Central executive system impairment in traumatic brain injury.

PRIMARY OBJECTIVE

This study investigated whether cognitive impairment after traumatic brain injury (TBI) can be considered a consequence of (1) a speed processing deficit or (2) an impairment of the Central Executive System (CES) of working memory.

METHODS AND PROCEDURES

Thirty-seven TBI patients underwent a standardized battery of neuropsychological tests evaluating speed processing, sustained attention, short-term memory, working memory, divided attention, executive functions and long-term memory.

MAIN OUTCOMES AND RESULTS

Patients showed severe deficits in working memory, divided attention, executive functions and long-term memory. Divided attention, long-term memory and executive functions deficits significantly correlated with working memory, but not with speed processing deficits. Moreover, multiple regression analyses showed that a CES impairment and not a speed processing deficit predicted divided attention, executive functions and long-term memory deficits. The severity and the site of brain lesions did not predict the level of CES or speed processing impairment.

CONCLUSIONS

The cognitive impairment following TBI seem to be caused by an impairment of the Central Executive System, rather than a speed processing deficit.