RESUMEN
In this paper, the effectiveness of interventions for executive disorders was reviewed. The objective was to evaluate the internal and external validity of intervention studies. A total of 46 papers, describing 54 studies, conducted in the last two decades meeting several preset inclusion criteria, was included in this review. The studies were categorized into three treatment approaches in order to enhance comparability. The overall results show that many interventions yield positive outcomes and seem to be effective in reducing executive problems in brain-injured subjects. However, several studies have only an explorative intent and are based on less sophisticated experimental designs. The verification of their results is generally more tenuous. The internal validity, or the set-up of experimental conditions necessary to draw valid conclusions about treatment effectiveness, including the choice of well-matched control groups, or the randomization of patients over treatment and control conditions, is not always strong. The same conclusion can be drawn for the external validity of a number of the intervention studies; often evidence of generalization to real-life situations, long-term follow-up, and transfer to non-trained situations, were (partially) lacking in the studies under review. The authors are aware that the design of proper randomized controlled trials for the investigation of the treatment effectiveness of executive disorders is cumbersome and time consuming. Nonetheless, the provisional results of several well-designed studies described in this review make the effort worthwhile.