAI).

  1. Diffuse axonal injury (DAI) is seen exclusively following TBI and results from acceleration-deceleration and rotational forces associated with high-velocity impact (motor vehicle accidents)
     
  2. Results in shearing forces which causes the axon to twist and tear which in turn results in death of neurons.
     
  3. Is responsible for the initial loss of consciousness seen in acute TBI.
     
  4. Damage is most often seen in midline structures, in particular the corpus callosum, the parasagittal white matter, the interventicular septum, the walls of the third ventricle and the brainstem in particular the midbrain and the pons.

Describe some of the clinical features seen following a DAI.

  1. Rostral brain stem involvement results in initial loss of consciousness, poor attention and concentration.
     
  2. Corticospinal tract involvement results in hemiparesis.
     
  3. Shearing of the grey-white matter junction results in slowed mental processing and fatigue.
     
  4.  Cerebellar peduncle involvement results in ataxia.
     
  5. Brainstem injury involvement results in dysarthria and dysphagia.

How does a DAI impact recovery and rehabilitation?

  1. Disrupted connections between nerves results in slowed mental processing, fatigue, poor attention and concentration.
     
  2. Rehabilitation has to be paced and organized (very structured environment) in a manner which allows for these difficulties.
     
  3. Good planning will consider that stamina to perform any skills (functional or otherwise) may be an issue.
     
  4. Poor attention combined with memory difficulties and behavioural concerns may require attendant care.