AVOIDANCE RESPONDING AND CLOSED-HEAD INJURY - REPLICATION AND REEVALUATION OF THE ANTICIPATORY BEHAVIOR DEFICIT

Previous research suggests that survivors of closed-head injury (CHI), tested while inpatients, took more trials to learn to avoid a noxious noise in a conditioning task than did controls. In contrast, patients with CHI learned to escape at latencies equal to those of controls. The authors attributed these results to defective anticipation of the consequences of either the warning stimulus and/or the subject's own behaviour. They called this pattern of intact escape with putatively impaired avoidance an Anticipatory Behaviour Deficit (ABD). We tried to detect an ABD in nonhospitalized CHI survivors who had sustained an injury significant enough to produce a dectable deficit on a standard neuropsychological battery. The CHI group (n=24) and controls (n=13) had comparable avoidance latencies, escape latencies, and trials to criterion. Both groups escaped more quickly than they avoided. We conclude that ABD may not be unbiquitous in CHI survivors or that it may be a temporary condition, limited to a few months posttrauma. Since uninjured controls also escaped faster than they avoided, we suggest a reevaluation of the operational definition of an ABD.