Separation of brain-damaged from psychiatric patients with ability and personality measures.

Previous research indicates that many brain-damage screening tests lack the ability to separate organic from functional patients at a satisfactory level. However, the Smith Symbol-Digit Modalities Test, the Benton Visual Retention Test, the Background Interference Procedure variation of the Minnesota Percepto-Diagnostic Test, and the MMPI Psychiatric-Organic Scale have shown some promise in earlier studies. Their abilities to separate brain-damaged patients from five functional samples in a psychiatric setting were compared here. The Smith proved capable of discriminating organics from all functional samples both before and after demographic matching. The Benton and the Minnesota Percepto-Diagnostic Test separated our organics from our functional groups before matching, but results with them after matching were unencouraging. The P-O scale separated the organics from four of the five functional samples before matching and two afterward. The combined use of the P-O and Smith provided a higher level of discrimination than that attained with either alone, correctly identifying 90% of the organics and 79% of the functional Ss.