Severe diffuse traumatic brain injury (TBI) may impair the performance of d
aily-life complex activities. The aim of the present study was to assess wh
ether these difficulties are related to a representational impairment of ac
tion knowledge. Two tasks requiring the manipulation of scripts were used.
The first (script reconstitution) required subjects to sort cards describin
g actions belonging to 4 different scripts, presented in a random order. Th
e second (script generation) required subjects to generate actions belongin
g to a given script. The results showed that TBI patients had preserved acc
ess to goal representation and action knowledge. However, they demonstrated
(1) significant impairments when they had to deal with simultaneous compet
ing sources of information and (2) a lack of inhibitory control on routine
overlearned skills. Patients' performance was significantly correlated with
behavioral modifications in everyday life. These data suggest that action
impairment in severe TBI patients cannot be attributed to an impairment of
action knowledge per se. As previously suggested by Schwartz et al., a rest
riction of limited-capacity processing resources may account for the observ
ed deficits.