ATTENTION DEFICITS AND DUAL-TASK DEMANDS AFTER MILD TRAUMATIC BRAIN INJURY

Attention deficits are a prominent aspect of cognitive dysfunction aft er mild traumatic brain injury (MTBI). Patients frequently complain of distractibility and difficulty attending to more than one thing at a time, and several neuropsychological studies have found evidence for a specific attention deficit without general neuropsychological impairm ent. The present study examined the nature of attentional disturbance after MTBI using an extended version of the 2 and 7 Test, which introd uced two conditions reflecting patients' subjective complaints: the ab ility to perform with background 'noise', and while simultaneously att ending to a secondary task. The dual task demands produced a significa nt slowing in processing speed for both the MTBI patients and control subjects. However, the relative decline in processing speed appeared m uch greater for the patients with MTBI, and they differed from control subjects only in this condition. The results are consistent with find ings that patients with MTBI exhibit relatively subtle cognitive defic its which are apparent primarily under conditions which require effort ful or controlled cognitive processing and exceed their available cogn itive resources. Thus, the attentional deficits apparent during dual t ask demands may represent decreased cognitive, and perhaps neural, eff iciency which reflects MTBI patients' subjective complaints and functi onal impairments.